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AL875 data sheets (version 1.01)
AL875 preliminary version subject to change without notice january 25, 2001 2 amendments (since june 29, 1999) 99.06.29 99.06.29 updated the document to reflect version a - 1 change. 99.07.19 99.07.19 output drive current provided 99.08.24 added section 6.6 clamping. 99.08.31 adtest1 & adtest2 de scription modified. 01.01.18 remove ?6.6 clamping?
AL875 preliminary version subject to change without notice january 25, 2001 3 contents 1.0 features ________________________________ ________________________________ ___ 4 2.0 applications ________________________________ ________________________________ 4 3.0 general description ________________________________ _________________________ 5 4.0 pinout diagrams ________________________________ ____________________________ 6 5.0 pin definition and description ________________________________ ________________ 6 5.0 pin definition and description ________________________________ ________________ 7 6.0 functional description ________________________________ ______________________ 14 6.1 adc inputs and c onversion ________________________________ _______________________ 14 6.2 adc outputs ________________________________ ________________________________ ___ 15 6.3 clock distribution ________________________________ _______________________________ 15 6.4 automatic positioning control ________________________________ _____________________ 16 6.5 clock phase test (for jitter - reductio n) ________________________________ ______________ 18 6.6 i 2 c programming ________________________________ _______________________________ 19 7.0 electrical characteristics ________________________________ ____________________ 22 7.1 recommended operating conditions ________________________________ _______________ 22 7.2 dc characteristics ________________________________ ______________________________ 22 7.3 ac characteristics ________________________________ ______________________________ 22 8.0 AL875 register definition ________________________________ ___________________ 24 8.1 index of control registers ________________________________ ________________________ 24 8.2 register description ________________________________ _____________________________ 25 9.0 board design and layout considerations ________________________________ _______ 31 9.1 grounding ________________________________ ________________________________ _____ 31 9.2 power planes and power supply decoupling ________________________________ _________ 31 9.3 digital signal and clock interconnect ________________________________ _______________ 31 9.4 analog signal interconnect ________________________________ _______________________ 31 10.0 mechanical drawing ________________________________ ______________________ 32 11.0 power consumption ________________________________ _______________________ 33
AL875 preliminary version subject to change without notice january 25, 2001 4 AL875 triple high speed, 8 - bit analog - to - dig ital converter 1.0 features high speed 8 - bit adc up to 110mhz conversion rate support display resolution up to 1280x1024 at 60hz refresh rate low power dissipation (0.9w typical at 3.3v, 110mhz) 0.6~2.0v p - p analog input range 10k~1mhz ckref locking ran ge full programmability via i 2 c interface automatic screen position support programmable clock phase adjustment ttl compatible digital inputs and outputs high impedance tri - state output power - down mode single 3.3 volt power with 5 volt tolerant i/o 100 - pin 14x20 mm pqfp package 2.0 applications lcd/pdp monitors lcd projectors other flat panel displays high - end video/graphics processing adc/r t/h rin vrt vn vrb adc/g t/h gin vrt vn vrb adc/b t/h bin vrt vn vrb output logic rout<7:0> output logic gout<7:0> output logic bout<7:0> /oe iic interface & control logic digital logic circuits hsync vsync ck ref cp ckext addr1/2 sda scl AL875-01a functional block diagram.vsd
AL875 preliminary version subject to change without notice january 25, 2001 5 3.0 general description the AL875 is a high - speed triple 8 - bit monolithic analog - to - digital converter (adc) design ed for digitizing rgb graphics/video signal or other applications. its 110 mhz conversion rate can support display resolution of up to 1280x1024 at 60hz refresh rate. the AL875 accepts 0.6~2.0v analog input range without using pre - amplifiers which may re duce the overall s/n ratio. digitized data is piped at the full clock rate to the 24 - bit output port. the AL875 uses 3.3v power with 5v tolerant i/o and low power dissipation. the sampling clock is provided by an external clock source, usually a pll, wh ich multiplies the frequency of the input reference clock (usually a hsync signal) to generate the sampling clock. the AL875 provides a programmable pll divider up to 4096. in addition, the input active horizontal and vertical starting and ending positio ns can be detected to ensure that the whole picture fits into the displayable region of the screen. through an i 2 c interface, the AL875 is fully programmable to support various graphic resolutions.
AL875 preliminary version subject to change without notice january 25, 2001 6 4.0 pinout diagrams AL875 AL875-03 pinout diagram testin3 1 testin2 2 testin1 3 testin0 4 vdd 5 vrbr 6 vnr 7 vrtr 8 nc 9 nc 10 vddar 11 rin 12 gndar 13 vrbg 14 vng 15 vrtg 16 nc 17 nc 18 vddag 19 gin 20 gndag 21 vrbb 22 vnb 23 vrtb 24 nc 25 nc 26 vddab 27 bin 28 gndab 29 adtest3 30 31 ckinten 32 rclamp 33 addr1 34 addr2 35 adtest1 36 adtest2 37 nc 38 nc 39 sda 40 vdd 41 gnd 42 scl 43 testin4 44 /reset 45 rof 46 gof 47 bof 48 gndb 49 bout0 50 gclamp bclamp 51 bout1 52 bout2 53 bout3 54 bout4 55 bout5 56 bout6 57 bout7 58 vddb 59 gndg 60 gout0 61 gout1 62 gout2 63 gout3 64 gout4 65 gout5 66 gout6 67 gout7 68 vddg 69 gndr 70 rout0 71 rout1 72 rout2 73 rout3 74 rout4 75 rout5 76 rout6 77 rout7 78 vddr 79 ckrefo 80 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 gnd vddapll nc cp gndapll vdd ckref vsync ckext inv hsync hsfb pwrdn /oe gnd vddpll ckadco ckbo gndpll ckao
AL875 preliminary version subject to change without notice january 25, 2001 7 5.0 pin definition and descript ion following is the pin definition of the AL875 with the corresponding tda8752 pin assignment attached. AL875 type pin# description tda8752 testin3 in (cmos) 1 test signal input 3 , can be left open. n.c. testin2 in (cmos) 2 test signal input 2 , can be left open. dec2 testin1 in (cmos) 3 test signal input 1 , can be left open. vref testin0 in (cmos) 4 test signal input 0 , can be left open. dec1 vdd power 5 digital power supply n.c. vrbr in 6 red channel bottom voltage reference ragc vnr in 7 red chan nel comparator voltage reference rbot vrtr in 8 red channel top voltage reference rgainc nc -- 9 not connected rclp nc -- 10 not connected rdec vddar power 11 red channel analog power supply vccar rin in 12 red channel analog input rin gndar ground 1 3 red channel analog ground agndr vrbg in 14 green channel bottom voltage reference gagc vng in 15 green channel comparator voltage reference gbot vrtg in 16 green channel top voltage reference ggainc nc -- 17 not connected gclp nc -- 18 not connected gdec vddag power 19 green channel analog power supply vccag gin in 20 green channel analog input gin gndag ground 21 green channel analog ground agndg vrbb in 22 blue channel bottom voltage reference bagc vnb in 23 blue channel comparator voltage ref erence bbot vrtb in 24 blue channel top voltage reference bgainc nc -- 25 not connected bclp nc -- 26 not connected bdec vddab power 27 blue channel analog power supply vccab bin in 28 blue channel analog input bin gndab ground 29 blue channel analog ground agndb
AL875 preliminary version subject to change without notice january 25, 2001 8 adtest3 in (cmosu) 30 internal adc test pin 3, to be pulled up. n.c. ckinten in (cmosd) 31 test pin, pulled down for normal operation. reserved for al876 internal clock enable (lo: external clock, hi: internal pll clock) n.c. rclamp out ( cmost) 32 red channel clamp control output (nc) i2c/3w addr1 in (cmosd) 33 i2c address control input 1 add1 addr2 in (cmosd) 34 i2c address control input 2 add2 adtest1 in (cmosd) 35 internal adc test pin 1 , to be pulled down. tck adtest2 in (cmosd) 36 internal adc test pin 2 , to be pulled down. tdo nc -- 37 not connected dis nc -- 38 not connected sen sda inout (cmossu) 39 i2c serial data input/output sda vdd power 40 logic digital power supply vddd gnd ground 41 logic digital ground vssd scl in (cmoss) 42 i2c serial clock input scl testin4 in (cmosd) 43 test signal input 4, to be pulled up n.c. /reset in (cmosu) 44 reset pin (active low) n.c. rof out (cmos) 45 red channel adc output overflow ror gof out (cmos) 46 green channel adc output over flow gor bof out (cmos) 47 blue channel adc output overflow bor gndb ground 48 blue channel adc output ground ogndb bout0 out (cmost) 49 blue channel adc output bit 0 b0 gclamp out (cmost) green channel clamp control output (nc) n.c. bclamp out (cmo st) 51 blue channel clamp control output (nc) n.c. bout1 out (cmost) 52 blue channel adc output bit 1 b1 bout2 out (cmost) 53 blue channel adc output bit 2 b2 bout3 out (cmost) 54 blue channel adc output bit 3 b3 bout4 out (cmost) 55 blue channel adc o utput bit 4 b4 bout5 out (cmost) 56 blue channel adc output bit 5 b5 bout6 out (cmost) 57 blue channel adc output bit 6 b6 bout7 out (cmost) 58 blue channel adc output bit 7 b7 vddb power 59 blue channel adc output power supply vccob gndg ground 60 gr een channel adc output ground ogndg
AL875 preliminary version subject to change without notice january 25, 2001 9 gout0 out (cmost) 61 green channel adc output bit 0 g0 gout1 out (cmost) 62 green channel adc output bit 1 g1 gout2 out (cmost) 63 green channel adc output bit 2 g2 gout3 out (cmost) 64 green channel adc output bit 3 g3 gout4 out (cmost) 65 green channel adc output bit 4 g4 gout5 out (cmost) 66 green channel adc output bit 5 g5 gout6 out (cmost) 67 green channel adc output bit 6 g6 gout7 out (cmost) 68 green channel adc output bit 7 g7 vddg power 69 green channel adc output power supply vccog gndr ground 70 red channel adc output ground ogndr rout0 out (cmost) 71 red channel adc output bit 0 r0 rout1 out (cmost) 72 red channel adc output bit 1 r1 rout2 out (cmost) 73 red channel adc output bit 2 r2 rout3 out (cmost) 74 red channel adc output bit 3 r3 rout4 out (cmost) 75 red channel adc output bit 4 r4 rout5 out (cmost) 76 red channel adc output bit 5 r5 rout6 out (cmost) 77 red channel adc output bit 6 r6 rout7 out (cmost) 78 red channel adc output bit 7 r7 vddr power 79 red channel adc output power supply vccor ckrefo out (cmos) 80 pll reference clock output with phase adjustment from ckref. usually used for external pll reference input. ckrefo ckao out (cmos) 81 output clock a (in phase with the in ternal digital logic clock) ckao gndpll ground 82 digital ground. reserved for al876 pll digital ground. ogndpll ckbo out (cmos) 83 output clock b (with phase adjustment) ckbo ckadco out (cmos) 84 adc sampling clock (in phase with the adc sampling clo ck) ckadco vddpll power 85 digital power supply. reserved for al876 pll digital power supply. suggested to be separated from the other vdd pins with a ferrite bead for al876 compatibility vcco(pll) gnd ground 86 digital ground dgnd
AL875 preliminary version subject to change without notice january 25, 2001 10 /oe in (cmos) 87 ou tput enable (when oe is high, the outputs are in hi - z) oe pwrdn in (cmosd) 88 power - down control (active high) pwoff hsfb out (cmos) 89 clock feedback divider output. used with optional external pll clp hsync in (cmos) 90 horizontal sync input hsync in v in (cmosd) 91 the invert control of the adc sampling clock inv ckext in (cmos) 92 external clock input ckext vsync in (cmos) 93 vertical sync input coast ckref in (cmos) 94 pll reference clock input ckref vdd power 95 digital power supply vccd gndap ll ground 96 analog ground. reserved for al876 pll analog ground. agndpll cp in 97 internal compensation pin. reserved for al876 pll filter input. please follow the reference design for external rc filter circuitry. cp nc -- 98 not connected cz vddap ll power 99 analog power supply. reserved for al876 pll analog power supply. suggested to be separated from the other vdd pins with a ferrite bead for al876 compatibility vccapll gnd ground 100 digital ground n.c. remarks: cmosd: cmos with internal pu ll - down cmoss: cmos with schmitt trigger input cmossu: cmos with schmitt trigger input and internal pull - up cmost: cmos with tri - state output cmosu: cmos with internal pull - up note: clamping feature is not supported in the chip. pin list grouped by funct ionality symbol type pin# description analog input rin in 12 red channel analog input
AL875 preliminary version subject to change without notice january 25, 2001 11 gin in 20 green channel analog input bin in 28 blue channel analog input vrtr in 8 red channel top voltage reference vrtg in 16 green channel top voltage reference vrtb in 24 blue channel top voltage reference vnr in 7 red channel comparator voltage reference vng in 15 green channel comparator voltage reference vnb in 23 blue channel comparator voltage reference vrbr in 6 red channel bottom voltage reference v rbg in 14 green channel bottom voltage reference vrbb in 22 blue channel bottom voltage reference digital output rout[7:0] out (cmost) 78 - 71 red channel adc output gout[7:0] out (cmost) 68 - 61 green channel adc output bout[7:0] out (cmost) 58 - 52, 49 bl ue channel adc output rof out (cmos) 45 red channel adc output overflow gof out (cmos) 46 green channel adc output overflow bof out (cmos) 47 blue channel adc output overflow rclamp out (cmost) 32 red channel clamp control output (nc) gclamp out (cmost ) 50 green channel clamp control output (nc) bclamp out (cmost) 51 blue channel clamp control output (nc) clock pins (and reserved pll pins for the al876) hsync in (cmos) 90 horizontal sync input vsync in (cmos) 93 vertical sync input ckref in (cmos) 94 pll reference clock input, which is usually hsync ckext in (cmos) 92 external clock input cp in 97 internal compensation pin. reserved for al876 pll filter input. please follow the reference design for external rc filter circuitry. ckrefo out (cmos) 80 pll reference clock output with phase adjustment from ckref. usually used for external pll reference input. ckao out (cmos) 81 output clock a (in phase with internal digital
AL875 preliminary version subject to change without notice january 25, 2001 12 logic clock) ckbo out (cmos) 83 output clock b, with phase adjustment cka dco out (cmos) 84 acd sampling clock output (in phase with adc sampling clock) hsfb out (cmos) 89 clock divided by n for external pll circuits reset, i 2 c and configuration pins /reset in (cmosu) 44 reset pin (active low) pwrdn in (cmosd) 88 power - down control (active high) scl in (cmoss) 42 i2c serial clock input sda inout (cmossu) 39 i2c serial data input/output addr[2:1] in (cmosd) 34, 33 i2c address control input ckinten in (cmosd) 31 test pin, pulled down for normal operation. reserved for al87 6 internal clock enable (lo: external clock, hi: internal pll clock) /oe in (cmos) 87 output enable (when oe is high, the outputs are in hi - z) inv in (cmosd) 91 the invert control of the adc sampling clock test pins adtest3 in (cmosu) 30 internal adc t est pins 3 adtest[2:1] in (cmosd) 36, 35 internal adc test pins 2~1 testin4 in (cmosd) 43 test signal input 4 testin[3:0] in (cmos) 1, 2, 3, 4 test signal input 3~0 power, ground and no connect vdd power 5, 40, 95 digital power supply vddr power 79 r ed channel adc output power supply vddg power 69 green channel adc output power supply vddb power 59 blue channel adc output power supply vddpll power 85 digital power supply; reserved for al876 pll power supply vddar power 11 red channel analog power supply vddag power 19 green channel analog power supply vddab power 27 blue channel analog power supply vddapll power 99 analog power supply. reserved for pll analog
AL875 preliminary version subject to change without notice january 25, 2001 13 power supply gnd ground 41, 86, 100 digital ground gndr ground 70 red channel adc ou tput ground gndg ground 60 green channel adc output ground gndb ground 48 blue channel adc output ground gndpll ground 82 digital ground. reserved for al876 pll digital ground gndar ground 13 red channel analog ground gndag ground 21 green channel an alog ground gndab ground 29 blue channel analog ground gndapll ground 96 analog ground. reserved for al876 pll analog ground nc -- 9, 10, 17, 18, 25, 26, 37, 38, 98 not connected
AL875 preliminary version subject to change without notice january 25, 2001 14 6.0 functional description 6.1 adc inputs and conversion the AL875 is a triple 8 - bit monolithic analog - to - digital converter optimized for digitizing rgb graphics signals from personal computers and workstations. its 110 msps encode rate capability supports display resolutions of up to 1280 1024 at 60 hz refresh rate with sufficient input bandwidth to acquire and digitize each pixel accurately. each of the three analog input signals is input to a track - and - hold (t/h) circuit. this t/h captures the value of the input at sampling and maintains it for the duration of the conve rsion. the sampling and conversion process is initiated by a rising edge on the sampling clock input. once the signal is captured by the t/h, the four most significant bits (msbs) are sequentially encoded by the msb coarse comparator array and msb fine com parator array. the residue signal is then encoded by the least significant bits (lsb) coarse comparator array and lsb fine comparator array to generate the four bits of lsb data. the comparator outputs are decoded and combined into the 8 - bit output. follo wing is the clock diagram of the adc (take r channel as an example): clock control & error correction unit msb coarse comparator array lsb fine comparator array lsb fine comparator array msb encoder lsb encoder lsb encoder msb data latch lsb data latch reference supply vrt vrb rout [7:4] rout [3:0] /oe rin AL875-02 block diagram r channel
AL875 preliminary version subject to change without notice january 25, 2001 15 6.2 adc outputs the adc outputs are straight binary. an output enable pin (/oe, active low) toggles the output status between active and high - impedance (/oe = high). the timing should be checked carefully if the output capacitive load is more than 10 pf. 6.3 clock distribution the adcs? sampling clock is usually from an external pll clock source. the AL875 provides a pll reference clock ckrefo (with phase adjustment) for the external pll to generate the pixel clock to ckext pin as the adc sampling clock. if the pll requires a feedback signal, it is provided by the AL875 hsfb pin which signal is obtained from ckext divided by n. the pll programming can be either by the external pll chip (if available) or by the AL875 registers. in order to adjust the phase of the reference clock for optimal pll quality, the ckrefo has programmable delay from the ckref input, which is usually a hsync signal. each programmable increment is equivale nt to approximately 1.6ns. the ckref delay adjustment diagram is as follows: the pll - generated pixel clock is input from the ckext pin, then distributed to different internal or output pins with different delay for different purposes. the internal log ic clock is available at ckao pin. the delay - adjustable clock is available at ckbo, which programmability is useful for the setup/hold time optimization for the lcd controller or any chip that captures the output of the AL875. the adc sampling clock is a lso available at ckadco pin. the hsfb divider can be up to 4096. the clock distribution circuitry is illustrated in the following diagram: inv delay ckref 4 phase a #0ch<7:4> ckrefo-inv #02h<4> ckrefo AL875-07a clock reference delay input/output pin 1 delay = 1.6ns max. 15 delays = 24ns
AL875 preliminary version subject to change without notice january 25, 2001 16 6.4 automatic positioning control the input horizontal and vertical starting and ending positions are detected to ensure that the whole picture fits into the displayable region of the screen. two modes of position detection are provided: 1 - line detection and whole - frame detection. the 1 - line detection can be performed by choosing any horizontal line (reg.#10h) or vertical line (reg.#19h), to check in what range the luma data is larger than the threshold value defined by data_th (reg.#11h). when the threshold for the vertical line is different from the horizontal line, an additional register vdata_th (reg.#0fh) c an be used for vertical threshold and it is enabled by reg.#06h<7>. any luma data lower than the threshold value is considered blanking period. the following drawing shows the related registers: delay ckref clock buffer ckao phase b (#0ch<3:0>) ckbo 4 /n counter hsfb divider #0ah<3:0> & #0bh<7:0> 12 input/output pin AL875-07b clock distribution circuitry inverter inv ckadco adc sampling clock internal logic clock
AL875 preliminary version subject to change without notice january 25, 2001 17 the whole frame detection scans the whole input vid eo/graphics to check in which range the luma data is larger than the threshold value defined by data_th or vdata_th. any luma data lower than the threshold value is considered blanking period. whole frame detection may be more accurate than 1 - line detec tion. the following drawing shows the related registers: input active region hsync vsync selected line for vertical positioning detection vcolumn, #19h selected line for horizontal positioning detection hnumber, #10h vde_st, #1ah<2:0> & 1bh<7:0> hcnt_tot, #16h<2:0> & #17h<7:0> hde_end, #14h<2:0> & #15h<7:0> vde_end, #1ch<2:0> & #1dh<7:0> hde_st, #12h<2:0> & #13h<7:0> hs_width, #18h<7:0> threshold = data_th, #11h when horizontal and vertical thresholds are different: threshold horizontal = data_th, #11h threshold vertical = vdata_th, #0fh, enabled by #06h<7> AL875-09 one-line position detection
AL875 preliminary version subject to change without notice january 25, 2001 18 details about these registers can be found in the register definition section. 6.5 clock phase test (for jitter - reduction) the AL875 provides a proprietary clock phase test mode for jitter - re duction. jitters may be experienced when sampling clock frequency and/or phase is not accurate. the AL875 can sample twice (with slightly different clock phases) on each odd or even pixel and count the total output value difference of the two phases (del ay controlled by register #07h). this information (stored in registers #08h and #09h) is then available for the micro - controller to adjust the sampling clock frequency and phase for optimization. additional reference can be found in the register definiti on section. input active region hsync vsync wvde_st, #25h<2:0> & #26h<7:0> whde_end, #23h<2:0> & #24h<7:0> wvde_end, #27h<2:0> & #28h<7:0> whde_st, #21h<2:0> & #22h<7:0> threshold = data_th, #11h when horizontal and vertical thresholds are different: threshold horizontal = data_th, #11h threshold vertical = vdata_th, #0fh, enabled by #06h<7> AL875-10 whole-frame position detection
AL875 preliminary version subject to change without notice january 25, 2001 19 6.6 i 2 c programming the AL875 i 2 c bus controls and monitors the status of the 3 adcs, pll and related registers. two pins (add1 and add2) are used to set the i 2 c address. therefore, up to four AL875s can be used in the same system and can be p rogrammed by the same i 2 c bus. for detailed description of the AL875 registers, please refer to the register definition section. the AL875 i 2 c programming interface follows the philips standard and consists of the scl (clock) and sda (data) signals. data c an be written to or read from the AL875. for both read and write, each byte is transferred msb first, and the sda data bit is valid when the scl is pulled high. the read/write command format is as follows: write :
read :
following are the details: < s >: start signal scl sda high high high low the start signal is high to low transition on the sda line when scl is high. < write sa >: write slave address: 98h, 9ah, 9ch, or 9eh < read sa >: read slave address: 99h, 9bh, 9dh, or 9fh < register index >: value of the AL875 register index. < a >: acknowledge stage the acknowledge - related clock pulse is generated by the host (master). the ho st releases the sda line (high) for the AL875 (slave) to pull down the sda line during the acknowledge clock pulse. < na >: not acknowledge stage scl sda sda scl sda scl scl sda scl data bit [1] or na data bit [0] or a start bit [s] stop bit [p] not significant al250-15 i2c drawing
AL875 preliminary version subject to change without notice january 25, 2001 20 the acknowledge - related clock pulse is generated by the host (master). the host releases the sda line (high) during the acknowledge clock pulse, but the AL875 does not pull it down during this stage. < data >: data byte write to or read from the register index. in read operation, the host must release the sda line (high) before the first clock pulse is transmitte d to the AL875. < p >: stop signal scl sda high low high high the stop signal is low to high transition on the sda line when scl is high. suppose data f0h is to be written to register 0fh using write slave address 98h, the timing is as follows: suppo se data is to be read from register 55h using read slave address 99h, the timing is as follows: start slave addr = 98h ack ack ack stop index = 0fh data = f0h sda scl AL875-04 i2c write timing start slave addr = 98h ack ack ack index = 55h read slave addr = 99h sda scl AL875-05 i2c read timing nack stop data read cycle stop start
AL875 preliminary version subject to change without notice january 25, 2001 21 more information on the AL875 functionality can be found in the register definition section.
AL875 preliminary version subject to change without notice january 25, 2001 22 7.0 electrical characteristics 7.1 recommended operating cond itions parameter min max unit vdd supply voltage +3.0 +3.6 v tamb ambient operating temperature 0 +70 c 7.2 dc characteristics parameter test conditions min typ. max unit i dd supply current 90mhz 115 ma p power consumption 380 mw v ih hi - leve l input voltage vdd+0.5 - vdd+0.5 v v il lo - level input voltage +0.8 - +0.8 v v oh hi - level output voltage vdd - vdd v v ol lo - level output voltage 0.5 - 0.5 v i o output current, stand data - 0.5v AL875 preliminary version subject to change without notice january 25, 2001 23 c l digital output load cap. 15 - 50 pf t oh o utput hold time c l = 15pf 3 - - ns t pd propagation delay c l = 40pf - - 5 ns snr signal - to - noise ratio - - 48 db f c conversion speed - - 110 mhz
AL875 preliminary version subject to change without notice january 25, 2001 24 8.0 AL875 register definition the AL875 is powered up to a default state depending on the hardware mod e - setting pins. hardware configuration is disabled by setting softconfig (bit 4 of register 0x03) as 1, then software configuration is determined by the values of register 0x02, which is programmable by software. i2c sub - address: addr2, addr1 pins i 2 c writ e address i 2 c read address low, low 98h 99h low, high 9ah 9bh high, low 9ch 9dh high, high 9eh 9fh 8.1 index of control registers the following is the summary of AL875 control registers register addr r/w description default note companyid 00h r onl y company id 0100 0110 46h revision 01h r only revision number 0000 0000 00h hwconfig 02h r/w hardware configuration general 03h r/w general register family 04h r only chip family 1000 0111 87h status 05h r status register jitter test registers phitest 06h r/w clock phase test uuu0 0000 00h delta 07h r/w main and delay clock select 0000 0000 diffh 08h r only difference count in a horizontal line (high) diffl 09h r only difference count in a horizontal line (low) pll - related registers dividerh 0ah r/w pll divider high - byte 0101 0011 53h dividerl 0bh r/w pll divider low - byte 0100 1000 46h phase 0ch r/w pll phase delay control 0000 0000 one - line auto - positioning registers hnumber 10h r/w horizontal line number for hde_st, 0000 0110 unit: 8 lines
AL875 preliminary version subject to change without notice january 25, 2001 25 hde_end det ection 6 * 8 = 48 data_th 11h r/w data threshold for 0001 0000 20h hde_sth 12h r only horizontal active data start (high - byte) hde_stl 13h r only horizontal active data start (low - byte) hde_endh 14h r only horizontal active data end (high - byte) hde_endl 15h r only horizontal active data end (low - byte) hcnt_toth 16h r only detected horizontal total value (high - byte) hcnt_totl 17h r only detected horizontal total value (low - byte) hs_width 18h r only detected horizo ntal sync width vcolumn 19h r/w vertical column number for vde_st, vde_end detection 0011 0111 unit: 8 lines 37h * 8=440 vde_sth 1ah r only vertical active data start (high - byte) vde_stl 1bh r only vertical active data start (low - byte) vde_endh 1 ch r only vertical active data end (high - byte) vde_endl 1dh r only vertical active data end (low - byte) whole - frame auto positioning registers whde_sth 21h r only detected horizontal active start pixel position (high - byte) whde_stl 22h r only dete cted horizontal active start pixel position (low - byte) whde_endh 23h r only detected horizontal active end pixel position (high - byte) whde_endl 23h r only detected horizontal active end pixel position (low - byte) wvde_sth 25h r only detected verti cal active start line (high byte) wvde_stl 26h r only detected vertical active start line (low - byte) wvde_endh 27h r only detected vertical active end line (high - byte) wvde_endl 28h r only detected vertical active end line (low - byte) note: u ? unused 8.2 register description 00h: company id (r) [companyid] companyid <7:0> company id (46h)
AL875 preliminary version subject to change without notice january 25, 2001 26 01h: revision (r) [revision] revision <7:0> revision number (00h) 02h: hardware/software configuration (r/w) [hwconfig] ckrefo_inv <4> invert the phase of ckrefo (reference clock output) inv <1> invert the phase of ckadco (adc sampling clock) pwrdn <0> power - down mode (active high) please refer to the clock distribution circuitry diagram in section 6.3 for additional reference. 03h: general (r/w) [ge neral] if softcinfig (0x03<4>) = 0, the values of hardware configuration pins are set/read. if softcinfig (0x03<4>) = 1, the values of software configuration registers are set/read. softconfig <4> enable configuration defined by software configuration registers 0x02. 04h: chip family (r) [family] family <7:0> 10000111, AL875 series 05h: status register (r) [status] vspol_det <7> detected input vsync polarity 1: positive, 0: negative. hspol_det <6> detected input hsync polarity 1: positive, 0: ne gative. vsync <4> input vsync signal (without any processing) hsync <3> input hsync signal (without any processing) hspeed <2> chips speed version; 1: high speed; 0: low speed. clock phase test (jitter test) 06h: clock phase test (r/w) [phitest] en v_th <7> enable vdata_th when env_th = 0, data_th (reg.#11h) applies for both horizontal and vertical threshold. when env_th = 1, data_th (reg.#11h) defines horizontal threshold only; vertical threshold is defined by vdata_th (reg.#0fh). adcdiff_th <6:5> bits 5 and 4 of adcdiff_th, threshold of data difference in clock phase test mode for auto phase detection phitest <4> clock phase test enable
AL875 preliminary version subject to change without notice january 25, 2001 27 adcdiff_th <3:0> bits 0~3 of adcdiff_th, threshold of data difference in clock phase test mode for auto p hase detection. any difference lower than the threshold is considered as noise and can be disregarded. 07h: delayed clock value select (r/w) [delta] delta <3:0> delayed clock phase - delay select this register defines the delay of the two adc sampling cl ocks in jitter detection mode 1. each delay is equivalent to 1.6ns. the detected value is stored in registers #08h and 09h. 08h: number of pixels with significant data difference in jitter detection mode (r) [diffh] diff (9:8) <1:0> 09h: number of p ixels with significant data difference in jitter detection mode (r) [diffl] diff (7:0) <7:0> in this jitter detection mode, all odd pixels in a designated line are sampled and digitized twice. the total number of data pairs with data value difference hi gher than the specified threshold value is stored in these two registers. the delay of the two sampling clocks can be programmed by register #07h. change of hsync and clock phase may result in different diff values. the lowest diff value usually in dicates the optimized hsync and clock phase setting. 0dh: difference of first and last pixel position (r) [diff2h] diff2 (10:8) <2:0> bits 11~8 of the difference of first and last pixel position 0eh: difference of first and last pixel position (r) [diff 2l] diff2 (7:0) <7:0> bits 7~0 of the difference of first and last pixel position in this jitter detection mode, position of the first active pixel of each line is compared with that of the previous line. when there is difference, this value is increment ed by 1. similarly, position of the last active pixel of each line is also compared with that of the previous line; when there is difference, this register values is incremented by 1. the total number is stored in diff2hand diff2l. pll - related regist ers 0ah: divider high - byte (r/w) [dividerh] dividerh(11:8) <3:0> bits 8~11 of the pll divider 0bh: divider low - byte (r/w) [dividerl] dividerl(7:0) <7:0> bits 7~0 of the pll divider this is the pll divider number when a non - programmable genlock pll suc h as ics9173 is used.
AL875 preliminary version subject to change without notice january 25, 2001 28 0ch: pll phase delay control (r/w) [phase] phasea <7:4> hsync phase delay adjustment phaseb <3:0> ckbo phase delay adjustment refer to the internal pll block diagram and AL875 clock distribution circuitry in section 6.3 for addi tional reference. one - line automatic positioning: 0fh: vertical data threshold (r/w) [vdata_th] vdata_th <7:0> luma (brightness) threshold value. this value is used to determine non - blanking pixel for vertical direction. any pixel luma value less than this value is considered as blanking. . hardware default value is 32 (20h). vertical column used to detect vertical active start and end is defined by register #19h. this register is enabled by register #06h<7>. 10h: horizontal line number for hde_st & hde_end detection (r/w) [hnumber] hnumber <7:0> horizontal line number for horizontal active start and end detection; refer to register #11h for additional reference. (unit: 8 lines) hardware default value is 06h, which means 6 x 8 = 48 lines 11h: d ata threshold (r/w) [data_th] data_th <7:0> luma (brightness) threshold value. this value is used to determine non - blanking pixel for horizontal direction. any pixel luma value less than this value is considered as blanking. . hardware default value is 32 (20h). horizontal line used to detect horizontal active start and end is defined by register #10h. this register is enabled by register #06h<7>. 12h: horizontal active start high (r only) [hde_sth] hde_sth <2:0> bits <10:8> of detected horizontal a ctive start pixel position. 13h: horizontal active start low (r only) [hde_stl] hde_stl <7:0> bits <7:0> of detected horizontal active start pixel position. (unit: 1 pixel) 14h: horizontal active end high (r only) [hde_endh] hde_endh <2:0> bits <10 :8> of detected horizontal active end - pixel position. 15h: horizontal active end low (r only) [hde_endl] hde_endl <7:0> bits <7:0> of detected horizontal active end - pixel position. (unit: 1 pixel) 16h: detected h total value (r only) [hcnt_toth] hcnt _toth <2:0> bits <10:8> of the detected horizontal total pixel number.
AL875 preliminary version subject to change without notice january 25, 2001 29 17h: detected h total value low (r only) [hcnt_totl] hcnt_totl <7:0> bits <7:0> of the detected horizontal total pixel number. 18h: detected hsync width (r only) [hs_width] hs_width <7:0> indicate the detected horizontal sync pulse width. 19h: vertical column for vdestart & vdeend detection (r/w) [vcolumn] vcolumn <7:0> vertical column number for vertical active start and end detection; refer to register #11h for additional referen ce. hardware default value: 37h = 55 x 8 = 440. (unit: 8 pixels) 1ah: vertical active start high (r only) [vde_sth] vde_sth <2:0> bits <10:8> of detected vertical active start line. 1bh: vertical active start low (r only) [vde_stl] vde_stl <7:0> bits <7:0> of detected vertical active start line. (unit: 1 line) 1ch: vertical active end high (r only) [vdeendh] vde_endh <2:0> bits <10:8> of detected vertical active end line. 1dh: vertical active end low (r only) [vde_endl] vde_endl <7:0> bits <7:0> of detected vertical active end line. (unit: 1 line) whole - frame automatic positioning: 21h: horizontal active start high (r only) [whde_sth] whde_sth <2:0> bits <10:8> of detected horizontal active start pixel position. 22h: horizontal active start low (r only) [whde_stl] whde_stl <7:0> bits <7:0> of detected horizontal active start pixel position. (unit: 1 pixel) 23h: horizontal active end high (r only) [whde_endh] whde_endh<2:0> bits <10:8> of detected horizontal active end pixel position. 24 h: horizontal active end low (r only) [whde_endl] whde_endl <7:0> bits <7:0> of detected horizontal active end pixel position (unit: 1 pixel) 25h: vertical active start high (r only) [wvde_sth] wvde_sth <2:0> bits <10:8> of detected vertical active start line 26h: vertical active start low (r only) [wvde_stl] wvde_stl <7:0> bits <7:0> of detected vertical active start line (unit: 1 line) 27h: vertical active end high (r only) [wvde_endh] wvde_endh<2:0> bits <10:8> of detected vertical active en d line
AL875 preliminary version subject to change without notice january 25, 2001 30 28h: vertical active end low (r only) [wvde_endl] wvde_endl <7:0> bits <7:0> of detected vertical active end line (unit: 1 line)
AL875 preliminary version subject to change without notice january 25, 2001 31 9.0 board design and layout considerations the AL875 contains both precision analog and high - speed digital circuitr y. noise coupling from digital circuits to analog circuits may result in poor video quality. the layout should be optimized for lowest noise on the power and ground planes by shielding the digital circuitry and providing good decoupling. 9.1 grounding a nalog and digital circuits are separated within the AL875 chip. to minimize system noise and prevent digital system noise from entering the analog portion, a common ground plane for all devices, including the AL875 is recommended. all the connections to th e ground plane should have very short leads. the ground plane should be solid, not cross - hatched. 9.2 power planes and power supply decoupling the analog portion of the AL875 and any associated analog circuitry should have their own power plane, referred t o as the analog power plane (avdd). the analog power plane should be connected to the digital power plane (dvdd) at a single point through a low resistance ferrite bead. additionally, in order to minimize cross interference, the analog power planes of r, g, b and pll should also be separated with low resistance ferrite beads. power supply connection pins should be individually decoupled. for best results, use 0.1 m f ceramic chip capacitors. lead lengths should be minimized. the power pins should be connec ted to the bypass capacitors before being connected to the power planes. 22 m f capacitors should also be used between the AL875 power planes and the ground planes to control low - frequency power ripple. 9.3 digital signal and clock interconnect digital sign als to the AL875 should be isolated as much as possible from the analog outputs and other analog circuitry. the high frequency clock reference or crystal should be handled carefully because jitters and noise on the clock will degrade the video performance . keep the clock paths to the decoder as short as possible to reduce noise pickup. 9.4 analog signal interconnect the AL875 should be located closely to the output connectors to minimize noise and reflections. keep the critical analog traces as short and wide as possible (20~30 mil). digital signals, especially pixel clocks and data signals should not overlap any of the analog signal circuitry and should be kept as far apart as possible. the AL875 and the decoder ic should have no inputs left floating.
AL875 preliminary version subject to change without notice january 25, 2001 32 10.0 mechanical drawing AL875: 14mm x 20mm 100 - pin 0.65 - pitch pqfp package
AL875 preliminary version subject to change without notice january 25, 2001 33 11.0 power consumption the AL875 works at single 3.3v power. the following table shows the current consumption of the AL875 at different operating frequencies. frequency cur rent AL875@3.3v 110mhz 135 ma (typ.) AL875@3.3v 90mhz 115 ma (typ.) AL875@3.3v 65mhz 95 ma (typ.) AL875@3.3v 40mhz 65 ma (typ.) for more information about the AL875 or other averlogic products, please contact your local authorized representatives, visit our website, or contact us directly.
contact information averlogic technologies, inc. 6840 via del oro suite 160 san jose, ca 95119 usa tel : 1 408 361 - 0400 fax : 1 408 361 - 0404 e - mail : sales@averlogic.com url : www .averlogic.com

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