_______________general description the max152 evaluation kit (ev kit) is fully assembled, and provides a proven design and pc board layout for fast, easy evaluation of the max152 at sample rates to 400ksps. an oscillator continuously triggers the converter, and an led displays the conversion results. several jumpers allow the board to be configured for the various operating modes of the max152, and the board includes the low-current shutdown circuit shown in the data sheet. a 16-pin data connector provides easy interface between the max152 ev kit and the user's system. the max152 ev kit can be used to evaluate the 5v max153 at sample rates to 1msps. ____________________component list ____________________________features ? high-speed 8-bit adc ? unipolar or bipolar input ? no clock circuit required ? +3v (max152) or +5v (max153) operation ? low-power shutdown mode ? led display of conversion results ? 3in 2 prototyping area ? 16-pin data connector for interface to external system ______________ordering information max152 ev kit max152 evaluation kit ________________________________________________________________________________________ 13 part temp. range board type MAX152EVKIT-dip 0? to +70? through-hole designation qty description u1 1 max152cpp 1 74hct574 u3 1 icm7555cpa 5 0.1? ceramic capacitors c2, c4 2 c5 1 100pf ceramic capacitor d1-d8 8 red leds q1 1 r1 1 300 5% resistor r2, r12 2 510k 5% resistors r3-r10 8 620 5% resistors r11 1 10k 5% resistor j1, j3 2 3-pin jumper headers 6 2-pin jumper headers none 8 shunts none 1 16-pin ribbon cable connector none 1 3.50" x 4.00" pc board none 4 rubber feet none 1 u2 the MAX152EVKIT may also be used to evaluate the max153. to receive a free sample of the max153cpp, call 1-800-998-8800. ______________________________ev kit c1, c3, c6, c7, c8 10? 16v radial electrolytic capacitors me12n06el nihon n-channel logic-level mosfet j2, j4, j5, j6, j7, j8 max152 data sheet and ev kit manual
max152 ev kit ___________________quick reference the evaluation kit as shipped, is configured for the continuous- conversion mode. to verify operation, follow these steps: 1. verify that the jumpers are configured as described in table 2. 2. connect the power supplies (+3v for max152, +5v for max153) to the power input connector. 3. connect an analog input to ain input. 4. read conversion results displayed on the leds. _______________general description jumper functions the max152 ev kit has several jumpers to alter the configuration. table 1 lists the jumpers and their func- tions. table 2 gives the jumper selection for a free-run- ning mode used for board verification. note that table 2's configuration drives both the rd and cs inputs and sets the mode pin low. the timing dia- gram for this configuration is shown in the max152 or max153 data sheet. refer to the data sheet for more information on the various operating modes. power requirements the max152 ev kit may be used with either the max152 or max153. the max152 will operate on sup- plies as low as 2.7v. the max153 operates on +5v or ?v. the positive supply is also connected to the octal latch and icm7555 timer on the board. the leds will cause the positive supply current to approach 60ma when all are on. the v ss input is connected only to the max152/max153's v ss pin. the v ss pin will draw less than 50?. optionally, j4 can be shorted to connect v ss to ground when not using a negative supply. max152/max153 reference voltage the vref+ and vref- pins may be connected to any potential between v dd and v ss . for single-supply operation, vref+ can be connected to v dd and vref- can be connected to ground. jumpers (j1 and j2) are provided for this configuration. if a reference voltage other than v dd or ground is desired, connect the source to the vref+ and/or vref- pads and set j1 and j2 accordingly. refer to table 1 for their use. max152/max153 data output/display the max152/max153's output is latched and buffered by a 74hct574 so it can drive an led display. the max152 evaluation kit 14 ______________________________________________________________________________________ table 2. jumper selection for free-running mode jumper connection function j1 2 & 3 vref- connected to gnd j2 short vref+ connected to v dd j3 2 & 3 cs driven by icm7555 j4 short v ss connected to gnd. leave j4 open if a v ss source is used. j5 open mode pin internally pulled low j6 short enable the icm7555 j7 short enable the led display j8 short rd driven by icm7555 table 1. jumper functions jumper connection function mode pin connected to v dd 1 & 2 vref- connected to the drain of q1 j2 short vref+ shorted to v dd j3 open used when an external digital signal is applied to the cs input j4 short v ss connected to ground j5 open mode pin open (internally pulled low) j6 open icm7555 circuit disabled j7 open led display disabled j8 open used when an external digital input is applied to the rd input j1 open used when connecting a voltage source to the vref- pad short 2 & 3 vref- connected to ground icm7555 circuit enabled open used when connecting a voltage source to the vref+ pad short 1 & 2 cs grounded short 2 & 3 cs driven by the icm7555 led display enabled open used when driving v ss with a negative source (-5v or -3v) short rd driven by the icm7555
leds display the output of the max152/max153 after each conversion. removing the j7 shunt will disable the led display and lower the positive supply current. the clock signal for the 74hct574 is taken off the rd input. this latches the max152/max153 conversion results on the trailing (positive going) edge of the rd signal. this technique works as long as rd pulse is longer than the conversion time of the max152/max153. the ready (rdy) signal can be observed by configur- ring the board per table 2 and inserting a 4.7k pull- up resistor in the location marked r13. the rdy signal will appear on the wr / rdy pin. the resistor is normally not installed, in order to keep the pin input current as low as possible. icm7555 circuit a simple icm7555 timer circuit on the board provides a clock for the stand-alone mode. the output can be connected to the cs and rd pins through j3 and j8. it will then trigger a conversion approximately every 2.5? when j6 is shorted. j6 is provided to disable the icm7555 when evaluating the shutdown currents. when using external signal sources for cs and rd , leave jumpers j3 and j8 open. refer to the data sheet for timing specifications with external sources. shutdown modes the function of the power-down pin ( pwrdn ) is to drop the max152/max153's supply current to typically 1?. note, however, that vref+ will continue to appear to the source as a 2k resistor, and this resistor draws current even when the device is in power-down mode. the addition of mosfet q1 opens vref- to discon- nect this internal reference resistor and remove its cur- rent drain. a 510k resistor acts as the pull-up for the gate of q1 and pwrdn . you can evaluate the power- down mode simply by grounding the pwrdn pad. the other chips on the board will continue to draw cur- rent if they are left enabled. be sure to disable the led display and the icm7555 circuits for a true measure- ment. with the device and leds enabled, the supply current may be 60ma. the current drops to less than 15ma with the leds disabled. using pwrdn with vref- con- nected to ground will reduce the current to about 3.5ma. finally, in power-down mode with vref- dis- abled by q1 and the icm7555 disabled, the supply current will typically be less than 50?. the actual reading will include the max152/mac153 v dd current, static current for the 74hct574, and 10? drawn through the 510k resistor r2. max152 ev kit max152 evaluation kit ______________________________________________________________________________________ 15
max152 ev kit max152 evaluation kit 16 ______________________________________________________________________________________ figure 1. max152 ev kit schematic d1 d3 d5 d7 2 4 6 8 + 2 q0 q1 q2 q3 q4 q6 q7 19 18 17 16 15 14 13 12 + v in r13
open wr /rdy r1
300 w j5 v dd rd int j8 vref- 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 v in d0 d1 d2 d3 wr /rdy mode rd int gnd v dd v ss pwrdn d7 d6 d5 d4 cs vref+ vref- max152
u1 r2
510k j2 j6 cs vref+ icm7555
u3 o v+ gnd rs cv thr dis tr 4 5 6 7 2 8 3 1 r11
10k w c5
100pf c7
0.1? j1 j1 3 1 1 c8
o.1f d1 d2 d3 d4 d5 d6 d7 d8 r3 620 w r4 620 w r5 620 w r6 620 w r7 620 w r8 620 w r9 620 w r10 620 w q5 d0 d1 d2 d3 d4 d6 d7 d5 2 3 4 5 6 7 8 9 clk ce 74hct574
u2 j7 r12
510k data connector wr /rd rd v dd gnd 10 12 14 16 1 3 5 7 9 11 13 15 d0 d2 d4 d6 cs int v dd gnd c2
22? v ss c1
0.1? gnd c3
0.1? c4
22? q1 1 2 3 pwrdn j4 j3 2 3 1 0.1?
max152 ev kit max152 evaluation kit ______________________________________________________________________________________ 17 figure 2. max152 ev kit component-side layout
max152 ev kit max152 evaluation kit 18 ______________________________________________________________________________________ figure 3. max152 ev kit solder-side layout (mirror image)
max152 ev kit max152 evaluation kit ______________________________________________________________________________________ 19 figure 4. max152 ev kit component placement guide
maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 20 __________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 (408) 737-7600 1993 maxim integrated products printed usa is a registered trademark of maxim integrated products. max152 ev kit max152 evaluation kit
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