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48
CY29948
2.5V or 3.3V, 200-MHz, 1:12 Clock Distribution Buffer
Features
* * * * * * * * * * * 2.5V or 3.3V operation 200-MHz clock support LVPECL or LVCMOS/LVTTL clock input LVCMOS-/LVTTL-compatible inputs 12 clock outputs: drive up to 24 clock lines Synchronous Output Enable Output three-state control 250 ps max. output-to-output skew Pin compatible with MPC948, MPC948L, MPC9448 Available in Commercial and Industrial temp. range 32-pin TQFP package
Description
The CY29948 is a low-voltage 200-MHz clock distribution buffer with the capability to select either a differential LVPECL or a LVCMOS/LVTTL compatible input clock. The two clock sources can be used to provide for a test clock as well as the primary system clock. All other control inputs are LVCMOS/LVTTL compatible. The 12 outputs are LVCMOS or LVTTL compatible and can drive 50 series or parallel terminated transmission lines. For series terminated transmission lines, each output can drive one or two traces giving the device an effective fanout of 1:24. The outputs can also be three-stated via the three-state input TS#. Low output-to-output skews make the CY29948 an ideal clock distribution buffer for nested clock trees in the most demanding of synchronous systems. The CY29948 also provides a synchronous output enable input for enabling or disabling the output clocks. Since this input is internally synchronized to the input clock, potential output glitching or runt pulse generation is eliminated.
Block Diagram
VDD PECL_CLK PECL_CLK# TCLK TCLK_SEL SYNC_OE TS# 0 1 VDDC
Pin Configuration
Q0 VDDC VDDC 26 VSS VSS Q2 28 27 Q1 Q3 25 24 23 22 21 20 19 18 17
32
31 30
12
Q0-Q11
TCLK_SEL TCLK PECL_CLK PECL_CLK# SYNC_OE TS# VDD VSS
1 2 3 4 5 6 7 8
29
CY29948
10 11 12 13 14 15 16 9
VSS Q4 VDDC Q5 VSS Q6 VDDC Q7
Q11
VDDC Q10
VSS
Q9 VDDC
Cypress Semiconductor Corporation Document #: 38-07288 Rev. *B
*
3901 North First Street
*
San Jose
*
CA 95134 * 408-943-2600 Revised December 22, 2002
VSS
Q8
CY29948
Pin Description[1]
Pin 3 4 2 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31 1 5 6 10, 14, 18, 22, 26, 30 7 8, 12, 16, 20, 24, 28, 32 Name PECL_CLK PECL_CLK# TCLK Q(11:0) VDDC PWR I/O I, PU I, PD I, PU O PECL Input Clock PECL Input Clock External Reference/Test Clock Input Clock Outputs Description
TCLK_SEL SYNC_OE TS# VDDC VDD VSS
I, PU I, PU I, PU
Clock Select Input. When LOW, PECL clock is selected and when HIGH TCLK is selected. Output Enable Input. When asserted HIGH, the outputs are enabled and when set LOW the outputs are disabled in a LOW state. Three-state Control Input. When asserted LOW, the output buffers are three-stated. When set HIGH, the output buffers are enabled. 2.5V or 3.3V Power Supply for Output Clock Buffers 2.5V or 3.3V Power Supply Common Ground
Note: 1. PD = Internal Pull-Down, PU = Internal Pull- UP
Output Enable/Disable
The CY29948 features a control input to enable or disable the outputs. This data is latched on the falling edge of the input clock. When SYNC_OE is asserted LOW, the outputs are disabled in a LOW state. When SYNC_OE is set HIGH, the outputs are enabled as shown in Figure 1.
TCLK SYNC_OE
Q
Figure 1. SYNC_OE Timing Diagram
Document #: 38-07288 Rev. *B
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CY29948
Maximum Ratings [2]
Maximum Input Voltage Relative to VSS: ............. VSS - 0.3V Maximum Input Voltage Relative to VDD:............. VDD + 0.3V Storage Temperature: ................................ -65C to + 150C Operating Temperature: ................................ -40C to +85C Maximum ESD protection ............................................... 2 kV Maximum Power Supply: ................................................5.5V Maximum Input Current: ............................................20 mA This device contains circuitry to protect the inputs against damage due to high static voltages or electric field; however, precautions should be taken to avoid application of any voltage higher than the maximum rated voltages to this circuit. For proper operation, Vin and Vout should be constrained to the range: VSS < (Vin or Vout) < VDD Unused inputs must always be tied to an appropriate logic voltage level (either VSS or VDD).
DC Parameters: VDD = VDDC = 3.3V 10% or 2.5V 5%, Over the specified temperature range
Parameter VIL Description Input Low Voltage Conditions VDD = 3.3V, PECL_CLK single ended VDD = 2.5V, PECL_CLK single ended All other inputs VIH Input High Voltage VDD = 3.3V, PECL_CLK single ended VDD = 2.5V, PECL_CLK single ended All other inputs IIL IIH VPP VCMR VOL VOH IDDQ IDD Input Low Current[3] Input High Current
[3]
Min. 1.49 1.10 VSS 2.135 1.75 2.0
Typ.
Max. 1.825 1.45 0.8 2.42 2.0 VDD -100 100
Unit V
V
A mV V V V
Peak-to-Peak Input Voltage PECL_CLK Common Mode Range[4] PECL_CLK Output Low Voltage[5] Output High Voltage[5] VDD = 3.3V VDD = 2.5V IOL = 20 mA IOH = -20 mA, VDD = 3.3V IOH = -20 mA, VDD = 2.5V Quiescent Supply Current Dynamic Supply Current VDD = 3.3V, Outputs @ 100 MHz, CL = 30 pF VDD = 3.3V, Outputs @ 160 MHz, CL = 30 pF VDD = 2.5V, Outputs @ 100 MHz, CL = 30 pF VDD = 2.5V, Outputs @ 160 MHz, CL = 30 pF
300 VDD - 2.0 VDD - 1.2 2.5 1.8 5 180 270 125 190 12 14 15 18 4
1000 VDD - 0.6 VDD - 0.6 0.4
7
mA mA
Zout Cin
Output Impedance Input Capacitance
VDD = 3.3V VDD = 2.5V
18 22
pF
Notes: 2. Multiple Supplies: The voltage on any input or I/O pin cannot exceed the power pin during power-up. Power supply sequencing is NOT required. 3. Inputs have pull-up/pull-down resistors that effect input current. 4. The VCMR is the difference from the most positive side of the differential input signal. Normal operation is obtained when the "High" input is within the VCMR range and the input lies within the VPP specification. 5. Driving series or parallel terminated 50 (or 50 to VDD/2) transmission lines.
Document #: 38-07288 Rev. *B
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CY29948
AC Parameters[6]: VDD = VDDC = 3.3V 10% or 2.5V 5%, Over the specified operating range
Parameter Fmax Tpd Description Input Frequency
[7]
Conditions VDD = 3.3V VDD = 2.5V VDD = 3.3V VDD = 2.5V Measured at VDD/2
Min.
Typ.
Max. 200 170
Unit MHz ns
PECL_CLK to Q Delay[7] TCLK to Q Delay
[7] [7]
4.0 4.4 6.0 6.4 45 2 2 150
8.0 8.9 10.0 10.9 55 10 10 250 1.5 2.0
PECL_CLK to Q Delay TCLK to Q Delay[7] FoutDC tpZL, tpZH tpLZ, tpHZ Tskew Tskew(pp) Ts Th Tr/Tf Output Duty Cycle
[7, 8, 9]
% ns ns ps ns ns ns
Output Enable Time (all outputs) Output Disable Time (all outputs) Output-to-Output Skew[7, 9] Part-to-Part Skew[11] Set-up Time
[7, 10]
PECL_CLK to Q TCLK to Q SYNC_OE to PECL_CLK SYNC_OE to TCLK PECL_CLK to SYNC_OE TCLK to SYNC_OE
[9]
1.0 0.0 0.0 1.0 0.20 0.20 1.0 1.3
Hold Time[7, 10] Output Clocks Rise/Fall Time
0.8V to 2.0V, VDD = 3.3V 0.6V to 1.8V, VDD = 2.5V
ns
Notes: 6. Parameters are guaranteed by design and characterization. Not 100% tested in production. All parameters specified with loaded outputs. 7. Outputs driving 50 transmission lines. 8. 50% input duty cycle. 9. See Figures 2 and 3. 10. Setup and hold times are relative to the falling edge of the input clock 11. Part-to-Part skew at a given temperature and voltage.
CY29948 DUT
Pulse Generator Z = 50 ohm Zo = 50 ohm Zo = 50 ohm
RT = 50 ohm
RT = 50 ohm
VTT
VTT
Figure 2. LVCMOS_CLK CY29948 Test Reference for VCC = 3.3V and VCC = 2.5V
Zo = 50 ohm Differential Pulse Generator Z = 50 ohm
CY29948 DUT
Zo = 50 ohm
Zo = 50 ohm RT = 50 ohm RT = 50 ohm
VTT
VTT
Figure 3. PECL_CLK CY29948 Test Reference for VCC = 3.3V and VCC = 2.5V
Document #: 38-07288 Rev. *B
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CY29948
PECL_CLK PECL_CLK
VPP
VCMR
VCC
Q
VCC /2
tPD
GND
Figure 4. Propagation Delay (TPD) Test Reference
LVCMOS_CLK
VCC VCC /2 GND VCC
Q
VCC /2
tPD
GND
Figure 5. LVCMOS Propagation Delay (TPD) Test Reference
VCC VCC /2
tP
T0
GND
DC = tP / T0 x 100%
Figure 6. Output Duty Cycle (FoutDC)
VCC VCC /2 GND VCC VCC /2
tSK(0)
Figure 7. Output-to-Output Skew tsk(0)
GND
Document #: 38-07288 Rev. *B
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CY29948
Ordering Information
Part Number CY29948AI CY29948AIT CY29948AC CY29948ACT Package Type 32 Pin TQFP 32 Pin TQFP - Tape and Reel 32 Pin TQFP 32 Pin TQFP - Tape and Reel Production Flow Industrial, -40C to +85C Industrial, -40C to +85C Commercial, 0C to +70C Commercial, 0C to +70C
Package Drawing and Dimensions
32-Lead Thin Plastic Quad Flatpack 7 x 7 x 1.0mm A32
51-85063-B
All product and company names mentioned in this document may be trademarks of their respective holders.
Document #: 38-07288 Rev. *B
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(c) Cypress Semiconductor Corporation, 2002. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in a Cypress Semiconductor product. Nor does it convey or imply any license under patent or other rights. Cypress Semiconductor does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress Semiconductor products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress Semiconductor against all charges.
CY29948
Revision History
Document Title: CY29948 2.5V or 3.3V, 200-MHz, 1:12 Clock Distribution Buffer Document Number: 38-07288 REV. ** *A *B ECN NO. 111099 116782 122880 Issue Date 02/13/02 08/14/02 12/22/02 Orig. of Change BRK HWT RBI Description of Change New datasheet Added Commercial Temperature Range Added power up requirements to Maximum Ratings
Document #: 38-07288 Rev. *B
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