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3
Integrated
Circuit
Systems, Inc.
ICS950902
0475F—10/13/03
Pin Description Continued
PIN
#
NAME
TYPE
29
DDRC5/SDRAM11
OUT
"Complementary" Clock of differential memory output / 3.3V SDRAM clock output
30
DDRT5/SDRAM10
OUT
"True" Clock of differential memory output / 3.3V SDRAM clock output
31
DDRC4/SDRAM9
OUT
"Complementary" Clock of differential memory output / 3.3V SDRAM clock output
32
DDRT4/SDRAM8
OUT
"True" Clock of differential memory output / 3.3V SDRAM clock output
33
GND
PWR
Ground pin.
34
VDD3.3_2.5
PWR
2.5V or 3.3V nominal power supply voltage.
35
DDRC3/SDRAM7
OUT
"Complementary" Clock of differential memory output / 3.3V SDRAM clock output
36
DDRT3/SDRAM6
OUT
"True" Clock of differential memory output / 3.3V SDRAM clock output
37
DDRC2/SDRAM5
OUT
"Complementary" Clock of differential memory output / 3.3V SDRAM clock output
38
DDRT2/SDRAM4
OUT
"True" Clock of differential memory output / 3.3V SDRAM clock output
39
GND
PWR
Ground pin.
40
VDD3.3_2.5
PWR
2.5V or 3.3V nominal power supply voltage.
41
DDRC1/SDRAM3
OUT
"Complementary" Clock of differential memory output / 3.3V SDRAM clock output
42
DDRT1/SDRAM2
OUT
"True" Clock of differential memory output / 3.3V SDRAM clock output
43
DDRC0/SDRAM1
OUT
"Complementary" Clock of differential memory output / 3.3V SDRAM clock output
44
DDRT0/SDRAM0
OUT
"True" Clock of differential memory output / 3.3V SDRAM clock output
45
BUF_IN
IN
Input Buffers for memory outputs.
46
FBOUT
OUT
Memory feed back output.
47
GND
PWR
Ground pin.
48
CPUT_CS
OUT
"True" clocks of differential pair 2.5V push-pull CPU outputs.
49
CPUC_CS
OUT
Complementary" clocks of differential pair 2.5V push-pull CPU outputs.
50
VDDCPU2.5
PWR
Power pin for the CPUCLKs. 2.5V
51
VDDCPU3.3
PWR
Power pin for the CPUCLKs. 3.3V
52
CPUCLKC/CPUCLKODC
OUT
"Complementary" clocks of differential pair CPU outputs. These are current mode outputs.
External resistors are required for voltage bias / "Complementary" clocks of differential pair
CPU outputs. These open drain outputs need an external 1.5V pull-up / 2.5V CPU clock
output.
53
CPUCLKT/CPUCLKODT
OUT
"True" clocks of differential pair CPU outputs. These are current mode outputs. External
resistors are required for voltage bias / "True" clocks of differential pair CPU outputs. These
open drain outputs need an external 1.5V pull-up / 2.5V CPU clock output.
54
GND
PWR
Ground pin.
55
VDDREF
PWR
Ref, XTAL power supply, nominal 3.3V
56
Vtt_PWRGD#**/REF1
IN
This 3.3V LVTTL input is a level sensitive strobe used to determine when latch inputs are
valid and are ready to be sampled. This is an active low input. / 14.318 MHz reference clock.
DESCRIPTION