IDT®

Programmable System Clock Chip for ATI RD790-K8TM Based Systems

1393—01/28/14

9LPRS477C

Programmable System Clock Chip for ATI RD790 - K8TM based Systems

2

VFQFPN Pin Description

PIN #

PIN NAME

PIN TYPE

DESCRIPTION

1

**SEL_DOC/48MHz_1

I/O

SEl_DOC: latched input to select pin functionality

1 = DOC input.

0 = SRCCLK5

/ 48MHz clock output.

2

**SEL_CPU1#/48MHz_0

I/O

SEL_CPU1 latched input to select pin functionality

1 = SRCCLK7

0 = CPUKG1

/ 48MHz clock output.

3

GND48

GND

Ground pin for the 48MHz outputs

4

SMBCLK

IN

Clock pin of SMBus circuitry, 5V tolerant.

5

SMBDAT

I/O

Data pin for SMBus circuitry, 5V tolerant.

6

**DOC_0/SRC5C_LPRS

OUT

Dynamic Over Clocking pin: real time frequency selection 0: Normal; 1: Frequency will transition to a

preprogrammed value in the I2c.

/ Complement clock of low power differential SRC clock pair. (no 50ohm shunt resistor to GND and no 33

ohm series resistor needed

7

**DOC_1/SRC5T_LPRS

OUT

Dynamic Over Clocking pin: real time frequency selection 0: Normal; 1: Frequency will transition to a

preprogrammed value in the I2c.

/ True clock of low power differential SRC clock pair. (no 50ohm shunt resistor to GND and no 33 ohm

series resistor needed

8

SRC4C_LPRS

OUT

Complement clock of low power differential SouthBridge SRC clock pair. (no 50ohm shunt resistor to GND

and no 33 ohm series resistor needed

9

SRC4T_LPRS

OUT

True clock of low power differential SRC clock pair. (no 50ohm shunt resistor to GND and no 33 ohm series

resistor needed

10

GNDSRC

GND

Ground pin for the SRC outputs

11

VDDSRC

PWR

Supply for SRC core, 3.3V nominal

12

SRC3C_LPRS

OUT

Complement clock of low power differential SouthBridge SRC clock pair. (no 50ohm shunt resistor to GND

and no 33 ohm series resistor needed

13

SRC3T_LPRS

OUT

True clock of low power differential SRC clock pair. (no 50ohm shunt resistor to GND and no 33 ohm series

resistor needed

14

SRC2C_LPRS

OUT

Complement clock of low power differential SouthBridge SRC clock pair. (no 50ohm shunt resistor to GND

and no 33 ohm series resistor needed

15

SRC2T_LPRS

OUT

True clock of low power differential SRC clock pair. (no 50ohm shunt resistor to GND and no 33 ohm series

resistor needed

16

VDDSRC

PWR

Supply for SRC core, 3.3V nominal

17

GNDSRC

GND

Ground pin for the SRC outputs

18

SRC1C_LPRS

OUT

Complement clock of low power differential SouthBridge SRC clock pair. (no 50ohm shunt resistor to GND

and no 33 ohm series resistor needed

19

SRC1T_LPRS

OUT

True clock of low power differential SRC clock pair. (no 50ohm shunt resistor to GND and no 33 ohm series

resistor needed

20

SRC0C_LPRS

OUT

Complement clock of low power differential SouthBridge SRC clock pair. (no 50ohm shunt resistor to GND

and no 33 ohm series resistor needed

21

SRC0T_LPRS

OUT

True clock of low power differential SRC clock pair. (no 50ohm shunt resistor to GND and no 33 ohm series

resistor needed

22

SB_SRC1C_LPRS

OUT

Complement clock of low power differential SouthBridge SRC clock pair. (no 50ohm shunt resistor to GND

and no 33 ohm series resistor needed

23

SB_SRC1T_LPRS

OUT

True clock of low power differential SouthBridge SRC clock pair. (no 50ohm shunt resistor to GND and no

33 ohm series resistor needed

24

GNDSB_SRC

GND

Ground pin for the SB_SRC outputs

25

VDDSB_SRC

PWR

Supply for SRC core, 3.3V nominal

26

SB_SRC0C_LPRS

OUT

Complement clock of low power differential SouthBridge SRC clock pair. (no 50ohm shunt resistor to GND

and no 33 ohm series resistor needed

27

SB_SRC0T_LPRS

OUT

True clock of low power differential SouthBridge SRC clock pair. (no 50ohm shunt resistor to GND and no

33 ohm series resistor needed

28

GNDATIG

GND

Ground pin for the ATIG outputs

29

ATIG3C_LPRS

OUT

Complementary clock of low-power differential push-pull PCI-Express pair with integrated series resistor.

(no 50ohm shunt resistor to GND and no 33 ohm series resistor needed)

30

ATIG3T_LPRS

OUT

True clock of low-power differential push-pull PCI-Express pair with integrated series resistor. (no 50ohm

shunt resistor to GND and no 33 ohm series resistor needed)

31

ATIG2C_LPRS

OUT

Complementary clock of low-power differential push-pull PCI-Express pair with integrated series resistor.

(no 50ohm shunt resistor to GND and no 33 ohm series resistor needed)

32

ATIG2T_LPRS

OUT

True clock of low-power differential push-pull PCI-Express pair with integrated series resistor. (no 50ohm

shunt resistor to GND and no 33 ohm series resistor needed)