2

ICS9LPRS355

Datasheet

1205—06/24/14

TSSOP Pin Description

PIN #

PIN NAME

TYPE

DESCRIPTION

1

PCI0/CR#_A

I/O

3.3V PCI clock output or Clock Request control A for either SRC0 or SRC2 pair

The power-up default is PCI0 output, but this pin may also be used as a Clock Request control

of SRC pair 0 or SRC pair 2 via SMBus. Before configuring this pin as a Clock Request Pin, the

PCI output must first be disabled in byte 2, bit 0 of SMBus address space . After the PCI output

is disabled (high-Z), the pin can then be set to serve as a Clock Request pin for either SRC pair

2 or pair 0 using the CR#_A_EN bit located in byte 5 of SMBUs address space.

Byte 5, bit 7

0 = PCI0 enabled (default)

1= CR#_A enabled. Byte 5, bit 6 controls whether CR#_A controls SRC0 or SRC2 pair

Byte 5, bit 6

0 = CR#_A controls SRC0 pair (default),

1= CR#_A controls SRC2 pair

2

VDDPCI

PWR

Power supply pin for the PCI outputs, 3.3V nominal

3

PCI1/CR#_B

I/O

3.3V PCI clock output/Clock Request control B for either SRC1 or SRC4 pair

The power-up default is PCI1 output, but this pin may also be used as a Clock Request control

of SRC pair 1 or SRC pair 4 via SMBus. Before configuring this pin as a Clock Request Pin, the

PCI output must first be disabled in byte 2, bit 1 of SMBus address space . After the PCI output

is disabled (high-Z), the pin can then be set to serve as a Clock Request pin for either SRC pair

1 or pair 4 using the CR#_B_EN bit located in byte 5 of SMBUs address space.

Byte 5, bit 5

0 = PCI1 enabled (default)

1= CR#_B enabled. Byte 5, bit 6 controls whether CR#_B controls SRC1 or SRC4 pair

Byte 5, bit 4

0 = CR#_B controls SRC1 pair (default)

1= CR#_B controls SRC4 pair

4

PCI2/TME

I/O

3.3V PCI clock output / Trusted Mode Enable (TME) Latched Input. This pin is sampled on

power-up as follows

0 = Overclocking of CPU and SRC Allowed

1 = Overclocking of CPU and SRC NOT allowed

After being sampled on power-up, this pin becomes a 3.3V PCI Output

5

PCI3

OUT

3.3V PCI clock output.

6

PCI4/27_Select

I/O

3.3V PCI clock output / 27MHz mode select for pin17, 18 strap. On powerup, the logic value on

this pin determines the power-up default of DOT_96/SRC0 and 27MHz/SRC1 output and the

function table for the pin17 and pin18.

7

PCI_F5/ITP_EN

I/O

Free running PCI clock output and ITP/SRC8 enable strap. This output is not affected by the

state of the PCI_STOP# pin. On powerup, the state of this pin determines whether pins 38 and

39 are an ITP or SRC pair.

0 =SRC8/SRC8#

1 = ITP/ITP#

8

GNDPCI

PWR

Ground for PCI clocks.

9

VDD48

PWR

Power supply for USB clock, nominal 3.3V.

10

USB_48MHz/FSLA

I/O

Fixed 48MHz USB clock output. 3.3V./ 3.3V tolerant input for CPU frequency selection. Refer to

input electrical characteristics for Vil_FS and Vih_FS values.

11

GND48

PWR

Ground pin for the 48MHz outputs.

12

VDD96_IO

PWR

1.05V to 3.3V from external power supply

13

DOTT_96/SRCT0

OUT

True clock of SRC or DOT96. The power-up default function depends on 27_Select,1= SRC0

0=DOT96

14

DOTC_96/SRCC0

OUT

Complement clock of SRC or DOT96. The power-up default function depends on 27_Select,1=

SRC0

0=DOT96

15

GND

PWR

Ground pin for the DOT96 clocks.

16

VDD

PWR

Power supply for SRC / SE1 and SE2 clocks, 3.3V nominal.