2

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P-0.1

04/27/11

PI6C20800B

PCI Express® 3.0 1:8 HCSL Clock Buffer

Serial Data Interface (SMBus)

PI6C20800B is a slave only SMBus device that supports indexed block read and indexed block write protocol using a single 7-bit address

and read/write bit as shown below.

Address assignment

A6

A5

A4

A3

A2

A1

A0

R/W

1

1

0

1

1

1

0

0/1

Data Write Protocol(1)

1 bit 7 bits

1

1

8 bits

1

8 bits

1

8 bits

1

8 bits

1

1 bit

Start

bit

Slave Addr

W

Ack

Register

offset

Ack Byte Count

= N

Ack

Data

Byte

Offset

Ack

Data

Byte N

- 1

Ack

Stop bit

Pinout Table

Pin Name

Type

Pin #

Descriptions

SRC_DIV#

Input

1

3.3V LVTTL input for selecting input frequency divide by 2, active

LOW.

SRC & SRC#

Input

4, 5

0.7V Differential SRC input from PI6C410 clock synthesizer

OE [0:7]

Input

6, 7, 14, 15, 35, 36,

43, 44

3.3V LVTTL input for enabling outputs, active HIGH.

OE_INV

Input

40

3.3V LVTTL input for inverting the OE, SRC_STOP# and

PWRDWN# pins.

When 0 = same stage

When 1 = OE[0:7], SRC_STOP#, PWRDWN# inverted.

OUT[0:7] & OUT[0:7]#

Output

8, 9, 12, 13, 16 17, 20,

21, 29, 30, 33, 34, 37,

38, 41, 42

0.7V Differential outputs

PLL/BYPASS#

Input

22

3.3V LVTTL input for selecting fan-out of PLL operation.

SCLK

Input

23

SMBus compatible SCLOCK input

SDA

I/O

24

SMBus compatible SDATA

I

REF

Input

46

External resistor connection to set the differential output current

SRC_STOP#

Input

27

3.3V LVTTL input for SRC stop, active LOW

PLL_BW#

Input

28

3.3V LVTTL input for selecting the PLL bandwidth

PWRDWN#

Input

26

3.3V LVTTL input for Power Down operation, active LOW

LOCK

Output

45

3.3V LVTTL output, transition high when PLL lock is achieved

(Latched output)

V

DD

Power

2, 11, 19, 31, 39

3.3V Power Supply for Outputs

V

SS

Ground 3, 10, 18, 25, 32

Ground for Outputs

V

SS_A

Ground 47

Ground for PLL

V

DD_A

Power

48

3.3V Power Supply for PLL

Note:

1.

Register offset for indicating the starting register for indexed block write and indexed block read. Byte Count in write mode cannot be 0.

11-0049