DATA SHEET

1-to-21, Differential HCSL Fanout Buffer

851021

851021 REVISION C 11/03/15

1

©2015 Integrated Device Technology, Inc.

General Description

The 851021 is a 1-to-21 Differential HCSL Fanout Buffer. The

851021 is designed to translate any differential signal levels to

differential HCSL output levels. An external reference resistor is

used to set the value of the current supplied to an external

load/termination resistor. The load resistor value is chosen to equal

the value of the characteristic line impedance of 50

. The 851021 is

characterized at an operating supply voltage of 3.3V.

The differential HCSL outputs, accurate crossover voltage and duty

cycle make the 851021 ideal for interfacing to PCI Express and

FBDIMM applications.

Features

• Twenty-one differential HCSL outputs

• Translates any differential input signal (LVPECL, LVHSTL, LVDS,

HCSL) to HCSL levels without external bias networks

• Maximum output frequency: 250MHz

• Output skew: 395ps (maximum)

• Part-to-part skew: 335ps (maximum)

• Output drift: 140ps (maximum)

• V

OH: 850mV (maximum)

• Full 3.3V supply voltage

• Available in lead-free (RoHS 6) package

• 0°C to 70°C ambient operating temperature

Q0

nQ0

Q1

nQ1

Q2

nQ2

Q3

nQ3

Q4

nQ4

Q5

nQ5

Q6

nQ6

Q7

nQ7

Q8

nQ8

Q9

nQ9

Q10

nQ10

Q20

nQ20

Q19

nQ19

Q18

nQ18

Q17

nQ17

Q16

nQ16

Q15

nQ15

Q14

nQ14

Q13

nQ13

Q12

nQ12

Q11

nQ11

CLK

nCLK

IREF

Q3

nQ3

VDD

nQ4

GND

Q5

nQ5

Q4

nQ8

Q6

VDD

nQ6

Q7

nQ7

VDD

Q8

VDD

nQ17

Q17

Q18

GND

nQ18

nQ16

Q16

Q13

VDD

nQ15

Q15

nQ14

Q14

VDD

nQ13

64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49

17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

48

47

46

45

44

43

42

41

40

39

38

37

36

35

34

33

Pin Assignment

Block Diagram

ICS851021

64-Lead TQFP, E-Pad

10mm x 10mm x 1.0mm package body

Y Package

Top View