18-Bit Registered Transceivers

CY74FCT16500T

CY74FCT162500T

SCCS056 - August 1994 - Revised March 2000

Data sheet acquired from Cypress Semiconductor Corporation.

Data sheet modified to remove devices not offered.

Copyright

Features

• FCT-C speed at 4.6 ns

• Power-off disable outputs permits live insertion

• Edge-rate control circuitry for significantly improved

noise characteristics

• Typical output skew < 250 ps

• ESD > 2000V

• TSSOP (19.6-mil pitch) and SSOP (25-mil pitch)

packages

• Industrial temperature range of

−40˚C to +85˚C

CY74FCT16500T Features:

• 64 mA sink current, 32 mA source current

CY74FCT162500T Features:

• Balanced 24 mA output drivers

• Reduced system switching noise

Functional Description

These 18-bit universal bus transceivers can be operated in

transparent, latched, or clock modes by combining D-type

latches and D-type flip-flops. Data flow in each direction is

controlled by output-enable (OEAB and OEBA), latch enable

(LEAB and LEBA), and clock inputs (CLKAB and CLKBA)

inputs. For A-to-B data flow, the device operates in transparent

mode when LEAB is HIGH. When LEAB is LOW, the A data is

latched if CLKAB is held at a HIGH or LOW logic level. If LEAB

is LOW, the A bus data is stored in the latch/flip-flop on the

HIGH-to-LOW transition of CLKAB. OEAB performs the output

enable function on the B port. Data flow from B-to-A is similar

to that of A-to-B and is controlled by OEBA, LEBA, and

CLKBA. The output buffers are designed with power-off

disable feature that allows live insertion of boards.

The

CY74FCT16500T

is

ideally

suited

for

driving

high-capacitance loads and low-impedance backplanes.

The CY74FCT162500T has 24-mA balanced output drivers

with current limiting resistors in the outputs. This reduces the

need for external terminating resistors and provides for

minimal undershoot and reduced ground bounce. The

CY74FCT162500T is ideal for driving transmission lines.

GND

Logic Block Diagram

Pin Configuration

1

2

3

4

5

6

7

8

9

10

11

12

33

32

31

30

29

36

35

OEAB

34

SSOP/TSSOP

Top View

13

14

15

16

17

18

19

20

21

22

23

24

45

44

43

42

41

37

38

39

40

48

47

46

LEAB

GND

GND

GND

GND

GND

GND

FCT16500-1

TO 17 OTHER CHANNELS

LEAB

OEBA

LEBA

CLKAB

CLKBA

OEAB

C

D

C

D

C

D

C

D

25

26

27

28

49

52

51

50

OEBA

LEBA

GND

CLKAB

53

56

55

54

GND

GND

CLKBA

FCT16500-2