Integrated Device Technology, Inc.

MILITARY AND COMMERCIAL TEMPERATURE RANGES

AUGUST 1996

©1996 Integrated Device Technology, Inc.

5.10

DSC-2547/8

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The IDT logo is a registered trademark of Integrated Device Technology, Inc.

IDT54/74FCT16501AT/CT/ET

IDT54/74FCT162501AT/CT/ET

IDT54/74FCT162H501AT/CT/ET

FAST CMOS

18-BIT REGISTERED

TRANSCEIVER

CMOS technology. These high-speed, low-power 18-bit reg-

istered bus transceivers combine D-type latches and D-type

flip-flops to allow data flow in transparent, latched and clocked

modes. Data flow in each direction is controlled by output-

enable (OEAB and

OEBA), latch enable (LEAB and LEBA)

and clock (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 LOW-to-HIGH transition of

CLKAB. OEAB is the output enable for the B port. Data flow

from the B port to the A port is similar but requires using

OEBA,

LEBA and CLKBA. Flow-through organization of signal pins

simplifies layout. All inputs are designed with hysteresis for

improved noise margin.

The FCT16501AT/CT/ET are ideally suited for driving

high-capacitance loads and low-impedance backplanes. The

output buffers are designed with power off disable capability

to allow "live insertion" of boards when used as backplane

drivers.

The FCT162501AT/CT/ET have balanced output drive

with current limiting resistors. This offers low ground bounce,

minimal undershoot, and controlled output fall times–reducing

the need for external series terminating resistors.

The

FCT162501AT/CT/ET are plug-in replacements for the

FCT16501AT/CT/ET and ABT16501 for on-board bus inter-

face applications.

The FCT162H501AT/CT/ET have "Bus Hold" which re-

tains the input's last state whenever the input goes to high

impedance. This prevents "floating" inputs and eliminates the

need for pull-up/down resistors.

DESCRIPTION:

The FCT16501AT/CT/ET and FCT162501AT/CT/ET 18-

bit registered transceivers are built using advanced dual metal

2547 drw 01

OEBA

CLKBA

LEBA

OEAB

CLKAB

LEAB

C

C

D

D

D

C

D

C

TO 17 OTHER CHANNELS

FUNCTIONAL BLOCK DIAGRAM

FEATURES:

• Common features:

–

0.5 MICRON CMOS Technology

–

High-speed, low-power CMOS replacement for

ABT functions

–

–

Low input and output leakage

≤ 1µA (max.)

–

ESD > 2000V per MIL-STD-883, Method 3015;

> 200V using machine model (C = 200pF, R = 0)

–

Packages include 25 mil pitch SSOP, 19.6 mil pitch

TSSOP, 15.7 mil pitch TVSOP and 25 mil pitch Cerpack

–

Extended commercial range of -40

°C to +85°C

• Features for FCT16501AT/CT/ET:

–

–

Power off disable outputs permit “live insertion”

–

°C

• Features for FCT162501AT/CT/ET:

–

Balanced Output Drivers:

±24mA (commercial),

±16mA (military)

–

Reduced system switching noise

–

°C

• Features for FCT162H501AT/CT/ET:

–

Bus Hold retains last active bus state during 3-state

–

Eliminates the need for external pull up resistors