SN54ABTH32501, SN74ABTH32501

36-BIT UNIVERSAL BUS TRANSCEIVERS

WITH 3-STATE OUTPUTS

SCBS229F – JUNE 1992 – REVISED MAY 1997

3

POST OFFICE BOX 655303

description

These 36-bit UBTs 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 the 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 data is stored in the latch/flip-flop on the low-to-high transition of CLKAB. Data flow for B to A is similar

to that of A to B, but uses OEBA, LEBA, and CLKBA.

Output-enable OEAB is active high. When OEAB is high, the outputs are active. When OEAB is low, the outputs

are in the high-impedance state. The output enables are complementary (OEAB is active high, and OEBA is

active low).

and OE should be tied to GND through a pulldown resistor; the minimum value of the resistor is determined by

the current-sinking/current-sourcing capability of the driver.

Active bus-hold circuitry is provided to hold unused or floating data inputs at a valid logic level.

The SN54ABTH32501 is characterized for operation over the full military temperature range of –55

°C to 125°C.

The SN74ABTH32501 is characterized for operation from –40

°C to 85°C.

FUNCTION TABLE†

INPUTS

OUTPUT

OEAB

LEAB

CLKAB

A

B

L

X

X

X

Z

H

HX

L

L

H

HX

H

H

H

L

↑

LL

H

L

↑

HH

H

LH

X

B0‡

H

L

L

X

B0§

† A-to-B data flow is shown: B-to-A flow is similar, but

uses OEBA, LEBA, and CLKBA.

‡ Output level before the indicated steady-state input

conditions were established

§ Output level before the indicated steady-state input

conditions were established, provided that CLKAB

was low before LEAB went low