SN74FB2033H

8-BIT TTL/BTL REGISTERED TRANSCEIVER

SCBS472B – MAY 1994 – REVISED JUNE 1996

2

POST OFFICE BOX 655303

description (continued)

Data flow in the B-to-A direction, regardless of the logic element selected, is further controlled by the

LOOPBACK input. When LOOPBACK is low, B-port data is the B-to-A input. When LOOPBACK is high, the

output of the selected A-to-B logic element (prior to inversion) is the B-to-A input.

AO port is in the high-impedance state. When OEA is high, the AO port is active (high or low logic levels).

is inactive. If OEB is high and OEB is low, the B port is active.

The A-to-B and B-to-A logic elements are active regardless of the state of their associated outputs. The logic

elements can enter new data (in flip-flop and latch modes) or retain previously stored data while the associated

outputs are in the high-impedance (AO port) or inactive (B port) states.

Output clamps are provided on the BTL outputs to reduce switching noise. One clamp reduces inductive ringing

Both of these clamps are active only during AC switching and do not affect the BTL outputs during steady-state

conditions.

The SN74FB2033H is characterized for operation from 0

°C to 70°C.

Function Tables

FUNCTION TABLE

INPUTS

FUNCTION/MODE

OEA

OEB

OEB

OMODE1

OMODE0

IMODE1

IMODE0

LOOPBACK

FUNCTION/MODE

L

L

X

X

X

X

X

X

Isolation

L

X

H

X

XXX

X

Isolation

X

H

L

L

L

X

X

X

AI to B, buffer mode

X

H

L

L

H

X

X

X

AI to B, flip-flop mode

X

H

L

H

X

X

X

X

AI to B, latch mode

H

L

X

X

X

L

L

L

B to AO buffer mode

H

XH

X

X

L

L

L

B to AO, buffer mode

H

L

X

X

X

L

H

L

B to AO flip flop mode

H

XH

X

X

L

H

L

B to AO, flip-flop mode

H

L

X

X

X

H

X

L

B to AO latch mode

H

XH

X

X

H

X

L

B to AO, latch mode

H

L

X

X

X

L

L

H

AI to AO buffer mode

H

XH

X

X

L

L

H

AI to AO, buffer mode

H

L

X

X

X

L

H

H

AI to AO flip flop mode

H

XH

X

X

L

H

H

AI to AO, flip-flop mode

H

L

X

X

X

H

X

H

AI to AO latch mode

H

XH

X

X

H

X

H

AI to AO, latch mode

H

H

L

X

X

X

X

L

AI to B, B to AO