SN54LVTH16652, SN74LVTH16652

3.3-V ABT 16-BIT BUS TRANSCEIVERS AND REGISTERS

WITH 3-STATE OUTPUTS

SCBS150K – JULY 1994 – REVISED APRIL 1999

2

POST OFFICE BOX 655303

description (continued)

Data on the A or B bus, or both, can be stored in the internal D flip-flops by low-to-high transitions at the

appropriate clock (CLKAB or CLKBA) inputs, regardless of the levels on the select-control or output-enable

inputs. When SAB and SBA are in the real-time transfer mode, it also is possible to store data without using the

internal D-type flip-flops by simultaneously enabling OEAB and OEBA. In this configuration, each output

reinforces its input. When all other data sources to the two sets of bus lines are at high impedance, each set

of bus lines remains at its last level configuration.

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.

disables the outputs, preventing damaging current backflow through the devices when they are powered down.

The power-up 3-state circuitry places the outputs in the high-impedance state during power up and power down,

which prevents driver conflict.

The SN54LVTH16652 is characterized for operation over the full military temperature range of –55

°C to 125°C.

The SN74LVTH16652 is characterized for operation from –40

°C to 85°C.

FUNCTION TABLE

INPUTS

DATA I/O†

OPERATION OR FUNCTION

OEAB

OEBA

CLKAB

CLKBA

SAB

SBA

A1–A8

B1–B8

OPERATION OR FUNCTION

L

H

H or L

H or L

X

X

Input

Input

Isolation

L

H

↑↑

X

X

Input

Input

Store A and B data

X

H

↑

H or L

X

X

Input

Unspecified‡

Store A, hold B

H

H

↑↑

X‡

X

Input

Output

Store A in both registers

L

X

H or L

↑

X

X

Unspecified‡

Input

Hold A, store B

L

L

↑↑

XX‡

Output

Input

Store B in both registers

L

L

X

X

X

L

Output

Input

Real-time B data to A bus

L

L

X

H or L

X

H

Output

Input

Stored B data to A bus

H

H

X

X

L

X

Input

Output

Real-time A data to B bus

H

H

H or L

X

H

X

Input

Output

Stored A data to B bus

H

L

H or L

H or L

H

H

Output

Output

Stored A data to B bus and

stored B data to A bus

† The data-output functions may be enabled or disabled by a variety of level combinations at OEAB or OEBA. Data-input functions always are

enabled; i.e., data at the bus terminals is stored on every low-to-high transition of the clock inputs.

‡ Select control = L; clocks can occur simultaneously.

Select control = H; clocks must be staggered to load both registers.