Function, Pinout, and Drive Compatible

With FCT and F Logic

Reduced VOH (Typically = 3.3 V) Versions

of Equivalent FCT Functions

Edge-Rate Control Circuitry for

Significantly Improved Noise

Characteristics

Ioff Supports Partial-Power-Down Mode

Operation

Matched Rise and Fall Times

Fully Compatible With TTL Input and

Output Logic Levels

3-State Outputs

ESD Protection Exceeds JESD 22

– 2000-V Human-Body Model (A114-A)

– 200-V Machine Model (A115-A)

– 1000-V Charged-Device Model (C101)

Separation Controls for Data Flow in Each

Direction

Back-to-Back Latches for Storage

CY54FCT543T

– 48-mA Output Sink Current

– 12-mA Output Source Current

CY74FCT543T

– 64-mA Output Sink Current

– 32-mA Output Source Current

description

The ’FCT543T octal latched transceivers contain two sets of eight D-type latches with separate latch-enable

(LEAB, LEBA) and output-enable (OEAB, OEBA) inputs for each set to permit independent control of input and

output in either direction of data flow. For data flow from A to B, for example, the A-to-B enable (CEAB) input

must be low in order to enter data from A or to take data from B, as indicated in the function table. With CEAB

low, a low signal on the A-to-B latch-enable (LEAB) input makes the A-to-B latches transparent; a subsequent

low-to-high transition of the LEAB signal puts the A latches in the storage mode and their outputs no longer

change with the A inputs. With CEAB and OEAB low, the 3-state B-output buffers are active and reflect the data

present at the output of the A latches. Control of data from B to A is similar, but uses CEBA, LEBA, and OEBA

inputs.

These devices are fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the

outputs, preventing damaging current backflow through the device when it is powered down.