74LVC544 查看數據表（PDF） - Philips Electronics

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74LVC544

Octal D-type registered transceiver, inverting (3-State)

Philips Electronics 

Philips Semiconductors

Octal D-type registered transceiver, inverting

(3-State)

Product specification

74LVC544A

AC WAVEFORMS

VM = 1.5V at VCC w 2.7V

VM = 0.5V * VCC at VCC t 2.7V

VOL and VOH are the typical output voltage drop that occur with the

output load.

VX = VOL + 0.3V at VCC w 2.7V

VX = VOL + 0.1VCC at VCC < 2.7V

VY = VOH – 0.3V at VCC w 2.7V

VY = VOH – 0.1VCC at VCC < 2.7V

VI

An, Bn

INPUT

GND

VOH

Bn, An

OUTPUT

VM

tPHL

VM

tPLH

VOL

SV00737

Figure 1. Input (An, Bn) to output (Bn, An) propagation delays.

VI

LEXX INPUT

GND

VOH

An, Bn

OUTPUT

VOL

VM

VM

tw

tPHL

VM

VM

tPLH

VM

SV00738

Figure 2. Latch enable input (LEXX) pulse width, the latch

enable input to output (An, Bn) propagation delays.

VI

ÉÉÉ An, Bn

INPUT

VM

ÉÉÉÉÉÉ GND

ÉÉÉthÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉth ÉÉÉÉÉÉ

tSU

tSU

VI

LEXX, EXX

INPUT

VM

GND

NOTE: The shaded areas indicate when the input is permitted to change

for predictable output performance.

SV00739

Figure 4. Data set-up and hold times for the (An, Bn) input to

the LEXX and EXX inputs

TEST CIRCUIT

VI

PULSE

GENERATOR

VCC

D.U.T.

RT

VO

CL 50pF

S1

500Ω

2 x VCC

Open

GND

500Ω

VCC

t 2.7V

2.7V – 3.6V

VI

VCC

2.7V

Test

tPLH/tPHL

tPLZ/tPZL

tPHZ/tPZH

S1

Open

2 x VCC

GND

SY00003

Figure 5. Load circuitry for switching times

VI

OEXX, EXX

VM

INPUT

GND

VCC

OUTPUT

LOW-to-OFF

OFF-to-LOW

VOL

tPLZ

VX

tPZL

VM

VOH

OUTPUT

HIGH-to-OFF

OFF-to-HIGH

GND

tPHZ

outputs

enabled

tPZH

VY

outputs

disabled

VM

outputs

enabled

SW00210

Figure 3. 3-State enable and disable times

1998 Jul 29

7

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