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74F621

Octal bus transceiver, non-inverting (open collector)

Philips Electronics 

Philips Semiconductors

Octal bus transceiver, non-inverting (open collector)

Product specification

74F621

FEATURES

• High-impedance NPN base inputs for reduced loading

(20µA in High and Low states)

• Octal bidirectional bus interface

• Open collector outputs sink 64mA

• Non-inverting

DESCRIPTION

The 74F621 is an octal transceiver featuring non-inverting open

collector bus-compatible outputs in both send and receive

directions. The outputs are capable of sinking 64mA, providing very

good capacitive drive characteristics.

This octal bus transceiver is designed for asynchronous two-way

communication between data buses. The control function

implementation allows for maximum flexibility in timing.

The device allows data transmission from the A bus to the B bus or

from the B bus to the A bus, depending upon the logic levels at the

Enable inputs (OEBA and OEAB). The Enable inputs can be used to

disable the device so that the buses are effectively isolated.

The dual-enable configuration gives the 74F621 the capability to

store data by the simultaneous enabling of OEBA and OEAB. Each

output reinforces its input in this transceiver configuration. Thus,

when both control inputs are enabled and all other data sources to

the two sets of the bus lines are at high impedance, both sets of bus

lines (16 in all) will remain in their last states.

PIN CONFIGURATION

OEAB 1

A0 2

A1 3

A2 4

A3 5

A4 6

A5 7

A6 8

A7 9

GND 10

20 VCC

19 OEBA

18 B0

17 B1

16 B2

15 B3

14 B4

13 B5

12 B6

11 B7

SF01135

TYPE

74F621

TYPICAL

PROPAGATION

DELAY

8.0ns

TYPICAL SUPPLY CURRENT

(TOTAL)

105mA

ORDERING INFORMATION

DESCRIPTION

COMMERCIAL RANGE

VCC = 5V ±10%,

Tamb = 0°C to +70°C

20-pin plastic DIP

N74F621N

20-pin plastic SOL

N74F621D

PKG

DWG #

SOT146-1

SOT163-1

INPUT AND OUTPUT LOADING AND FAN-OUT TABLE

PINS

DESCRIPTION

74F(U.L.)

HIGH/LOW

A0 - A7, B0 - B7

Data inputs

1.0/0.033

OEBA, OEAB

Output Enable inputs

1.0/0.033

A0 - A7

Data outputs

OC/40

B0 - B7

Data outputs

OC/106.7

NOTE: One (1.0) FAST unit load is defined as: 20µA in the High state and 0.6mA in the Low state. OC = Open Collector.

LOAD VALUE

HIGH/LOW

20µA/20µA

20µA/20µA

OC/24mA

OC/64mA

1996 Jan 05

2

853–0380 16185

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