Philips Semiconductors

Product specification

74F779

8-bit bidirectional binary counter (3-State)

2

1989 Sep 20

853–0385 97676

FEATURES

DESCRIPTION

The 74F779 is a fully synchronous 8-stage Up/Down Counter with

multiplexed 3-State I/O ports for bus-oriented applications. All

control functions (hold, count up, count down, synchronous load) are

controlled by two mode pine (S0, S1). The device also features

carry look-ahead for easy cascading. All state changes are initiated

by the rising edge of the clock. When CET is High the data outputs

are held in their current state and TC is held High. The TC output is

not recommended for use as a clock or asynchronous reset due to

the possibility of decoding spikes.

PIN CONFIGURATION

16

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

I/O1

I/O0

CP

CET

TC

S0

S1

OE

I/O2

I/O3

GND

I/O4

I/O5

I/O7

I/O6

SF01259

TYPE

TYPICAL

SUPPLY CURRENT

(TOTAL)

74F779

145MHz

90mA

ORDERING INFORMATION

DESCRIPTION

COMMERCIAL RANGE

PKG DWG #

16-Pin Plastic DIP

N74F779N

SOT38-4

16-Pin Plastic SOL

N74F779D

SOT 162-1

INPUT AND OUTPUT LOADING AND FAN-OUT TABLE

PINS

DESCRIPTION

74F(U.L.)

HIGH/LOW

LOAD VALUE

HIGH/LOW

I/On

Data inputs

3.5/1.0

70

µA/0.6mA

I/On

Data outputs

150/40

3.0mA/24mA

S0, S1

Select inputs

1.0/1.0

20

µA/0.6mA

OE

Output Enable input (active Low)

1.0/1.0

20

µA/0.6mA

CET

Count Enable Trickle input (active Low)

1.0/1.0

20

µA/0.6mA

CP

Clock input (active rising edge)

1.0/1.0

20

µA/0.6mA

TC

Terminal Count output (active Low)

50/33

1.0mA/20mA

NOTE:

One (1.0) FAST Unit Load is defined as: 20

µA in the High state and 0.6mA in the Low state.