Philips Semiconductors Product specification
74F7798-bit bidirectional binary counter (3-State)
2
1989 Sep 20 853–0385 97676
FEATURES
• Multiplexed 3-State I/O ports for bus oriented applications
• Built-in look-ahead carry capability
• Center power pins to reduce effects of package inductance
• Count frequency 145MHz typical
• Supply current 90mA typical
• See 74F269 for 24-pin separate I/O port version
• See 74F579 for 20-pin version
• See 74F1779 for extended function version of the 74F799
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
98
7
6
5
4
3
2
1I/O1 I/O0
CP
CET
V
CC
TC
S0
S1
OE
I/O2
I/O3
GND
I/O4
I/O5
I/O7
I/O6
SF01259
TYPE TYPICAL f
MAX
TYPICAL
SUPPLY CURRENT
(TOTAL)
74F779 145MHz 90mA
ORDERING INFORMATION
DESCRIPTION
COMMERCIAL RANGE
V
CC
= 5V ±10%,
T
amb
= 0°C to +70°C
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
Data inputs 3.5/1.0 70µA/0.6mA
Data outputs 150/40 3.0mA/24mA
S0, S1 Select inputs 1.0/1.0 20µA/0.6mA
OE Output Enable input (active Low) 1.0/1.0 20µA/0.6mA
CET Count Enable Trickle input (active Low) 1.0/1.0 20µA/0.6mA
CP Clock input (active rising edge) 1.0/1.0 20µA/0.6mA
TC Terminal Count output (active Low) 50/33 1.0mA/20mA
NOTE:
One (1.0) FAST Unit Load is defined as: 20µA in the High state and 0.6mA in the Low state.
