Philips 74f779 DATASHEETS
INTEGRATED CIRCUITS
74F779
8-bit bidirectional binary counter (3-State)
Product specification
IC15 Data Handbook
1989 Sep 20
Philips Semiconductors Product specification
I/On
74F7798-bit bidirectional binary counter (3-State)
FEA TURES
•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
are held in their current state and TC
not recommended for use as a clock or asynchronous reset due to
the possibility of decoding spikes.
is High the data outputs
is held High. The TC output is
PIN CONFIGURATION
1I/O1 I/O0
I/O2
2
I/O3
3
GND
4
I/O4
5
I/O5
6
I/O6
7
I/O7
TYPE TYPICAL f
MAX
74F779 145MHz 90mA
16
CP
15
CET
14
V
13
CC
TC
12
S0
11
S1
10
OE
98
TYPICAL
SUPPLY CURRENT
(TOTAL)
ORDERING INFORMATION
COMMERCIAL RANGE
DESCRIPTION
16-Pin Plastic DIP N74F779N SOT38-4
16-Pin Plastic SOL N74F779D SOT 162-1
VCC = 5V ±10%,
T
= 0°C to +70°C
amb
PKG DWG #
SF01259
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS DESCRIPTION
74F(U.L.)
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.
LOAD VALUE
HIGH/LOW
1989 Sep 20 853–0385 97676
2
Philips Semiconductors Product specification
74F7798-bit bidirectional binary counter (3-State)
LOGIC SYMBOL
11 10
S0 S1
=Pin 13
V
CC
GND=Pin 4
14OECET
15
CP
9
I/O0 I/O1 I/O2 I/O3 I/O4 I/O5 I/O6 I/O7
161235678
LOGIC SYMBOL (IEEE/IEC)
CTR DIV 256
11
0
10
1
14
15
EN4
2 +/C5
1–
9
EN6
0
—
M
3
LOAD
DOWN
UP
HOLD
[1]
[2]
[4]
[8]
[16]
[32]
[64]
[128]
4, 5, 8 CT=256
4, 5, 8 CT=0
6
16
1
2
3
5
6
7
8
SF01261
12
SF01260
FUNCTION TABLE
INPUTS OPERATING MODE
S1 S0 CET OE CP
X X X H X I/O0 to I/O7 in High impedance
12TC
X X X L X Flip-flop outputs appear on I/O lines
L L X H ↑ Parallel load all flip-flops
(not LL) H X ↑ Hold (TC held High)
H L L X ↑ Count up
L H L X ↑ Count down
H = High voltage level
L = Low voltage level
X = Don’t care
↑ = Low-to-High clock transition
(not LL) = S0 and S1 should never be Low voltage level at the
same time in the hold mode only.
1989 Sep 20
3
Philips Semiconductors Product specification
74F7798-bit bidirectional binary counter (3-State)
LOGIC DIAGRAM
11
OE
S0
10
S1
9
16
I/O0
LOAD CONTROL
UP
DOWN
DETAIL A
CP
15
I/O1
I/O2
I/O3
I/O4
I/O5
I/O6
I/O7
1
2
3
5
6
7
8
DETAIL A
DETAIL A
DETAIL A
DETAIL A
DETAIL A
DETAIL A
DETAIL A
V
=Pin 13
CC
GND=Pin 4
1989 Sep 20
CET
14
12
TC
DETAIL A
CP
D
Q
CP
Q
SF01262
TOGGLE
DATA
LOAD
Q
Q
4
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