Philips Semiconductors
Product specification
4-bit binary ripple counter
FEATURES
•
Various counting modes
•
Asynchronous master reset
•
Output capability: standard
•
I
CC
category: MSI
GENERAL DESCRIPTION
The 74HC/HCT93 are high-speed
Si-gate CMOS devices and are pin
compatible with low power Schottky
TTL (LSTTL). They are specified in
compliance with JEDEC standard
no. 7A.
The 74HC/HCT93 are 4-bit binary
ripple counters. The devices consist
of four master-slave flip-flops
internally connected to provide a
QUICK REFERENCE DATA
GND = 0 V; T
amb
= 25
°C;
t
r
= t
f
= 6 ns
divide-by-two section and a
divide-by-eight section. Each section
has a separate clock input (CP
0
and
CP
1
) to initiate state changes of the
counter on the HIGH-to-LOW clock
transition. State changes of the Q
n
outputs do not occur simultaneously
because of internal ripple delays.
Therefore, decoded output signals
are subject to decoding spikes and
should not be used for clocks or
strobes.
A gated AND asynchronous master
reset (MR
1
and MR
2
) is provided
which overrides both clocks and
resets (clears) all flip-flops.
Since the output from the
divide-by-two section is not internally
connected to the succeeding stages,
74HC/HCT93
the device may be operated in various
counting modes. In a 4-bit ripple
counter the output Q
0
must be
connected externally to input CP
1
.
The input count pulses are applied to
clock input CP
0
. Simultaneous
frequency divisions of 2, 4, 8 and 16
are performed at the Q
0
, Q
1
, Q
2
and
Q
3
outputs as shown in the function
table. As a 3-bit ripple counter the
input count pulses are applied to input
CP
1
.
Simultaneous frequency divisions of
2, 4 and 8 are available at the Q
1
, Q
2
and Q
3
outputs. Independent use of
the first flip-flop is available if the reset
function coincides with reset of the
3-bit ripple-through counter.
TYPICAL
SYMBOL
t
PHL
/ t
PLH
f
max
C
I
C
PD
Notes
1. C
PD
is used to determine the dynamic power dissipation (P
D
in
µW):
P
D
= C
PD
×
V
CC2
×
f
i
+ ∑
(C
L
×
V
CC2
×
f
o
) where:
f
i
= input frequency in MHz; f
o
= output frequency in MHz
∑
(C
L
×
V
CC2
×
f
o
) = sum of outputs
C
L
= output load capacitance in pF; V
CC
= supply voltage in V
2. For HC the condition is V
I
= GND to V
CC
; for HCT the condition is V
I
= GND to V
CC
−
1.5 V
ORDERING INFORMATION
See
“74HC/HCT/HCU/HCMOS Logic Package Information”.
PARAMETER
propagation delay CP
0
to Q
0
maximum clock frequency
input capacitance
power dissipation capacitance per package
notes 1 and 2
CONDITIONS
HC
C
L
= 15 pF; V
CC
= 5 V
12
100
3.5
22
HCT
15
77
3.5
22
ns
MHz
pF
pF
UNIT
December 1990
2
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