Philips Semiconductors
Product specification
8-bit synchronous binary down counter
FEATURES
•
Cascadable
•
Synchronous or asynchronous preset
•
Output capability: standard
•
I
CC
category: MSI
GENERAL DESCRIPTION
The 74HC/HCT40103 are high-speed Si-gate CMOS
devices and are pin compatible with the “40103” of the
“4000B” series. They are specified in compliance with
JEDEC standard no. 7A.
The 74HC/HCT40103 consist each of an 8-bit
synchronous down counter with a single output which is
active when the internal count is zero. The “40103”
contains a single 8-bit binary counter and has control
inputs for enabling or disabling the clock (CP), for clearing
the counter to its maximum count, and for presetting the
counter either synchronously or asynchronously. All
control inputs and the terminal count output (TC) are
active-LOW logic.
In normal operation, the counter is decremented by one
count on each positive-going transition of the clock (CP).
QUICK REFERENCE DATA
GND = 0 V; T
amb
= 25
°C;
t
r
= t
f
= 6 ns
74HC/HCT40103
Counting is inhibited when the terminal enable input (TE)
is HIGH. The terminal count output (TC) goes LOW when
the count reaches zero if TE is LOW, and remains LOW for
one full clock period.
When the synchronous preset enable input (PE) is LOW,
data at the jam input (P
0
to P
7
) is clocked into the counter
on the next positive-going clock transition regardless of the
state of TE. When the asynchronous preset enable input
(PL) is LOW, data at the jam input (P
0
to P
7
) is
asynchronously forced into the counter regardless of the
state of PE, TE, or CP. The jam inputs (P
0
to P
7
) represent
a single 8-bit binary word.
When the master reset input (MR) is LOW, the counter is
asynchronously cleared to its maximum count (decimal
255) regardless of the state of any other input. The
precedence relationship between control inputs is
indicated in the function table.
If all control inputs except TE are HIGH at the time of zero
count, the counters will jump to the maximum count, giving
a counting sequence of 256 clock pulses long.
The “40103” may be cascaded using the TE input and the
TC output, in either a synchronous or ripple mode.
TYPICAL
SYMBOL PARAMETER
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
propagation delay CP to TC
maximum clock frequency
input capacitance
power dissipation capacitance per package
notes 1 and 2
CONDITIONS
HC
C
L
= 15 pF; V
CC
= 5 V
30
32
3.5
24
30
31
3.5
27
HCT
ns
MHz
pF
pF
UNIT
1998 Jul 08
2
Philips Semiconductors
Product specification
8-bit synchronous binary down counter
ORDERING INFORMATION
PACKAGE
TYPE NUMBER
NAME
74HC40103N;
74HCT40103N
74HC40103D;
74HCT40103D
74HC40103DB;
74HCT40103DB
74HC40103PW;
DIP16
SO16
SSOP16
DESCRIPTION
plastic dual in-line package; 16 leads (300 mil); long body
74HC/HCT40103
VERSION
SOT38-1
SOT109-1
SOT338-1
SOT403-1
plastic small outline package; 16 leads; body width 3.9 mm
plastic shrink small outline package; 16 leads; body width 5.3 mm
TSSOP16 plastic thin shrink small outline package; 16 leads; body width 4.4 mm
PIN DESCRIPTION
PIN NO.
1
2
3
4, 5, 6, 7, 10, 11, 12, 13
8
9
14
15
16
SYMBOL
CP
MR
TE
P
0
to P
7
GND
PL
TC
PE
V
CC
NAME AND FUNCTION
clock input (LOW-to-HIGH, edge-triggered)
asynchronous master reset input (active LOW)
terminal enable input
jam inputs
ground (0 V)
asynchronous preset enable input (active LOW)
terminal count output (active LOW)
synchronous preset enable input (active LOW)
positive supply voltage
Fig.1 Pin configuration.
Fig.2 Logic symbol.
Fig.3 IEC logic symbol.
1998 Jul 08
3
Analog electronics
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