Philips 74lvc161 DATASHEETS
INTEGRATED CIRCUITS
74LVC161
Presettable synchronous 4-bit binary
counter; asynchronous reset
Product specification
Supersedes data of 1996 Aug 23
IC24 Data Handbook
1998 May 20
Philips Semiconductors Product specification
Presettable synchronous 4-bit binary counter;
asynchronous reset
FEA TURES
•Wide supply voltage range of 1.2 V to 3.6 V
•In accordance with JEDEC standard no. 8–1A
•Inputs accept voltages up to 5.5 V
•CMOS low power consumption
•Direct interface with TTL levels
•Asynchronous reset
•Synchronous counting and loading
•Two count enable inputs for n–bit cascading
•Positive edge–triggered clock
•Output drive capability 50 transmission lines @85C
DESCRIPTION
The 74LVC161 is a high–performance, low–power, low–voltage,
Si–gate CMOS device and superior to most advanced CMOS
compatible TTL families.
The 74LVC161 is a synchronous presettable binary counter which
features an internal look–head carry and can be used for
high–speed counting. Synchronous operation is provided by having
all flip–flops clocked simultaneously on the positive–going edge of
the clock (CP). The outputs (Q
preset to a HIGH or LOW level. A LOW level at the parallel enable
input (PE) disables the counting action and causes the data at the
data inputs (D
positive–going edge of the clock (provided that the set–up and hold
time requirements for PE are met). Preset takes place regardless of
the levels at count enable inputs (CEP and CET). A low level at the
master reset input (MR) sets all four outputs of the flip–flops
(Q
to Q3) to LOW level regardless of the levels at CP, PE, CET
0
and CEP inputs (thus providing an asynchronous clear function).
The look–ahead carry simplifies serial cascading of the counters.
Both count enable inputs (CEP and CET) must be HIGH to count.
The CET input is fed forward to enable the terminal count output
(TC). The TC output thus enabled will produce a HIGH output pulse
of a duration approximately equal to a HIGH level output of Q
pulse can be used to enable the next cascaded stage. The
maximum clock frequency for the cascaded counters is determined
by the CP to TC propagation delay and CEP to CP set–up time,
according to the following formula:
74L VC161
to Q3) of the counters may be
0
to D3) to be loaded into the counter on the
0
. This
0
_______________________________
f
=
max
tp
(CP to TC) + tSU (CEP to CP)
(max)
1
QUICK REFERENCE DATA
GND = 0V; T
SYMBOL
t
PHL/tPLH
f
MAX
C
I
C
PD
NOTES:
is used to determine the dynamic power dissipation (PD in µW)
1. C
PD
P
= CPD x V
D
= input frequency in MHz; CL = output load capacity in pF;
f
i
f
= output frequency in MHz; VCC = supply voltage in V;
o
Σ (C
L
2. The condition is V
= 25°C; TR = TF 2.5ns
amb
Propagation delay
CP to Q
CP to TC
MR to Q
MR to TC
CET to TC
maximum clock frequency 200 MHz
input capacitance 5.0 pF
power dissipation capacitance per gate notes 1 and 2 39 pF
2
x fi +Σ (CL x V
CC
2
x V
x f
CC
= sum of the outputs
o )
= GND to V
1
PARAMETER CONDITIONS TYPICAL UNIT
CL = 50 pF
n
n
2
x f
CC
CC
where:
o )
VCC = 3.3V 4.9
5.7
5.2
5.7
4.5
ORDERING INFORMATION
PACKAGES TEMPERATURE RANGE OUTSIDE NORTH AMERICA NORTH AMERICA DWG NUMBER
16-Pin Plastic SO –40°C to +85°C 74LVC161 D 74LVC161 D SOT109-1
16-Pin Plastic SSOP Type II –40°C to +85°C 74LVC161 DB 74LVC161 DB SOT338-1
16-Pin Plastic TSSOP Type I –40°C to +85°C 74LVC161 PW 74LVC161PW DH SOT403-1
ns
1998 May 20 853-1864 19421
2
Philips Semiconductors Product specification
Presettable synchronous 4-bit binary counter;
asynchronous reset
PIN CONFIGURATION
LOGIC SYMBOL
MR
CP
CEP
1
2
D0
3
D1
4
D2
5
D3
6
16
V
CC
TC
15
Q0
14
Q1
13
Q2
12
Q3
11
CET
107
98GND PE
SF00656
15
74LVC161
PIN DESCRIPTION
PIN NUMBER SYMBOL FUNCTION
1 MR
2 CP
3,4,5,6 D0 to D
7 CEP count enable inputs
8 GND ground (0V)
9 PE
10 CET count enable carry input
14,13,12,11 Q0 to Q
15 TC terminal count output
16 V
CC
LOGIC SYMBOL (IEEE/IEC)
asynchronous master
reset (active LOW)
clock input (LOW-to-HIGH,
edge-triggered)
data inputs
3
parallel enable input
(active LOW)
flip-flop outputs
3
positive supply voltage
3
4
5
6
9PE
V
= Pin 16
CC
GND = Pin 8
D
0
D
1
D
2
D
3
CEP
CET
710
TC
CP MR
21
Q
0
Q
1
Q
2
Q
3
14
13
12
11
SY00065
1
9
7
10
2
3
4
5
6
R
M1
G3
G4
C2 /1,3,4+
,2 D
1
CTR4
4 CT=15
14
13
12
11
15
SY00066
1998 May 20
3
Philips Semiconductors Product specification
Parallel load
Presettable synchronous 4-bit binary counter;
asynchronous reset
FUNCTIONAL DIAGRAM
3456
D
D
3
2
TC 15
Q
Q
3
2
PE9
CET
10
7
CEP
2CP
1
MR
D
D
1
0
PARALLEL LOAD
CIRCUITRY
BINARY
COUNTER
Q
Q
1
0
14 13 12 11
74LVC161
FUNCTION TABLE
OPERATING
MODES
MR CP CEP CET PE Dn Qn TC
Reset (clear) L X X X X X L L
H ↑ X X l l L L
H ↑ X X l h H *
Count H ↑ h h h X count *
Hold H X l X h X q
(do nothing) H X X l h X q
NOTES:
* = The TC output is High when CET is High and the counter
is at Terminal Count (HHHH)
H = High voltage level
h = High voltage level one setup time prior to the Low-to-High
clock transition
L = Low voltage level
l = Low voltage level one setup time prior to the Low-to-High
clock transition
q = Lower case letters indicate the state of the referenced
output one setup time prior to the Low-to-High clock
transition
X = Don’t care
↑ = Low-to-High clock transition
INPUTS OUTPUTS
n
n
*
L
STATE DIAGRAM
0 1 2 3
15
14
13
12 11 10 9
SF00664
SY00068
4
5
6
7
8
TYPICAL TIMING SEQUENCE
MR
PE
D0
D1
D2
D3
CP
CEP
CET
Q0
Q1
Q2
Q3
TC
12 13 14 15 0 1 2
RESET PRESET
INHIBITCOUNT
SY00069
Typical timing sequence: reset outputs to zero; preset to binary
twelve; count to thirteen, fourteen, fifteen, zero, one, and two;
inhibit
1998 May 20
4
Philips Semiconductors Product specification
Presettable synchronous 4-bit binary counter;
asynchronous reset
LOGIC DIAGRAM
D0
CET
CEP
D1
74LVC161
D3D2
PE
CP
MR
FF0 FF1 FF2 FF3
DCPQ
R
D
Q
Q0
DCPQ
R
D
DCPQ
Q
Q1
Q
R
D
Q2 Q3
DCPQ
Q
R
D
TC
SY00070
1998 May 20
5
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