74lvc161bq NXP Semiconductors, 74lvc161bq Datasheet - Page 2

• Manufacturer Part Number: 74lvc161bq
• Description: Presettable Synchronous 4-bit Binary Counter; Asynchronous Reset
• Manufacturer: NXP Semiconductors

Philips Semiconductors
FEATURES
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
2004 Mar 30
5 V tolerant inputs for interfacing with 5 V logic
Wide supply voltage range from 1.2 V to 3.6 V
CMOS low power consumption
Direct interface with TTL levels
Inputs accept voltages up to 5.5 V
Complies with JEDEC standard no. JESD8B/JESD36
Asynchronous reset
Synchronous counting and loading
Two count enable inputs for n-bit cascading
Positive edge-triggered clock
ESD protection:
– HBM EIA/JESD22-A114-B exceeds 2000 V
– MM EIA/JESD22-A115-A exceeds 200 V.
Specified from 40 C to +85 C and 40 C to +125 C.
Presettable synchronous 4-bit binary
counter; asynchronous reset
2
is provided by having all flip-flops clocked simultaneously
on the positive-going edge of the clock (pin CP). The
outputs (pins Q0 to Q3) of the counters may be preset to a
HIGH-level or a LOW-level. A LOW-level at the parallel
enable input (pin PE) disables the counting action and
causes the data at the data inputs (pins D0 to D3) to be
loaded into the counter on the 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 (pins CEP and CET). A LOW-level
at the master reset input (pin MR) sets all four outputs of
the flip-flops (pins Q0 to Q3) to LOW-level regardless of
the levels at input pins CP, PE, CET and CEP (thus
providing an asynchronous clear function).
The look-ahead carry simplifies serial cascading of the
counters. Both count enable inputs (pins CEP and CET)
must be HIGH to count. The CET input is fed forward to
enable the terminal count output (pin TC). The TC output
thus enabled will produce a HIGH output pulse of a
duration approximately equal to a HIGH-level output of Q0.
This pulse can be used to enable the next cascaded stage.
The maximum clock frequency for the cascaded counters
is determined by t
(set-up time CEP to CP) according to the following
formula: f
max
=
------------------------------------ -
t
PHL max
PHL
(propagation delay CP to TC) and t
1
+
t
su
Product specification
74LVC161
su