74HC/HCT161

General description

The 74HC/HCT161 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/HCT161 are synchronous presettable binary counters which feature an internal look-ahead 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 (Q₀ to Q₃) of the counters may be 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 (D₀ to D₃) to be loaded into the counter on the positive-going edge of the clock (providing 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 (Q₀ to Q₃) to LOW level regardless of the levels at CP, PE, CET 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 Q₀. This 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:

f_max = (1) / (t_P(max) (CP to TC) + t_SU (CEP to CP) )

Features

• Synchronous counting and loading
• Two count enable inputs for n-bit cascading
• Positive-edge triggered clock
• Asynchronous reset
• Output capability: standard
• I_CC category: MSI

Products/packages

Pricing/ordering/availability

Applications

• Television sets
• Home-sound sets
• Multimedia systems
• All mains fed audio systems
• Car audio (boosters).

Block diagrams/pinning

Technical documents

Support Documents

HCT_USER_GUIDE; HC/T User Guide (1997-11-01)

75013486; Philips Logic Competitive Cross Reference Guide (2004-09-14)

Parametrics/similar products

Similar products

74HC/HCT161 links to the similar products page containing an overview of products that are similar in function or related to the type number(s) as listed on this page. The similar products page includes products from the same catalog tree(s), relevant selection guides and products from the same functional category.

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