Nexperia USA Inc. 74HC191D,653

Overview

74HC191D,653 from Nexperia is a presettable synchronous 4-bit binary up/down counter in SO16 package, featuring asynchronous parallel load (PL), synchronous count enable (CE), and dual-direction control via U/D input. It operates from 2.0 V to 6.0 V, delivers TC/RC overflow/underflow signaling, and supports industrial temperature range (−40 °C to +125 °C). Used in digital timing, frequency division, and multistage counter chains.

For engineers reviewing the 74HC191D,653 datasheet, 74HC191D,653 pinout, 74HC191D,653 application, or 74HC191D,653 equivalent, key selection considerations include synchronous reversible counting behavior, TC/RC propagation delay at 4.5 V (≤55 ns), parallel load setup/hold timing, SO16 thermal derating (12.4 mW/K above 110 °C), and compatibility with 74HCT-level logic interfaces.

Technical Context

The 74HC191D,653 implements a master/slave flip-flop architecture with internal steering logic for true synchronous up/down counting and asynchronous preset. Its terminal count (TC) output asserts HIGH at 0 (count-down) or 15 (count-up), while ripple clock (RC) follows CP only when TC = HIGH and CE = LOW - enabling cascaded counter designs without external gating.

Count direction is determined solely by the U/D input level during active CE/CP transitions; U/D must be stable when CE or CP is HIGH. The RC output is edge-aligned to CP but subject to cumulative propagation delay in ripple-cascaded configurations, whereas parallel-gated carry schemes (e.g., Fig. 7) eliminate skew by using TC signals as stage enables.

Key Specifications

Pinout & Package

74HC191D,653 is housed in SOT109-1 (SO16), a plastic small outline package with 16 leads and 3.9 mm body width. Thermal derating is 12.4 mW/K above 110 °C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-bit synchronous up/down counter applications.

Compared with 74HC191D,653, the 74HC193D,653 offers finer event control but sacrifices direction flexibility and preset convenience, while SN74LS191N trades power efficiency and voltage range for TTL interoperability - making the 74HC191D,653 optimal for modern mixed-signal embedded timing where configurability and low-power operation are critical.

Availability

74HC191D,653 is available at Aetrix Electronics and suitable for programmable timers, digital panel meters, multistage frequency dividers, and position encoder interfaces requiring stable component supply across automotive, industrial, and test equipment programs.

Supply support for 74HC191D,653 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Nexperia is a leading semiconductor manufacturer specializing in high-performance logic, analog, and discrete components, with global R&D and manufacturing infrastructure focused on reliability and energy efficiency.

The 74HC191D,653 belongs to Nexperia's 74HC high-speed CMOS logic family, designed specifically for low-power, noise-immune digital control and timing applications in harsh industrial and automotive environments.

FAQ

Can the TC output be used as a clock signal for downstream logic?

No. The TC output is subject to decoding spikes and is not edge-clean; it is intended solely for status indication or enabling ripple-clock generation (RC). Using TC directly as a clock may cause metastability or false triggering in synchronous circuits. Always route RC - not TC - to clock inputs of cascaded stages.

What is the minimum pulse width required for the PL (parallel load) input?

At VCC = 6.0 V, the minimum PL pulse width is 21 ns (typical) and 26 ns (max) across −40 °C to +125 °C. This ensures reliable sampling of D0–D3 data into the flip-flops. Shorter pulses risk partial or failed load, especially under temperature extremes or voltage droop.

How does the U/D input interact with CE and CP timing constraints?

The U/D input must be stable when CE or CP is HIGH; changes during CE = LOW and CP = LOW are permitted, but violating the setup/hold window relative to CP rising edge (e.g., U/D change within 11 ns before CP at VCC = 6.0 V) risks indeterminate counting direction or metastable TC assertion.

Is the 74HC191D,653 pin-compatible with the 74HCT191 series?

Yes - identical SO16 pinout and function mapping. However, 74HCT191 uses TTL-compatible input thresholds (VIH ≈ 2.0 V), while 74HC191D,653 uses CMOS thresholds (VIH = 0.7 × VCC). Interchange is safe only if driving logic meets both threshold requirements; otherwise, level-shifting may be needed for 3.3 V systems driving 74HC191D,653.