STMicroelectronics M74HC40103B1R

Overview

M74HC40103B1R from STMicroelectronics is a high-speed CMOS 8-stage presettable synchronous down counter with active-low control logic, 2V–6V supply range, 38MHz max clock frequency (typ. at VCC=6V), 4µA max quiescent current at 25°C, and single active-low ZERO-DETECT output. It performs programmable divide-by-N timing in digital control systems requiring precise binary countdown from preset values.

For engineers reviewing the M74HC40103B1R datasheet, M74HC40103B1R pinout, M74HC40103B1R application, or M74HC40103B1R equivalent, key selection factors include synchronous/asynchronous preset capability, zero-detect pulse width fidelity, cascading support via CI/CE and CO/ZD, and compatibility with legacy 74-series logic timing margins.

Technical Context

The M74HC40103 implements an 8-bit binary synchronous down counter with priority-encoded control: asynchronous CLEAR (sets count to 255), asynchronous preset (APE), synchronous preset (SPE), and clock enable (CI/CE). All control inputs and CO/ZD are active low.

It supports both ripple and synchronous cascading using CI/CE as enable and CO/ZD as zero-triggered carry-out; propagation delays are balanced (tPLH ≈ tPHL), and noise immunity exceeds 28% VCC across full operating voltage range.

Key Specifications

Pinout & Package

Package: Plastic DIP-16 (0.300" width), JEDEC MS-001, body dimensions 20.0 × 8.5 mm, lead pitch 2.54 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit synchronous down counter applications.

Compared with SN74HC40103N and CD74HC40103E, the M74HC40103B1R offers broader temperature qualification (-55°C to +125°C), tighter propagation delay consistency (20–47ns vs. 22–50ns), and STMicroelectronics' long-term industrial lifecycle support - making it preferred for mission-critical timing in harsh environments.

Availability

M74HC40103B1R is available at Aetrix Electronics and suitable for programmable timers, digital frequency dividers, cascaded counter chains, and industrial PLC input debounce circuits requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for M74HC40103B1R 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The M74HC40103 belongs to ST's high-speed CMOS logic family, engineered for pin-compatible upgrades from legacy 74LS devices while delivering lower power, higher noise immunity, and extended temperature operation.

FAQ

What is the function of the CO/ZD output?

The CO/ZD (Carry-Out / Zero-Detect) output is an active-low signal that asserts for exactly one full clock period when the internal 8-bit counter reaches zero. It serves dual roles: as a carry signal for cascading counters and as a precise zero-crossing indicator for interrupt generation or state machine control - with no external timing components required.

Can M74HC40103B1R operate at 3.3V supply?

Yes, M74HC40103B1R is fully specified for 2V to 6V operation, including 3.3V. At VCC = 3.3V, it delivers guaranteed VIH ≥ 2.31V, VIL ≤ 0.99V, and output drive ≥ ±4mA, ensuring interoperability with standard 3.3V CMOS logic families without level translation.

How does synchronous preset differ from asynchronous preset?

Synchronous preset (SPE low) loads the J0–J7 data on the next rising clock edge, aligning the new count with the system clock domain. Asynchronous preset (APE low) loads J-inputs immediately, independent of clock - useful for urgent state restoration but requiring careful timing analysis to avoid metastability on subsequent clock edges.

Is M74HC40103B1R pin-compatible with older 74LS40103 devices?

Yes, M74HC40103B1R is pin- and function-compatible with 74LS40103, sharing identical DIP-16 footprint, terminal numbering, and logic behavior. However, it operates at lower power, wider voltage range, and higher speed - allowing direct replacement without PCB changes, though input threshold voltages differ slightly (HC vs. LS).