STMicroelectronics HCF40103BEY

Overview

HCF40103BEY from STMicroelectronics is an 8-stage synchronous 8-bit binary down counter with asynchronous clear, synchronous/asynchronous preset, and active-low carry-out/zero-detect output. It operates up to 3.6 MHz at VDD = 10 V, supports 5–20 V supply, features 100 nA max input leakage at 18 V, and is packaged in 16-pin plastic DIP for industrial timing and microprocessor interrupt applications.

For engineers reviewing the HCF40103BEY datasheet, HCF40103BEY pinout, HCF40103BEY application, or HCF40103BEY equivalent, key selection criteria include its active-low control logic, cascading capability via CI/CE and CO/ZD, synchronous preset timing (t_setup = 100 ns min at VDD = 15 V), and guaranteed quiescent current spec up to 20 V.

Technical Context

This device implements a fully synchronous 8-bit binary down counter with dedicated control hierarchy: asynchronous CLEAR dominates all inputs, followed by APE, then SPE and CI/CE. Counting occurs on positive clock edges, and zero detection triggers a one-cycle low pulse on CO/ZD only when CI/CE is asserted low.

It supports both synchronous and ripple-mode cascading using CI/CE and CO/ZD pins, enabling N-modulus division and extended-count timer functions. All logic thresholds scale with VDD - VIH = 11 V min at 15 V supply, ensuring robust noise margins across 5/10/15 V operation.

Key Specifications

Pinout & Package

Package: 16-pin plastic dual in-line package (DIP-16), 0.3-inch body width, through-hole mount, RoHS-compliant lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD40103BE and MC140103BD, HCF40103BEY offers superior speed (3.6 MHz vs. 2.4/2.0 MHz), lowest leakage (100 nA vs. 500 nA/1 µA), and tighter propagation delay control - making it optimal for precision industrial timers where supply stability and thermal drift matter.

Availability

HCF40103BEY is available at Aetrix Electronics and suitable for microprocessor interrupt timing, divide-by-N frequency synthesis, synchronous cascading timers, and legacy industrial control sequencers requiring stable component supply across extended temperature and voltage ranges.

Supply support for HCF40103BEY 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.

HCF40103BEY belongs to the HCF4000B series of radiation-hardened, high-voltage CMOS logic devices engineered for reliability in harsh environments and long-lifecycle industrial systems.

FAQ

What is the minimum clock pulse width required for reliable operation at VDD = 15 V?

The minimum clock pulse width is 40 ns high and 40 ns low at VDD = 15 V, per the datasheet's t_W specification. This ensures sufficient setup/hold time for internal flip-flop triggering and prevents metastability during count transitions. Operating below this width risks skipped counts or erratic CO/ZD behavior.

Can HCF40103BEY be used with a 3.3 V supply?

No - the absolute minimum recommended VDD is 3 V, but DC specifications (VIH/VIL, VOH/VOL, I_OH/I_OL) are only guaranteed from 5 V onward. At 3.3 V, logic thresholds become undefined, output drive degrades significantly, and timing margins collapse. Use only within 5–20 V range for production designs.

How does the precedence between CLEAR, APE, and SPE work in practice?

CLEAR has unconditional priority: when low, it forces count to 255 regardless of APE/SPE state. APE overrides SPE - if APE is low, JAM data loads immediately, ignoring clock and SPE. SPE only takes effect when APE is high and a rising clock edge occurs. This hierarchy is hardwired in silicon and verified in the truth table.

Is there a recommended decoupling strategy for HCF40103BEY in high-noise industrial environments?

Place a 100 nF X7R ceramic capacitor between VDD and VSS within 5 mm of pins 16 and 8, plus a 10 µF tantalum or aluminum electrolytic capacitor at the board's main 15 V rail entry point. Ground planes must be solid under the DIP footprint, and clock traces should avoid routing parallel to CLEAR or APE lines to prevent coupling-induced false triggers.