STMicroelectronics HCF4538M013TR

Overview

HCF4538M013TR from STMicroelectronics is a dual retriggerable/resettable monostable multivibrator IC in SO-16 package, operating from 3 V to 20 V supply, delivering precise pulse widths (57 µs to 1.07 s) via external RX/CX networks, with independent trigger and reset propagation delays (as low as 100 ns at 15 V), and buffered Q/Q̅ outputs-used in timing control, pulse shaping, and debounce circuits for industrial PLC modules.

For engineers reviewing the HCF4538M013TR datasheet, HCF4538M013TR pinout, HCF4538M013TR application, or HCF4538M013TR equivalent, key selection criteria include edge-triggering flexibility (+TR/-TR), Schmitt-trigger input tolerance for slow signals, guaranteed quiescent current up to 20 V, and dual-section independence for asynchronous timing functions.

Technical Context

The HCF4538M013TR implements two independent CMOS monostable sections, each supporting leading-edge (+TR) or trailing-edge (-TR) triggering with Schmitt-trigger inputs enabling unlimited rise/fall time immunity. Each section features separate active-low RESET inputs and buffered complementary Q/Q̅ outputs.

Timing is externally set by RX and CX, with T = RX × CX; minimum RX = 4 kΩ, CX range = 5 nF to 100 µF. Trigger and reset propagation delays are independent of RX/CX values and scale inversely with VDD (e.g., tPLH = 100–200 ns at 15 V).

Key Specifications

Pinout & Package

SO-16 surface-mount package (JEDEC MO-136, 9.8 × 5.9 mm body, 1.27 mm pitch), compliant with RoHS and rated for -55 °C to +125 °C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual monostable multivibrator applications.

Compared with CD4538BE and 74HC4538D, the HCF4538M013TR uniquely combines wide-voltage operation (3–20 V), Schmitt-triggered inputs for noise immunity, and SO-16 packaging for space-constrained industrial PCBs - making it optimal for ruggedized timing where reliability trumps raw speed.

Availability

HCF4538M013TR is available at Aetrix Electronics and suitable for industrial timer modules, motor control debounce circuits, power sequencing controllers, and test equipment pulse generators requiring stable component supply across extended temperature and voltage ranges.

Supply support for HCF4538M013TR 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, designing and manufacturing microcontrollers, power management ICs, sensors, and analog/mixed-signal devices for industrial, automotive, and consumer markets.

The HCF4538B series belongs to ST's legacy high-voltage CMOS logic family, engineered specifically for precision timing in harsh environments where wide supply range, noise immunity, and long-term stability are critical - not general-purpose logic replacement.

FAQ

What is the minimum external resistor value for stable timing with HCF4538M013TR?

The minimum external resistor (RX) is 4 kΩ, as specified in the datasheet. Using lower values risks excessive current draw through the internal discharge transistor, causing timing inaccuracy and potential thermal stress. At VDD = 20 V, 4 kΩ yields ~5 mA peak discharge current - within safe SO-16 package limits.

Can unused trigger inputs be left floating?

No. Unused +TR inputs must be tied to VSS; unused -TR inputs must be tied to VDD. Floating inputs cause unpredictable Schmitt-trigger behavior and increased quiescent current due to internal node oscillation. This requirement is explicitly stated in the functional terminal table and verified in application note AN2277.

How does temperature affect output pulse width accuracy?

Pulse width exhibits a typical temperature coefficient of 0.3 %/°C, as confirmed in dynamic electrical characteristics. Over -55 °C to +125 °C, total drift is ±4.5 % relative to 25 °C value. For high-accuracy applications, use NP0/C0G capacitors and metal-film resistors to minimize passive component drift contribution.

Is HCF4538M013TR pin-compatible with CD4538 variants?

Yes - HCF4538M013TR shares identical pinout and logic function with CD4538BE (DIP) and CD4538BM (SO-16). All variants follow the same JEDEC pin numbering: VDD (16), VSS (8), dual-section I/O arranged symmetrically. No PCB redesign is needed when migrating from CD4538BM to HCF4538M013TR.