Nexperia USA Inc. 74HC4538PW,112

Overview

74HC4538PW,112 from Nexperia is a dual retriggerable-resettable precision monostable multivibrator in TSSOP16 package, operating from 2.0 V to 6.0 V over -40 °C to +125 °C. Each section features independent A/B edge-trigger inputs, active-low direct reset (nCD), complementary outputs (nQ/nQ), and external REXT/CEXT timing control. Output pulse width is precisely defined as TW = 0.7 × REXT × CEXT, with ±0.2 % typical variation over temperature-used in precision timing, pulse shaping, and debouncing circuits for industrial control interfaces.

For engineers reviewing the 74HC4538PW,112 datasheet, 74HC4538PW,112 pinout, 74HC4538PW,112 application, or 74HC4538PW,112 equivalent, key selection criteria include retriggerable monostable behavior, Schmitt-trigger input tolerance for slow edges, dual independent timing channels, guaranteed operation up to +125 °C, and compatibility with 2.0–6.0 V logic systems.

Technical Context

The device implements two fully independent CMOS monostable sections, each with dual-edge trigger capability (nA rising-edge, nB falling-edge) and asynchronous active-low reset (nCD). Pulse generation relies on external REXT and CEXT components connected to dedicated pins (nREXT/CEXT and nCEXT), enabling programmable pulse widths from ~100 ns to seconds. Linear design techniques ensure stable timing accuracy across voltage and temperature.

Schmitt-trigger inputs provide hysteresis for noise immunity and robust operation with slow-rising/falling signals. Input clamp diodes allow safe interfacing to voltages exceeding VCC when used with current-limiting resistors. The architecture supports retriggering during an active output pulse, extending duration without requiring full timeout completion.

Key Specifications

Pinout & Package

TSSOP16 plastic thin shrink small outline package (SOT403-1), 16-pin, body width 4.4 mm, lead pitch 0.65 mm, surface-mount compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HC4538PW,112, the SO16 variant offers better thermal performance in high-power scenarios but larger footprint, while the SN74LV4538AD trades temperature range and speed for lower-voltage compatibility-neither provides identical +125 °C retriggerable precision in TSSOP form factor.

Availability

74HC4538PW,112 is available at Aetrix Electronics and suitable for industrial automation, test equipment, and embedded control systems requiring stable component supply, long-term lifecycle support, and guaranteed TSSOP16 packaging.

Supply support for 74HC4538PW,112 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 global semiconductor expert delivering high-performance, reliable, and efficient discrete, logic, and MOSFET solutions for automotive, industrial, and consumer markets.

The 74HC4538 belongs to Nexperia's high-speed CMOS logic family, designed specifically for precision timing applications demanding retriggerable behavior, wide supply range, and robust operation across extended industrial temperatures.

FAQ

What is the minimum recommended value for REXT when using the 74HC4538PW,112?

The datasheet specifies REXT ≥ 2 kΩ at VCC = 5.0 V to ensure stable monostable operation and avoid excessive current draw through the timing network. Lower values may cause timing inaccuracies or increased power consumption due to leakage paths. For VCC = 2.0 V, the minimum is 10 kΩ per Figure 12 and Table 10.

Can the 74HC4538PW,112 generate asymmetric pulses using a single timing network?

No-the device generates symmetric pulse widths determined solely by REXT × CEXT per channel. Asymmetry requires external circuitry (e.g., diode-steered discharge paths) or cascading two monostables. The internal timing architecture does not support independent rise/fall time control or duty-cycle adjustment.

Is the 74HC4538PW,112 qualified for automotive applications?

No-it is specified for industrial temperature range (-40 °C to +125 °C) but is not AEC-Q200 qualified or automotive-grade screened. Nexperia explicitly states non-automotive qualification in Section 15 of the datasheet; use requires customer validation for safety-critical vehicle subsystems.

How does the 74HC4538PW,112 handle simultaneous trigger and reset events?

The direct reset (nCD) input has priority over trigger inputs: a LOW on nCD immediately terminates the output pulse regardless of concurrent nA/nB activity. This asynchronous reset behavior is confirmed in Section 6 (Functional description) and Figure 5 timing diagram, ensuring deterministic pulse abort under fault conditions.