Nexperia USA Inc. 74HC4538PW,118

Overview

74HC4538PW,118 from Nexperia is a dual retriggerable-resettable precision monostable multivibrator in TSSOP16 package, operating from 2.0 V to 6.0 V supply, delivering ±0.2 % pulse width stability over -40 °C to +125 °C, with output pulse width defined by external REXT and CEXT (TW = 0.7 × REXT × CEXT), used for timing control in industrial logic systems and digital signal conditioning.

For engineers reviewing the 74HC4538PW,118 datasheet, 74HC4538PW,118 pinout, 74HC4538PW,118 application, or 74HC4538PW,118 equivalent, key selection criteria include retriggerable monostable behavior, Schmitt-trigger input tolerance, dual independent timing channels, direct active-LOW reset per channel, and precise external RC-based pulse width control across extended temperature range.

Technical Context

The device implements two independent monostable circuits, each with dual edge-trigger inputs (nA rising-edge, nB falling-edge), separate active-LOW direct reset (nCD), and complementary outputs (nQ/nQ). Pulse generation relies on external REXT/CEXT network connected to dedicated pins (nREXT/CEXT and nCEXT), enabling programmable timing without internal oscillators.

Each monostable features linear design techniques ensuring stable pulse width accuracy, Schmitt-trigger action at all inputs for robust noise immunity and slow-edge tolerance, and clamp diodes allowing interface to voltages exceeding VCC via current-limiting resistors.

Key Specifications

Pinout & Package

TSSOP16 plastic thin shrink small outline package (SOT403-1); 16 leads; body width 4.4 mm; lead pitch 0.65 mm; RoHS-compliant surface-mount package optimized for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HC4538D,118, the 74HC4538PW,118 offers superior board-area efficiency and finer thermal control in compact designs; versus SN74LVC1G123DBVR, it delivers dual-channel retriggerable precision timing with full external RC configurability-making it irreplaceable for adaptive, multi-event timing architectures.

Availability

74HC4538PW,118 is available at Aetrix Electronics and suitable for industrial motor control timing, digital signal glitch filtering, precision pulse width modulation, and legacy system logic interface requiring stable component supply across extended temperature ranges.

Supply support for 74HC4538PW,118 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 focused on essential semiconductors for automotive, industrial, computing, consumer, and communications markets, delivering high-performance, reliable, and efficient components.

The 74HC4538 belongs to Nexperia's HC logic family-designed for robust, low-power, wide-supply-voltage digital timing and signal conditioning in harsh industrial and automotive-adjacent environments.

FAQ

What is the minimum and maximum value for REXT and CEXT to ensure stable operation?

The datasheet specifies REXT from 2 kΩ to 1000 kΩ and no limits on CEXT value. Stable operation requires CEXT ≥ 100 pF for reliable triggering and reduced sensitivity to stray capacitance. For optimal accuracy, use CEXT ≥ 1 nF and REXT between 10 kΩ and 100 kΩ-verified across -40 °C to +125 °C with <±0.2 % variation. Values outside this range increase timing error due to leakage and parasitic effects.

Can both monostables be triggered simultaneously without interference?

Yes-each monostable operates independently with fully isolated timing paths, inputs, and outputs. Simultaneous triggering of Channel 1 (pins 1A/1B) and Channel 2 (pins 11A/12B) produces concurrent, non-interacting output pulses. No shared internal nodes or timing resources exist between channels, and cross-talk is suppressed by CMOS isolation and layout design verified per JEDEC JESD78 latch-up testing (>100 mA).

How does the device behave during power-down when CEXT holds charge?

During rapid VCC collapse, stored energy in CEXT can discharge through input protection diodes, risking latch-up or damage. Nexperia recommends adding a damping diode (e.g., Schottky BAT54) between nREXT/CEXT and GND, as shown in Figure 10 of the datasheet. This path safely bleeds CEXT charge without stressing internal clamps, preserving reliability in systems with uncontrolled power sequencing.

Is the 74HC4538PW,118 qualified for automotive applications?

No-the 74HC4538PW,118 is not automotive-qualified. It is specified for industrial temperature range (-40 °C to +125 °C) but lacks AEC-Q100 qualification, automotive-grade screening, or guaranteed PPAP documentation. For automotive use, Nexperia offers separate AEC-Q100 qualified variants (e.g., 74HC4538PW-Q100), which undergo additional stress testing and lot traceability not present in the standard 74HC4538PW,118.