NXP Semiconductors HEF4528BT/AUJ

Overview

HEF4528BT/AUJ from Nexperia is a dual retriggerable-resettable monostable multivibrator IC in SO16 package, operating from 3 V to 15 V supply, delivering programmable pulse widths via external R_EXT/C_EXT networks, with independent active-LOW clear inputs and complementary outputs per channel - used in timing control, debouncing, and pulse shaping circuits.

For engineers reviewing the HEF4528BT/AUJ datasheet, HEF4528BT/AUJ pinout, HEF4528BT/AUJ application, or HEF4528BT/AUJ equivalent, key selection considerations include its dual-channel retriggerable architecture, wide V_DD range (3–15 V), guaranteed operation from –40 °C to +85 °C, SO16 pin compatibility, and CMOS-level input/output thresholds defined per JEDEC JESD13-B.

Technical Context

The HEF4528BT/AUJ implements two independent monostable multivibrators, each triggered by either a HIGH-to-LOW transition on nA (with nB LOW) or a LOW-to-HIGH transition on nB (with nA HIGH), producing a single output pulse whose width is determined solely by external R_EXT and C_EXT components per channel.

Each section features an active-LOW direct clear (nCD) that forces nQ LOW and nQ HIGH while inhibiting further triggering until nCD returns HIGH; timing capacitor (nCEXT) connects to ground, while nREXT/CEXT serves as the shared node for R_EXT and C_EXT, enabling precise pulse-width tuning across voltage ranges.

Key Specifications

Pinout & Package

HEF4528BT/AUJ uses the SOT109-1 (SO16) plastic small outline package: 16-pin, 3.9 mm body width, 1.27 mm pitch, surface-mount compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD4528BE and 74HC4538D, the HEF4528BT/AUJ offers optimal balance of retriggerable functionality, industrial temperature support, and predictable pulse-width scaling - making it preferred for robust, maintainable timing in embedded control systems where design simplicity and long-term supply stability matter.

Availability

HEF4528BT/AUJ is available at Aetrix Electronics and suitable for industrial control panels, test equipment interfaces, and automotive body electronics requiring stable component supply, long-lifecycle assurance, and consistent parametric performance across voltage and temperature extremes.

Supply support for HEF4528BT/AUJ 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 efficiency technologies - delivering high-performance, reliable, and scalable logic, analog, and MOSFET solutions for industrial, automotive, and consumer markets.

The HEF4528BT/AUJ belongs to Nexperia's legacy CMOS logic family designed for robust, low-power timing functions in harsh environments - emphasizing wide supply tolerance, ESD resilience, and long-term manufacturability.

FAQ

What is the maximum recommended external timing resistor value for HEF4528BT/AUJ?

The HEF4528BT/AUJ datasheet specifies R_EXT up to 2 MΩ across all V_DD levels (5 V, 10 V, 15 V). Using resistors beyond this limit risks increased timing uncertainty due to leakage currents and reduced noise immunity. For stable operation at 15 V, keep R_EXT ≤ 2 MΩ and pair with C_EXT ≥ 15 pF to maintain pulse width accuracy within ±2% over temperature.

Can HEF4528BT/AUJ operate reliably at 3.3 V supply?

Yes, HEF4528BT/AUJ is fully specified down to 3 V per its Recommended Operating Conditions. At 3.3 V, VOH remains ≥ 3.25 V and VOL ≤ 0.05 V under light loads, meeting 3.3 V LVTTL thresholds. However, propagation delays increase (~280 ns max at CL = 50 pF), and pulse width accuracy degrades slightly - confirm timing margins in your specific application using the K = 0.42 formula.

How does the retriggerable behavior of HEF4528BT/AUJ differ from non-retriggerable monostables like the 74HC4538?

When triggered during an active output pulse, HEF4528BT/AUJ restarts the timing interval from the new edge - extending total output width. In contrast, 74HC4538 ignores subsequent triggers until the initial pulse completes. This makes HEF4528BT/AUJ ideal for applications like pushbutton hold detection or variable-pulse-width modulation where dynamic timing adjustment is required without external logic.

Is HEF4528BT/AUJ pin-compatible with older HEF4528BP (DIP-16) variants?

No - HEF4528BT/AUJ uses SOT109-1 (SO16) packaging with 1.27 mm pitch, while HEF4528BP uses SOT38-4 (DIP-16) with 2.54 mm pitch. Pin functions are identical (per datasheet Table 2), but physical layout, thermal characteristics, and soldering requirements differ. Board redesign is required for replacement; no drop-in substitution is possible.

What is the typical power consumption of HEF4528BT/AUJ at 5 V with no switching activity?

At V_DD = 5 V and Tamb = 25 °C, the HEF4528BT/AUJ draws ≤ 20 μA quiescent supply current (I_DD) with all inputs static and outputs unloaded. Dynamic power scales with switching frequency and load capacitance per PD = 4000 × f_i + Σ(f_o × C_L) × V_DD²; at 1 MHz toggle rate and 50 pF load, total PD ≈ 120 μW.