Nexperia USA Inc. HEF4021BT-Q100J

Overview

HEF4021BT-Q100 from Nexperia is an AEC-Q100 Grade 1 qualified 8-bit static shift register (parallel-to-serial converter) with synchronous serial input (DS), asynchronous parallel load (PL), and buffered Q5–Q7 outputs. It operates from 3 V to 15 V, features Schmitt-trigger clock input for noise immunity, and supports automotive ambient temperatures up to +125 °C. Used in body control modules for LED multiplexing and sensor data serialization.

For engineers reviewing the HEF4021BT-Q100 datasheet, HEF4021BT-Q100 pinout, HEF4021BT-Q100 application, or HEF4021BT-Q100 equivalent, key selection criteria include parallel-load timing (tW ≥ 24 ns at 15 V), propagation delay (tPHL ≤ 80 ns at 15 V), output drive capability (IOL = 2.4 mA at VO = 1.5 V), and SO16 package compatibility with legacy 4000-series PCB footprints.

Technical Context

This device implements an 8-stage D-type master-slave flip-flop architecture with independent SD/CD direct set/clear per stage. Parallel loading occurs asynchronously when PL is HIGH, overriding clock and serial input - enabling immediate state capture from microcontroller GPIOs or sensor buses.

Serial shifting is edge-triggered on the LOW-to-HIGH transition of CP, with Schmitt-trigger input ensuring reliable operation despite slow-rising clock signals (Δt/ΔV down to 0.08 μs/V at 15 V). Output buffering on Q5–Q7 provides fan-out capability while maintaining CMOS-level voltage thresholds across -40 °C to +125 °C.

Key Specifications

Pinout & Package

HEF4021BT-Q100 is housed in a plastic small outline package (SO16), SOT109-1, with 16 leads and 3.9 mm body width. Pin 1 index is marked by a bevelled corner or notch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit parallel-to-serial shift register applications.

Compared with SN74HC165QPWRQ1 and 74LVC164APWJ, HEF4021BT-Q100 uniquely combines wide-voltage operation, true asynchronous parallel load, Schmitt-trigger clock tolerance, and automotive qualification - making it the sole option for mixed-supply, noise-prone, and safety-critical shift-register functions.

Availability

HEF4021BT-Q100 is available at Aetrix Electronics and suitable for automotive body control modules, instrument cluster diagnostics, LED matrix displays, and power distribution unit monitoring requiring stable component supply across extended temperature ranges.

Supply support for HEF4021BT-Q100 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 logic, discrete, and MOSFET solutions optimized for automotive, industrial, and mobile applications with emphasis on reliability and efficiency.

The HEF4021B-Q100 belongs to Nexperia's automotive-qualified 4000-series logic family, designed specifically to replace legacy CD4021 devices in harsh-environment applications demanding AEC-Q100 compliance and extended temperature operation.

FAQ

What is the minimum pulse width required for the PL input?

The minimum high-time pulse width (tW) for PL is 24 ns at VDD = 15 V and Tamb = +125 °C, as specified in Table 7. This ensures reliable asynchronous capture of all eight parallel inputs without metastability. At lower voltages or temperatures, the requirement relaxes to 35 ns (10 V) or 70 ns (5 V), allowing firmware to use fixed-delay loops without dynamic adjustment.

Can unused inputs be left floating?

No - all unused inputs must be connected to VDD, VSS, or another driven input, per Section 1 of the datasheet. Floating CMOS inputs cause increased supply current, unpredictable logic states, and potential latch-up due to internal parasitic paths. This requirement applies to DS, CP, PL, and all D0–D7 pins not actively used in the design.

Does the device support hot insertion or live swapping?

No - the HEF4021BT-Q100 lacks Ioff protection or power-off isolation circuitry. Applying VDD before VSS, or inserting the device while power is applied, risks exceeding absolute maximum ratings (e.g., VI > VDD + 0.5 V), potentially damaging input clamping diodes. Board-level hot-swap controllers or sequencing circuits are required for such use cases.

How does the Schmitt-trigger clock input improve system robustness?

The Schmitt-trigger on CP provides ~1.5 V hysteresis (typical), rejecting noise spikes and slow-rising signals common in automotive environments. This eliminates false clocking from alternator ripple, relay switching transients, or long PCB traces, ensuring deterministic single-bit advancement per valid edge - critical for accurate LED sequencing and fault logging.