NXP Semiconductors HEF4557BT,652

Overview

HEF4557BT,652 from Nexperia is a static 1-to-64-bit programmable-length serial shift register with dual data inputs (DA/DB), asynchronous master reset (MR), and dual-edge clocking (CP0/CP1). It operates from 3 V to 15 V over −40 °C to +85 °C and supports recirculation via A/B select. Used in industrial control logic, legacy bus interface buffering, and configurable timing delay chains.

For engineers reviewing the HEF4557BT,652 datasheet, HEF4557BT,652 pinout, HEF4557BT,652 application, or HEF4557BT,652 equivalent, key selection criteria include variable bit-length configuration (1–64 bits), dual-clock edge sensitivity, wide supply voltage range (3–15 V), and SO16 package compatibility with legacy CMOS systems.

Technical Context

This device implements a fully static, cascaded 64-stage shift register with length controlled by six binary-weighted inputs (L1–L32), where register length = Σ(enabled L_n) + 1. Data shifts right on either CP0↑ (with CP1 low) or CP1↓ (with CP0 high), enabling flexible clock domain interfacing.

It features complementary buffered outputs (Q and Q̅), rail-to-rail input thresholds (VIH/VIL scalable with VDD), and guaranteed operation across 3 V, 10 V, and 15 V parametric ratings. The MR input forces Q = LOW and Q̅ = HIGH asynchronously, independent of clock state.

Key Specifications

Pinout & Package

HEF4557BT,652 is housed in a plastic small outline package (SO16), SOT109-1, with 16 leads and 3.9 mm body width. Pin pitch is 1.27 mm; package is RoHS-compliant and suitable for reflow soldering.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar programmable-length shift register applications.

Compared with CD4015BE and 74HC165, HEF4557BT,652 uniquely supports hardware-programmable length (1–64 bits), dual-edge clocking, and recirculation-making it irreplaceable in adaptive delay, protocol bridging, and legacy system retrofit scenarios where fixed-length alternatives introduce design constraints.

Availability

HEF4557BT,652 is available at Aetrix Electronics and suitable for industrial bus interface, legacy system timing delay, and recirculating data buffer applications requiring stable component supply across extended temperature and voltage ranges.

Supply support for HEF4557BT,652 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 logic, discrete, and MOSFET solutions for industrial, automotive, and consumer markets.

HEF4557BT,652 belongs to Nexperia's HEF4000B series of high-voltage CMOS logic devices, engineered for robust operation in legacy and mixed-voltage industrial control systems where wide supply tolerance and static functionality are essential.

FAQ

What is the minimum clock pulse width required for reliable operation?

At 15 V, the minimum CP0 LOW pulse width is 20 ns and CP1 HIGH pulse width is 20 ns per datasheet Table 8. These values scale inversely with VDD: 90 ns at 5 V, 30 ns at 10 V. Pulse widths below these cause metastability or skipped shifts.

How does the A/B select input affect data flow during shifting?

A/B selects the active data source: A/B = LOW routes DA to the first register stage; A/B = HIGH routes DB. This occurs before each shift event, enabling dynamic input switching mid-operation without interrupting the clock sequence.

Can unused length control inputs (e.g., L32) be left floating?

No. All unused inputs-including L1–L32, A/B, DA, DB, CP0, CP1, and MR-must be tied to VDD, VSS, or a defined logic level. Floating inputs risk unintended bit-length configuration, increased ICC, or oscillation due to CMOS input threshold uncertainty.

Is HEF4557BT,652 suitable for automotive applications?

No. HEF4557BT,652 is not automotive-qualified. It is specified for −40 °C to +85 °C industrial operation only and lacks AEC-Q100 qualification, automotive-grade screening, or extended lifetime validation required for vehicle systems.