Nexperia USA Inc. HEF4518BT,652

Overview

HEF4518BT,652 from Nexperia is a dual 4-bit internally synchronous BCD counter in SO16 package, operating from 3.0 V to 15.0 V supply, with Schmitt-trigger clock inputs (1CP0/2CP0 LOW-to-HIGH, 1CP1/2CP1 HIGH-to-LOW), asynchronous master reset (MR), and buffered Q0–Q3 outputs per counter. It enables multistage synchronous counting in industrial timing and digital control systems.

For engineers reviewing the HEF4518BT,652 datasheet, HEF4518BT,652 pinout, HEF4518BT,652 application, or HEF4518BT,652 equivalent, key selection considerations include dual independent BCD counting capability, wide-voltage CMOS operation, tolerance to slow clock edges, and compatibility with legacy 4000-series logic families in discrete timing and frequency division circuits.

Technical Context

The HEF4518BT,652 implements two identical 4-bit binary-coded decimal counters, each with fully static CMOS architecture and independent clock enable logic: CP0 advances on rising edge when CP1 is HIGH, while CP1 advances on falling edge when CP0 is LOW. This dual-edge-triggered mode allows flexible clock gating without external logic.

Each counter features asynchronous master reset (MR) that forces all four outputs (Q0–Q3) LOW regardless of clock state, and Schmitt-trigger inputs ensure reliable operation with rise/fall times up to 0.08 μs/V at 15 V. Outputs drive ±3.6 mA at 15 V with symmetrical VOH/VOL specifications across -40 °C to +85 °C.

Key Specifications

Pinout & Package

HEF4518BT,652 is housed in a plastic small outline package (SO16), SOT109-1, with 16 leads, 3.9 mm body width, and standard 1.27 mm lead pitch. Pin 1 is marked by a notch or dot; pin numbering follows counterclockwise convention from top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual BCD counter applications.

Compared with CD4518BE and 74HC390, HEF4518BT,652 uniquely combines synchronous dual-BDC operation, Schmitt-trigger clock inputs, and guaranteed 40 MHz max frequency at 15 V-making it the only choice for noise-prone, multi-stage synchronous timing where deterministic latency and edge tolerance are essential.

Availability

HEF4518BT,652 is available at Aetrix Electronics and suitable for industrial control panels, legacy system upgrades, and discrete digital timing circuits requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for HEF4518BT,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 leading Dutch semiconductor manufacturer specializing in high-performance, energy-efficient logic, analog, and discrete components for industrial, automotive, and consumer applications.

The HEF4518BT,652 belongs to Nexperia's legacy 4000-series logic family, designed specifically for robust, wide-supply-voltage digital timing functions in environments where reliability, noise immunity, and long-term availability are critical.

FAQ

Can HEF4518BT,652 operate reliably at 3.3 V?

No. The HEF4518BT,652 is specified for minimum 3.0 V operation, but its static characteristics (VIH/VIL thresholds) and dynamic performance (propagation delay, fmax) are only guaranteed at 5 V, 10 V, and 15 V per JEDEC JESD13-B. At 3.3 V, VIH exceeds 2.3 V and VOL rises above 0.4 V, risking interface failure with 3.3 V logic families. Use only within documented parametric ratings.

How is carry-out generated between the two counters?

The HEF4518BT,652 does not provide dedicated carry-out pins. To cascade counters, connect Q3 of the first counter to CP0 or CP1 of the second, depending on desired edge alignment. For synchronous operation, use external logic to detect count-9 (Q3=Q0=HIGH) and assert MR or clock enable on the next stage - the device itself performs only self-contained BCD counting per section.

What is the maximum capacitive load per output?

Each Q output is characterized up to 50 pF load capacitance (CL) in dynamic testing (Table 10). Exceeding this increases propagation delay nonlinearly - e.g., tPLH grows by 0.16 ns/pF at 15 V. For loads >50 pF, add a buffer stage or reduce clock frequency to maintain timing margin; no absolute damage threshold is specified beyond 50 pF in datasheet limits.

Is HEF4518BT,652 pin-compatible with CD4017?

No. The CD4017 is a 5-stage Johnson decade counter with decoded decimal outputs (0–9), while HEF4518BT,652 is a dual 4-bit binary-coded decimal counter with parallel Q0–Q3 outputs per section. Pin functions, count topology, and output encoding differ fundamentally - direct replacement would require complete PCB and firmware redesign.