STMicroelectronics HCF4035BEY

Overview

HCF4035BEY from STMicroelectronics is a 4-stage CMOS parallel-in/parallel-out shift register with synchronous parallel entry, serial D/JK input on Stage 1, asynchronous true/complement output control, master-slave flip-flop architecture, and buffered I/O. It operates from 3V to 20V, delivers 12 MHz typical clock frequency at VDD = 10 V, and supports industrial temperature range (–55°C to +125°C). Used in binary-to-BCD conversion and bidirectional sequence generation.

For engineers reviewing the HCF4035BEY datasheet, HCF4035BEY pinout, HCF4035BEY application, or HCF4035BEY equivalent, key selection criteria include its dual-mode (serial/parallel) data loading, asynchronous output polarity control, JK-enabled first-stage flexibility for counter design, and guaranteed operation up to 20 V supply with <100 nA input leakage at 18 V.

Technical Context

The HCF4035BEY implements four cascaded master-slave D-type flip-flops with independent parallel load capability per stage and serial shift path enabled via J/K logic on the first stage. Its asynchronous TRUE/COMPLEMENT (T/C) input directly inverts all four outputs without clock dependency, enabling real-time output polarity switching.

Operation is strictly edge-triggered on positive clock transitions for both parallel load and serial shift modes, controlled by the P/S (Pin 7) signal. The common asynchronous RESET (Pin 5) forces all stages low independently of clock or mode control, supporting deterministic initialization in timing-critical systems.

Key Specifications

Pinout & Package

Package: 16-pin plastic DIP (Dual In-line Package), 0.3-inch body width, standard through-hole mounting compatible with MIL-STD-883 and JEDEC MS-001.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-bit parallel-load shift register applications.

Compared with CD4035BE and MC14035BDR2G, the HCF4035BEY offers balanced drive capability (±1.1 mA), verified 20 V absolute max rating, and ST's industrial-grade screening-making it optimal for high-reliability, wide-supply applications where robustness trumps marginal speed gain.

Availability

HCF4035BEY is available at Aetrix Electronics and suitable for industrial control logic, legacy system interface adapters, binary-to-BCD conversion, and bidirectional sequence generation requiring stable component supply across extended temperature and voltage ranges.

Supply support for HCF4035BEY 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management solutions with broad analog, digital, and mixed-signal product portfolios.

The HCF4035BEY belongs to ST's legacy B-series CMOS logic family, designed specifically for robust, wide-voltage-range digital control functions in harsh environments where reliability and long-term availability are critical.

FAQ

What is the maximum clock frequency supported by the HCF4035BEY at 5 V supply?

The HCF4035BEY supports a maximum clock frequency of 4 MHz at VDD = 5 V, as specified in the Dynamic Electrical Characteristics table (fMAX = 2–4 MHz range, typ. 4 MHz). This value is validated under CL = 50 pF and Tamb = 25°C, with propagation delays scaling inversely with supply voltage.

Can the HCF4035BEY operate with a 3.3 V supply?

Yes - the HCF4035BEY is rated for VDD = 3 V minimum per Recommended Operating Conditions. At 3.3 V, it meets all DC specifications including VIH ≥ 2.0 V and VOL ≤ 0.1 V, though clock frequency drops to ~2.5 MHz typical and output drive reduces to ±0.5 mA. Full functionality is preserved.

Is the RESET input active-high or active-low?

The RESET input (Pin 5) is active-low: applying a logic low to this pin asynchronously forces all Q outputs to logic low, regardless of clock, P/S, or T/C states. The input is CMOS-compatible with VIH ≥ 70% VDD and VIL ≤ 30% VDD across the full supply range.

Does the HCF4035BEY support hot insertion or live-state changes on the T/C pin?

Yes - the TRUE/COMPLEMENT (T/C) input (Pin 2) operates asynchronously and is fully functional during active clocking. Changing T/C state mid-operation instantly inverts all Q/Q outputs without disrupting register contents or requiring clock synchronization, enabling dynamic polarity switching in real-time control loops.