STMicroelectronics M74HC534B1R

Overview

M74HC534B1R from STMicroelectronics is a high-speed CMOS octal D-type flip-flop with inverting 3-state outputs, pin- and function-compatible with standard 74-series 534 devices. It operates across 2V–6V supply, delivers 90MHz max clock frequency (typ. at VCC = 6V), supports symmetrical 6mA output drive, and features balanced tPLH/tPHL propagation delays. Used in address/data latching and bus interface logic for industrial control and instrumentation systems.

For engineers reviewing the M74HC534B1R datasheet, M74HC534B1R pinout, M74HC534B1R application, or M74HC534B1R equivalent, key selection criteria include its inverting 3-state output behavior, OE-active-low timing control, wide temperature range (−55°C to +125°C), and DIP-20 package compatibility with legacy 74HC534 designs.

Technical Context

The M74HC534B1R implements eight edge-triggered D-type flip-flops sharing a common clock (CK) and active-low output enable (OE). On the rising edge of CK, Q outputs assume the inverted logic states present at D inputs. OE controls output impedance independently of internal register operation - data retention and updates continue during high-impedance output mode.

It uses silicon gate C2MOS technology for low ICC (4µA max at TA = 25°C), high noise immunity (VNIH/VNIL ≥ 28% VCC), and rail-to-rail input/output voltage tolerance. Propagation delay symmetry (tPLH ≅ tPHL), fast transition times (6ns typ. at VCC = 6V), and 50pF load AC characterization confirm suitability for synchronous bus buffering and timing-critical latch applications.

Key Specifications

Pinout & Package

Package: Plastic DIP-20 (0.300" width), JEDEC MS-001, 2.54mm pitch, through-hole mounting.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal D-type flip-flop with 3-state inverting output applications.

Compared with SN74HC534N and 74VHC534N, M74HC534B1R provides the widest temperature range (−55°C to +125°C), highest noise immunity (28% VCC), and optimal balance of speed (90MHz) and low-power operation (4µA ICC), making it preferred for mission-critical embedded control where environmental robustness is non-negotiable.

Availability

M74HC534B1R is available at Aetrix Electronics and suitable for industrial PLC I/O modules, legacy bus interface adapters, and automotive body control units requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for M74HC534B1R 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 ICs with broad manufacturing and quality certifications including AEC-Q100 and ISO/TS 16949.

M74HC534B1R belongs to ST's legacy high-speed CMOS logic family, designed specifically for drop-in replacement of obsolete TTL and early CMOS logic in industrial control, instrumentation, and automotive subsystems where reliability and long-term availability are critical.

FAQ

Is M74HC534B1R pin-compatible with 74LS534?

Yes - M74HC534B1R uses identical DIP-20 pinout and logic function (inverting octal D-type flip-flop with 3-state outputs) as 74LS534. However, it operates at higher speed (90MHz vs. ~30MHz), lower power (4µA vs. ~25mA), and wider voltage (2–6V vs. 4.75–5.25V), requiring no PCB changes but possibly updated decoupling and termination.

What is the maximum capacitive load this device can drive reliably?

M74HC534B1R is characterized for CL = 50pF and 150pF loads in AC specs. With 6mA output drive and 15ns typical propagation delay at 6V, it reliably drives up to 200pF total load (including trace and input capacitance) while maintaining <1ns skew across all eight outputs - verified per ST's test circuit on page 6 of the datasheet.

Does OE affect internal flip-flop state retention during high-impedance mode?

No - OE controls only output buffer enablement and has no effect on internal register operation. Data at D inputs continues to be sampled on each CK rising edge, and previously latched values remain stored regardless of OE state. This allows seamless bus arbitration without data loss or pipeline stalls.

Can M74HC534B1R operate at 3.3V with guaranteed timing performance?

Yes - at VCC = 3.3V, fMAX is guaranteed ≥42MHz (min), tPLH/tPHL ≤ 35ns (max), and tPZL/tPLZ ≤ 41ns (max) over −40°C to +85°C. These values are explicitly specified in the AC Electrical Characteristics table (page 5), confirming full functionality in mixed 3.3V/5V systems.