STMicroelectronics M74HC590B1R

Overview

M74HC590B1R from STMicroelectronics is a high-speed CMOS 8-bit binary counter register with 3-state outputs, featuring separate counter and register clocks, ripple-carry output (RCO), and asynchronous clear (CCLR). It operates from 2V to 6V, delivers 61 MHz max clock frequency at 6V, and supports cascading via RCO–CCKEN chaining. Used in digital timing control, address sequencing, and data capture in industrial logic systems.

For engineers reviewing the M74HC590B1R datasheet, M74HC590B1R pinout, M74HC590B1R application, or M74HC590B1R equivalent, key selection criteria include its dual-clock architecture, 3-state output enable (G), RCO propagation delay (16–43 ns), symmetrical drive strength (±6 mA for QA–QH), and wide temperature range (–55°C to +125°C).

Technical Context

The M74HC590B1R implements an 8-bit binary counter feeding an independent 8-bit storage register, both edge-triggered on rising clock edges. Its CCK and RCK inputs are functionally isolated - enabling precise staging of count vs. latch operations without internal synchronization constraints.

It features a dedicated ripple-carry output (RCO) generated as the logical AND of all eight internal counter bit complements (QA′·QB′·…·QH′), supporting synchronous or asynchronous cascading. The 3-state output enable (G) controls QA–QH only; RCO remains active regardless of G state.

Key Specifications

Pinout & Package

DIP-16 package (0.300" width), JEDEC MS-001 compliant, through-hole mountable with 2.54 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit binary counter register applications.

Compared with SN74HC590N and CD74HC590E, the M74HC590B1R offers broader temperature qualification (–55°C to +125°C), tighter propagation delay consistency (14–37 ns vs. up to 50 ns), and guaranteed 61 MHz operation - making it optimal for mission-critical industrial and automotive timing functions.

Availability

M74HC590B1R is available at Aetrix Electronics and suitable for industrial PLC timing modules, motor control position counting, and legacy bus address generation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for M74HC590B1R 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, power, and microcontroller solutions with vertical manufacturing and broad IP portfolio.

The M74HC590B1R belongs to ST's legacy HC logic family, designed for drop-in compatibility with 74-series TTL while delivering CMOS power efficiency and enhanced noise immunity for industrial control and instrumentation.

FAQ

Can M74HC590B1R operate reliably at 3.3 V?

Yes - the device is fully specified from 2 V to 6 V, including 3.3 V operation. At VCC = 3.3 V, VOH is guaranteed ≥3.15 V (VIH threshold), VOL ≤0.26 V, and fMAX reaches ~33 MHz. All DC and AC parameters in the datasheet include 3.3 V test conditions, confirming robust interoperability with 3.3 V microcontrollers and FPGAs.

What happens to QA–QH outputs when G = HIGH?

When G = HIGH (active-low enable), QA–QH enter high-impedance (Hi-Z) state - electrically disconnecting them from the bus. Internal register and counter states remain fully preserved. This allows safe bus sharing without external tri-state buffers. RCO output remains active and unaffected by G state.

Is the RCO output synchronized to CCK or RCK?

RCO is synchronized to CCK - it changes only on the rising edge of CCK, reflecting the internal counter state after that edge. It is not gated by RCK or G. This makes RCO suitable for cascading counters or generating clock-enable signals for downstream stages, independent of register latching timing.

How does CCKEN interact with CCLR?

CCKEN is ignored during CCLR assertion: when CCLR = LOW, the counter resets to zero immediately, regardless of CCKEN state or CCK edges. CCKEN only gates CCK when CCLR = HIGH. This priority ensures deterministic reset behavior - critical for fault recovery in safety-related logic circuits.