STMicroelectronics M74HC590TTR

Overview

M74HC590TTR 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 output enable (G). It operates from 2V to 6V, delivers 61 MHz max clock frequency at 6V, and provides symmetrical 6 mA output drive (QA–QH) and 4 mA RCO drive. Used in digital timing and data capture systems requiring synchronized counting and latched parallel output.

For engineers reviewing the M74HC590TTR datasheet, M74HC590TTR pinout, M74HC590TTR application, or M74HC590TTR equivalent, key selection factors include its dual-clock architecture, 3-state output control, RCO cascading capability, -55°C to +125°C operating range, and TSSOP-16 package compatibility with high-density PCB layouts.

Technical Context

The M74HC590TTR integrates an 8-bit binary counter feeding an 8-bit storage register, both edge-triggered on positive clock transitions. Its counter has asynchronous clear (CCLR) and synchronous count-enable (CCKEN), while the register uses independent RCK for data capture - enabling precise separation of counting and latching phases.

RCO is active-low and generated as QA′·QB′·QC′·QD′·QE′·QF′·QG′·QH′, supporting seamless multi-stage counter expansion. All inputs include ESD protection, and output enable (G) controls full 3-state operation across QA–QH, allowing bus-sharing in shared-data-path systems.

Key Specifications

Pinout & Package

TSSOP-16 package: 4.9 mm × 6.4 mm body, 0.65 mm pitch, 1.2 mm height, lead-free and RoHS-compliant.

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 74AC590SCX, the M74HC590TTR uniquely balances high speed (61 MHz), ultra-low quiescent current (4 µA), and TSSOP-16 packaging - making it optimal for space-constrained, thermally demanding, and power-sensitive industrial counting applications.

Availability

M74HC590TTR is available at Aetrix Electronics and suitable for industrial PLC modules, automotive transmission controllers, energy metering systems, and test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for M74HC590TTR 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, specializing in automotive, industrial, and power management ICs with broad analog, digital, and embedded processing portfolios.

The M74HC590TTR belongs to ST's high-speed CMOS logic family, designed specifically for robust, low-power digital counting and data registration in harsh-environment industrial and automotive control systems.

FAQ

What is the function of the RCO pin, and how is it used in multi-stage counting?

RCO is the ripple-carry output, active-low, defined as QA′·QB′·QC′·QD′·QE′·QF′·QG′·QH′ - it asserts when the counter reaches 0xFF. In multi-stage setups, RCO from one M74HC590TTR connects to CCKEN of the next stage, enabling automatic carry propagation and seamless 16-bit or wider counting without external combinational logic.

Can the counter and register clocks be tied together, and what is the timing consequence?

Yes, CCK and RCK may be connected, but doing so causes the register to always hold the previous count - i.e., the counter advances one step ahead of the latched value. This occurs because both are positive-edge-triggered and the register captures the counter's prior state before the new count propagates fully, resulting in a fixed one-cycle pipeline delay.

How does the G (output enable) pin interact with the 3-state outputs during power-up or reset?

The G pin is not internally pulled - it must be actively driven low to enable QA–QH outputs. During power-up, if G is left floating or high, all outputs remain in high-impedance state, preventing bus contention. No internal power-on reset affects G; external circuitry must ensure valid logic level before first register clock.

Is the M74HC590TTR compatible with 3.3 V logic systems, and what are the drive limitations?

Yes - with VCC = 3.3 V, VOH ≥ 3.15 V (min) and VOL ≤ 0.33 V (max) at 6 mA load, meeting 3.3 V LVTTL and most 3.3 V CMOS input thresholds. However, RCO output drive is limited to ±4 mA, so avoid driving heavy capacitive loads or long traces directly from RCO without buffering.