STMicroelectronics M74HC390RM13TR

Overview

M74HC390RM13TR from STMicroelectronics is a high-speed CMOS dual decade counter with two independent ripple-carry counters-each comprising a divide-by-2 and divide-by-5 stage-operating across 2V–6V supply, delivering 79MHz max clock frequency at 6V, 4µA max quiescent current at 25°C, and negative-edge-triggered clock inputs for BCD or bi-quinary counting in timing and frequency-division circuits.

For engineers reviewing the M74HC390RM13TR datasheet, M74HC390RM13TR pinout, M74HC390RM13TR application, or M74HC390RM13TR equivalent, this device supports precise asynchronous reset, balanced propagation delays (tPLH ≅ tPHL), wide temperature operation (−55°C to +125°C), and pin/function compatibility with legacy 74-series 390 logic for drop-in replacement in industrial control, instrumentation, and digital clocking systems.

Technical Context

The M74HC390RM13TR implements two cascaded 4-bit binary counters per section: one triggered by CLOCK A (divide-by-2) and the other by CLOCK B (divide-by-5), enabling configurable BCD (0–9) or bi-quinary outputs. Each section features independent asynchronous CLEAR inputs that force all Q outputs low on active-low assertion.

Its silicon gate C2MOS process ensures high noise immunity (VNIH/VNIL ≥ 28% VCC), low power consumption, and rail-to-rail output swing. Propagation delays are tightly matched (e.g., tPLH/tPHL = 12/13 ns typical at 6V), and input rise/fall time limits are specified per supply voltage (400 ns max at 6V), supporting reliable edge-sensitive operation in mixed-signal timing chains.

Key Specifications

Pinout & Package

SO-16 surface-mount package (JEDEC MS-012, 3.9mm width), 1.27 mm pitch, lead-free ECOPACK® compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC390N and CD74HC390E, the M74HC390RM13TR offers superior high-frequency performance (79 MHz), lowest quiescent current (4 µA), and certified lead-free packaging-making it optimal for space-constrained, thermally demanding, and energy-sensitive SMT deployments.

Availability

M74HC390RM13TR is available at Aetrix Electronics and suitable for industrial control panels, digital instrumentation, and embedded timing modules requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for M74HC390RM13TR 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, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The M74HC390 belongs to ST's high-speed HC logic family, engineered for pin-compatible upgrades of legacy 74-series devices while delivering enhanced speed, noise immunity, and power efficiency in industrial timing and control systems.

FAQ

What clock edge does the M74HC390RM13TR respond to?

The M74HC390RM13TR triggers on the high-to-low (negative) transition of both CLOCK A and CLOCK B inputs. This edge sensitivity is hardwired in the silicon gate C2MOS design and cannot be configured. All counter stages advance synchronously with each detected falling edge, ensuring deterministic ripple-carry behavior across both decade sections.

Can the two counters operate at different clock frequencies?

Yes-CLOCK A and CLOCK B inputs are fully independent per counter section, allowing Counter 1 and Counter 2 to accept asynchronous clock signals of differing frequencies and phases. The only constraint is that each clock must meet minimum pulse width requirements (e.g., 5 ns high/low time at 6V) to guarantee reliable state transitions and avoid metastability.

Is the M74HC390RM13TR functionally identical to the obsolete M74HC390B1R?

No-the M74HC390B1R uses a DIP-14 package and lacks the second set of Q outputs (2QA–2QD) and associated CLOCK B pins. The RM13TR is a full dual-counter variant in SO-16, whereas the B1R is a single-decade version. They are not pin- or function-compatible; RM13TR supersedes earlier partial-function variants in modern SMT designs.

Does the CLEAR input affect both counters simultaneously?

Each CLEAR pin (pins 2 and 14) controls only its associated counter: pin 2 clears Counter 1 (1QA–1QD), and pin 14 clears Counter 2 (2QA–2QD). This independence allows selective reset of one decade channel without disturbing the other-critical for multi-stage timing sequences where partial restart is required, such as in programmable interval generators.