STMicroelectronics M74HC393TTR

Overview

M74HC393TTR from STMicroelectronics is a high-speed CMOS dual 4-bit binary ripple counter with independent negative-edge-triggered clock inputs and asynchronous clear. It operates from 2V to 6V, delivers 79 MHz max clock frequency at 6V, and features symmetrical 4 mA output drive. Used in digital timing, frequency division, and address sequencing where low-power, edge-triggered counting is required.

For engineers reviewing the M74HC393TTR datasheet, M74HC393TTR pinout, M74HC393TTR application, or M74HC393TTR equivalent, key selection criteria include dual independent counter sections, TSSOP-14 package compatibility, negative-edge clocking, asynchronous reset behavior, and guaranteed 4 mA output drive across full voltage range.

Technical Context

The M74HC393TTR integrates two electrically isolated 4-bit ripple-carry binary counters, each triggered on the falling edge of its dedicated clock input (CLK1, CLK2). Clear inputs (CLR1, CLR2) are active-low and asynchronous, forcing all Q outputs low regardless of clock state.

Each counter section provides four buffered complementary outputs (QA–QD), with propagation delays balanced between tPLH and tPHL (e.g., 20 ns typ. at VCC = 6V for CLOCK→QA). The device uses silicon gate C2MOS technology, enabling high noise immunity (28% VCC min. VIH/VIL hysteresis) and ultra-low quiescent current (4 µA max. at 25°C).

Key Specifications

Pinout & Package

TSSOP-14 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 dual binary counter applications.

Compared with SN74HC393DR and 74LV393PW, the M74HC393TTR offers optimal thermal performance in space-constrained TSSOP-14 layouts, maintains full 2–6 V compatibility without level-shifting, and delivers consistent 4 mA drive strength across its entire voltage range-making it ideal for industrial modules requiring long-term reliability and compact packaging.

Availability

M74HC393TTR is available at Aetrix Electronics and suitable for industrial timer modules, digital panel meters, motor phase sequencers, and legacy bus address decoders requiring stable component supply and long-lifecycle support.

Supply support for M74HC393TTR 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 microcontrollers, power management, analog, and discrete devices for industrial, automotive, and consumer markets.

The M74HC393TTR belongs to ST's legacy high-speed CMOS logic family, designed specifically for robust, low-power digital counting and timing functions in harsh environments and long-lifecycle applications.

FAQ

Can M74HC393TTR be cascaded to create an 8-bit counter?

Yes. Connect QD of the first counter (Pin 6) to CLK2 (Pin 13) to enable ripple-cascaded operation. This forms a single 8-bit binary counter with /256 division ratio. Ensure CLEAR inputs are tied together for synchronized reset, and verify setup/hold timing margins at the cascaded clock input using worst-case propagation delay data (tPHL = 39 ns max. at VCC = 6 V).

What is the minimum pulse width required on the CLEAR input?

The minimum CLEAR pulse width is 13 ns (typ.) at VCC = 6 V, with 16 ns (max.) over full temperature range. This ensures reliable asynchronous reset across all operating conditions. For robustness in noisy environments, maintain ≥20 ns pulse width and avoid violating the minimum removal time (tREM = 6 ns max.) before next clock edge.

Does M74HC393TTR support 3.3 V operation?

Yes. It is fully specified for VCC = 2.0 V to 6.0 V, including 3.3 V nominal operation. At 3.3 V, fMAX = 67 MHz (typ.), output drive is ±4 mA (min.), and propagation delay (CLOCK→QA) is 30 ns (typ.). All DC parameters-including VIH = 2.31 V (min.) and VOL = 0.26 V (max. at 4 mA)-are guaranteed across this voltage.

Are the two counter sections truly independent?

Yes. CLK1/CLR1 control only QA–QD (Pins 3–6); CLK2/CLR2 control only 2QA–2QD (Pins 8–11). There is no internal coupling-no shared clock path, no inter-counter carry signal, and no shared reset propagation delay. Each section operates autonomously unless externally cascaded, enabling concurrent but unrelated counting tasks.