Texas Instruments UC2638N

Overview

UC2638N from Texas Instruments is a dual full-bridge PWM motor driver IC designed for bidirectional DC motor control in industrial motion systems. It features 20-pin PDIP packaging, operates from –40°C to +85°C, supports up to ±1.5 A output current per H-bridge, and integrates logic-level inputs with built-in protection against overcurrent and thermal shutdown. It is used in precision lab equipment requiring discrete, non-communication-based motor actuation.

For engineers reviewing the UC2638N datasheet, UC2638N pinout, UC2638N application, or UC2638N equivalent, key selection considerations include its dual H-bridge topology, TTL-compatible input interface, independent enable control per bridge, and lack of integrated current sensing or serial configuration - making it suitable for fixed-function, low-complexity motor drive stages where external feedback and timing are managed by companion controllers.

Technical Context

The UC2638N implements two independent full-bridge drivers using bipolar transistor output stages, each capable of sourcing and sinking up to ±1.5 A continuously. It accepts standard TTL/CMOS logic inputs (IN1–IN4, EN1, EN2) and provides complementary high-side/low-side drive without internal dead-time generation.

No internal oscillator or PWM generator is present - all timing and duty-cycle control must be supplied externally. The device lacks current-sense outputs, fault reporting pins, or SPI/I²C interfaces, distinguishing it from modern integrated motor drivers and positioning it as a legacy analog-control-stage component.

Key Specifications

Pinout & Package

UC2638N is housed in a 20-pin plastic dual in-line package (PDIP-N), 0.300-inch wide body, with 0.100-inch lead pitch. Pin 1 is located at the left end of the top row, identified by a notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual H-bridge motor drive applications.

Compared with UC3638N and L298N, the UC2638N offers wider industrial temperature support and integrated thermal protection, but requires dual supplies and lacks modern features like current sensing or PWM input - making it best suited for fixed-function, high-reliability legacy motion subsystems.

Availability

UC2638N is available at Aetrix Electronics and suitable for industrial motion control, laboratory instrumentation, and legacy CNC retrofitting requiring stable component supply and long-lifecycle support.

Supply support for UC2638N 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

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies since 1930.

The UC2638N belongs to TI's legacy motor driver family designed for discrete, high-reliability industrial motion control - emphasizing robustness, wide temperature operation, and compatibility with analog and TTL control architectures.

FAQ

What is the maximum continuous output current per bridge for UC2638N?

The UC2638N supports ±1.5 A continuous output current per H-bridge at 25°C ambient with adequate PCB copper area. Derating is required above 25°C - at 85°C ambient, maximum continuous current drops to approximately ±0.9 A per bridge due to thermal limits. This value is measured under specified test conditions with 2 oz copper and minimal heatsinking, and applies to both sourcing and sinking modes.

Does UC2638N include an internal PWM generator or clock?

No, the UC2638N does not contain an internal oscillator or PWM generator. It is a pure gate-driver IC requiring externally generated logic-level signals for IN1–IN4 and EN1/EN2. Timing, frequency, and duty cycle must be provided by upstream circuitry such as a microcontroller, FPGA, or analog timer - the UC2638N performs only power-stage amplification and protection.

Can UC2638N operate from a single supply voltage?

No, UC2638N requires dual symmetric supply rails (V+ and V−) to bias its bipolar output stage. It is not compatible with single-ended supplies. Typical configurations use ±5 V, ±12 V, or ±15 V - the absolute maximum rating is ±18 V. Attempting single-supply operation will result in improper biasing and potential device failure.

Is UC2638N pin-compatible with UC3638N?

Yes, UC2638N and UC3638N share identical pinout, electrical characteristics, and functional behavior - differing only in temperature grade (–40°C to +85°C vs. 0°C to +70°C) and qualification level. Both use the same PDIP-20 (N) package and support identical logic inputs, output configurations, and protection mechanisms.

What protection features are implemented in UC2638N?

The UC2638N integrates thermal shutdown and overcurrent limiting. Thermal shutdown activates when junction temperature exceeds ~170°C, disabling all outputs until temperature falls below ~150°C. Overcurrent limiting clamps peak output current to approximately 2.5 A per bridge during short-circuit events. Neither feature provides fault-flag signaling - recovery is automatic upon condition removal.