Texas Instruments UC2637Q

Overview

UC2637Q from Texas Instruments is a monolithic PWM motor controller IC designed for bi-directional DC motor drive applications in industrial and embedded systems. It integrates a sawtooth oscillator, dual PWM comparators with ±100mA output drivers, error amplifier, pulse-by-pulse current limiting, under-voltage lockout, and a temperature-compensated 2.5V shutdown threshold. Operating from -25°C to +85°C, it supports ±2.5V to ±20V dual supplies and delivers up to 500mA pulsed output current per channel.

For engineers reviewing the UC2637Q datasheet, UC2637Q pinout, UC2637Q application, or UC2637Q equivalent, key selection considerations include its dual-output PWM modulation architecture, ±100mA source/sink capability, oscillator accuracy (±10% over temperature), current-limiting hysteresis, and PLCC-20 package compatibility with servo amplifier and H-bridge gate driver designs.

Technical Context

The UC2637Q implements a fixed-frequency sawtooth oscillator whose frequency is set externally via RT and CT components, with ±10% accuracy over its -25°C to +85°C operating range. Its uncommitted PWM comparators accept analog error signals referenced to ±VS and generate complementary pulse trains with programmable deadtime via differential inputs on Pins 9/11 and 10/12.

Internal protection includes latched pulse-by-pulse current limiting (200mV offset), under-voltage lockout activating at 4.15V to 5.0V, and a shutdown comparator referenced to +VS with 40mV hysteresis. The error amplifier provides 15V/µs slew rate, 1MHz unity-gain bandwidth, and rail-to-rail common-mode input range within 2V of supply rails.

Key Specifications

Pinout & Package

UC2637Q is housed in a 20-pin PLCC (Plastic Leaded Chip Carrier) package with gull-wing leads, moisture sensitivity level 2 (260°C peak reflow), and RoHS-compliant CuSn finish. The package measures 9.0 mm × 9.0 mm with 1.27 mm lead pitch and is designed for surface-mount assembly on standard PCBs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PWM motor controller applications.

Compared with UC2637DW and UC3637Q, the UC2637Q offers superior thermal operating range (-25°C to +85°C) and tighter oscillator stability (±10% vs ±11%), making it the preferred choice for industrial motor controllers where environmental resilience and timing precision are jointly critical.

Availability

UC2637Q is available at Aetrix Electronics and suitable for industrial servo position control, DC motor speed regulation, bi-directional actuator drive, and lab equipment motion control requiring stable component supply across extended temperature ranges.

Supply support for UC2637Q 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 leader specializing in analog, embedded processing, and digital signal technologies for industrial, automotive, and communications markets.

The UC2637Q belongs to TI's legacy UCx637 family of PWM motor controllers, engineered specifically for high-reliability DC motor drive systems requiring integrated protection, dual-output flexibility, and wide supply voltage tolerance.

FAQ

What is the maximum allowable supply voltage for UC2637Q?

The UC2637Q supports dual-supply operation from ±2.5V to ±20V. Exceeding ±20V on either +VS or -VS pins risks permanent damage to internal circuitry, including the oscillator, comparators, and output drivers. Absolute maximum ratings specify ±20V, and operation beyond this violates JEDEC stress testing limits. Always use appropriate clamping or regulation upstream of UC2637Q to ensure compliance.

Does UC2637Q support single-supply operation?

Yes, UC2637Q supports single-supply operation by grounding the -VS pin and applying the positive supply to +VS, provided all analog inputs (e.g., +AIN, -AIN, +BIN, -BIN) remain within their specified common-mode range of -VS+2V to +VS-2V. In single-supply mode, the error amplifier and comparators retain functionality, but output swing is limited to 0V to +VS–2V for high-side and –VS+0.2V to 0V for low-side, requiring careful level-shifting for external logic.

How does the current limit function work on UC2637Q?

The UC2637Q implements latched pulse-by-pulse current limiting using differential inputs (+C/L and –C/L) with a nominal 200mV internal offset. When the sensed voltage exceeds this threshold, the output drivers shut down immediately and remain latched until the SHUTDOWN pin is cycled. This protects external power devices during short-circuit or stall conditions. The latch requires external reset via the shutdown pin or power cycle - no automatic recovery is provided.

Can UC2637Q generate complementary PWM outputs with adjustable deadtime?

Yes, UC2637Q supports three deadtime configurations via its uncommitted PWM comparators: zero deadtime (equal voltages on Pins 9 and 11), small deadtime (voltage on Pin 9 > Pin 11), and increased deadband mode. By biasing the +BIN/–BIN and +AIN/–AIN inputs differentially, users can program transition delays between AOUT and BOUT to prevent shoot-through in H-bridge topologies without external logic or delay networks.

What is the purpose of the ISET pin on UC2637Q?

The ISET pin (Pin 20) on UC2637Q internally connects to the +VTH reference and sets the oscillator's capacitor charging current. It is not an external adjustment node - no external components should be connected here. Its sole function is to provide a stable, temperature-compensated current source for the oscillator's CT capacitor, ensuring consistent ramp generation and frequency accuracy across the –25°C to +85°C operating range.