Texas Instruments UCC37321DR

Overview

UCC37321DR from Texas Instruments is an inverting 9-A low-side MOSFET driver with enable functionality, designed to interface PWM controllers with power N-channel MOSFETs in high-frequency switching applications. It delivers ±9 A peak current during the Miller plateau region, supports 4.5–15 V supply voltage, and features 20-ns typical rise/fall times with 10-nF load - enabling fast, robust gate drive for synchronous rectifiers and buck-derived converters.

For engineers reviewing the UCC37321DR datasheet, UCC37321DR pinout, UCC37321DR application, or UCC37321DR equivalent, key selection considerations include its inverting logic configuration, industry-standard SOIC-8 package with dedicated ENBL pin, thermal performance (θ_JA = 56.7°C/W), and compatibility with high-dV/dt power stages requiring precise timing control and shoot-through mitigation.

Technical Context

The UCC37321DR implements a hybrid TrueDrive output stage combining bipolar and MOSFET transistors to deliver high-current sourcing/sinking precisely at the Miller plateau - where gate charge demands peak during MOSFET turn-on/turn-off transitions. Its input threshold (1.2–2.2 V) remains stable across 4.5–15 V V_DD, and the enable pin (ENBL) features 100-kΩ internal pull-up and hysteresis (0.25–0.9 V) for noise-immune control.

Unlike standard drivers, it separates AGND (control ground) and PGND (power ground) to minimize switching-induced ground bounce, and requires dual V_DD connections (pins 1 and 8) and external 0.1-µF decoupling per supply rail. The device operates from –40°C to +105°C and is rated for 150°C junction temperature.

Key Specifications

Pinout & Package

UCC37321DR is packaged in an 8-pin SOIC (D package) with 3.91 mm × 4.90 mm body size and standard industry footprint. Thermal resistance is θ_JA = 56.7°C/W and θ_JC = 42°C/W, supporting up to 344 mW continuous power dissipation at 70°C ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-side MOSFET driver applications.

Compared with UCC37321P and UCC27321DR, the UCC37321DR uniquely combines inverting logic, SOIC-8 thermal performance (344 mW @ 70°C), and industry-standard footprint - making it optimal for production-grade synchronous rectifier and high-frequency SMPS designs where polarity conversion and thermal reliability are both critical.

Availability

UCC37321DR is available at Aetrix Electronics and suitable for switch-mode power supplies, motor controllers, and Class-D amplifier designs requiring stable component supply, long-term industrial lifecycle support, and consistent parametric performance across temperature extremes.

Supply support for UCC37321DR 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 power management technologies, with decades of expertise in high-reliability power interface solutions.

The UCC3732x product line was engineered specifically for high-speed, high-current gate driving in demanding power conversion systems - targeting applications where Miller plateau current delivery, timing precision, and noise immunity are non-negotiable.

FAQ

What is the logic configuration of the UCC37321DR?

The UCC37321DR is an inverting low-side MOSFET driver: when the IN pin is high, the OUT pin goes low, and vice versa. This configuration enables direct gate drive of N-channel synchronous rectifiers in buck converters without external inverters. The inverting behavior is intrinsic to the UCC37321DR silicon design and cannot be altered by external circuitry.

Does the UCC37321DR require external pull-up or pull-down resistors on the ENBL pin?

No - the UCC37321DR includes a 100-kΩ internal pull-up resistor on the ENBL pin, enabling active-high operation with no external components required. Leaving ENBL unconnected defaults the device to enabled state. External resistors are only needed if custom enable thresholds or power-up delay timing (via RC network to AGND) is required.

Can the UCC37321DR drive multiple MOSFETs in parallel?

Yes - the UCC37321DR's ±9-A peak output current and low output impedance (0.4–0.6 Ω) allow it to drive multiple paralleled MOSFET gates, provided total gate charge (Q_g) and Miller charge (Q_gd) remain within the driver's energy delivery capability. Layout must maintain symmetric trace lengths and shared PGND connection to avoid current imbalance.

What is the purpose of separate AGND and PGND pins on the UCC37321DR?

The UCC37321DR separates AGND (analog ground) and PGND (power ground) to isolate sensitive input/enable circuitry from high-di/dt return currents. AGND references the input stage; PGND carries output switching current. They must connect via a single low-inductance trace under the device - this minimizes ground bounce that could cause false triggering or timing jitter in the UCC37321DR.

Is the UCC37321DR pin-compatible with other drivers in the UCC3732x family?

Yes - the UCC37321DR shares identical SOIC-8 pinout and footprint with UCC37322DR (non-inverting), UCC27321DR (inverting, different temp grade), and UCC27322DR (non-inverting, different temp grade). All variants use the same VDD, IN, ENBL, AGND, PGND, and dual-OUT pin assignments - enabling direct substitution where logic polarity and temperature range align.