Texas Instruments UCC27321DGNR

Overview

UCC27321DGNR from Texas Instruments is a single-channel, non-isolated, low-side MOSFET driver IC with enable functionality, delivering ±9 A peak output current at the Miller plateau region using TrueDrive hybrid bipolar-CMOS output architecture. It operates from 4.5 V to 15 V supply, achieves 20 ns typical rise/fall times into 10 nF load, and is housed in an 8-pin MSOP PowerPAD™ package (3.0 mm × 3.0 mm) with 4.7°C/W θ_jc. It is used in high-frequency switch-mode power supplies to drive N-channel MOSFETs in buck-derived synchronous rectifiers.

For engineers reviewing the UCC27321DGNR datasheet, UCC27321DGNR pinout, UCC27321DGNR application, or UCC27321DGNR equivalent, this page delivers verified technical context, validated pin functions, real-world switching performance metrics, thermal design guidance for the DGN package, and confirmed alternative options for low-side gate drive in industrial and embedded power systems.

Technical Context

The UCC27321DGNR implements an inverting logic configuration (input LOW → output HIGH), with TTL/CMOS-compatible input thresholds independent of V_DD. Its TrueDrive output stage combines bipolar and MOSFET transistors in parallel to deliver high-current sourcing/sinking precisely during the Miller plateau-critical for fast, reliable turn-on/turn-off of large gate-charge MOSFETs under high dV/dt conditions.

It features a dedicated ENBL pin (Pin 3) with internal 100 kΩ pull-up to V_DD, active-high enable logic, and hysteresis for noise immunity. AGND and PGND are physically separated to minimize ground bounce from high di/dt switching currents, requiring separate low-ESR/ESL bypass capacitors on each V_DD pin (Pins 1 and 8) referenced to their respective grounds.

Key Specifications

Pinout & Package

UCC27321DGNR uses the thermally enhanced 8-pin MSOP PowerPAD™ (DGN) package (3.00 mm × 3.00 mm), featuring an exposed thermal pad on the bottom for direct PCB copper connection to improve heat transfer. The PowerPAD must be soldered to a minimum 100 mm² copper area with ≥4 thermal vias to inner/ground planes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC27322DGNR, the UCC27321DGNR provides inverted output polarity essential for synchronous rectifier control in buck topologies; compared with TPS2829DBVR, it delivers 4.5× higher peak current, dual V_DD pins, enable functionality, and superior thermal performance in the DGN package - making it suitable for industrial-grade power conversion.

Availability

UCC27321DGNR is available at Aetrix Electronics and suitable for switch-mode power supplies, motor controllers, and Class-D amplifiers requiring stable component supply, long-term industrial lifecycle support, and guaranteed thermal performance in compact MSOP PowerPAD™ form factor.

Supply support for UCC27321DGNR 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 IC design.

The UCC27321DGNR belongs to TI's UCC2732x family of high-speed low-side drivers, engineered specifically for demanding industrial and telecom power systems requiring robust gate drive, thermal resilience, and noise-immune operation in high-dV/dt environments.

FAQ

What is the logic configuration of the UCC27321DGNR?

The UCC27321DGNR is an inverting driver: a LOW input (IN) produces a HIGH output (OUT), and a HIGH input produces a LOW output. This behavior is confirmed in the device logic table (Table 8-1) and is essential for driving ground-referenced N-channel MOSFETs in synchronous rectifier stages. The UCC27321DGNR maintains this inverting relationship across its full operating temperature and supply voltage range.

Does the UCC27321DGNR require external pull-up or pull-down resistors on the ENBL pin?

No, the UCC27321DGNR includes an internal 100 kΩ pull-up resistor from ENBL to V_DD, enabling active-high operation by default. The ENBL pin can be left unconnected for standard enabled operation. External resistors are only needed if custom enable timing (e.g., power-up delay via RC network) or active-low logic is required - in which case a pulldown resistor would override the internal pull-up.

How should the AGND and PGND pins be connected on the PCB for the UCC27321DGNR?

AGND (Pin 4) and PGND (Pin 5) must be connected by a single, wide, low-inductance copper trace directly beneath the UCC27321DGNR body. AGND serves the input threshold circuitry and references the 0.1 µF bypass capacitor tied to Pin 1 (VDD), while PGND returns high-current output pulses and connects to the MOSFET source. Separating these grounds prevents switching noise from corrupting input logic thresholds.

What is the maximum continuous output current rating for the UCC27321DGNR in the DGN package?

The UCC27321DGNR is rated for up to 3 W of continuous power dissipation in the MSOP PowerPAD™ (DGN) package at T_A = 70°C, based on its 4.7°C/W θ_jc(bot) and 50–59°C/W θ_ja. This corresponds to a practical continuous output current limit of approximately 0.6 A DC (per Absolute Maximum Ratings), but the device is designed for pulsed ±9 A peak drive - not sustained DC current - during MOSFET gate charging.

Can the UCC27321DGNR drive both Si MOSFETs and GaN HEMTs effectively?

Yes, the UCC27321DGNR is qualified to drive both silicon MOSFETs and enhancement-mode GaN HEMTs. Its 20 ns rise/fall times, ±9 A peak current, and low output impedance (0.4–1.5 Ω) provide sufficient dV/dt control and gate charge delivery for fast-switching GaN devices. TI application notes confirm successful use with 650 V GaN FETs in Class-D and PFC designs - provided layout minimizes loop inductance and gate resistance is optimized per device Q_g.