Texas Instruments LM5109MA/NOPB

Overview

LM5109MA/NOPB from Texas Instruments is a high-voltage, 1A peak half-bridge gate driver IC designed to independently control high-side and low-side N-channel MOSFETs in synchronous buck or half-bridge topologies. It supports 100V rail voltage on the high-side, delivers 1.0A sink/source output current, features TTL-compatible inputs, and operates with bootstrap supply up to 118V DC. It is used in high-efficiency DC-DC power converters requiring robust level-shifting and fast switching.

For engineers reviewing the LM5109MA/NOPB datasheet, LM5109MA/NOPB pinout, LM5109MA/NOPB application, or LM5109MA/NOPB equivalent, key selection criteria include high-side rail tolerance (100V), matched propagation delay (2 ns typical), UVLO thresholds on both VDD and HB rails, SOIC-8 package compatibility, and independent HI/LI input control for flexible PWM timing schemes.

Technical Context

The LM5109MA/NOPB integrates a robust high-side level shifter capable of operating with HS node voltages from −1V to 100V and HB-to-VSS up to 118V. Its dual-output architecture uses separate TTL-compatible HI and LI inputs to drive HO and LO independently, enabling non-overlapping or complementary gate drive with external logic.

It implements under-voltage lockout on both VDD (6.0–7.4V rising threshold) and HB (5.7–7.1V relative to HS), ensuring safe turn-off during insufficient supply conditions. Propagation delays are tightly matched (tMON/tMOFF ≤15 ns max), and rise/fall times remain ≤15 ns into 1000 pF loads at 12V supply.

Key Specifications

Pinout & Package

LM5109MA/NOPB is packaged in an 8-pin SOIC (D) package with 1.27 mm pitch, 1.75 mm max height, and RoHS-compliant NiPdAu lead finish. The exposed pad is not present-thermal management relies on PCB copper area under leads and proper decoupling.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar half-bridge gate driver applications.

Compared with LM5109MX/NOPB, LM5109MA/NOPB offers identical performance in a tube-packaged form ideal for evaluation and small-batch builds; versus UCC27201DR, it trades peak current and integrated diode for precise dual-input timing control and lower cost in established silicon MOSFET designs.

Availability

LM5109MA/NOPB is available at Aetrix Electronics and suitable for current-fed push-pull converters, half-bridge power converters, and solid-state motor drives requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for LM5109MA/NOPB 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 ICs, with decades of expertise in high-reliability power conversion solutions.

The LM5109 product line delivers cost-optimized, high-voltage gate drivers for half-bridge and synchronous buck topologies-designed specifically for industrial, telecom, and motor control applications demanding robustness and ease of use.

FAQ

What is the maximum allowable voltage on the HS pin of the LM5109MA/NOPB?

The LM5109MA/NOPB specifies an absolute maximum HS-to-VSS voltage of −5V to +100V. In normal operation, the HS node is clamped by the body diode of the low-side MOSFET and typically stays above −1V. However, transient negative excursions must not exceed VDD − 15V-for example, if VDD = 12V, HS must stay above −3V. Exceeding these limits risks parasitic device activation and IC damage.

Does the LM5109MA/NOPB require external bootstrap diodes?

Yes, the LM5109MA/NOPB requires an external bootstrap diode connected from VDD to HB. The IC does not integrate this diode. A fast-recovery or Schottky diode with <100 ns reverse recovery and sufficient current rating (≥10 mA average) is recommended. Placement must be adjacent to the HB and VDD pins to minimize loop inductance and ensure reliable bootstrap capacitor recharge.

Can the LM5109MA/NOPB drive both MOSFETs simultaneously in a synchronous rectifier configuration?

No-the LM5109MA/NOPB is not designed for synchronous rectification. Its HO and LO outputs are intended for active switching devices only. For synchronous rectifier control, a dedicated low-side driver or controller with adaptive timing (e.g., LM5112 or UCC27201 with external logic) is required. Simultaneous high- and low-side conduction would cause shoot-through and device failure.

What is the purpose of the NRND designation in the LM5109MA/NOPB datasheet?

NRND (Not Recommended for New Designs) indicates that Texas Instruments no longer recommends LM5109MA/NOPB for future products, though it remains in active production and supported for existing designs. This reflects TI's roadmap prioritization-not obsolescence. LM5109MA/NOPB continues to ship with full datasheet compliance, lifetime availability commitments, and technical support through authorized channels including Aetrix Electronics.

How does the LM5109MA/NOPB handle propagation delay matching between HO and LO outputs?

The LM5109MA/NOPB achieves tight delay matching via matched internal driver paths and a shared level-shifting architecture. Typical delay mismatch (tMON and tMOFF) is 2 ns, with a maximum of 15 ns over temperature and voltage. This ensures minimal overlap between high- and low-side conduction-critical for preventing shoot-through in hard-switched half-bridge topologies operating above 100 kHz.