Texas Instruments LM5105SDX/NOPB

Overview

LM5105SDX/NOPB from Texas Instruments is a 100-V half-bridge gate driver IC designed to control high-side and low-side N-channel MOSFETs in synchronous buck or half-bridge power stages. It delivers 1.8-A peak source/sink current, supports bootstrap supply up to 118 V DC, integrates a bootstrap diode, and provides programmable dead time (75–705 ns) via external RDT resistor. Used in motor drives and isolated DC-DC converters.

For engineers reviewing the LM5105SDX/NOPB datasheet, LM5105SDX/NOPB pinout, LM5105SDX/NOPB application, or LM5105SDX/NOPB equivalent, key selection criteria include its 100-V HS rail capability, TTL-compatible single-input control, 26-ns typical turnoff propagation delay, integrated UVLO on both VDD and HB rails, and thermally enhanced 4 mm × 4 mm WSON package with exposed pad.

Technical Context

The LM5105SDX/NOPB employs robust level-shift technology to drive the floating high-side output HO referenced to HS, enabling operation with HS voltages up to 100 V. Its dual UVLO circuits independently monitor VDD (6.9 V threshold) and HB–HS (6.6 V threshold), disabling respective outputs during undervoltage conditions.

Dead time is generated by matched leading-edge delay circuits tied to the RDT pin, where resistor values from 5 kΩ to 100 kΩ set total dead time between LO-OFF-to-HO-ON and HO-OFF-to-LO-ON from 80 ns to 570 ns. The single TTL-compatible IN pin controls both outputs with hysteresis, while EN enables/disables both drivers simultaneously.

Key Specifications

Pinout & Package

LM5105SDX/NOPB uses a thermally enhanced 10-pin WSON package (4 mm × 4 mm) with an exposed pad soldered to PCB ground for optimal thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC27201D and IRS21844PbF, LM5105SDX/NOPB uniquely combines programmable dead time, integrated bootstrap diode, and compact WSON package-making it optimal for space-constrained, medium-voltage (≤100 V) half-bridge applications requiring design flexibility and reduced component count.

Availability

LM5105SDX/NOPB is available at Aetrix Electronics and suitable for motor control systems, isolated DC-DC converters, and industrial motor drives requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LM5105SDX/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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management technologies.

The LM5105SDX/NOPB belongs to TI's high-voltage gate driver product line, engineered specifically for half-bridge and synchronous buck topologies in industrial, automotive, and telecom power systems where reliability, integration, and thermal performance are critical.

FAQ

What is the maximum allowable voltage on the HS pin of the LM5105SDX/NOPB?

The LM5105SDX/NOPB specifies a maximum HS-to-VSS voltage of 100 V under recommended operating conditions. Absolute maximum rating allows transient excursions down to −5 V relative to VSS, provided HS remains ≥ (VDD − 15 V). This enables safe operation in hard-switched topologies with body-diode clamping and controlled negative transients.

How does the RDT pin program dead time in the LM5105SDX/NOPB?

The RDT pin on the LM5105SDX/NOPB accepts a resistor to VSS that sets matched turnon delays for both HO and LO outputs. With RDT = 10 kΩ, dead time is ~80 ns; with RDT = 100 kΩ, it increases to ~570 ns. The internal 3-V bias and 1-mA current limit ensure linear, temperature-stable delay generation across the full resistor range.

Does the LM5105SDX/NOPB require an external bootstrap diode?

No, the LM5105SDX/NOPB integrates a bootstrap diode between VDD and HB pins. Its forward voltage is 0.9 V at 100 µA and 1.1 V at 100 mA, eliminating the need for an external diode and reducing PCB footprint and parasitic inductance in the bootstrap loop.

What thermal performance can be expected from the LM5105SDX/NOPB WSON package?

The LM5105SDX/NOPB in its 10-pin WSON package achieves a junction-to-board thermal resistance (R_θJB) of 14.9°C/W when the exposed pad is soldered to a solid copper ground plane. This enables reliable operation at 125°C junction temperature even under continuous 1.8-A peak output current loads.

How does the LM5105SDX/NOPB handle undervoltage conditions on VDD and HB rails?

The LM5105SDX/NOPB implements independent UVLO circuits: VDD UVLO triggers at 6.9 V (0.5-V hysteresis), disabling both outputs; HB UVLO triggers at 6.6 V (0.4-V hysteresis), disabling only HO. This prevents partial drive and ensures safe startup and fault recovery in half-bridge configurations.