Texas Instruments LM2105DR

Overview

LM2105DR from Texas Instruments is a high-voltage half-bridge gate driver IC designed to control two N-channel MOSFETs in synchronous buck or half-bridge topologies. It delivers 0.5-A peak source and 0.8-A peak sink current per output, features integrated bootstrap diode, 5-V typical UVLO on GVDD, and supports up to 107-V BST voltage. It targets motor drive applications such as cordless power tools and e-bikes.

For engineers reviewing the LM2105DR datasheet, LM2105DR pinout, LM2105DR application, or LM2105DR equivalent, this page provides verified functional role, validated thermal performance in SOIC-8, confirmed UVLO thresholds (4.6 V rising / 4.3 V falling on GVDD), real-world SH transient tolerance (–19.5 V), and accurate propagation delay (115 ns typical) - all critical for BLDC and PMSM gate-drive design validation.

Technical Context

The LM2105DR implements independent TTL/CMOS-compatible INH and INL inputs with no built-in dead time, enabling precise microcontroller-controlled timing. Its level-shifting architecture isolates the high-side driver (GH referenced to SH) from logic ground while maintaining tight delay matching (<30 ns between GL and GH transitions).

UVLO protection operates separately on GVDD (low-side rail) and BST–SH (high-side rail), with hysteresis (0.3 V on GVDD, 0.25 V on BST) preventing chattering during supply transients. The –19.5-V negative transient rating on SH and integrated bootstrap diode (VF = 2.1 V @ 100 mA) directly support robust operation in noisy, high-dV/dt motor-phase environments.

Key Specifications

Pinout & Package

LM2105DR is supplied in an 8-pin SOIC package (D package), 4.90 mm × 3.91 mm body size, with exposed pad not present - thermal path relies on PCB copper area under leads. Pinout matches industry-standard half-bridge driver layout for drop-in compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM5109BDR and UCC27211D, the LM2105DR trades peak current for integrated bootstrap diode and superior SH transient tolerance (–19.5 V), making it optimal for cost-sensitive, space-constrained BLDC systems where reliability under motor-phase ringing is prioritized over raw drive strength.

Availability

LM2105DR is available at Aetrix Electronics and suitable for brushless-DC motor drives, cordless power tools, and e-bike controllers requiring stable component supply, long-term industrial lifecycle support, and SOIC-8 package compatibility.

Supply support for LM2105DR 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 specializing in analog and embedded processing technologies, with leadership in power management and motor control ICs.

The LM2105DR belongs to TI's high-voltage gate driver product line, engineered specifically for compact, cost-optimized half-bridge motor drives in battery-powered equipment where integration, thermal efficiency, and transient robustness are essential.

FAQ

What is the absolute maximum voltage rating on the BST pin of the LM2105DR?

The LM2105DR has an absolute maximum BST voltage rating of 107 V relative to SH. This rating is defined in the Absolute Maximum Ratings table and enables use in 48-V battery systems with sufficient margin for bus transients. Operation beyond this voltage risks permanent device damage, and the 105-V recommended operating maximum ensures reliable long-term performance under normal conditions.

Does the LM2105DR include an integrated bootstrap diode, and what is its forward voltage?

Yes, the LM2105DR integrates a bootstrap diode with a typical forward voltage of 2.1 V at 100 mA. This eliminates the need for an external discrete diode, reducing BOM count and PCB area. The diode is rated for low-current operation (0.6 V @ 100 µA) and supports bootstrap capacitor recharge in high-frequency half-bridge applications up to 500 kHz.

What is the propagation delay specification for the LM2105DR, and how is it measured?

The LM2105DR has a typical propagation delay of 115 ns, measured from 50% of the input transition (INH or INL) to 90% of the corresponding output transition (GH or GL) under no-load conditions at TJ = 25°C and VGVDD = VBST = 12 V. This value is consistent across both rising and falling edges and is critical for timing-critical BLDC commutation where inter-channel skew must remain below 30 ns.

How does the LM2105DR handle negative voltage transients on the SH pin?

The LM2105DR supports –19.5-V repetitive negative transients on the SH pin (pulse width <100 ns), significantly exceeding standard –5-V ratings. This capability allows direct connection to noisy motor-phase nodes without external clamping diodes. The device maintains functionality as long as SH remains above –1 V DC and GH stays within its specified voltage window relative to SH.

What are the UVLO thresholds for GVDD and BST in the LM2105DR, and how do they differ?

The LM2105DR features dual UVLO: GVDD rising threshold is 4.6 V (falling 4.3 V, hysteresis 0.3 V), while BST–SH rising threshold is 4.7 V (falling 4.0 V, hysteresis 0.25 V). GVDD UVLO disables both outputs; BST UVLO disables only GH. This separation ensures low-side operation continues during bootstrap capacitor recharge, improving fault resilience in motor control loops.