Texas Instruments LM2105DSGR

Overview

LM2105DSGR 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 features integrated bootstrap diode, 5-V typical GVDD undervoltage lockout, 107-V BST absolute maximum rating, –19.5-V negative transient handling on SH, and 0.5-A/0.8-A peak source/sink currents - enabling robust motor drive in cordless power tools and e-bikes.

For engineers reviewing the LM2105DSGR datasheet, LM2105DSGR pinout, LM2105DSGR application, or LM2105DSGR equivalent, key selection considerations include its WSON-8 package thermal performance (RθJB = 44.6°C/W), SH node transient tolerance, bootstrap diode forward voltage (2.1 V @ 100 mA), propagation delay matching (±0 ns mismatch between GH/GL), and UVLO hysteresis (0.3 V on GVDD, 0.25 V on BST).

Technical Context

The LM2105DSGR implements independent TTL/CMOS-compatible INH and INL inputs with no built-in dead time, requiring external MCU-level timing control. Its floating high-side driver uses a robust level shifter referenced to SH, delivering matched 115-ns propagation delays for both GH and GL outputs under 12-V supply conditions.

UVLO protection operates separately on GVDD (4.6 V rising threshold) and BST–SH (4.7 V rising threshold), disabling only GH during BST UVLO while maintaining GL functionality. The integrated bootstrap diode eliminates external discrete diodes but exhibits 12.5 Ω dynamic resistance at 100 mA, directly impacting charge replenishment efficiency in high-duty-cycle applications.

Key Specifications

Pinout & Package

The LM2105DSGR is housed in an 8-pin WSON package (2.00 mm × 2.00 mm) with exposed thermal pad soldered to PCB ground plane for enhanced heat dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with UCC27211D and DRV8300D, the LM2105DSGR offers lowest BOM cost via integrated bootstrap diode and best thermal performance in WSON-8, but trades off programmable features and higher drive strength - making it optimal for cost-sensitive, thermally constrained 10–50-V motor drives where external diode omission is prioritized.

Availability

LM2105DSGR is available at Aetrix Electronics and suitable for cordless power tools, e-bike motor controllers, and battery test equipment requiring stable component supply across industrial production cycles.

Supply support for LM2105DSGR 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 and embedded processing technologies with broad industrial and automotive design expertise.

The LM2105DSGR belongs to TI's high-voltage gate driver product line, engineered specifically for compact, thermally efficient half-bridge motor control in battery-powered equipment where integration, reliability, and transient robustness are critical.

FAQ

What is the absolute maximum voltage rating on the BST pin of the LM2105DSGR?

The LM2105DSGR has an absolute maximum BST voltage rating of 107 V relative to SH. This rating allows operation in 48-V and 60-V battery systems with substantial overvoltage margin. Exceeding this voltage risks permanent damage to the internal high-side driver stage. Designers must ensure bootstrap capacitor voltage - including ringing and transients - stays below 107 V, especially during startup and fault conditions. The LM2105DSGR datasheet specifies this value in Section 6.1 Absolute Maximum Ratings.

Does the LM2105DSGR include an integrated bootstrap diode, and what is its forward voltage?

Yes, the LM2105DSGR integrates a bootstrap diode to eliminate the need for an external discrete diode. Its forward voltage is 0.6 V at 100 µA (low-current) and 2.1 V at 100 mA (high-current). This 2.1-V drop directly reduces the effective VBST voltage available to the high-side driver, impacting minimum duty cycle and bootstrap capacitor recharge time. The LM2105DSGR's integrated diode simplifies layout but requires careful capacitor sizing - particularly in high-frequency or high-duty-cycle applications.

What is the propagation delay matching between GH and GL outputs in the LM2105DSGR?

The LM2105DSGR provides matched 115-ns typical propagation delay for both GH and GL outputs under standard conditions (VGVDD = VBST = 12 V, TJ = 25°C). Delay matching is confirmed across all four transitions (INH→GH, INL→GL, rising and falling edges), with no specified mismatch in the datasheet - indicating inherent symmetry in the driver architecture. This tight matching enables precise synchronous switching without controller-level dead-time compensation, a key advantage of the LM2105DSGR in motor control timing-critical applications.

How does the LM2105DSGR handle negative voltage transients on the SH pin?

The LM2105DSGR supports –19.5-V negative transients on the SH pin for pulses shorter than 100 ns, and –1-V DC. This capability protects against undershoot during MOSFET body-diode conduction and high-dI/dt switching events common in BLDC and PMSM drives. The LM2105DSGR achieves this via robust internal level-shifter design and ESD structures optimized for transient immunity. Layout best practices - such as minimizing SH node loop area and using local ceramic decoupling - are essential to maintain this rating in actual LM2105DSGR implementations.

What package type and thermal characteristics define the LM2105DSGR?

The LM2105DSGR uses an 8-pin WSON package (2.00 mm × 2.00 mm) with exposed thermal pad. Its key thermal metric is RθJB = 44.6 °C/W, measured from junction to PCB board - significantly lower than the SOIC-8 variant (76.7 °C/W). This enables higher power dissipation in space-constrained motor-control modules. The LM2105DSGR requires soldering the thermal pad to a solid ground plane for optimal performance, as specified in TI's packaging guidelines and confirmed in Section 6.4 Thermal Information of the LM2105DSGR datasheet.