Drives the two MOSFETs of a half-bridge from separate high-side and low-side inputs, with the high-side gate referenced to a floating node that swings up to 100 V. A bootstrap diode-and-capacitor at HB/HS supplies the high-side driver, and the outputs source and sink about 1 A to switch the FETs quickly. Independent HI and LI inputs let a controller set the timing and dead-time. A compact half-bridge driver for buck stages, motor phases, and class-D outputs up to 100 V.

Pinout

Pin	Name	Type	Function
1	VDD	power_in	Positive gate drive supply (8V to 14V recommended). Locally decouple to VSS using a low-ESR/ESL capacitor located as close to the IC as possible.
2	HI	input	High-side control input. TTL-compatible input thresholds (VIL=0.8V, VIH=2.2V max). Internal ~200kΩ pulldown. Unused HI input should be tied to ground and not left open.
3	LI	input	Low-side control input. TTL-compatible input thresholds (VIL=0.8V, VIH=2.2V max). Internal ~200kΩ pulldown. Unused LI input should be tied to ground and not left open.
4	VSS	power_in	Ground reference. All signals are referenced to this ground.
5	LO	output	Low-side gate driver output. Connect to the gate of the low-side N-MOS device. 1.0A peak source/sink capability.
6	HS	passive	High-side source connection. Connect to the negative terminal of the bootstrap capacitor and to the source of the high-side N-MOS device. Recommended operating range -1V to 90V.
7	HO	output	High-side gate driver output. Connect to the gate of the high-side N-MOS device. Referenced to HS with 1.0A peak source/sink capability.
8	HB	power_in	High-side gate driver positive supply rail (bootstrap). Connect the positive terminal of the bootstrap capacitor to HB and the negative terminal to HS. The bootstrap capacitor should be placed as close to the IC as possible. HB to VSS max 108V.

Key specifications

Parameter	Value
Type	Half-bridge gate driver (high + low side)
Bus voltage	Up to 100 V
Peak current	1 A source / sink
Inputs	Independent HI, LI
Bootstrap	HB/HS high-side supply
Supply (VDD)	9-14 V
Package	SOIC-8

Ordering variants

Same part, different packaging or reel option.

LM5109AMA (SOIC-8)
LM5109AMAX (SOIC-8, tape & reel)
LM5109BMA (matched delay)

CAD (KiCad official)

Symbol: Driver_FET:LM5109AMA (KiCad official)
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOIC-8 (KiCad packages3D, STEP)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Texas Instruments datasheet (29 pp, sha256 808ea6839f052259, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF