Synchronous buck converter that steps a 4 to 36 V input down to a regulated rail at up to 3 A, in a small SOT-23-6 with both MOSFETs integrated. A resistor divider at FB sets the output, EN gives an adjustable enable threshold, and a bootstrap cap at CB drives the high-side switch. The wide input and small footprint suit it to point-of-load rails off a 12 or 24 V bus. A compact, low-part-count buck for space-limited boards.

Pinout

Pin	Name	Type	Function
1	GND	power_in	Power ground terminal. Connects to the source of the low-side FET internally. Connect to system ground and the ground side of CIN and COUT; the path to CIN must be as short as possible.
2	SW	power_out	Switching output of the converter. Connects internally to the source of the high-side FET and drain of the low-side FET. Connect this pin to the power inductor. Rated -0.3 V to 38 V DC (transient -3.0 V for < 20 ns).
3	VIN	power_in	Supply input terminal to internal bias LDO and high-side FET. Operating range 4.5 V to 36 V (abs max 38 V). Input bypass capacitors CIN must be directly connected between this pin and GND.
4	FB	input	Feedback input to the converter. Connect a resistor divider from VOUT to set the output voltage; internal reference is 0.6 V typical (0.591 V to 0.609 V). Never short this pin to ground during operation.
5	EN	input	Precision enable input. Do not float. High = on, low = off. Rising threshold ~1.227 V, falling ~1.08 V. Can be tied to VIN or used with an external divider to set adjustable UVLO. If left floating, the device is disabled.
6	CB	passive	Bootstrap capacitor connection for the high-side FET driver. Connect a high-quality 100-nF capacitor from this pin to the SW pin. CB to SW rated max 5.5 V.

Key specifications

Parameter	Value
Type	Synchronous step-down converter
Input	4-36 V
Output current	3 A
Integrated FETs	Yes (high + low side)
Control	FB divider, EN, bootstrap (CB)
Package	SOT-23-6

Ordering variants

Same part, different packaging or reel option.

LMR51430XDBVR (SOT-23-6, FPWM)
LMR51430YDBVR (SOT-23-6, auto mode)

CAD (KiCad official)

Symbol: Regulator_Switching:LMR51430 (KiCad official)
Footprint: Package_TO_SOT_SMD:SOT-23-6
3D model: SOT-23-6 (KiCad packages3D, STEP)

Provenance

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

Datasheet: Texas Instruments datasheet (33 pp, sha256 f7d8053844fb07ae, 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