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Contents

README

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LMR51406YFDBVR

Texas Instruments · IC · SOT-23-6

LMR51406YFDBVR from Texas Instruments, in a SOT-23-6. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 CB passive Bootstrap capacitor connection for the high-side FET driver; connect a high quality 100nF capacitor from this pin to the SW pin.
2 GND power_in Power ground connected to the source of the low-side FET internally; connect to system ground and the ground side of CIN and COUT, with the path to CIN as short as possible.
3 FB input Feedback input to the converter; connect a resistor divider to set the output voltage and never short this terminal to ground during operation.
4 EN input Precision enable input (High = on, Low = off) that must not be floated, can be tied to VIN, and allows an adjustable UVLO via an external resistor divider.
5 VIN power_in Supply input to the internal bias LDO and high-side FET (4V to 42V operating); connect to the input supply with input bypass capacitors CIN directly connected to this pin and GND.
6 SW passive Switching output of the converter, internally connected to the source of the high-side FET and drain of the low-side FET; connect to the power inductor.

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package SOT-23-6
Category
Pins 6

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter Symbol Min Typ Max Unit Conditions Page
VIN quiescent current IQ(VIN) 420 µA VEN = 3V, FPWM Operation 5
VIN shutdown supply current ISD(VIN) 0.8 3 µA VEN = 0V 5
VIN UVLO rising threshold VIN_UVLO(R) 3.82 4 V VIN rising 5
VIN UVLO falling threshold VIN_UVLO(F) 3.4 3.56 V VIN falling 5
EN voltage rising threshold VEN(R) 1.1 1.227 1.36 V EN rising, enable switching 5
EN voltage falling threshold VEN(F) 0.85 1 1.15 V EN falling, disable switching 5
EN pin sourcing current post EN rising threshold IEN(P2) 10 50 nA VEN = 3V 5
Reference voltage VFB 0.788 0.8 0.812 V 5
Switching frequency, CCM operation, Y version fSW(CCM) 0.935 1.1 1.265 MHz "Y" Version 5
High-side peak current limit IHS_PK(OC) 0.8 1.1 1.4 A LMR51406 6
Low-side valley current limit ILS_V(OC) 0.62 0.8 0.98 A LMR51406 6
Adjustable output voltage regulation VOUT -1.5 2.5 % PFM operation 6
Input voltage VIN to GND (abs max) VIN -0.3 45 V 4
Input voltage EN to GND (abs max) EN -0.3 V max VIN + 0.3 V 4
Input voltage FB to GND (abs max) FB -0.3 5.5 V 4
Output voltage SW to GND (abs max) SW -0.3 45 V 4
SW to GND transient (abs max) SW -5 50 V less than 10ns transients 4
CBOOT to SW (abs max) CBOOT -0.3 5.5 V 4
Junction temperature (abs max) TJ -40 150 °C 4
Storage temperature Tstg -55 150 °C 4
ESD HBM V(ESD) -2500 2500 V Human-body model, ANSI/ESDA/JEDEC JS-001 4
ESD CDM V(ESD) -750 750 V Charged-device model, ANSI/ESDA/JEDEC JS-002 4
Input voltage VIN to GND VIN 4 42 V 4
Input voltage EN EN 0 V max VIN 4
Input voltage FB FB 0 4.5 V 4
Output voltage VOUT VOUT 0.8 28 V 4
Output current LMR51406 Iout 0.6 A 4
Operating junction temperature TJ -40 150 °C 4
Junction-to-ambient thermal resistance RθJA 147.8 °C/W DBV (SOT-23-6), 6 pins 5
Junction-to-ambient thermal resistance with EVM RθJA(Effective) 95 °C/W DBV (SOT-23-6), 6 pins 5
Junction-to-case (top) thermal resistance RθJC(top) 71.1 °C/W DBV (SOT-23-6), 6 pins 5
Junction-to-board thermal resistance RθJB 36.6 °C/W DBV (SOT-23-6), 6 pins 5
Junction-to-top characterization parameter ψJT 14.2 °C/W DBV (SOT-23-6), 6 pins 5
Junction-to-board characterization parameter ψJB 36.4 °C/W DBV (SOT-23-6), 6 pins 5
Low-side negative current limit ILS(NOC) -0.36 A LMR51406 FPWM Only 6
High-side MOSFET on-resistance RDSON(HS) 0.7 Ω VIN = 12V, TJ = 25°C 5
Low-side MOSFET on-resistance RDSON(LS) 0.36 Ω VIN = 12V, TJ = 25°C 5
Minimum ON pulse width tON_MIN 80 ns VIN = 12V, IOUT = 0.1A 5
Minimum OFF pulse width tOFF_MIN 200 ns VIN = 5V 6
Internal fixed soft-start time tSS 2.3 ms 5
Thermal shutdown threshold TJ(SD) 165 °C Junction temperature rising 6

Materials and finish

As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).

Part Material Colour / plating Datasheet says Page
contacts copper The SW pin connecting to the inductor must be as short as possible, and just wide enough to carry the load current without excessive heating. Short, thick traces or copper pours (shapes) must be used 21

CAD (KiCad official)

  • Symbol: LMR51406YFDBVR
  • Footprint: Package_TO_SOT_SMD:SOT-23-6
  • 3D model: SOT-23-6 (KiCad packages3D, STEP)
  • 3D model files: lmr51406yfdbvr-etched.step / lmr51406yfdbvr-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lmr51406yfdbvr.step / lmr51406yfdbvr.glb are the bare package body.

Provenance

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

  • Datasheet: Texas Instruments datasheet (33 pp, sha256 a61ac445a7c8c97e, retrieved 2026-10-23, tier: lcsc)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-sonnet-5-5 (text), consensus claude-sonnet-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF