Part Datasheet Review

Created a project doc

LMR51420XDDCR Part Review

View Document
Date: 2026-07-20 Official datasheet found: https://www.ti.com/lit/ds/symlink/lmr51420.pdf

flux

Completed the part review and updated the Datasheet URL to the official TI PDF. I created the detailed report here: LMR51420XDDCR Part Review.
Open items:
  • Part Type is still incorrect: Linear Regulator vs. datasheet’s synchronous buck switching regulator.
  • Package property is still incorrect: TO vs. SOT-23-THIN (DDC), 6 pins.
  • Description includes likely incorrect claims: power-good output and 100% duty-cycle operation.
  • Pin names/numbers match, but terminal pin types/descriptions are missing.
  • Footprint is plausible SOT-23-6, but its land pattern should be verified against TI’s DDC0006A example.
Suggested next steps:
  1. Update the incorrect part metadata.
  2. Populate pin descriptions/types from the datasheet.
  3. Adjust or verify the footprint land pattern before publishing.
Fix metadata and pins
Fix part metadata
Populate pin metadata
Verify footprint geometry
Run part review
GND
Pin Number
1
VIN
Pin Number
3
FB
Pin Number
4
EN
Pin Number
5
CB
Pin Number
6
SW
Pin Number
2

Refine this doc
Ask about this doc
LMR51420XDDCR Part Review
Date: 2026-07-20
Datasheet Source
  • Official datasheet found: https://www.ti.com/lit/ds/symlink/lmr51420.pdf
  • The part project's Datasheet URL property was updated to the official TI PDF.
  • Source identified by TI search result as: LMR51420 SIMPLE SWITCHER Power Converter 4.5-V to 36-V, 2-A, Synchronous Buck datasheet (Rev. C).
Current Part Metadata Reviewed

Table

FieldCurrent valueDatasheet/reference check
Project/part nameLMR51420XDDCRMatches TI orderable part number.
Manufacturer Part NumberLMR51420XDDCRMatches datasheet orderable part number.
Manufacturer NameTexas InstrumentsMatches.
DescriptionSynchronous buck DC-DC converter, 4.5 V to 36 V, 2 A, 500 kHz, PFM, adjustable output, etc.Mostly matches, but see mismatches below.
Datasheet URLhttps://www.ti.com/lit/ds/symlink/lmr51420.pdfUpdated to official TI URL.
Package or Case CodeTOMismatch: datasheet package is SOT-23-THIN, drawing DDC, 6 pins.
Part TypeLinear RegulatorMismatch: device is a synchronous buck switching regulator / DC-DC converter, not a linear regulator.
Designator PrefixICReasonable for an integrated regulator.
Pin count6 terminal components / 6 padsMatches datasheet.
Key Datasheet Specs

Table

ParameterDatasheet value
Device familyLMR51420 SIMPLE SWITCHER power converter
FunctionSynchronous buck / step-down switching regulator
Orderable partLMR51420XDDCR
Frequency variant500 kHz
Mode variantPFM
OutputAdjustable
Recommended VIN4.5 V to 36 V
Recommended output current2 A max
Recommended VOUT0.6 V to 95% of VIN
Operating junction temperature-40°C to +150°C
Typical quiescent current40 µA, 65 µA max, PFM variant, non-switching
FB reference0.591 V min, 0.600 V typ, 0.609 V max
Switching frequency450 kHz min, 500 kHz typ, 560 kHz max for 500-kHz trim
Soft-start3.2 ms min, 4.0 ms typ, 5.4 ms max
High-side RDSON0.12 Ω typ at TJ = 25°C
Low-side RDSON0.07 Ω typ at TJ = 25°C
Peak high-side current limit2.7 A min, 3.5 A typ, 5.1 A max
PackageSOT-23-THIN, DDC, 6 pins
Body sizeNominal 2.90 mm × 1.60 mm
Max package height1.1 mm
MSL / reflowLevel-1, 260°C, unlimited
Part marking4AXP
Pin Cross-Check
Datasheet Table 6-1 lists these pins:

Table

PinNameTypeDatasheet descriptionCurrent symbol terminal
1GNDGPower ground; connect to system ground and ground side of CIN/COUT; CIN path must be short.Present as GND, pin number 1.
2SWPSwitching output; connect to power inductor.Present as SW, pin number 2.
3VINPSupply input to internal bias LDO and high-side FET; connect to input supply and bypass capacitors.Present as VIN, pin number 3.
4FBAFeedback input; connect resistor divider; never short to ground during operation.Present as FB, pin number 4.
5ENAPrecision enable; do not float; high = on, low = off; may tie to VIN.Present as EN, pin number 5.
6CBPBootstrap capacitor connection; connect 100 nF capacitor from CB to SW.Present as CB, pin number 6.
Pin names and pin numbers match the datasheet. Pin descriptions and functional pin types are not populated in the current terminal properties; all symbol terminal Pin Type values are Unspecified.
Schematic Symbol Review
  • The symbol exposes the correct six terminals: GND, SW, VIN, FB, EN, CB.
  • Pin numbers match the datasheet mapping exactly.
  • Terminal placement is schematic-logical rather than package-top-view. This is acceptable: VIN is placed toward the top-left, GND lower-left, SW mid-left, and control/feedback/bootstrap pins on the right.
  • Missing metadata: terminal Pin Type, Pin Description, Pin Group, Section, and Terminal Order are not set on the terminals.
Footprint Review
Current footprint asset: SOT95P280X110-6N.kicad_mod with model LMR51420XDDCR.stp.
Observed footprint geometry from the KiCad module:
  • 6 SMD rectangular pads.
  • Pad pitch: 0.95 mm vertically between pins on each side.
  • Pad centers: left row at x = -1.25 mm, right row at x = +1.25 mm.
  • Pad size in module: 0.6 mm × 1.25 mm, rotated 90 degrees.
  • Fab body: 1.6 mm × 2.9 mm, matching TI nominal body size.
  • Courtyard: 4.25 mm × 3.55 mm.
  • Pin-1 indicator is present.
Datasheet package/land-pattern data for DDC0006A:
  • Package: SOT-23-THIN / DDC / 6 pins.
  • Body nominal: 2.90 mm × 1.60 mm.
  • Example land pattern: 6 pads of 1.1 mm × 0.6 mm, 0.95 mm pitch, 2.7 mm pad-row span, R0.05 pad corners.
Footprint assessment:
  • Correct pin count and SOT-23-6 style geometry.
  • Body outline matches datasheet nominal body dimensions.
  • Pitch matches datasheet 0.95 mm.
  • Potential land-pattern mismatch: current pad length is 1.25 mm instead of TI example 1.1 mm, and current pad-row center span appears to be 2.5 mm versus TI example 2.7 mm. This may still be an IPC-7351 alternate footprint, but it is not an exact copy of the TI example land pattern and should be verified before publishing/manufacturing.
Flagged Mismatches / Issues

Table

SeverityIssueCurrent valueDatasheet-correct value / recommendation
HighPart Type is incorrect.Linear RegulatorSwitching Regulator / DC-DC Converter / Synchronous Buck Regulator.
HighPackage property is incorrect.Package or Case Code = TOSOT-23-THIN (DDC), 6 pins.
MediumDescription includes unsupported feature.Mentions power-good output.LMR51420XDDCR 6-pin pinout has no PG / power-good pin; remove this claim unless another variant is intended.
MediumDescription overstates duty cycle.Mentions 100% duty-cycle operation.Datasheet feature list states 98% maximum duty cycle.
MediumSymbol terminal metadata is incomplete.Pin Type = Unspecified; no Pin Description/Pin Group/Section.Populate pin types and descriptions from Table 6-1.
MediumFootprint land pattern may not match TI example exactly.0.6 mm × 1.25 mm pads, apparent 2.5 mm row center span.TI example: 1.1 mm × 0.6 mm pads, 0.95 mm pitch, 2.7 mm span. Verify if current footprint is an acceptable IPC-7351 alternate.
LowFootprint asset name is generic and slightly ambiguous.SOT95P280X110-6NPackage should be identified as DDC0006A / SOT-23-THIN-6. Geometry appears mostly compatible, but naming could be clearer.
  1. Change Part Type from Linear Regulator to Switching Regulator, DC-DC Converter, or Synchronous Buck Regulator.
  2. Change Package or Case Code from TO to SOT-23-THIN (DDC) or DDC0006A.
  3. Remove power-good output from the description.
  4. Replace 100% duty-cycle operation in the description with 98% maximum duty cycle.
  5. Populate terminal metadata:
    • GND: Type Ground, description from datasheet.
    • SW: Type Power, switching output to inductor.
    • VIN: Type Power, supply input and bypass-cap connection.
    • FB: Type Analog/Input, feedback divider input.
    • EN: Type Analog/Input, precision enable, do not float.
    • CB: Type Power, bootstrap capacitor connection to SW.
  6. Verify or adjust the footprint land pattern against TI DDC0006A before publishing if exact TI land-pattern compliance is required.

  • Datasheet Source

  • Current Part Metadata Reviewed

  • Key Datasheet Specs

  • Pin Cross-Check

  • Schematic Symbol Review

  • Footprint Review

  • Flagged Mismatches / Issues

  • Recommended Fixes

Documents

Assets

LMR51420XDDCR

LMR51420XDDCR

LMR51420XDDCR.stp3D Model
kicad_mod

LMR51420XDDCR

SOT95P280X110-6N.kicad_modFootprint
svg

LMR51420XDDCR

LMR51420XDDCR Symbol.svgDefault
LMR51420XDDCR-thumb.png

LMR51420XDDCR-thumb.png

LMR51420XDDCR-thumbThumbnail

LMR51420XDDCR

LMR51420XDDCR thumbnail
Synchronous Buck DC-DC Converter – 2 A synchronous step-down (buck) switching regulator for high-efficiency power conversion in industrial, automotive, and embedded applications. Operates from a 4.5 V to 36 V input voltage, provides an adjustable output voltage from 0.6 V to 34.2 V, and switches at a 500 kHz fixed frequency. Features 40 µA typical quiescent current, 100% duty-cycle operation, synchronous rectification, cycle-by-cycle current limiting, hiccup short-circuit protection, thermal shutdown, undervoltage lockout (UVLO), power-good output, and enable input. Operates over a −40°C to +150°C junction temperature range and is housed in a 6-pin SOT-23-THIN (DDC) package.
#TexasInstruments #LMR51420 #LMR51420XDDCR #BuckConverter #DCDCConverter #SynchronousBuck #SwitchingRegulator #PowerManagement #2A #SIMPLESWITCHER #SOT236 #EmbeddedSystems

Properties

LMR51420XDDCR

Texas Instruments

Linear Regulator

ti.com/lit/ds/symlink/lmr51420.pdf

IC

TO

parametric-v1

Pricing & Availability

See prices from popular manufacturers for your project.

Controls