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LM5155-Q1

Boost, SEPIC and flyback controller

A controller for boost/SEPIC/flyback designs with an external power stage. Operation from 1.5V requires BIAS≥3.5V; it does not promise unaided startup at 1.5V. Separate startup and running conditions.

AutomotiveActiveExample package: WSON (DSS) · 12 pinVerified 2026-11-06
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5-second verdict

AutomotiveAEC-Q100 Grade 1
Temperature−40°C to +125°C (TA)
Functional safetyFunctional Safety-Capable
LifecycleActive
In one sentence: Qualification is grounded in this TI product's documentation; no grade is inferred from temperature. An ordering table may show junction or variant-specific limits, which must be distinguished from ambient conditions. TI explicitly lists Functional Safety-Capable. This is a device-documentation category, not system ASIL certification; assess the exact function, assumptions and safety manual.

Key specifications

Standard operating range3.5–45 V
Low-input operation1.5 V boost input only with BIAS ≥3.5 V
BIAS tied to VCC2.97–16 V
Switching frequency100 kHz–2.2 MHz
External MOSFET driver1.5 A peak
Feedback-reference accuracy±1%

Orderable variants (OPNs)

The GPN is for selection; the full OPN is for ordering. These examples were observed on the verification date, not live stock. Variants may differ in package, temperature, gain/threshold and, for PMICs, NVM/sequencing. Distinguish TA from TJ in the exact datasheet.

OPNPackageTemperatureNote
LM5155QDSSRQ1WSON (DSS) · 12 pin-40 to +150°C (TI OPN listing; verify TA/TJ)Verify exact OPN, temperature definition and revision; not a stock claim.
LM5155QDSSTQ1WSON (DSS) · 12 pin-40 to +150°C (TI OPN listing; verify TA/TJ)Verify exact OPN, temperature definition and revision; not a stock claim.
LM5155QUDSSRQ1WSON (DSS) · 12 pin-40 to +125°C (TI OPN listing; verify TA/TJ)Verify exact OPN, temperature definition and revision; not a stock claim.
LM5155QUDSSTQ1WSON (DSS) · 12 pin-40 to +125°C (TI OPN listing; verify TA/TJ)Verify exact OPN, temperature definition and revision; not a stock claim.
LM5155QDSSRQ1-40 to +150°C (TI OPN listing; verify TA/TJ)
WSON (DSS) · 12 pinVerify exact OPN, temperature definition and revision; not a stock claim.
LM5155QDSSTQ1-40 to +150°C (TI OPN listing; verify TA/TJ)
WSON (DSS) · 12 pinVerify exact OPN, temperature definition and revision; not a stock claim.
LM5155QUDSSRQ1-40 to +125°C (TI OPN listing; verify TA/TJ)
WSON (DSS) · 12 pinVerify exact OPN, temperature definition and revision; not a stock claim.
LM5155QUDSSTQ1-40 to +125°C (TI OPN listing; verify TA/TJ)
WSON (DSS) · 12 pinVerify exact OPN, temperature definition and revision; not a stock claim.

Official ordering page: https://www.ti.com/product/LM5155-Q1

Typical applications

Automotive cold-crank boost supportSEPIC / flyback supply designs

FAQ

Can it start directly at 1.5V?

Do not equate run voltage with start voltage. Low-input operation needs BIAS≥3.5V; tying BIAS to VCC has a separate operating range.

Can LM5155 and LM51551 be mixed freely?

Not from the family name. Protection behavior differs; check the Device Comparison Table, external circuit and fault strategy.

How should I verify the LM5155-Q1 orderable?

The page lists 4 OPN examples from official material checked on 2026-11-06. Match package, function options and temperature definitions; obtain live price/stock from TI or authorized distributors.

Sources and verification

Related selection and design checks

All selection guides →What does TI Q1 mean →AEC-Q100 grades →Model Y TI BOM →

NuAxi is an independent semiconductor market-intelligence platform and is not affiliated with Texas Instruments. Information is for selection reference only and is not a design, certification or procurement guarantee; verify against TI's official datasheet, ordering page and terms.

LM5155-Q1: Boost, SEPIC and flyback controller — AEC-Q100, OPNs, alternates | NuAxi