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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear + Switching

Allegro MicroSystems A4408KLVTR-T

Name: A4408KLVTR-T
Brand: Allegro MicroSystems
SKU: A4408KLVTR-T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: A4408KLVTR-T

Manufacturer:: Allegro MicroSystems

Category:: Voltage Regulators - Linear + Switching

Package:: 38-TFSOP (0.173", 4.40mm Width) Exposed Pad

Datasheet:: A4408KLVTR-T.pdf

Description:: IC REG TRPL BCK/BST/LNR 38ETSSOP

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Product details

Overview

A4408KLVTR-T from Allegro MicroSystems is an automotive-grade power management IC featuring a buck or buck-boost pre-regulator, adjustable synchronous buck regulator (1.25 V nominal), three internal LDOs (5 V / 325 mA, 3.3 V / 165 mA, and 5 V tracking / 115 mA), programmable watchdog timer, NPOR output, and dual fault flags (FF0/FF1). It operates across 2.8–36 V input, supports −40°C to 150°C junction temperature, and is designed for underhood microprocessor and CAN power supplies.

For engineers reviewing the A4408KLVTR-T datasheet, A4408KLVTR-T pinout, A4408KLVTR-T application, or A4408KLVTR-T equivalent, this page delivers verified specifications including PWM frequency range (250 kHz–2.4 MHz), thermal shutdown threshold (155–185°C), dual bandgap architecture (BGVREF/BGFAULT), TRACK pin functionality for V5P reference selection, and ENBAT1/ENBAT2 high-voltage ignition enable inputs.

Technical Context

The A4408KLVTR-T integrates a buck-boost pre-regulator generating a tightly regulated 5.35 V intermediate rail (VREG) that powers all downstream regulators. Its adjustable synchronous buck stage uses external feedback (1V25/FBadj pin) to set output voltage, while three LDOs provide isolated, foldback-protected rails with short-to-battery protection on V5P.

Control logic includes dual enable paths (logic-level ENB and high-voltage ENBAT1/ENBAT2), MODE pin-selectable NPOR undervoltage thresholds, and diagnostic outputs (NPOR, POK5V, FF0, FF1) with latched fault reporting. The watchdog timer features programmable delay via WDADJ and active-low enable (WDENn), with dual bandgaps ensuring independent regulation and fault detection integrity.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	2.8 V to 36 V operating; 40 V absolute maximum - supports wide automotive battery transients including cold-crank and load-dump conditions.
Pre-regulator Output (VREG)	5.35 V typical / ±100 mV accuracy - stable intermediate rail supplying all LDOs and synchronous buck regulator.
Synchronous Buck Output	Adjustable from 1.25 V nominal; 1.23–1.27 V reference accuracy - enables precise core voltage regulation for MCUs or ASICs.
LDO Outputs	V5: 5 V / 325 mA max; V3V3: 3.3 V / 165 mA max; V5P: 5 V tracking / 115 mA max with short-to-battery protection - dedicated rails for microcontroller I/O, sensors, and CAN transceivers.
Switching Frequency	250 kHz to 2.4 MHz adjustable via FSET/SYNC pin; supports external clock synchronization - allows EMI optimization and inductor size reduction.
Watchdog Timer	Programmable activation delay (via WDADJ); fixed startup delay; active-low enable (WDENn) - ensures safe MCU boot and runtime supervision without external components.
Junction Temperature	−40°C to +150°C - qualified for underhood automotive applications per AEC-Q100 Grade 0.
Package	38-pin eTSSOP with exposed thermal pad (suffix LV) - low-profile (1.2 mm max height), optimized for thermal dissipation in high-temperature environments.

Pinout & Package

Package: 38-pin eTSSOP (LV) with exposed thermal pad, 1.2 mm maximum height, matte tin lead frame, RoHS-compliant.

Pin/Terminal	Circuit Role	Design Meaning
VIN (pins 2,3)	Main input voltage supply	Accepts 2.8–36 V automotive battery input; dual pins reduce IR drop and improve current handling.
GND (pins 4,9)	Analog/digital ground reference	Separate ground connections minimize noise coupling between control and power sections.
TRACK (pin 10)	Tracking reference selector	Configures V5P to track either V5 or V3V3 output - enables flexible platform adaptation across sensor supply requirements.
MODE (pin 5)	NPOR undervoltage threshold select	Chooses between two UVLO thresholds for V5/V5P during power-on reset - supports different system brownout criteria.
ENBAT1/ENBAT2 (pins 16,17)	High-voltage ignition enable inputs	Accept −13 V to 40 V ignition signals with internal current limiting - eliminates need for external level-shifting circuitry.
WDENn (pin 22)	Watchdog enable control	Active-low pin disables watchdog during factory programming or field firmware updates - prevents unintended resets.
FF0/FF1 (pins 13,14)	Latched fault flag outputs	Open-drain indicators retaining last fault type (UV, OV, TSD, hiccup) - simplifies MCU fault diagnostics without continuous polling.
V5P (pin 23)	5 V tracking LDO output	Provides 115 mA with foldback overcurrent and short-to-battery protection - safeguards against battery feed-through faults in harsh environments.

Key Features

Feature	Design Value
Dual bandgap references (BGVREF, BGFAULT)	Independent regulation and fault monitoring paths increase long-term reliability and prevent single-point failure from compromising both functions.
Frequency dithering and slew rate control (SLEW pin)	Reduces peak EMI emissions by spreading switching energy across spectrum and controlling LX1 edge rates - aids EMC compliance without added filtering.
Pin-to-pin and pin-to-ground tolerance	All pins withstand −0.3 V to +7 V (except VIN, ENBATx, LX) - enhances robustness against board-level transients and assembly errors.
Thermal shutdown with 20°C hysteresis	Shuts down at 155–185°C and restarts only after cooling below threshold - prevents thermal runaway while enabling automatic recovery after transient overload.
Four-rail UV/OV protection	Monitors V5, V5P, V3V3, and FBadj independently - ensures system-level power integrity even if one rail fails.
Logic and high-voltage enable inputs	ENB (microcontroller-controlled) and ENBAT1/ENBAT2 (ignition-switched) support multi-stage power sequencing - enables precise control of startup/shutdown behavior.

Applications

Electronic Power Steering (EPS)	Transmission Control Units (TCU)
Use Scenario: High-temperature EPS controller requiring stable 3.3 V and 5 V rails for MCU, motor drivers, and position sensors under hood. IC Role / Device Role / Timing Role: Central power manager delivering regulated VREG, V5, V3V3, and V5P with integrated watchdog and fault logging. Use Value: Eliminates need for discrete pre-regulator + multiple LDOs; TRACK pin adapts V5P to match sensor supply requirements across vehicle platforms.	Use Scenario: TCU operating in engine bay with wide input voltage swings (cold crank to load dump) and strict functional safety requirements. IC Role / Device Role / Timing Role: Primary power IC providing fault-monitored 5 V/325 mA for MCU core, 3.3 V/165 mA for communication interfaces, and 1.25 V adjustable buck for ASICs. Use Value: Dual bandgap architecture and latched FF0/FF1 outputs enable ASIL-B compliant diagnostics without external supervision circuitry.
Advanced Braking Systems (ABS)	Emissions Control Modules
Use Scenario: ABS module needing fast, reliable power-on reset (NPOR with 15 ms fixed delay) and fail-safe shutdown during voltage anomalies. IC Role / Device Role / Timing Role: Power sequencer and supervisor with programmable watchdog, POK5V status indicator, and mode-selectable NPOR thresholds. Use Value: MODE pin allows tuning NPOR UVLO to match ABS-specific brownout limits; POK5V provides real-time rail health feedback to safety MCU.	Use Scenario: Diesel emissions control unit exposed to extreme ambient temperatures and vibration, requiring robust power delivery with short-circuit resilience. IC Role / Device Role / Timing Role: Integrated power solution with foldback-protected LDOs, short-to-battery protected V5P, and hiccup-mode overcurrent protection on all switching stages. Use Value: Use Value: V5P short-to-battery protection prevents latch-up during battery reversal events; thermal derating curve supports operation up to 150°C junction temperature.

Electronic Power Steering (EPS)

Transmission Control Units (TCU)

Use Scenario: High-temperature EPS controller requiring stable 3.3 V and 5 V rails for MCU, motor drivers, and position sensors under hood.

IC Role / Device Role / Timing Role: Central power manager delivering regulated VREG, V5, V3V3, and V5P with integrated watchdog and fault logging.

Use Value: Eliminates need for discrete pre-regulator + multiple LDOs; TRACK pin adapts V5P to match sensor supply requirements across vehicle platforms.

Use Scenario: TCU operating in engine bay with wide input voltage swings (cold crank to load dump) and strict functional safety requirements.

IC Role / Device Role / Timing Role: Primary power IC providing fault-monitored 5 V/325 mA for MCU core, 3.3 V/165 mA for communication interfaces, and 1.25 V adjustable buck for ASICs.

Use Value: Dual bandgap architecture and latched FF0/FF1 outputs enable ASIL-B compliant diagnostics without external supervision circuitry.

Advanced Braking Systems (ABS)

Emissions Control Modules

Use Scenario: ABS module needing fast, reliable power-on reset (NPOR with 15 ms fixed delay) and fail-safe shutdown during voltage anomalies.

IC Role / Device Role / Timing Role: Power sequencer and supervisor with programmable watchdog, POK5V status indicator, and mode-selectable NPOR thresholds.

Use Value: MODE pin allows tuning NPOR UVLO to match ABS-specific brownout limits; POK5V provides real-time rail health feedback to safety MCU.

Use Scenario: Diesel emissions control unit exposed to extreme ambient temperatures and vibration, requiring robust power delivery with short-circuit resilience.

IC Role / Device Role / Timing Role: Integrated power solution with foldback-protected LDOs, short-to-battery protected V5P, and hiccup-mode overcurrent protection on all switching stages.

Use Value:

Use Value: V5P short-to-battery protection prevents latch-up during battery reversal events; thermal derating curve supports operation up to 150°C junction temperature.

Equivalent & Alternatives

The following parts are listed as comparable options for similar automotive power management applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MPQ4332-AEC1	Single-channel synchronous buck (3.5–36 V, 2 A), no integrated LDOs or watchdog - requires external regulators and supervision circuitry.	Lacks integrated 3.3 V/5 V LDOs, NPOR, FF0/FF1, and watchdog - suitable only when discrete power tree is acceptable.	Select when cost-sensitive design can accommodate external LDOs and separate fault monitoring; not a functional replacement for A4408KLVTR-T's integrated feature set.
TPS65381A-Q1	Automotive PMIC with 3 buck converters, 4 LDOs, watchdog, and SPI interface - higher integration but fixed 1.2 V/1.8 V/3.3 V outputs, no adjustable buck.	Fixed-output topology and SPI configuration limit flexibility for custom voltage rails; larger QFN package than eTSSOP.	Choose for systems requiring SPI-configurable sequencing and more output channels; avoid when adjustable 1.25 V buck or TRACK-based V5P adaptation is required.

Compared with MPQ4332-AEC1 and TPS65381A-Q1, the A4408KLVTR-T uniquely combines adjustable synchronous buck regulation, TRACK-selectable 5 V tracking LDO, dual-bandgap fault monitoring, and high-voltage ignition enables in a thermally optimized 38-pin eTSSOP - making it optimal for cost-constrained, high-reliability underhood applications where integration reduces BOM count and layout complexity.

Availability

A4408KLVTR-T is available at Aetrix Electronics and suitable for Electronic Power Steering (EPS), Transmission Control Units (TCU), and Advanced Braking Systems (ABS) requiring stable component supply, AEC-Q100 qualification, and long-term automotive lifecycle support.

Supply support for A4408KLVTR-T includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Allegro MicroSystems is a global leader in precision sensing and power ICs, specializing in magnetic sensors, motor drivers, and automotive-qualified power management solutions.

The A4408 product line is engineered for demanding automotive underhood applications - integrating pre-regulation, multiple protected LDOs, watchdog supervision, and fault diagnostics into a single AEC-Q100 qualified device.

FAQ

What is the operating input voltage range for the A4408KLVTR-T?

The A4408KLVTR-T operates from 2.8 V to 36 V in buck-boost mode and 5.7 V to 36 V in buck-only mode, with 40 V absolute maximum rating. This range accommodates automotive battery transients including cold-crank (down to ~2.8 V) and load-dump (up to 40 V), making the A4408KLVTR-T suitable for direct connection to vehicle battery rails without external protection circuitry.

How does the TRACK pin function in the A4408KLVTR-T?

The TRACK pin on the A4408KLVTR-T selects the reference voltage for the V5P tracking LDO: when pulled high or left open, V5P tracks the 3.3 V (V3V3) output; when pulled low, it tracks the 5 V (V5) output. This feature allows a single A4408KLVTR-T design to support multiple sensor platforms with differing supply requirements without hardware changes.

What protection features does the A4408KLVTR-T include for its LDO outputs?

The A4408KLVTR-T provides foldback overcurrent protection on all three LDOs (V5, V3V3, V5P) and adds short-to-battery protection specifically on the V5P output. This dual-layer protection prevents damage during output shorts or battery feed-through events common in automotive environments, enhancing system reliability without requiring external current-limiting components.

Is the A4408KLVTR-T suitable for new designs despite its "Not for New Design" status?

No - the A4408KLVTR-T is classified as "Not for New Design" as of November 8, 2023. While still in production for existing customer applications, Allegro recommends transitioning to newer alternatives for new designs due to probable near-term obsolescence. Aetrix Electronics supports legacy programs but advises evaluating next-generation PMICs for long-term design viability.

What is the purpose of the dual bandgap architecture (BGVREF and BGFAULT) in the A4408KLVTR-T?

The A4408KLVTR-T employs two independent bandgap references: BGVREF for regulation stability and BGFAULT for fault detection. This separation ensures that a drift or failure in the regulation path does not compromise fault monitoring integrity - a critical requirement for automotive functional safety, improving long-term reliability and enabling robust diagnostic coverage per ISO 26262.

A4408KLVTR-T Specifications

Product attributes: Attribute value

Manufacturer:: Allegro MicroSystems

Series:: -

Package/Case:: 38-TFSOP (0.173", 4.40mm Width) Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Not For New Designs

Topology:: Step-Down (Buck) (1) Synchronous or Step-Down/Step-Up (Buck/Boost) (1), Linear (LDO) (3)

Number of Outputs:: 3

Frequency - Switching:: 250kHz ~ 2.4MHz

Voltage/Current - Output 1:: 5V, 115mA

Voltage/Current - Output 2:: 3.3V, 165mA

Voltage/Current - Output 3:: 5V, 325mA

w/LED Driver:: No

w/Supervisor:: No

w/Sequencer:: Yes

Voltage - Supply:: 2.8V ~ 36V

Operating Temperature:: -40°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 38-eTSSOP

A4408KLVTR-T FAQ

1.How can I place an order for A4408KLVTR-T through Aetrix?

Please submit a Request for Quotation (RFQ) for A4408KLVTR-T on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for A4408KLVTR-T reliable?

The price and inventory of A4408KLVTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A4408KLVTR-T is usually 5 days.

3.What payment methods are accepted for A4408KLVTR-T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A4408KLVTR-T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for A4408KLVTR-T?

A4408KLVTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your A4408KLVTR-T order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for A4408KLVTR-T?

For technical support, including A4408KLVTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A4408KLVTR-T requirements.

6.How does Aetrix verify that A4408KLVTR-T is sourced from the original manufacturer or authorized distributors?

All A4408KLVTR-T products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that A4408KLVTR-T meets industry standards.

7.What is the process for return or replacement of A4408KLVTR-T?

All A4408KLVTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A4408KLVTR-T, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The A4408KLVTR-T part is unused and in its original packaging.

Return procedure for A4408KLVTR-T:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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