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

Infineon Technologies IR3871MTRPBF

Name: IR3871MTRPBF
Brand: Infineon Technologies
SKU: IR3871MTRPBF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IR3871MTRPBF

Manufacturer:: Infineon Technologies

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 17-PowerVQFN

Datasheet:: IR3871MTRPBF.pdf

Description:: IC REG BUCK ADJ 8A PQFN

Quantity:: RFQ Add To RFQ list

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Inventory:2,621

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Product details

Overview

IR3871MTRPBF from Infineon Technologies is a highly integrated synchronous buck regulator with integrated high- and low-side MOSFETs, constant on-time control, and 8A continuous output current capability. It operates from 3V to 26V input, delivers 0.5V–12V output with ±1% reference accuracy, and features programmable switching frequency, soft-start, over-current protection, and power-good signaling - used in notebook POL supplies and consumer DC-DC point-of-load applications.

For engineers reviewing the IR3871MTRPBF datasheet, IR3871MTRPBF pinout, IR3871MTRPBF application, or IR3871MTRPBF equivalent, key selection criteria include its 5×6mm QFN-17 package, integrated 14.5mΩ/8mΩ MOSFETs, pre-bias startup support, 0.5V precision reference, and feed-forward (FF) pin for input-voltage-dependent on-time tuning.

Technical Context

The IR3871MTRPBF implements a constant on-time (COT) hysteretic control architecture that eliminates external loop compensation while maintaining fast transient response across wide load and input ranges. Its internal 0.5V reference feeds the FB comparator, and the FF pin adjusts on-time proportionally to VIN via an external resistor, enabling stable operation without voltage-mode loop design overhead.

It integrates dual MOSFETs (14.5mΩ high-side, 8mΩ low-side at 25°C), a bootstrap gate driver (BOOT–PHASE ≤ 8V), and dedicated PGND/GND separation for accurate current sensing and noise immunity. The ISET pin sets over-current threshold via resistor-to-PHASE connection, and PGOOD provides open-drain fault signaling with adjustable delay.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	3V to 26V - supports wide-input industrial and computing rails including 5V, 12V, 19V adapters.
Output Voltage Range	0.5V to 12V - set via FB resistor divider; 0.5V ±1% reference enables sub-1V core supply accuracy.
Continuous Output Current	8A - sustained at 60°C ambient without airflow, enabled by low R_DS(on) MOSFETs and thermal QFN package.
Switching Frequency	Programmable up to 1MHz - adjusted via R_FF on FF pin; allows optimization of size vs. efficiency trade-offs.
Reference Accuracy	±1% at 0.5V - ensures tight output regulation under line/load transients without external trimming.
Soft-Start Time	User-defined via C_SS on SS pin - prevents inrush current; shutdown via <0.3V pull-down.
Power Good Threshold	V_FB = 0.58–0.66V rising - asserts PGOOD after output reaches regulation window; delay configurable via V_SS.

Pinout & Package

IR3871MTRPBF uses a thermally enhanced 5mm × 6mm QFN-17 package with exposed thermal pad (PGND-connected), 0.5mm pitch, and RoHS-compliant matte tin lead finish.

Pin/Terminal	Circuit Role	Design Meaning
PHASE (12)	Switching node	Connects to inductor; carries high dv/dt switching waveform; referenced for BOOT capacitor and ISET current sense.
BOOT (14)	Bootstrap supply	Drives high-side MOSFET gate; requires ceramic capacitor to PHASE; max 8V differential limits gate drive headroom.
ISET (2)	Over-current threshold	Current source (20µA typ); resistor to PHASE sets OCP trip point - enables scalable current limiting without sense resistor.
FB (5)	Feedback input	Inverting input to PWM comparator; monitors output via resistor divider; triggers UV/OV faults at 0.37–0.43V / 0.58–0.66V.
EN (16)	Enable with monitoring	Turn-on threshold 3.9–4.2V; hysteresis 150mV; supports input voltage supervision using external resistor divider.
PGOOD (3)	Fault signaling	Open-drain output; pulled high externally; asserts when V_OUT is within ±5% of target for >1ms (configurable).
VIN (13), PGND (11), GND (4,17)	Power and signal returns	Separate PGND (power return) and GND (signal reference) minimize ground bounce in high-di/dt paths.

Key Features

Feature	Design Value
No external compensation required	Constant on-time control eliminates loop stability analysis and external compensation components - reduces BOM count and layout sensitivity.
Pre-bias start-up	Allows safe startup into pre-charged output capacitors without reverse current flow - critical for hot-swap and multi-rail sequencing.
Integrated dual MOSFETs	14.5mΩ high-side + 8mΩ low-side (25°C) enable high efficiency at 8A without discrete FET selection or gate driver design.
Feed-forward (FF) pin	Adjusts on-time proportional to VIN - maintains consistent ripple and transient response across wide input range without loop re-tuning.
Ultra-small 5×6mm QFN	17-pin thermally optimized package with exposed pad - achieves high power density while supporting automated optical inspection (AOI) and reflow.

Applications

Notebook CPU Core Supply

Gaming Console SoC Rail

Use Scenario: Delivering tightly regulated 0.85V/6A to mobile CPU cores during burst workloads with rapid load steps.

IC Role / Device Role / Timing Role: Primary POL regulator with COT control ensuring <10µs transient response and no phase-margin tuning.

Use Value: Pre-bias startup avoids output collapse during cold boot; 0.5V ±1% reference guarantees ±5mV output tolerance at 0.85V.

Use Scenario: Powering GPU and memory interface rails (1.1V/8A) in compact console designs with limited airflow.

IC Role / Device Role / Timing Role: High-current synchronous buck converter with integrated FETs eliminating external driver and layout complexity.

Use Value: 8A continuous rating at 60°C ambient enables fanless operation; QFN-17 thermal pad lowers θ_JA to 35°C/W.

Smart TV DDR Memory Supply

STB Application Processor Rail

Use Scenario: Generating 1.2V/5A for LPDDR4 memory subsystems requiring low-noise, high-PSRR regulation.

IC Role / Device Role / Timing Role: Point-of-load regulator with programmable soft-start and PGOOD sequencing for system-level power management.

Use Value: Programmable switching frequency (up to 1MHz) allows EMI spread-spectrum tuning and smaller output inductors.

Use Scenario: Providing 1.05V/4A to ARM-based application processors in set-top boxes with strict cost and footprint constraints.

IC Role / Device Role / Timing Role: Fully integrated buck regulator replacing controller + external FET solution to reduce component count and assembly cost.

Use Value: Integrated 3.3V LDO (3VCBP) powers auxiliary circuitry; EN pin supports input voltage monitoring for brown-out detection.

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MP2315DJ-LF-Z	4A rated, 3–36V input, no integrated FF pin or pre-bias startup; requires external compensation.	Suitable for lower-current, non-sequencing applications where cost is prioritized over feature set.	Select when 4A output suffices and board space allows external compensation network.
TPS54821RHLR	8A rated, 4.5–20V input, voltage-mode control with external compensation; includes PMBus interface.	Preferred for systems requiring telemetry, dynamic voltage scaling, or digital configuration via I²C.	Choose when digital control, telemetry, or tighter input voltage range aligns with system architecture.

Compared with MP2315DJ-LF-Z and TPS54821RHLR, IR3871MTRPBF uniquely combines 8A integration, COT control without compensation, pre-bias startup, and FF-based input adaptation - making it optimal for compact, analog-controlled POL designs demanding robustness and minimal external components.

Availability

IR3871MTRPBF is available at Aetrix Electronics and suitable for notebook CPU core supplies, gaming console SoC rails, and smart TV DDR memory supplies requiring stable component supply and long-term production continuity.

Supply support for IR3871MTRPBF 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

Infineon Technologies is a German semiconductor manufacturer specializing in power management, automotive, and industrial control ICs, with leadership in silicon and silicon carbide power devices.

The IR3871 belongs to Infineon's SupIRBuck™ family - designed specifically for high-density, high-efficiency DC-DC point-of-load conversion in space-constrained computing and consumer electronics.

FAQ

What is the maximum allowable voltage on the BOOT pin relative to PHASE?

The absolute maximum BOOT-to-PHASE voltage is 8.0V per the datasheet Absolute Maximum Ratings table. Exceeding this risks permanent damage to the internal bootstrap diode and high-side gate driver. Designers must select a BOOT capacitor with sufficient voltage rating and low ESR to maintain this differential during switching transitions.

How is over-current protection configured on the IR3871MTRPBF?

OCP is set by connecting a resistor between ISET (pin 2) and PHASE (pin 12). The ISET pin sources a precise 20µA current; the resulting voltage drop across the resistor determines the current limit threshold. For example, a 10kΩ resistor yields ~200mV across the high-side MOSFET, corresponding to ~8A trip point based on R_DS(on) and sensing gain.

Does the IR3871MTRPBF support forced continuous conduction mode (FCCM)?

No - the IR3871MTRPBF operates exclusively in constant on-time (COT) mode and does not include an FCCM pin or control mechanism. It automatically transitions between CCM and DCM based on load; light-load efficiency is maintained via pulse-frequency modulation (PFM)-like behavior inherent to COT architecture.

Can the IR3871MTRPBF be used with an output voltage below 0.5V?

No - the internal reference is fixed at 0.5V ±1%, and the FB comparator is designed to regulate only down to this voltage. Attempting to set V_OUT < 0.5V violates the specified operating conditions and results in loss of regulation, as confirmed by the Electrical Specifications table listing 0.5V as the minimum V_OUT value.

IR3871MTRPBF Specifications

Product attributes: Attribute value

Manufacturer:: Infineon Technologies

Series:: SupIRBuck®

Package/Case:: 17-PowerVQFN

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 3V

Voltage - Input (Max):: 26V

Voltage - Output (Min/Fixed):: 0.5V

Voltage - Output (Max):: 12V

Current - Output:: 8A

Frequency - Switching:: Up to 1MHz

Synchronous Rectifier:: Yes

Operating Temperature:: 0°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: PQFN (5x6)

IR3871MTRPBF FAQ

1.How can I place an order for IR3871MTRPBF through Aetrix?

Please submit a Request for Quotation (RFQ) for IR3871MTRPBF 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 IR3871MTRPBF reliable?

The price and inventory of IR3871MTRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IR3871MTRPBF is usually 5 days.

3.What payment methods are accepted for IR3871MTRPBF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IR3871MTRPBF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IR3871MTRPBF?

IR3871MTRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IR3871MTRPBF 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 IR3871MTRPBF?

For technical support, including IR3871MTRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IR3871MTRPBF requirements.

6.How does Aetrix verify that IR3871MTRPBF is sourced from the original manufacturer or authorized distributors?

All IR3871MTRPBF 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 IR3871MTRPBF meets industry standards.

7.What is the process for return or replacement of IR3871MTRPBF?

All IR3871MTRPBF units undergo pre-shipment inspection (PSI). If there is an issue with IR3871MTRPBF, 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 IR3871MTRPBF part is unused and in its original packaging.

Return procedure for IR3871MTRPBF:

1.Submit a request within 90 days.

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

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