Infineon Technologies IR3899MTRPBF

Overview

IR3899MTRPBF from Infineon Technologies is a 9A synchronous buck regulator with integrated high- and low-side MOSFETs, programmable 300–1500 kHz switching frequency, 0.5 V ±0.5% reference accuracy, and 1.0–21 V input range. It delivers regulated output from 0.5 V to 0.86×Vin in compact 4 mm × 5 mm PQFN, used in server point-of-load power delivery.

For engineers reviewing the IR3899MTRPBF datasheet, IR3899MTRPBF pinout, IR3899MTRPBF application, or IR3899MTRPBF equivalent, key selection factors include thermally compensated current limit (±9 A), monotonic start-up, precision tracking capability via Vp pin, and internal LDO biasing for efficiency across light-to-full load.

Technical Context

The IR3899 operates as a voltage-mode PWM controller with feed-forward line regulation and zero-crossing detection for accurate duty-cycle control. Its error amplifier supports margining (Vref = 0.4–1.2 V), tracking (Vp ±9 A sink/source), and precise PGood sequencing with dual thresholds (85–95% turn-on, 80–90% lower turn-off).

It integrates bootstrap diode, smart internal LDO (6.4 V typical output), and robust protection including hiccup-mode OCP, thermal shutdown, and UVLO on both Enable (1.2 V start) and Vcc (4.2 V start). The 5 ns dead-band prevents shoot-through during high-frequency operation up to 1.5 MHz.

Key Specifications

Pinout & Package

IR3899MTRPBF uses a 17-pin 4 mm × 5 mm Power QFN (PQFN) package with exposed thermal pad. Pin 17 and Pin 4 are signal ground; Pin 11 is dedicated power ground (PGnd) for MOSFET driver return; Pin 13 (PVin) handles high-current input; Pin 12 (SW) connects directly to output inductor.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP8765GQ-Z and TPS549D22, IR3899MTRPBF uniquely combines 9 A capability, integrated LDO biasing, Vp-based tracking, and monotonic start-up in one 4×5 mm package-making it optimal for space-constrained, multi-rail server and telecom PoL designs where sequencing integrity and thermal efficiency are critical.

Availability

IR3899MTRPBF is available at Aetrix Electronics and suitable for server core voltage regulation, telecom line card power, and storage controller power requiring stable component supply and long-term industrial lifecycle support.

Supply support for IR3899MTRPBF 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 ICs, with leadership in high-efficiency DC/DC conversion and silicon power devices.

The SupIRBuck™ product line targets high-density, high-reliability point-of-load applications in datacenter, networking, and telecom infrastructure-designed to replace discrete buck controllers + MOSFETs with fully integrated, thermally optimized regulators.

FAQ

What is the maximum supported output voltage for IR3899MTRPBF?

The IR3899MTRPBF supports output voltages from 0.5 V up to 0.86×Vin. With maximum Vin of 21 V, the theoretical upper limit is 18.06 V; however, practical use is constrained by SW node voltage rating (25 V absolute max) and recommended operating conditions limiting VO to ≤15 V for reliability. Output is set via resistor divider on Fb pin referenced to 0.5 V internal reference.

Does IR3899MTRPBF require an external bootstrap capacitor?

Yes, a 100 nF ceramic capacitor must be placed between Boot and SW pins per datasheet recommendation. This capacitor supplies gate drive voltage for the high-side MOSFET during each switching cycle. Failure to install it results in insufficient high-side drive, leading to erratic operation or complete failure to regulate.

Can IR3899MTRPBF operate without connecting the Vcc/LDO_Out pin?

No. The Vcc/LDO_Out pin must be decoupled with ≥2.2 µF to PGnd and either powered externally or tied to Vin (if Vin ≥6.8 V). When Vin drops below 6.8 V, the internal LDO enters dropout; unpowered Vcc/LDO_Out causes loss of gate drive and control logic functionality, resulting in shutdown.

How does the Vp pin function in tracking mode?

In tracking mode, Vp accepts an external voltage reference (e.g., from another regulator's output) and forces the IR3899's output to follow it with ±9 A sink/source capability. The error amplifier compares Vp to Fb, enabling precise ramp alignment during power-up/down. Vp must be biased within 0–1.2 V; floating Vp disables tracking and defaults to standard regulation.