Infineon Technologies IR3899MTR1PBF

Overview

IR3899MTR1PBF 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 internal smart LDO biasing. It operates from 1.0 V to 21 V input, delivers 0.5 V to 0.86×Vin output, and supports monotonic pre-bias startup in server point-of-load applications.

For engineers reviewing the IR3899MTR1PBF datasheet, IR3899MTR1PBF pinout, IR3899MTR1PBF application, or IR3899MTR1PBF equivalent, key selection criteria include thermally compensated current limit (±9 A), Vp tracking capability, programmable power good with margining, and 4 mm × 5 mm PQFN package thermal performance under 125 °C junction temperature.

Technical Context

The IR3899 implements a voltage-mode PWM controller with feed-forward line regulation and zero-crossing detection for precise duty-cycle control. Its error amplifier features 100–120 dB DC gain, 20–40 MHz GBWP, and ±1.5% input offset-enabling stable regulation across 0.5 V to 1.2 V output rails.

It integrates bootstrap diode, MOSFET drivers, and an internal LDO that supplies 6.4 V ±0.3 V at up to 30 mA while maintaining <0.7 V dropout. Protection includes hiccup-mode overcurrent (robust at 9 A), OVP (115–125% Vref), UVLO on Enable (1.2 V start), and thermal shutdown at 150 °C.

Key Specifications

Pinout & Package

IR3899MTR1PBF uses a 4 mm × 5 mm, 17-pin Power QFN (PQFN) package with exposed thermal pad. Pin 11 (PGND) and Pin 17 (GND) are electrically isolated to separate power and signal return paths, minimizing ground bounce in high-dI/dt buck operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP8765GQ-Z and TPS53689RTAT, IR3899MTR1PBF uniquely combines 9 A capability, Vp-based analog tracking, internal LDO biasing down to 1.0 V input, and monotonic pre-bias startup-making it optimal for tightly sequenced, space-constrained enterprise POLs where analog coordination and wide VIN flexibility are critical.

Availability

IR3899MTR1PBF is available at Aetrix Electronics and suitable for server applications, telecom baseband power, and enterprise SSD controller supply requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.

Supply support for IR3899MTR1PBF 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 silicon and GaN-based power conversion solutions.

The IR3899 belongs to Infineon's SupIRBuck™ family-designed specifically for high-efficiency, space-constrained point-of-load regulation in enterprise computing and communications infrastructure.

FAQ

What is the minimum input voltage required for reliable operation with internal LDO biasing?

When using internal LDO biasing (Vin connected to PVin), the minimum input voltage is 6.8 V. Below this, the LDO enters dropout, degrading Vcc regulation and potentially affecting gate drive strength. For 1.0 V–6.8 V operation, an external 4.5–7.5 V bias must be applied to Vcc/LDO_Out, and Vin must be shorted to Vcc/LDO_Out per datasheet Section 6.

How does the Vp pin function in tracking mode, and what external circuitry is required?

In tracking mode, Vp accepts an external reference voltage (e.g., from a master rail) and sources or sinks up to ±9 A to force the IR3899's output to match that reference. No external op-amp or buffer is needed-the pin directly drives the error amplifier's non-inverting input. A 100 pF capacitor to GND is recommended if Vp is left floating in normal operation.

Can IR3899MTR1PBF operate without an external bootstrap capacitor?

No. A 100 nF ceramic capacitor must be placed between Boot and SW pins to sustain high-side gate drive. Omitting it causes immediate failure of the upper MOSFET driver, resulting in no switching action and potential damage due to shoot-through during startup. The internal bootstrap diode cannot replace this capacitor.

What is the purpose of the separate PGnd and Gnd pins, and how should they be routed on PCB?

PGnd (Pin 11) carries high-frequency, high-current return paths for the power stage and MOSFET drivers; Gnd (Pins 4 and 17) serves low-noise analog and control circuitry. They must connect to separate copper polygons joined at a single star point near the IC's thermal pad to prevent noise coupling into feedback and reference circuits.