Infineon Technologies IR3897MTR1PBF

Overview

IR3897MTR1PBF from Infineon Technologies is a 4A 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 1.0–21 V input and delivers 0.5–0.86×Vin output, supporting monotonic pre-bias startup and tracking in server point-of-load applications.

For engineers reviewing the IR3897MTR1PBF datasheet, IR3897MTR1PBF pinout, IR3897MTR1PBF application, or IR3897MTR1PBF equivalent, key selection criteria include thermally compensated current limit, external synchronization capability, precision margining via Vref, and robust hiccup-mode overcurrent protection under transient load conditions.

Technical Context

The IR3897 implements a voltage-mode PWM controller with feed-forward line regulation and zero-crossing detection for accurate duty-cycle control. Its error amplifier features 100–120 dB DC gain, 20–40 MHz GBWP, and ±1.5% input offset-enabling tight regulation across temperature and load.

Internal architecture integrates bootstrap diode, MOSFET drivers, and a smart LDO that supplies gate drive while optimizing efficiency at light and full load. The device supports three operating modes: normal (Vref referenced), sequencing (Vp tracking), and margining (Vref adjustable between 0.4–1.2 V).

Key Specifications

Pinout & Package

IR3897MTR1PBF uses a thermally enhanced 4 mm × 5 mm PQFN package with exposed thermal pad (PD-97663). Pin numbering follows top-view layout with dedicated power ground (PGnd) and signal ground (Gnd) separation for noise immunity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP2451DT-LF-Z and TPS544B20RJRT, IR3897MTR1PBF uniquely balances analog simplicity, analog tracking capability, and thermal performance in a 4 mm × 5 mm footprint-making it optimal for analog-sequenced, high-reliability server and telecom PoL where digital overhead is unnecessary.

Availability

IR3897MTR1PBF is available at Aetrix Electronics and suitable for server point-of-load, telecom line card power, and embedded networking switch applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for IR3897MTR1PBF 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 global manufacturing and quality certification to ISO/TS 16949 and IECQ QC 080000.

The SupIRBuck™ product line delivers highly integrated, thermally optimized DC/DC regulators for demanding point-of-load applications in datacenter, telecom, and storage infrastructure-emphasizing reliability, efficiency, and ease of use without digital complexity.

FAQ

What is the minimum recommended output capacitance for stable operation at 4 A load?

The datasheet specifies ≥220 µF ceramic output capacitance with ≤5 mΩ ESR for 1.2 V output at 4 A. Lower ESR improves transient response and reduces output voltage deviation during 2 A/µs load steps. Use parallel X7R/X5R MLCCs with derated voltage rating (≥2× V_OUT) to ensure stability across temperature and aging.

Can IR3897MTR1PBF operate without an external Vcc supply?

Yes-it supports single-rail operation from PVin (1.0–21 V) using its internal smart LDO, which powers gate drivers and control circuitry. When Vin ≥6.8 V, the LDO operates in regulation; below 6.8 V, external Vcc must be supplied to Vcc/LDO_Out to maintain functionality and prevent dropout-induced instability.

How does the Vp pin function in tracking mode?

In tracking mode, Vp accepts an external voltage ramp (e.g., from another regulator's output) and forces IR3897's output to follow it with ±4 A sink/source capability. This enables precise power-rail sequencing during system startup/shutdown, avoiding backfeeding or latch-up in multi-rail systems with mixed voltage domains.

Is the PGood output compatible with 3.3 V logic systems?

Yes-PGood is open-drain and rated for ≤3.9 V maximum voltage. A 49.9 kΩ pull-up to any supply ≤Vcc (e.g., 3.3 V) configures it for direct interfacing with standard CMOS logic. The output asserts low when V_OUT falls outside the ±5% window, providing clean reset signaling without level-shifting.