Infineon Technologies IR3843WMTR1PBF

Overview

IR3843WMTR1PBF from Infineon Technologies is a highly integrated 2A synchronous buck regulator with on-die high- and low-side MOSFETs, programmable switching frequency up to 1.5 MHz, precision 0.7 V ±1% reference, and hiccup-mode overcurrent protection. It operates from 1.5 V to 16 V input and delivers 0.7 V to 0.9×Vin output, targeting point-of-load regulation in server VRMs and telecom power modules.

For engineers reviewing the IR3843WMTR1PBF datasheet, IR3843WMTR1PBF pinout, IR3843WMTR1PBF application, or IR3843WMTR1PBF equivalent, key selection criteria include its integrated bootstrap diode, Seq pin for voltage tracking, PGood open-drain status output, and thermal shutdown at 140°C junction temperature.

Technical Context

The IR3843W implements a current-mode PWM control architecture with a high-bandwidth error amplifier (GBWP: 20–40 MHz, slew rate: 7–20 V/μs) and programmable fixed off-time (130–200 ns) for fast transient response. Its internal oscillator supports frequency setting via external Rt resistor (225–1650 kHz), and the OCSet pin enables precise current-limit threshold adjustment using an external resistor to SW.

It features dual ground separation (Gnd for signal, PGnd for power), dedicated boot capacitor node (Boot–SW), and enhanced pre-bias startup capability. The device integrates thermal shutdown with 20°C hysteresis and supports sequencing via the Seq pin with external resistor dividers for synchronized power-up across multiple rails.

Key Specifications

Pinout & Package

IR3843WMTR1PBF uses a 5 mm × 6 mm Power QFN package with 0.9 mm height, 15-pin layout, exposed thermal pad, and RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP2315DJ-LF-Z and TPS54202DRCT, IR3843WMTR1PBF offers superior integration (integrated MOSFETs + bootstrap diode), tighter reference accuracy (±1% vs ±2%), and built-in sequencing support - reducing design cycle time for compact, thermally constrained PoL applications.

Availability

IR3843WMTR1PBF is available at Aetrix Electronics and suitable for server applications, storage subsystems, and embedded telecom systems requiring stable component supply, long-term lifecycle assurance, and consistent parametric performance across production batches.

Supply support for IR3843WMTR1PBF 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 MCUs, and industrial control ICs, with global manufacturing and quality certification to ISO/TS 16949 and IATF 16949 standards.

The IR3843W belongs to Infineon's SupIRBuck™ family of integrated DC-DC regulators, designed specifically for high-density, high-efficiency point-of-load conversion in datacenter and communications infrastructure where thermal performance and layout simplicity are critical.

FAQ

What is the minimum recommended output capacitance for stable operation at 2 A load?

The IR3843WMTR1PBF datasheet specifies a minimum 22 μF ceramic output capacitor with ≤5 mΩ ESR for stability across the full 0.7–0.9×Vin range. Using two 10 μF X5R 0805 capacitors in parallel meets both capacitance and ESR requirements while improving thermal derating margin at 125°C junction temperature.

Can the IR3843WMTR1PBF operate with a 3.3 V input supply?

Yes - the device supports input voltages as low as 1.5 V, making it fully compatible with 3.3 V input rails. At Vin = 3.3 V, the maximum regulated output is 0.9×3.3 V = 2.97 V, and the 0.7 V reference ensures accurate regulation down to sub-1 V outputs such as 0.85 V for low-power logic rails.

How is the overcurrent protection threshold set and verified?

The OCSet pin connects via an external resistor to the SW node; the resulting current (e.g., 48.8 μA at 500 kHz) sets the current limit threshold. This value is validated by measuring inductor current during overload and confirming hiccup-mode activation occurs within ±5% of the calculated trip point based on MOSFET Rds(on) and sense resistance.

Is the thermal pad on the Power QFN package required to be soldered to PCB ground?

Yes - the exposed thermal pad must be soldered to a solid copper pour connected to PGnd for effective heat dissipation. The datasheet specifies θJA = 35°C/W with a 4-layer PCB having 2 in² of 2-oz copper on the bottom layer; omitting thermal pad connection increases junction temperature by >40°C at full 2 A load.