Infineon Technologies IR3853MTRPBF

Overview

IR3853MTRPBF from Infineon Technologies is a fully integrated 4A synchronous buck regulator with on-die high- and low-side MOSFETs, 0.7V ±1% reference voltage, programmable 225–1650 kHz switching frequency, and dedicated PGood output. It delivers up to 95% efficiency at 12V_IN/1.8V_OUT/4A and supports pre-bias start-up, hiccup current limiting, and thermal shutdown for server point-of-load applications.

For engineers reviewing the IR3853MTRPBF datasheet, IR3853MTRPBF pinout, IR3853MTRPBF application, or IR3853MTRPBF equivalent, key selection considerations include its 4mm × 5mm Power QFN-17 package, bootstrap-diode integration, programmable OCSet threshold (20.8–172 µA), Seq pin for voltage tracking, and Vcc UVLO thresholds (4.15 V start / 3.85 V stop).

Technical Context

The IR3853MTRPBF implements a current-mode PWM controller with an internal error amplifier (GBWP = 20–40 MHz, slew rate = 7–20 V/µs) and precision 0.7 V feedback reference. Its oscillator uses an external Rt resistor to set frequency, and the COMP pin enables full loop compensation via external RC networks.

Protection architecture includes over-voltage detection on Vsns (trip at 110–120% V_REF, 150 ns delay), thermal shutdown at 140°C with 20°C hysteresis, and programmable current limit via OCSet pin (R_DS(on) of top/bottom FETs: 21/19.75 mΩ typ at 25°C). The device operates across –40°C to +125°C junction temperature.

Key Specifications

Pinout & Package

IR3853MTRPBF is housed in a thermally enhanced 4 mm × 5 mm Power QFN-17 package with exposed thermal pad connected to PGND. Pin 17 is GND (signal ground); pins 4 and 17 are both signal ground but functionally distinct-pin 4 serves as analog ground for control circuitry, while pin 17 is digital ground referenced to internal logic.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS544B20RTWR and MP2315GJ-Z, IR3853MTRPBF uniquely balances 4 A capability, full programmability (frequency, OC, soft-start), and compact 4 mm × 5 mm footprint-making it optimal for space-constrained, multi-rail telecom and server POL designs requiring precise sequencing and fault resilience.

Availability

IR3853MTRPBF is available at Aetrix Electronics and suitable for server applications, storage applications, embedded telecom systems, and distributed point-of-load power architectures requiring stable component supply and long-term industrial-grade availability.

Supply support for IR3853MTRPBF 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 IATF 16949 standards.

The IR3853 belongs to Infineon's SupIRBuck™ family-designed specifically for high-efficiency, space-constrained point-of-load regulation in computing, networking, and telecom infrastructure where integration, thermal performance, and programmability are critical.

FAQ

What is the minimum recommended input voltage for reliable operation?

The IR3853MTRPBF specifies a minimum input voltage of 1.5 V under all operating conditions. Below this, the internal gate drivers cannot maintain sufficient V_GS for the integrated MOSFETs, leading to increased conduction losses and potential instability. Operation at 1.5 V is validated only with V_OUT ≤ 0.9 × V_IN and full thermal derating applied.

How does the OCSet pin configure overcurrent protection?

The OCSet pin sets the peak inductor current limit by sinking a current (20.8–172 µA depending on switching frequency) through an external resistor to the SW node. This creates a voltage drop across the resistor that the internal comparator monitors; typical values range from 10 kΩ (higher current limit) to 100 kΩ (lower limit), per the OCSet vs. R_OCSET curve in the datasheet.

Can the IR3853MTRPBF operate without an external compensation network on the COMP pin?

No. The COMP pin requires an external Type II or Type III compensation network (resistor and capacitor from COMP to Fb) to stabilize the control loop. Omitting this results in oscillation or poor transient response. The recommended network values depend on output capacitance, ESR, and target crossover frequency-design tools and application note AN-1132 provide specific guidance.

Is the exposed thermal pad electrically connected to any internal node?

Yes-the exposed thermal pad is internally connected to PGnd (Pin 11), not Gnd (Pins 4/17). It must be soldered to a dedicated PGnd copper pour on the PCB to ensure proper thermal dissipation and low-inductance return path for high-current switching nodes. Connecting it to signal Gnd violates isolation between power and control grounds.