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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

Infineon Technologies IR3859MTR1PBF

Name: IR3859MTR1PBF
Brand: Infineon Technologies
SKU: IR3859MTR1PBF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: IR3859MTR1PBF

Manufacturer:: Infineon Technologies

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 17-PowerVQFN

Datasheet:: IR3859MTR1PBF.pdf

Description:: IC REG BUCK ADJ 9A 17PQFN

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Product details

Overview

IR3859MTR1PBF from Infineon Technologies is a highly integrated 9A synchronous buck regulator with co-packaged high- and low-side MOSFETs, PWM controller, bootstrap diode, and precision 0.7V ±1% reference. It operates from 1.5V to 21V input, delivers 0.7V–0.9×Vin output, supports up to 1.5MHz switching, and targets point-of-load power delivery in server VRMs and telecom DC-DC converters.

For engineers reviewing the IR3859MTR1PBF datasheet, IR3859MTR1PBF pinout, IR3859MTR1PBF application, or IR3859MTR1PBF equivalent, key selection factors include programmable current limit (via OCSet), dedicated voltage monitoring (Vsns), PGood open-drain status, thermal shutdown at 140°C, and pre-bias start-up capability for reliable cold-start in distributed power architectures.

Technical Context

The IR3859 implements a voltage-mode PWM control architecture with a high-bandwidth error amplifier (GBWP: 20–40 MHz, slew rate: 7–20 V/μs) and internal ramp compensation. Its integrated power stage features top-side R_DS(on) = 21–29 mΩ and bottom-side R_DS(on) = 11–16 mΩ at T_j = 25°C, enabling >95% peak efficiency at 12V_IN/1.8V_OUT/9A.

Protection logic includes hiccup-mode overcurrent (4096-cycle off-time), overvoltage trip at 110–120% V_REF, UVLO on V_CC (start: 3.95–4.35V, stop: 3.65–4.05V), and enable-input threshold (1.14–1.36V start, 0.9–1.06V stop), all verified across –40°C to +125°C junction temperature range.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Current	Continuous 9A load capability - supports high-current POL rails without external current-sense amplifiers or discrete FETs.
Input Voltage Range	1.5V to 21V - enables single-regulator compatibility across 3.3V, 5V, 12V, and 19V intermediate bus systems.
Output Voltage Range	0.7V to 0.9×V_IN - supports sub-1V core supplies (e.g., 0.7V–0.85V CPU/GPU rails) with resistor-divider feedback.
Switching Frequency	225kHz to 1.5MHz (programmable via Rt resistor) - allows optimization of size (high-freq) vs. efficiency (mid-freq) and EMI filtering.
Reference Voltage	0.7V ±1% (0°C–125°C), ±2% (–40°C–125°C) - ensures tight output regulation tolerance critical for modern low-voltage ASICs.
Thermal Protection	Junction shutdown at 140°C with 20°C hysteresis - prevents latch-up during sustained overload or airflow loss in dense server PCBs.
Package	4mm × 5mm Power QFN, 17-pin, exposed thermal pad - provides low θ_JA = 45°C/W on 4-layer 2oz copper, supporting high-power density layouts.

Pinout & Package

IR3859MTR1PBF uses a 4mm × 5mm Power QFN package with 17 pins and an exposed thermal pad connected to PGND. The pin layout supports compact 2-layer routing and efficient thermal dissipation when soldered to a 4-layer PCB with internal ground/power planes.

Pin/Terminal	Circuit Role	Design Meaning
1 Fb	Inverting input to error amplifier	Connects directly to output via resistor divider; sets regulated V_OUT with 0.7V reference - determines accuracy and loop stability.
2 Vsns	Voltage sense for PGood comparator	Monitors output rail independently of Fb; triggers PGood assertion at 80–90% V_REF with 256/F_s delay - enables precise power sequencing.
3 Comp	Error amplifier output	Drives external RC compensation network between Comp and Fb - sets phase margin and transient response bandwidth.
4,17 Gnd	Signal ground reference	Provides low-noise return for internal bias and reference circuits - must be isolated from noisy PGnd to avoid control-loop coupling.
5 Rt	Frequency set resistor node	Connects external resistor to Gnd; sets f_SW from 225kHz to 1.5MHz - enables EMI compliance and inductor size optimization.
6 SS	Soft-start/shutdown control	Capacitor-to-Gnd sets startup time; <0.3V forces shutdown - prevents inrush current and supports controlled power-down.
7 OCSet	Overcurrent threshold programming	Resistor from OCSet to SW sets current limit; IOCSET = 20.8–172 μA depending on f_SW - enables scalable fault protection.
8 PGood	Open-drain power-good indicator	Asserts high after V_OUT reaches 80–90% V_REF; requires external pull-up to V_CC - used for downstream enable sequencing.
9 Sync	External clock synchronization input	Accepts 225–1650kHz square wave; aligns switching edges across multiple IR3859s - eliminates beat frequencies in multi-phase systems.
10 Vcc	Bias supply for controller/driver	Requires ≥1μF HF ceramic cap to PGnd; UVLO thresholds ensure safe startup/shutdown - powers gate drivers and logic core.
11 PGnd	Power ground for MOSFET drivers	Separate from signal Gnd; connects to system power plane near SW node - minimizes switching noise injection into control circuitry.
12 SW	Switch node	Connects to inductor and boot capacitor; handles full switching voltage/current swing - requires short, low-inductance layout to reduce ringing.
13 VIN	Main input voltage supply	Accepts 1.5–21V; feeds high-side FET and internal LDO - must be decoupled with bulk + HF capacitors near package.
14 Boot	Bootstrap supply for high-side driver	0.1μF capacitor to SW generates floating gate drive voltage - eliminates need for external charge pump or isolated supply.
15 Enable	Input enable/disable control	Two-resistor divider sets turn-on threshold (1.14–1.36V); leakage <15μA - supports power sequencing and brown-out hold-off.
16 Seq	Power-up sequencing control	Two-resistor divider sets tracking ratio vs. master rail; connect to V_CC if unused - enables simultaneous or staggered startup with other regulators.

Key Features

Feature	Design Value
Integrated bootstrap diode	Eliminates external Schottky diode, reducing BOM count and board area while maintaining >95% efficiency at 9A.
Programmable hiccup OCP	Auto-retry protection with 4096-cycle off-time prevents thermal runaway during sustained short-circuit conditions.
Enhanced pre-bias start-up	Allows safe turn-on even when output is pre-charged - essential for hot-swap and redundant power systems.
Dedicated Vsns pin	Enables independent voltage monitoring for PGood without affecting feedback loop stability or accuracy.
External sync capability	Supports deterministic multi-rail timing alignment across up to 16 synchronized IR3859s - reduces system-level EMI peaks.

Applications

Server VRM

Storage Controller Power

Use Scenario: Primary 1.8V/9A core supply for dual-socket x86 server CPUs with dynamic load steps up to 6A/μs.

IC Role / Device Role / Timing Role: Synchronous buck regulator delivering tightly regulated POL voltage with <1% load regulation and <50μs transient recovery.

Use Value: Integrated MOSFETs and 0.7V ±1% reference ensure stable operation under rapid DVFS transitions without external compensation tuning.

Use Scenario: 3.3V/5A auxiliary rail for NVMe SSD controllers requiring clean, low-noise power with sequencing dependency on main 12V bus.

IC Role / Device Role / Timing Role: Programmable soft-start and Seq pin enable synchronized ramp-up with host SoC, preventing back-drive during insertion.

Use Value: Dedicated Vsns and PGood with 256/F_s delay provide precise power-good assertion timing aligned to PCIe reset timing requirements.

Embedded Telecom System

Industrial Edge AI Module

Use Scenario: 1.2V/6A supply for packet-processing ASIC in carrier-grade access equipment operating at –40°C to +85°C ambient.

IC Role / Device Role / Timing Role: Thermal shutdown at 140°C with 20°C hysteresis protects against airflow blockage in sealed chassis.

Use Value: Wide input range (1.5–21V) accommodates both 3.3V and 12V intermediate buses, simplifying platform power architecture.

Use Scenario: 0.75V/7A core rail for edge inference accelerator (e.g., Intel Movidius Myriad X) in fanless industrial gateway.

IC Role / Device Role / Timing Role: Pre-bias start-up and hiccup OCP ensure robust operation during field firmware updates with partial power cycling.

Use Value: 4mm × 5mm QFN footprint and 45°C/W θ_JA allow thermal design within 12W power envelope without heatsink.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MP2451DT-LF-Z	3A max output, no integrated high-side FET, requires external bootstrap capacitor, 0.8V reference, fixed 500kHz f_SW	Targeted at lower-current, cost-sensitive applications; lacks PGood, sequencing, and sync inputs	Select when output current ≤3A and system-level sequencing is handled externally.
TPS549D22RQFT	9A output, 0.6V reference, D-CAP3 control, 4.5–18V input, integrated MOSFETs, but no dedicated Vsns pin or Seq input	Optimized for ultra-fast transient response in compute applications; lacks independent voltage monitor for PGood	Select when fastest load-step response is prioritized over independent power-good timing or multi-rail sequencing.

Compared with MP2451DT-LF-Z and TPS549D22RQFT, the IR3859MTR1PBF uniquely combines 9A capability, dedicated Vsns/Pgood/Seq/Sync pins, and pre-bias start-up - making it the only choice for telecom and server designs requiring coordinated multi-rail power management with guaranteed cold-start reliability.

Availability

IR3859MTR1PBF is available at Aetrix Electronics and suitable for server VRMs, storage controller power, embedded telecom systems, and industrial edge AI modules requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for IR3859MTR1PBF 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 leader specializing in power management, automotive ICs, and industrial control solutions, with global manufacturing and quality certification to ISO/TS 16949 and IATF 16949 standards.

The IR3859 belongs to Infineon's SupIRBuck™ family - engineered specifically for high-efficiency, space-constrained point-of-load conversion in datacenter, networking, and telecom infrastructure where integration, thermal performance, and programmability are critical.

FAQ

What is the minimum recommended input voltage for reliable operation?

The IR3859MTR1PBF specifies a minimum input voltage of 1.5V per absolute maximum ratings and recommended operating conditions. Below this level, the internal LDO cannot sustain V_CC regulation, and gate drive voltage collapses - causing uncontrolled dropout or oscillation. Operation at 1.5V is validated only with V_OUT ≤0.9×V_IN and full thermal derating applied.

How does the OCSet pin determine overcurrent threshold?

The OCSet pin sources a current (20.8–172 μA, dependent on switching frequency) that flows through an external resistor to the SW node. The resulting voltage drop across the resistor sets the current-sense threshold for the internal comparator. For example, at 500kHz, 48.8 μA into a 10kΩ resistor yields ~488mV, corresponding to ~25A sensed at the bottom FET source.

Can the IR3859MTR1PBF operate without an external bootstrap capacitor?

No - the Boot pin requires a 0.1μF ceramic capacitor connected directly to the SW node to generate the floating gate drive voltage for the high-side MOSFET. Omitting this capacitor causes immediate high-side FET failure due to insufficient V_GS, confirmed in functional testing and absolute maximum ratings (Boot–SW voltage limit: –0.3V to V_CC+0.3V).

Is the exposed thermal pad electrically connected internally?

Yes - the exposed pad on the underside of the 4mm × 5mm Power QFN package is internally connected to PGnd, not Gnd or V_IN. Per package documentation, it must be soldered to a dedicated PGnd copper pour on the PCB with thermal vias to inner ground planes to achieve the specified θ_JA = 45°C/W and prevent thermal shutdown under 9A load.

IR3859MTR1PBF Specifications

Product attributes: Attribute value

Manufacturer:: Infineon Technologies

Series:: SupIRBuck®

Package/Case:: 17-PowerVQFN

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 1.5V

Voltage - Input (Max):: 21V

Voltage - Output (Min/Fixed):: 0.7V

Voltage - Output (Max):: 18.9V

Current - Output:: 9A

Frequency - Switching:: 225kHz ~ 1.65MHz

Synchronous Rectifier:: Yes

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 17-PQFN (5x6)

IR3859MTR1PBF FAQ

1.How can I place an order for IR3859MTR1PBF through Aetrix?

Please submit a Request for Quotation (RFQ) for IR3859MTR1PBF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for IR3859MTR1PBF reliable?

The price and inventory of IR3859MTR1PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IR3859MTR1PBF is usually 5 days.

3.What payment methods are accepted for IR3859MTR1PBF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IR3859MTR1PBF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for IR3859MTR1PBF?

IR3859MTR1PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your IR3859MTR1PBF order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for IR3859MTR1PBF?

For technical support, including IR3859MTR1PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IR3859MTR1PBF requirements.

6.How does Aetrix verify that IR3859MTR1PBF is sourced from the original manufacturer or authorized distributors?

All IR3859MTR1PBF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that IR3859MTR1PBF meets industry standards.

7.What is the process for return or replacement of IR3859MTR1PBF?

All IR3859MTR1PBF units undergo pre-shipment inspection (PSI). If there is an issue with IR3859MTR1PBF, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The IR3859MTR1PBF part is unused and in its original packaging.

Return procedure for IR3859MTR1PBF:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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