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Infineon Technologies IR3843AMTR1PBF
- Part No.:
- IR3843AMTR1PBF
- Manufacturer:
- Infineon Technologies
- Package:
- 15-PowerVQFN
- Datasheet:
-
IR3843AMTR1PBF.pdf
- Description:
- IC REG BUCK ADJ 3A PQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,385
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Product details
Overview
IR3843AMTR1PBF from Infineon Technologies is a fully integrated 3A synchronous buck regulator with on-die high- and low-side MOSFETs, programmable switching frequency (250–1200 kHz), precision 0.7 V ±1% reference, and hiccup-mode overcurrent protection. It operates from 1.5 V to 21 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 IR3843AMTR1PBF datasheet, IR3843AMTR1PBF pinout, IR3843AMTR1PBF application, or IR3843AMTR1PBF equivalent, key selection criteria include its integrated bootstrap diode, sequenced enable/soft-start capability via Seq and SS/SD pins, thermal shutdown at 140°C, and compatibility with 5 mm × 6 mm Power QFN packaging for high-density DC-DC designs.
Technical Context
The IR3843A implements a current-mode PWM controller with an internal error amplifier (GBWP = 20–40 MHz, slew rate = 7–20 V/μs) and programmable ramp generator (1.8 Vp-p, 0.6 V offset). Its dual ground structure-separate PGND and GND-minimizes noise coupling between power and signal paths.
Protection architecture includes adjustable overcurrent threshold via OCSet resistor-to-SW connection, pre-bias startup support, and open-drain PGood with 256-cycle delay (256/Fs). The Enable pin features voltage monitoring with UVLO thresholds (1.14–1.36 V start, 0.9–1.06 V stop) and leakage <15 μA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.5 V to 21 V - supports wide-range industrial and telecom inputs including 3.3 V, 5 V, 12 V, and 19 V rails. |
| Output Current | Continuous 3 A - sufficient for CPU core, GPU, or FPGA I/O rail regulation without external current sharing. |
| Reference Voltage | 0.7 V ±1% (0°C–125°C) - enables accurate low-VOUT setting (e.g., 0.8 V, 1.0 V, 1.2 V) with minimal drift. |
| Switching Frequency | 250 kHz to 1.2 MHz - selectable via Rt resistor; higher frequencies reduce inductor size but increase switching loss. |
| Thermal Shutdown | 140°C with 20°C hysteresis - prevents latch-up during sustained overload or poor PCB thermal design. |
| Package | 5 mm × 6 mm Power QFN, 0.9 mm height, 15-pin - optimized for thermal dissipation and layout compactness in multi-rail PMUs. |
| Soft-Start Time | Programmable via SS/SD capacitor - controls inrush current and avoids output overshoot during power-up. |
Pinout & Package
IR3843AMTR1PBF uses a 15-pin 5 mm × 6 mm Power QFN package with exposed thermal pad (PGND-connected) and 0.9 mm profile. Pin 1 is Seq; pin 15 is Gnd. Signal and power grounds are separated (Gnd vs. PGnd) to isolate control-loop noise from high di/dt paths.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 Seq | Sequencing input | Enables simultaneous or staggered power-up with other regulators using external resistor divider; tied to Vcc if unused. |
| 2 FB | Error amplifier inverting input | Connects to output voltage divider; sets regulated VOUT = 0.7 V × (1 + R1/R2). |
| 3 COMP | Error amplifier output | Drives external RC compensation network to stabilize loop response and ensure phase margin >45°. |
| 4, 15 GND | Signal ground | Reference return for internal bias, error amp, and logic; must be routed separately from PGND. |
| 5 Rt | Frequency set input | Resistor to GND programs fSW: 59 kΩ → 250 kHz, 28.7 kΩ → 500 kHz, 11.5 kΩ → 1.2 MHz. |
| 6 SS/SD | Soft-start/shutdown | Capacitor to GND sets soft-start time; <0.3 V forces shutdown with hiccup recovery. |
| 7 OCSet | Overcurrent threshold | Resistor from OCSet to SW sets current limit: e.g., 500 kHz operation → 43–54.6 μA threshold. |
| 8 PGood | Power-good status | Open-drain output asserts high after VOUT reaches 0.77–0.84 V with 256-cycle delay; requires external pull-up. |
| 9 VCC | Bias supply input | Powers internal logic and gate drivers; requires ≥1 μF ceramic cap to PGND for stability. |
| 10 PGND | Power ground | Return path for high-side/low-side MOSFETs and SW node; must connect directly to thermal pad and power plane. |
| 11 SW | Switch node | Connects to inductor; carries full switching waveform (0 V to Vin); critical for EMI and layout. |
| 12 VIN | Main input supply | Accepts 1.5–21 V; decoupling required near pin with low-ESR capacitors. |
| 13 Boot | High-side driver supply | 0.1 μF capacitor to SW provides floating bias for upper MOSFET gate drive. |
| 14 Enable | Startup control | UVLO-controlled input: device enables only when voltage exceeds 1.14–1.36 V; leakage <15 μA. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Bootstrap Diode | Eliminates external bootstrap diode, reducing BOM count and layout area while maintaining reliable high-side drive. |
| Enhanced Pre-Bias Start-up | Allows safe startup into pre-biased output without reverse current flow or output collapse. |
| Programmable Hiccup Current Limit | Auto-retries after fault instead of latching off, enabling self-recovery in transient overload conditions. |
| Separate PGND/GND Pins | Minimizes ground bounce and improves PSRR by isolating power-switching noise from sensitive analog circuitry. |
| Tracking Sequencing (Seq Pin) | Supports precise voltage ramp alignment across multiple rails using resistor-based tracking ratio. |
Applications
| Server VRM Core Regulation | Telecom Line Card Power |
|---|---|
Use Scenario: Regulating 0.8 V/3 A CPU core voltage from 12 V intermediate bus in 1U rack servers. IC Role / Device Role / Timing Role: Primary synchronous buck controller with integrated FETs, delivering fast transient response (<10 μs) and tight load regulation (±1%). Use Value: Reduces solution footprint by 35% vs. discrete controller+FETs and eliminates external bootstrap diode placement errors. | Use Scenario: Generating 3.3 V/2.5 A auxiliary supply for DSPs and SerDes on 48 V-powered telecom line cards. IC Role / Device Role / Timing Role: Point-of-load regulator with sequencing (Seq) and PGood signaling to coordinate with main 12 V and -48 V rails. Use Value: Enables hot-swap compliance via controlled soft-start and hiccup-mode fault handling during card insertion. |
| Storage Controller I/O Supply | Embedded Networking Switch ASIC Bias |
Use Scenario: Providing 1.2 V/3 A I/O voltage for NVMe SSD controllers with strict ripple (<10 mVpp) and fast load-step response. IC Role / Device Role / Timing Role: High-bandwidth buck regulator using COMP compensation to achieve >200 kHz crossover and >60° phase margin. Use Value: Maintains stable VIO during 0–3 A load transients with <20 mV undershoot, preventing data corruption. | Use Scenario: Delivering 0.95 V/2.8 A core voltage to 28 nm switch ASICs in fanless edge networking gear. IC Role / Device Role / Timing Role: Thermally robust PoL regulator operating up to 125°C junction temperature with built-in thermal shutdown. Use Value: Sustains full 3 A output without derating in sealed enclosures, eliminating need for forced air cooling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2315DJ-LF-Z (Monolithic Power) | 2.5 A rated, fixed 500 kHz fSW, no Seq pin, smaller 3 mm × 4 mm QFN | Lacks tracking sequencing and programmable frequency; limited to single-rail, space-constrained apps | Select when board area is critical and multi-rail coordination is unnecessary. |
| TPS543320RHLT (Texas Instruments) | 3 A, 2.2 MHz max fSW, PMBus interface, integrated telemetry, larger 4 mm × 5 mm QFN | Supports digital configuration and real-time monitoring but requires firmware integration | Select when system-level telemetry, dynamic voltage scaling, or remote fault logging is required. |
Compared with MP2315DJ-LF-Z and TPS543320RHLT, IR3843AMTR1PBF offers balanced analog programmability (Rt, OCSet, SS), robust analog sequencing (Seq), and thermal resilience (125°C TJ) without digital overhead-ideal for cost-sensitive, high-reliability analog power domains.
Availability
IR3843AMTR1PBF is available at Aetrix Electronics and suitable for server VRMs, telecom line cards, and embedded storage controllers requiring stable component supply, long-lifecycle availability, and RoHS-compliant packaging.
Supply support for IR3843AMTR1PBF 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 9001 and IATF 16949.
The SupIRBuck™ product line delivers highly integrated, thermally optimized DC-DC buck regulators targeting high-efficiency, space-constrained point-of-load applications in datacenter, telecom, and industrial infrastructure.
FAQ
What is the minimum recommended output capacitance for stable operation?
The IR3843AMTR1PBF requires ≥22 μF total output capacitance with ≤5 mΩ ESR for stable 3 A operation at 500 kHz. Use ceramic capacitors placed close to the SW and PGND pins; typical designs use three 10 μF X5R 0805 caps in parallel to meet ripple and transient requirements.
Can the IR3843AMTR1PBF operate with a 3.3 V input supply?
Yes - the device supports input voltages as low as 1.5 V. At 3.3 VIN, it can regulate down to 0.7 VOUT with full 3 A capability, provided thermal design maintains TJ ≤ 125°C. Efficiency exceeds 88% at 3.3 VIN/1.0 VOUT/2 A per datasheet Fig. 12.
How is the overcurrent threshold adjusted using the OCSet pin?
A resistor from OCSet to SW sets the current limit: ROCSET = VREF / IOCSET, where IOCSET varies with fSW (e.g., 48.8 μA at 500 kHz). For 3.5 A limit at 500 kHz, use R = 0.7 V / 48.8 μA ≈ 14.3 kΩ. The threshold is internally scaled and does not require calibration.
Is the IR3843AMTR1PBF pin-compatible with earlier IR3843 variants?
Yes - IR3843AMTR1PBF is a drop-in replacement for IR3843MTR1PBF and IR3843PMTR1PBF, sharing identical pinout, package, and electrical specifications. The "A" suffix denotes enhanced MSL2 moisture sensitivity rating and updated thermal performance validation per Rev 16.0.
IR3843AMTR1PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Infineon Technologies
- Series:
- SupIRBuck®
- Package/Case:
- 15-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:
- 3A
- Frequency - Switching:
- 225kHz ~ 1.32MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- PQFN (5x6)
IR3843AMTR1PBF FAQ
1.How can I place an order for IR3843AMTR1PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for IR3843AMTR1PBF 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 IR3843AMTR1PBF reliable?
The price and inventory of IR3843AMTR1PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for IR3843AMTR1PBF is usually 5 days.
3.What payment methods are accepted for IR3843AMTR1PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for IR3843AMTR1PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for IR3843AMTR1PBF?
IR3843AMTR1PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your IR3843AMTR1PBF 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 IR3843AMTR1PBF?
For technical support, including IR3843AMTR1PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your IR3843AMTR1PBF requirements.
6.How does Aetrix verify that IR3843AMTR1PBF is sourced from the original manufacturer or authorized distributors?
All IR3843AMTR1PBF 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 IR3843AMTR1PBF meets industry standards.
7.What is the process for return or replacement of IR3843AMTR1PBF?
All IR3843AMTR1PBF units undergo pre-shipment inspection (PSI). If there is an issue with IR3843AMTR1PBF, 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 IR3843AMTR1PBF part is unused and in its original packaging.
Return procedure for IR3843AMTR1PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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