Monolithic Power Systems Inc. MPL-AL4020-3R3

Overview

MPL-AL4020-3R3 from Monolithic Power Systems is a low-resistance molded power inductor with 3.3 µH nominal inductance, 34.5 mΩ typical DCR, 4.4 A rated current (ΔT = 40 K), and 5.2 A saturation current at both 25°C and 100°C ambient - optimized for high-current, high-frequency DC-DC converters in FPGA and POL applications.

For engineers reviewing the MPL-AL4020-3R3 datasheet, MPL-AL4020-3R3 pinout (though non-pin device), MPL-AL4020-3R3 application in SMPS output filtering or buck converter energy storage, or MPL-AL4020-3R3 equivalent for low-DCR, soft-saturation molded inductors, this page delivers verified electrical specs, thermal behavior, package dimensions, and design-critical performance trade-offs.

Technical Context

This molded inductor uses composite magnetic material with distributed air gap to achieve soft saturation characteristics and stable inductance over temperature (–40°C to +155°C). Its 4.1 mm × 4.1 mm × 1.9 mm footprint supports high-density PCB layouts in space-constrained POL and embedded computing designs.

Designed for switching frequencies up to 30 MHz (typical self-resonant frequency), it minimizes AC losses and audible noise while maintaining low DCR - critical for efficiency in high-current buck regulators powering FPGAs and ASICs where thermal headroom and ripple current handling are tightly constrained.

Key Specifications

Pinout & Package

As a two-terminal surface-mount molded inductor, MPL-AL4020-3R3 has no active pins or signal routing - terminals are symmetric, non-polarized copper pads conforming to the land pattern specified in the datasheet (4.1 mm × 4.1 mm body, 1.9 mm height). Marking includes dot indicating start of winding and "3R3" inductance code.

Key Features

Applications

Availability

MPL-AL4020-3R3 is available at Aetrix Electronics and suitable for FPGA core rails, POL converters, and high-current SMPS requiring stable component supply, consistent thermal performance, and RoHS-compliant manufacturing.

Supply support for MPL-AL4020-3R3 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

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance power management ICs and passive components, headquartered in Kirkland, WA, with global design and support centers.

The MPL-AL series is engineered specifically for high-efficiency, high-density DC-DC conversion - emphasizing low DCR, soft saturation, and thermal resilience in compact molded packages for next-generation embedded and computing power systems.

FAQ

What is the maximum allowable PCB temperature rise when operating at rated current?

The rated current of 4.4 A is defined as the DC current causing a 40 K temperature rise above ambient on a standardized test board (35 µm Cu, 30×50 mm single layer). Actual rise depends on PCB copper area, thickness, and nearby heat sources - real-world layouts may require thermal simulation or empirical validation.

Does MPL-AL4020-3R3 have polarity or winding direction sensitivity?

Yes - the dot marking indicates the start of winding. While electrically non-polarized, consistent orientation improves EMI performance in differential layouts and simplifies current-sense resistor placement. The datasheet recommends aligning dots across parallel inductors to minimize mutual coupling effects.

How does saturation current change with ambient temperature?

Unlike many inductors, MPL-AL4020-3R3 specifies identical typical saturation current (5.2 A) at both 25°C and 100°C ambient - reflecting its thermally stable composite core formulation. This means inductance retains ≥70% of nominal value under peak load even at elevated temperatures, critical for high-ambient industrial use.

Can this inductor be used in synchronous rectifier buck converters above 1 MHz?

Yes - with a typical self-resonant frequency of 30 MHz, it remains dominantly inductive up to at least 5 MHz. At 1–2 MHz, core and winding losses are minimized due to low AC resistance and optimized geometry, making it suitable for high-frequency synchronous buck stages powering modern processors and FPGAs.

Is tape-and-reel packaging compatible with standard SMT pick-and-place equipment?

Yes - MPL-AL4020-3R3 ships in EIA-481-compliant tape-and-reel format (8 mm carrier tape, 2000 pcs/reel). The 4.1 mm × 4.1 mm footprint and 1.9 mm height meet JEDEC standards for automated placement; no special nozzle or vacuum settings are required beyond standard 0805–1210 handling parameters.

What is the moisture sensitivity level (MSL) for this component?

MPL-AL4020-3R3 is rated MSL3 per IPC/JEDEC J-STD-020 - meaning it can be stored for up to 168 hours at ≤30°C/60% RH before reflow. Bake time is not required if assembled within that window; if exceeded, standard 125°C/24h bake per J-STD-033 applies.

How does its DCR tolerance affect power supply efficiency calculations?

With R_DC specified as 34.5 mΩ typical and 38.4 mΩ maximum, efficiency modeling must use the max value for worst-case conduction loss (P_loss = I² × R_DC(MAX)). At 4.4 A, worst-case loss is 742 mW - a 1.9% efficiency penalty at 12 V input / 3.3 V @ 4 A output, versus using typical DCR.