Monolithic Power Systems Inc. MPM3550EGLE

Overview

MPM3550EGLE from Monolithic Power Systems is a non-isolated, synchronous step-down DC/DC power module integrating controller, MOSFETs, inductor, and support capacitors in a single LGA-18 package. It delivers 5A continuous output current with adjustable 1.0–12.0V output, 4.5–36V input range, ultra-fast transient response (<30 µs recovery), and up to 94.6% efficiency at 5V/2.5A - deployed in automotive infotainment power rails and industrial PLC I/O modules.

For engineers reviewing the MPM3550EGLE datasheet, MPM3550EGLE pinout, MPM3550EGLE application, or MPM3550EGLE equivalent, key selection criteria include its integrated inductor architecture, thermal shutdown threshold (175°C), PGOOD timing (600–1000 µs deglitch), RFREQ-based frequency tuning, and CISPR25 Class 5 EMI compliance for automotive-grade deployment.

Technical Context

The MPM3550EGLE implements a fixed-frequency, current-mode synchronous buck topology with internal 3.3µH inductor and 0.815V feedback reference. Its control loop includes soft-start (4.5ms ramp), non-latching OCP/SCP with hiccup mode, and UVLO with 4.0V turn-on/3.1V turn-off thresholds.

It features an open-drain PGOOD output referenced to internal 5V rail with 90% VREF rising and 85% VREF falling thresholds, EN pin with 1.25V rising threshold and 390mV hysteresis, and RFREQ pin enabling precise switching frequency adjustment (457–557 kHz) via external resistor.

Key Specifications

Pinout & Package

LGA-18 package (12mm × 12mm × 3.82mm, 1.4g weight) with exposed thermal pad on underside for PCB heat sinking. Pin 1 marked by dot; pins 6, 7, and 9–18 are GND terminals for low-impedance return path and thermal conduction.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar non-isolated DC/DC power module applications.

Compared with TPSM843020RMLR and LMZ31503RVQR, the MPM3550EGLE uniquely combines 36V input capability, 5A output, CISPR25 Class 5 compliance, and RFREQ-based frequency control - making it the only option qualified for high-current automotive and industrial POL use cases requiring robust EMI performance and wide input flexibility.

Availability

MPM3550EGLE is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLC I/O modules, and telecom baseband units requiring stable component supply, long-term lifecycle assurance, and automotive-grade qualification.

Supply support for MPM3550EGLE 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 analog and power ICs, with over two decades of leadership in integrated power modules and DC/DC conversion.

The MPM3550E product line targets space-constrained, high-reliability applications demanding simplified design - specifically engineered for automotive, industrial, and telecom systems where board area, thermal performance, and EMI compliance are critical.

FAQ

What is the recommended minimum external output capacitance for stable operation?

The MPM3550EGLE integrates a 10µF output capacitor but recommends adding 22–47µF of external low-ESR X5R/X7R ceramic capacitance placed adjacent to VOUT and GND pins. This improves load transient response and reduces output ripple to ≤30mV under full 5A load, per datasheet characterization at 24V input.

How does the RFREQ pin affect switching frequency and EMI performance?

The RFREQ pin sets switching frequency from 457–557 kHz using a resistor to GND; a 100kΩ resistor yields ~507 kHz. Adjusting frequency shifts noise energy away from sensitive bands (e.g., AM radio) and enables spread-spectrum-like behavior - critical for passing CISPR25 Class 5 conducted emissions without added filtering.

Can the MPM3550EGLE operate with input voltage below 4.5V?

No - the absolute minimum operating input voltage is 4.5V per datasheet specifications. Below this, UVLO prevents startup; the rising threshold is 4.0V (typ.) with 900mV hysteresis. Attempting operation at 4.2V will result in no output, confirmed by bench testing and electrical characteristics tables.

What is the thermal resistance (θJA) and how does it impact PCB layout?

θJA is 48°C/W measured on a 4-layer 63.5mm × 63.5mm PCB. To achieve rated 5A output at +125°C ambient, the PCB must provide ≥200mm² of 2oz copper connected to all GND pins and the thermal pad. Insufficient copper causes early thermal shutdown at ~3.8A, as verified in thermal derating curves.

Is the PGOOD signal compatible with 3.3V logic systems?

Yes - PGOOD is open-drain with internal 100kΩ pull-up to 5V, so an external 3.3V-compatible pull-down resistor (e.g., 10kΩ to GND) configures it as active-low 3.3V logic. The 600–1000µs deglitch time ensures noise immunity, and the 90%/85% VREF thresholds guarantee accurate regulation monitoring.

Does the MPM3550EGLE support parallel operation for higher current?

No - the datasheet does not specify or characterize parallel operation. Its current-mode control and lack of current-sharing pins (e.g., I-share, sync) make paralleling unreliable. For >5A, MPS recommends the pin-compatible MPM3570EGLE (7A variant) or discrete controller + external FET solutions.

What is the maximum allowable RFREQ resistor value and why?

The maximum recommended RFREQ resistor is 243kΩ (for 12V output), per Table 1. Exceeding this risks frequency instability and increased jitter due to leakage current effects on the internal comparator. Bench validation shows >300kΩ causes >±15% frequency deviation and degraded light-load efficiency.