Monolithic Power Systems Inc. MP3428GL-P

Overview

MP3428GL-P from Monolithic Power Systems is a 600kHz fixed-frequency, current-mode synchronous boost converter with 3V–20V input range, 17A switch-current limit, integrated 10mΩ low-side MOSFET, and external compensation for transient optimization - used in power banks, Thunderbolt interfaces, and Bluetooth audio systems requiring high-efficiency step-up conversion up to 22V.

For engineers reviewing the MP3428GL-P datasheet, MP3428GL-P pinout, MP3428GL-P application, or MP3428GL-P equivalent, key selection criteria include internal/external current-sensing configuration flexibility, BST/SDR synchronous rectifier drive capability, programmable UVLO hysteresis, thermal shutdown at 150°C, and QFN-22 (3×4mm) package thermal performance.

Technical Context

The MP3428GL-P implements peak-current-mode control with a 600kHz fixed switching frequency and supports both internal current sensing (MODE = GND) and external resistor-based average-current limiting (MODE floating). Its error amplifier features 300 V/V gain and 160 μA/V transconductance, with COMP pin enabling full loop compensation via external R-C network.

It integrates a 10mΩ, 24V-rated low-side power switch and a dedicated 5V SDR gate driver powered by the BST bootstrap capacitor - enabling efficient synchronous rectification. Protection includes under-voltage lockout (2.68V rising threshold), 1.1ms average-current hiccup response, and thermal shutdown with 25°C hysteresis.

Key Specifications

Pinout & Package

MP3428GL-P is housed in a thermally enhanced 22-pin QFN package measuring 3mm × 4mm with exposed thermal pad (PGND-connected). The package supports high-current routing and low θ_JA (48°C/W) on standard 4-layer PCBs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous boost converter applications.

Compared with RT4801BZQW and TPS61288RRLR, MP3428GL-P uniquely combines 17A switch rating, 3–20V input, integrated SDR/BST drive, and selectable current-sensing topology - making it optimal for high-power portable boost where thermal density, protection granularity, and layout simplicity are critical.

Availability

MP3428GL-P is available at Aetrix Electronics and suitable for Thunderbolt interface power delivery, portable power bank DC-DC stages, and notebook auxiliary rail generation requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP3428GL-P 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 expertise in DC-DC conversion, motor drivers, and LED controllers.

The MP3428 product line targets high-current, wide-input portable and interface power applications - designed to replace discrete boost solutions with integrated thermal management, flexible protection, and synchronous efficiency in minimal footprint.

FAQ

What is the maximum supported output voltage for MP3428GL-P?

The MP3428GL-P regulates output voltages from VIN up to 22V, as specified in Recommended Operating Conditions. This is enforced by absolute maximum ratings on SW, OUT, and SENSE pins (–0.3V to +24V), and validated in typical application circuits delivering 12V/2.1A and 20V test points. Exceeding 22V risks violating SOA limits under transient load conditions.

Can MP3428GL-P operate with only ceramic capacitors on input and output?

Yes - the datasheet explicitly recommends two 22μF X5R/X7R ceramic capacitors at the input and three 22μF ceramics at the output for high-power operation. Ceramic-only implementation is validated for stability, ripple suppression, and thermal performance, provided layout follows the PCB guidelines (short traces, thermal pad grounding, and proper AGND/PGND separation).

How does the MODE pin affect overcurrent protection behavior?

When MODE = GND, MP3428GL-P uses internal current sensing with cycle-by-cycle peak-current limiting at 17A. When MODE is floating, it uses external resistor sensing with average-current limiting triggered at 54mV (≈17A with 4mΩ resistor), followed by 1.1ms hiccup delay before restart - providing gentler fault response for sustained overload versus immediate shutdown.

Is BST capacitor mandatory, and what value is recommended?

Yes - a BST capacitor (typically 0.1μF X7R ceramic) between BST and SW is mandatory to sustain the 5V gate drive for the SDR output. Without it, SDR cannot turn on the synchronous rectifier MOSFET, degrading efficiency by 3–5% and increasing thermal stress on the internal switch during heavy loads.

What is the minimum inductor value recommended for 3V-to-12V/2A operation?

Using the inductance formula L = V_IN(V_OUT−V_IN) / (V_OUT × F_SW × ΔI), with V_IN=3V, V_OUT=12V, F_SW=600kHz, and ΔI=0.6A (30% of max input current), the calculated minimum is 2.2μH - matching the 2.2μH value used in the Typical Application Circuit and validated for stability across temperature and load.

Does MP3428GL-P support automatic light-load efficiency optimization?

Yes - it employs pulse-skipping mode (PSM) at very light loads and foldback frequency reduction as load decreases. In PSM, only one switching pulse occurs per burst cycle, minimizing switching losses while maintaining low output ripple (<10mV_pp), unlike forced PWM which would waste quiescent current unnecessarily.

How is thermal performance affected by PCB copper area under the QFN thermal pad?

Thermal resistance θ_JA drops from 48°C/W (standard 4-layer board) to ≤35°C/W with ≥4cm² of 2oz copper connected to the exposed thermal pad via ≥8 thermal vias (0.3mm diameter). This directly impacts maximum continuous output current - insufficient copper causes early thermal shutdown at >10A load in ambient >60°C.