Monolithic Power Systems Inc. MP3435GL-P

Overview

MP3435GL-P from Monolithic Power Systems is a 600kHz synchronous boost converter with integrated 10mΩ low-side and 15mΩ high-side MOSFETs, supporting 3V–20V input and up to 22V output, featuring input disconnect, configurable input average current limit, and thermal shutdown at 150°C - deployed in power banks and Thunderbolt interfaces for battery-safe voltage boosting.

For engineers reviewing the MP3435GL-P datasheet, MP3435GL-P pinout, MP3435GL-P application, or MP3435GL-P equivalent, key selection criteria include its 19A internal switch current limit, QFN-20 (3mm×4mm) package thermal resistance (θJA = 27°C/W), input disconnect control via GATE pin, and soft-start capacitor configuration on SS pin for inrush management.

Technical Context

The MP3435GL-P implements fixed-frequency peak-current-mode control with an internal transconductance error amplifier (GEA = 160µA/V) and 1.225V reference at FB. Its dual current-sense architecture supports either internal sensing (GATE grounded) or external resistor-based average current limiting (GATE floating or connected to external MOSFET gate).

It integrates a bootstrap regulator powered from SOUT to drive the 15mΩ HS-FET, with BST UVLO protection; VDD is auto-switched between VIN and VOUT to maintain efficiency at low input voltages. The 5–9µA SS charge current enables precise soft-start timing, while the 0.5ms linear charge SCP blanking time ensures robust short-circuit recovery.

Key Specifications

Pinout & Package

MP3435GL-P is housed in a thermally enhanced QFN-20 (3mm × 4mm) package with exposed thermal pad (PGND-connected). Pin 1 is located at the bottom-left corner adjacent to the notch mark; top marking includes "MP", year/week code, and lot number.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RT4801BZSP and TPS61088RHLR, MP3435GL-P uniquely combines 22V output capability, 19A current handling, and hardware-enforced input disconnect - making it the only choice for high-power, battery-isolated USB-C PD sink designs requiring >15W output.

Availability

MP3435GL-P is available at Aetrix Electronics and suitable for power banks, Thunderbolt interfaces, and point-of-sale systems requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MP3435GL-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 power management ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP3435 belongs to MPS's high-current synchronous boost converter product line, engineered specifically for portable and interface-powered systems needing efficient, isolated, and protected voltage step-up from single- or multi-cell batteries.

FAQ

What is the purpose of the GATE pin on MP3435GL-P?

The GATE pin drives an external N-channel MOSFET to implement input disconnect - isolating VIN from VOUT during shutdown or output short-circuit events. When GATE is grounded, the IC uses internal current sensing; when floating or connected to an external FET gate, it enables external RSENSE-based average current limiting with programmable trip level (45–63mV).

How does MP3435GL-P achieve input disconnect during shutdown?

When EN is pulled low or VIN falls below UVLO, the IC pulls GATE low, turning off the external input MOSFET. This physically breaks the connection between input and output, preventing reverse current flow and battery depletion - a critical feature for power banks and always-on portable devices.

Can MP3435GL-P operate with input voltage below 3V?

No. The absolute minimum operating input voltage is 3V per datasheet specifications. Below this, UVLO prevents startup, and internal regulators cannot sustain bias. Applications requiring sub-3V operation (e.g., deeply discharged Li-ion) must use pre-regulation or alternative architectures.

What is the role of the SOUT pin beyond BST charging?

SOUT serves dual functions: it samples VOUT to charge the BST capacitor and - critically - powers VDD once VOUT exceeds VIN. This auto-switching ensures the internal bias rail remains at ~5V even when VIN drops to 3.3V, maintaining low R_DS(on) and high efficiency across the full input range.

How is soft-start configured, and what happens if SS is left unconnected?

Soft-start is enabled by connecting a capacitor (CSS) from SS to AGND; the IC charges it with 5–9µA current to control ramp rate. If SS is left open, soft-start is disabled - resulting in immediate full-frequency startup and higher inrush current, which may stress input capacitors or trigger upstream current limits.

Does MP3435GL-P support output over-voltage protection (OVP)?

Yes. If the FB voltage exceeds 108% of the 1.225V reference (i.e., >1.323V), the IC disables switching immediately to prevent damage to downstream loads. OVP operates independently of the main regulation loop and activates within microseconds of overvoltage detection.

What thermal derating guidance applies to MP3435GL-P in QFN-20 package?

With θJA = 27°C/W on a 4-layer 2oz PCB (EVL3435-L-00A), the IC sustains ~4.6W continuous dissipation at 25°C ambient. At 60°C ambient, max safe power drops to ~3.1W - corresponding to ~3.5A at 12V out from 5V in. Layout optimization (thermal pad soldering, copper pour) is essential for >3A operation.