Monolithic Power Systems Inc. MP3910AGS

Overview

MP3910AGS from Monolithic Power Systems is a peak current mode PWM controller for external N-channel MOSFETs in flyback, boost, and SEPIC topologies. It delivers 1A gate drive, supports 30–400kHz programmable switching frequency, features pulse-skipping light-load operation, and operates from 9V to 14V VCC supply. Used in telecom isolated power supplies and PoE-powered devices.

For engineers reviewing the MP3910AGS datasheet, MP3910AGS pinout, MP3910AGS application, or MP3910AGS equivalent, key selection criteria include its cycle-by-cycle current limit (185mV ISENSE threshold), hiccup-mode OLP/OVP/SCP protection, SOIC-8 thermal resistance (θJA = 90°C/W), and feedback mode auto-detection via ISENSE pin current pulse.

Technical Context

The MP3910AGS implements a peak current mode control architecture with integrated slope compensation, enabling stable loop compensation and inherent cycle-by-cycle current limiting. Its programmable oscillator uses an external RT-to-GND resistor (6.81kΩ–80.6kΩ) to set frequency between 30kHz and 400kHz, with maximum operating frequency rated at 500kHz.

It supports dual feedback configurations: un-isolated (FB pin referenced to 1.237V internal reference) and isolated (COMP pin direct optocoupler interface), selected automatically by ISENSE pin voltage detection (185mV threshold). Protection logic includes UVLO (8V rising, 650mV hysteresis), thermal shutdown (160°C), and hiccup-mode recovery triggered by SS pin discharge to 0.2V.

Key Specifications

Pinout & Package

MP3910AGS is housed in a standard SOIC-8 package (4.9mm × 3.9mm, 1.27mm pitch), optimized for thermal dissipation (θJA = 90°C/W on 4-layer PCB) and surface-mount assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar peak current mode PWM controller applications.

Compared with UCC28C43DR and TL3845P, MP3910AGS provides superior system-level integration-its programmable frequency, 1A gate drive, and auto-feedback mode reduce BOM count and layout complexity while enabling higher efficiency and reliability in isolated and high-current boost applications.

Availability

MP3910AGS is available at Aetrix Electronics and suitable for telecom isolated power supplies, PoE-powered devices, and off-line controller designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP3910AGS 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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP3910A belongs to MPS's high-voltage PWM controller product line, engineered for flexible, robust, and thermally efficient primary-side regulation in isolated and non-isolated DC-DC converters targeting telecom, industrial, and PoE applications.

FAQ

What is the minimum recommended RT resistor value for stable 400kHz operation?

The MP3910AGS datasheet specifies a maximum switching frequency of 400kHz, achieved with an RT resistor of approximately 6.81kΩ. Using a lower value risks exceeding the 500kHz absolute maximum rating and may cause instability due to reduced noise immunity. For reliable 400kHz operation, use 6.81kΩ ±1% metal-film resistor with short, low-inductance routing to GND.

How does the MP3910AGS detect isolated vs. non-isolated feedback configuration?

At power-up, the MP3910AGS applies a 55µA current pulse for 180µs to the ISENSE pin. If the resulting voltage exceeds 185mV, it disables the internal error amplifier and enables the 14.4kΩ pull-up on COMP, configuring for isolated feedback. If voltage remains below 185mV, it enables the FB-to-COMP amplifier and disables the pull-up, selecting non-isolated mode.

Can the MP3910AGS drive a 600V N-channel MOSFET directly in a 48V-input boost converter?

Yes-the MP3910AGS gate driver is rated for 1A continuous sourcing/sinking and supports VGS up to 16V. When paired with a 600V-rated N-MOSFET (e.g., SiC or superjunction), ensure VCC is clamped to ≤14V, gate resistor limits dV/dt, and layout minimizes source inductance to prevent false triggering during high dv/dt switching transitions.

What causes the MP3910AGS to enter hiccup mode instead of latching off during a short circuit?

Hiccup mode is triggered when the SS pin voltage discharges to 2.9V (OLP entry) then further to 0.2V (hiccup restart threshold). This two-stage discharge-first with 17.8µA (OLP), then 1.66µA (hiccup)-ensures temporary fault recovery attempts before full shutdown, improving system resilience in intermittent short conditions like connector arcing or transient surges.

Is external slope compensation required when using the MP3910AGS in continuous conduction mode (CCM) boost?

No-slope compensation is fully integrated. The MP3910AGS embeds programmable slope compensation synchronized to the oscillator, eliminating external components. This ensures stable current-mode control across all duty cycles, including CCM operation above 50%, without risk of subharmonic oscillation.

How does pulse-skipping mode improve light-load efficiency compared to traditional burst mode?

In pulse-skipping mode, the MP3910AGS halts switching entirely when COMP voltage falls below 0.95V, reducing gate drive and switching losses to near-zero. Unlike burst mode-which fires clusters of pulses-the MP3910AGS enters deep sleep, cutting quiescent current to 400µA and eliminating all switching-related losses until load demand resumes.