Monolithic Power Systems Inc. MP2491CGQB-P

Overview

MP2491CGQB-P from Monolithic Power Systems is a fully integrated 32V, 6A synchronous step-down converter with programmable current limit and dual voltage scaling control (VSEL1/VSEL2). It delivers tight output regulation across 4.0–32V input and 0.5–30V output ranges using Constant-On-Time (COT) control, supports dynamic DVS slew rate control (10–18 mV/μs), and integrates 33mΩ/22mΩ MOSFETs in a QFN-13 (2.5mm×3mm) package for USB PD power supplies and automotive cigarette lighter adapters.

For engineers reviewing the MP2491CGQB-P datasheet, MP2491CGQB-P pinout, MP2491CGQB-P application, or MP2491CGQB-P equivalent, this page provides verified technical context on COT transient response, VSEL1/VSEL2 reference selection (0.5V–2.0V), hiccup-mode OCP, PG open-drain signaling, and EN-controlled discharge - all critical for high-reliability 6A DC-DC design in constrained space applications.

Technical Context

The MP2491CGQB-P implements Constant-On-Time (COT) control with internal ramp compensation, enabling fixed ~490kHz switching frequency and fast load-transient response without external loop compensation. Its dual voltage scaling pins (VSEL1/VSEL2) select five distinct FB reference voltages (0.5V to 2.0V) via resistor dividers or direct logic-level connections, enabling precise output voltage sequencing and dynamic scaling.

It integrates high-side and low-side MOSFETs (33mΩ/22mΩ R_DS(on)) with dead-time control to prevent shoot-through, features an active EN shutdown discharge path, and uses a dedicated BST bootstrap circuit with internal 5V LDO (VCC) that remains active even when EN is low - supporting pre-biased start-up and robust gate drive under wide VIN conditions.

Key Specifications

Pinout & Package

MP2491CGQB-P is housed in a thermally enhanced QFN-13 package (2.5mm × 3mm, 0.5mm pitch) with exposed thermal pad for efficient heat dissipation in high-current applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down converter applications.

Compared with MP2491CGQB-P, MP2491DGQB-Z offers identical performance in tape-and-reel form for production, while RT7295BGJ8F trades DVS flexibility and integration for slightly higher input voltage tolerance and lower cost in non-scaling applications.

Availability

MP2491CGQB-P is available at Aetrix Electronics and suitable for USB-C PD adapters, automotive cigarette lighter converters, and smart display power supplies requiring stable component supply, full RoHS compliance, and guaranteed long-term availability.

Supply support for MP2491CGQB-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 core expertise in DC-DC converters, LED drivers, and motor drivers.

The MP2491C product line targets high-efficiency, high-current buck conversion in space-constrained applications - designed specifically for USB PD, automotive auxiliary power, and industrial displays where programmable voltage scaling and integrated power stages are critical.

FAQ

What is the minimum recommended input voltage for reliable operation?

The MP2491CGQB-P has a guaranteed operating range starting at 4.0V, with an under-voltage lockout (UVLO) rising threshold of 3.8V ±0.2V. Below 4.0V, the device may not sustain regulation or deliver full 6A output; operation below 3.6V disables switching entirely. For automotive cold-crank scenarios, ensure input stays above 4.0V during transient dips.

How does the dual VSEL pin configuration affect output voltage accuracy?

VSEL1 and VSEL2 select one of five factory-trimmed FB reference voltages (0.5V to 2.0V) with ±1.5% tolerance at +25°C. Accuracy degrades slightly over temperature (±0.02%/°C drift), but the internal reference remains stable enough for ≤1% total output error when using 1% resistors in the feedback divider.

Can the MP2491CGQB-P operate in forced PWM mode with zero load?

Yes - connecting MODE to AGND configures forced PWM mode, which maintains fixed 490kHz switching regardless of load. At zero load, this increases light-load inefficiency versus auto PFM mode but eliminates audible noise and ensures deterministic EMI behavior, critical for noise-sensitive applications like audio amplifiers or medical sensors.

What thermal derating applies above 85°C ambient temperature?

With θ_JA = 32°C/W on a 4-layer 2oz PCB (EV2491C-QB-00A), maximum continuous output current drops linearly above 85°C ambient: at 100°C ambient, max current is ~4.8A; at 125°C, it falls to ~3.2A. Derating follows TJ = TA + (P_LOSS × θ_JA), where P_LOSS includes conduction, switching, and gate drive losses.

Is the PG pin compatible with 3.3V logic systems?

Yes - PG is an open-drain output with 1mA sink capability and 0.4V max saturation voltage at 1mA. It can be pulled up to 3.3V (or any voltage ≤6V) with a 10kΩ resistor, providing clean 3.3V-compatible power-good signaling for microcontrollers and PMICs without level-shifting.

How is the current limit set using the ILIM pin?

A resistor (R_LIMIT) from ILIM to AGND programs the output current limit: 30kΩ yields ~7.19A, 64.9kΩ → ~5.6A, 95.3kΩ → ~3.6A, and 110kΩ → ~3.11A. The relationship is nonlinear and documented in the "Current Limit vs. RLIMIT" curve (page 8 of datasheet); values outside 30–230kΩ are unsupported.

Does the MP2491CGQB-P support pre-biased output start-up?

Yes - the internal soft-start circuit detects pre-biased outputs and disables switching until the internal SS capacitor voltage exceeds the selected VREF. This prevents reverse current flow and ensures controlled ramp-up even when VOUT is initially held at 5V or higher by external sources.