Monolithic Power Systems Inc. MP2499MGQB-P

Overview

MP2499MGQB-P from Monolithic Power Systems is a synchronous step-down DC/DC converter with integrated 85mΩ/55mΩ MOSFETs, 5V–36V input range, and 3A continuous output current capability. It features output line drop compensation, internal soft-start (1.6ms), and programmable current limit via external sense resistor - deployed in USB DCP and automotive cigarette lighter adapters for stable 5V/2.4A delivery over long cables.

For engineers reviewing the MP2499MGQB-P datasheet, MP2499MGQB-P pinout, MP2499MGQB-P application, or MP2499MGQB-P equivalent, key selection criteria include its 270kHz default switching frequency, ±12mV feedback reference accuracy, thermal shutdown at 170°C, and QFN-13 (2.5mm×3mm) package with exposed PGND pads for thermal management.

Technical Context

The MP2499MGQB-P operates in fixed-frequency peak-current-mode control with internal 0.8V reference and optimized compensation network, enabling stable regulation without external loop components. Its EN/SYNC pin supports both enable/disable logic and external clock synchronization from 200kHz to 2.4MHz.

Line drop compensation is implemented by sinking 4–8μA at FB proportional to load current through an external R_SENSE, generating a compensating voltage across R₁ to offset trace IR loss. Over-current protection includes cycle-by-cycle limiting and hiccup-mode recovery during sustained short-circuit faults.

Key Specifications

Pinout & Package

MP2499MGQB-P is housed in a thermally enhanced QFN-13 (2.5mm × 3mm, 0.5mm pitch) package with exposed PGND pads on the bottom for efficient heat dissipation. The package supports reflow soldering and requires strict adherence to JEDEC MS-012AC footprint guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP2499MGQB-P, MP2499AGQB-Z offers tighter feedback accuracy and formal obsolescence mitigation, while MPQ2499GQB-Z adds AEC-Q100 qualification and extended temperature operation - both retain identical pinout and basic compensation architecture but differ in reliability validation and spec tolerances.

Availability

MP2499MGQB-P is available at Aetrix Electronics and suitable for USB charging, automotive adapter, and industrial peripheral power supply applications requiring stable component supply and known thermal performance characteristics.

Supply support for MP2499MGQB-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 core expertise in DC/DC conversion, LED drivers, and motor control.

The MP2499M product line targets compact, high-efficiency buck converters for USB power delivery and automotive accessory applications, emphasizing integration, thermal robustness, and line-drop compensation for real-world cabling constraints.

FAQ

Is MP2499MGQB-P still recommended for new designs?

No - Monolithic Power Systems explicitly states "NOT RECOMMENDED FOR NEW DESIGNS" and directs users to MP2499A. While MP2499MGQB-P remains available for legacy support and existing production, new projects should use MP2499AGQB-Z for updated specifications, guaranteed supply, and full documentation support.

What is the function of the NC pin (Pin 3) on MP2499MGQB-P?

Pin 3 is a no-connect terminal - it is internally unconnected and must remain unpopulated and un-routed on the PCB. Connecting or floating this pin may cause mechanical stress on the die bond wire or introduce parasitic coupling; MPS recommends leaving it isolated per datasheet layout guidance.

How does line drop compensation work in MP2499MGQB-P?

MP2499MGQB-P sinks 4–8μA at the FB pin proportional to load current sensed via R_SENSE. This current flows through the upper feedback resistor R₁, generating a compensating voltage (e.g., 384mV at 2.4A) that offsets cable IR drop - maintaining constant voltage at the remote load without requiring separate sense lines.

Can MP2499MGQB-P synchronize to an external clock?

Yes - the EN/SYNC pin accepts a 200kHz–2.4MHz external clock signal. When driven with a clean CMOS-level square wave, the internal oscillator locks to the rising edge of the external clock, enabling EMI reduction and deterministic switching in multi-rail systems.

What is the maximum duty cycle and minimum on-time specification?

The MP2499MGQB-P supports up to 97% maximum duty cycle and has a 70ns minimum on-time. These parameters enable operation down to ~0.8V output from 12V input (6.7% duty) and support high-input, low-output conversions such as 36V→5V (14% duty) without pulse-skipping instability.

Does MP2499MGQB-P require a bootstrap diode?

No - the IC integrates a floating driver with internal bootstrap charging circuitry. An external BST diode (e.g., IN4148) is optional and only recommended for high-duty-cycle applications (>65%) to improve efficiency; a 0.1–1μF ceramic capacitor with 20Ω series resistor is mandatory regardless.

What thermal resistance values apply to the QFN-13 package?

The QFN-13 (2.5mm×3mm) package has θ_JA = 60°C/W and θ_JC = 13°C/W when mounted on a 4-layer JEDEC JESD51-7 test board. Effective thermal performance in end equipment depends on PCB copper area, number of thermal vias under the exposed PGND pad, and airflow - typical board-level θ_JA ranges from 45–55°C/W with proper layout.