Monolithic Power Systems Inc. MPQ2451DG-LF-P

Overview

MPQ2451DG-LF-P from Monolithic Power Systems is an AEC-Q100 Grade 1 qualified, non-synchronous step-down DC/DC converter with integrated 500mΩ high-side MOSFET, delivering up to 0.6A output across 3.3V–36V input range, fixed 2MHz switching frequency, and 130µA quiescent current-designed for automotive infotainment power rails and industrial sensor node supplies.

For engineers reviewing the MPQ2451DG-LF-P datasheet, MPQ2451DG-LF-P pinout, MPQ2451DG-LF-P application, or MPQ2451DG-LF-P equivalent, key selection criteria include its AEC-Q100 qualification, internal compensation enabling ceramic-capacitor-only designs, precision current limit without external sense resistor, and thermal shutdown with 150°C junction limit.

Technical Context

The MPQ2451DG-LF-P implements peak-current-mode control with a 2MHz fixed-frequency PWM architecture and pulse-skipping mode under light load to maintain >90% efficiency down to 1mA. Its internal error amplifier uses a 0.794V reference and RC-compensated COMP node, eliminating external compensation components for standard output configurations.

Startup employs a 0.5ms internal soft-start ramping the reference voltage to prevent output overshoot; bootstrap charging is managed via an internal regulator that maintains ~5V between BST and SW pins, requiring external 33pF BST capacitor and low-VF Schottky diode at SW.

Key Specifications

Pinout & Package

MPQ2451DG-LF-P is housed in a RoHS-compliant, thermally enhanced QFN-6L package (2mm × 2mm × 0.75mm, exposed thermal pad), optimized for high-power-density automotive PCB layouts with low θ_JA = 80°C/W on 4-layer boards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ2451DG-LF-P, the MPQ2451DJ-AEC1 trades thermal performance for smaller footprint, while the LM61480-Q1 adds EMI control flexibility and current headroom at the cost of design complexity and higher quiescent current in light-load operation.

Availability

MPQ2451DG-LF-P is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial sensor networks, and portable medical diagnostics requiring stable component supply with AEC-Q100 assurance and long-term production continuity.

Supply support for MPQ2451DG-LF-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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MPQ2451 belongs to MPS's automotive-grade DC/DC converter product line, engineered specifically for harsh-environment power conversion in vehicles and industrial equipment where reliability, wide input range, and low quiescent current are critical.

FAQ

What is the maximum recommended output current for MPQ2451DG-LF-P at 85°C ambient?

At 85°C ambient with 2-layer PCB and no airflow, the QFN-6L package supports 0.6A continuous output only if the input voltage is ≤12V and thermal pad is soldered to ≥1in² copper pour. At 24V input, derate to 0.45A due to increased conduction loss and junction temperature rise.

Can MPQ2451DG-LF-P operate with a 3.0V input supply?

No - the absolute minimum operating input voltage is 3.3V per datasheet specifications. Below 3.3V, the internal regulator cannot sustain 2.6V bias for control circuitry, and UVLO prevents startup. The 3.0V figure applies only to internal regulator dropout, not functional operation.

Is an external bootstrap diode required for MPQ2451DG-LF-P?

An external bootstrap diode is optional but recommended when VIN ≤ 5V and VOUT > 3.3V, or when duty cycle exceeds 65%. It improves bootstrap capacitor charging efficiency and prevents dropout during high-duty-cycle operation, especially with low-VIN automotive start-stop conditions.

How does the MPQ2451DG-LF-P handle short-circuit conditions?

Under short-circuit, the device enters hiccup mode: it limits peak switch current to ~1A, shuts down for ~2ms upon overcurrent detection, then attempts restart. This prevents thermal runaway while limiting average power dissipation to safe levels until fault clearance.

What is the minimum output voltage achievable with MPQ2451DG-LF-P using FB pin configuration?

The minimum regulated output is 0.8V, set by the internal 0.794V feedback reference plus tolerance. Using the FB pin with a resistive divider, outputs as low as 0.8V can be achieved - e.g., [email protected] for low-voltage FPGA I/O rails - provided the inductor DCR and PCB trace resistance are minimized to avoid regulation error.

Does MPQ2451DG-LF-P support forced PWM mode?

No - MPQ2451DG-LF-P operates exclusively in automatic PWM/pulse-skipping mode. It lacks a MODE pin or external control to force continuous conduction; light-load efficiency is prioritized over EMI predictability, making it unsuitable for applications requiring constant-frequency operation across all loads.

What is the purpose of the 33pF capacitor between BST and SW pins?

The 33pF ceramic capacitor provides high-frequency charge reservoir for the bootstrap driver, maintaining stable ~5V gate drive voltage during high-side switch conduction. Its small value minimizes charge injection noise while ensuring sufficient energy for gate turn-on without excessive BST node ringing.