Monolithic Power Systems Inc. MPQ2451DT-LF-P

Overview

MPQ2451DT-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 a 3.3V–36V input range, fixed 2MHz switching frequency, and 130µA quiescent current-designed for automotive body control modules requiring stable 5V rail generation from battery-supplied 12V/24V systems.

For engineers reviewing the MPQ2451DT-LF-P datasheet, MPQ2451DT-LF-P pinout, MPQ2451DT-LF-P application, or MPQ2451DT-LF-P equivalent, key selection criteria include its industrial/automotive temperature rating (−40°C to +125°C), internal soft-start, precision current limit without external sense resistor, ceramic-capacitor compatibility, and bootstrap-driven high-side gate drive architecture.

Technical Context

The MPQ2451DT-LF-P employs peak-current-mode control with a 2MHz fixed-frequency oscillator and adaptive pulse-skipping at light load to maintain >90% efficiency across 0.1–0.6A output. Its error amplifier uses an internal 0.794V reference and RC-compensated COMP node, eliminating external compensation components for standard configurations.

Startup sequencing includes 0.5–1ms internal soft-start ramp, UVLO with 2.9V rising/2.6V falling thresholds, and thermal shutdown at 150°C. The floating high-side driver relies on BST–SW bootstrap capacitor charging during low-side conduction, requiring ≥100ns minimum off-time and sufficient VIN–VOUT headroom for reliable bootstrapping.

Key Specifications

Pinout & Package

MPQ2451DT-LF-P is packaged in RoHS-compliant, lead-free SOT23-6L (TSOT23-6L) - a 6-pin, surface-mount package with 0.95mm pitch, optimized for automated assembly and thermal performance up to 0.57W at 25°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM61480RQWR and TPS62810QWRWYRQ1, MPQ2451DT-LF-P uniquely balances wide 3.3V–36V operation, AEC-Q100 Grade 1 certification, and SOT23-6L manufacturability-making it optimal for cost-sensitive, space-constrained automotive body electronics where 0.6A output suffices.

Availability

MPQ2451DT-LF-P is available at Aetrix Electronics and suitable for automotive body control units, industrial PLC I/O modules, and telematics gateways requiring stable component supply with AEC-Q100 compliance, extended temperature support, and RoHS/lead-free manufacturing.

Supply support for MPQ2451DT-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 distribution through authorized partners.

The MPQ2451 belongs to MPS's automotive-grade DC/DC converter product line, engineered specifically for harsh-environment power management in vehicles-including start-stop systems, ADAS sensors, and infotainment subsystems-where reliability, thermal robustness, and qualification rigor are mandatory.

FAQ

What is the maximum recommended PCB copper area for thermal relief in SOT23-6L layout?

The SOT23-6L package has θ_JA = 220°C/W on a 2-layer board. For continuous 0.6A operation at 36V input, thermal simulation shows ≥80mm² of 2oz copper connected to GND pins (pins 2 and 5) reduces junction temperature rise by 35°C. Use thermal vias under the exposed pad (if present) and avoid routing high-speed signals beneath the IC.

Can MPQ2451DT-LF-P operate with 100% duty cycle?

No. The MPQ2451DT-LF-P requires minimum off-time ≥100ns for bootstrap capacitor recharge. At 36V input and 5V output, maximum theoretical duty cycle is ~14%; practical limit is ~85% due to BST charging constraints. For high-VIN-to-VOUT ratios, ensure V_IN–V_OUT ≥ 2V to sustain bootstrap voltage above 2.4V.

Is external compensation required for 5V fixed-output configuration?

No. The MPQ2451DT-LF-P is internally compensated for standard 5V (MPQ2451-5) and 3.3V (MPQ2451-33) variants. External compensation (R2/C3) is only needed for adjustable outputs or when using non-standard output capacitors (e.g., high-ESR tantalum) or inductors outside 2.2–4.7µH range.

Does the EN pin have internal pull-down?

Yes. When left floating, the EN pin is internally pulled down to GND, disabling the device. Its rising threshold is 1.35–1.8V and hysteresis is 400mV, enabling noise-immune enable sequencing. Pulling EN to 0V achieves 3µA shutdown current; pulling to 1.2V keeps it disabled with slightly higher leakage.

What is the minimum output capacitor ESR for stability with ceramic types?

Ceramic capacitors are inherently stable with the MPQ2451DT-LF-P due to its Type-II compensation. No minimum ESR is required - 10µF X5R/X7R MLCCs (e.g., 0805 10µF/16V) provide adequate phase margin (>45°) and <10mVpp ripple at 0.6A. Avoid ultralow-ESR polymer caps unless validated, as they may shift crossover frequency.

How does frequency fold-back improve startup reliability?

During startup, frequency fold-back reduces switching frequency below 2MHz when output voltage is low, limiting peak inductor current and preventing saturation. This avoids current runaway in high-inductance/low-ESR output networks - critical for systems using ≥10µH chokes or large bulk capacitance before the regulator.

Is the BST capacitor polarity-sensitive?

Yes. The BST capacitor must be placed between BST and SW pins with correct orientation: positive terminal to BST, negative to SW. Reversal causes reverse bias during SW low-state, degrading capacitor lifetime and risking dielectric failure. Use 0.1µF 16V X7R ceramic with ≤100mΩ ESL.