Monolithic Power Systems Inc. MPQ2451DT-LF-Z

Overview

MPQ2451DT-LF-Z 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 MPQ2451DT-LF-Z datasheet, MPQ2451DT-LF-Z pinout, MPQ2451DT-LF-Z application, or MPQ2451DT-LF-Z equivalent, key selection criteria include its AEC-Q100 qualification, internal current-limiting without external sense resistor, bootstrap capacitor–based high-side gate drive, and compatibility with ceramic output capacitors in space-constrained automotive modules.

Technical Context

The MPQ2451DT-LF-Z implements peak-current-mode control with a 2MHz fixed-frequency oscillator and internal compensation, enabling stable regulation without external loop components. Its current-sense architecture uses a dedicated MOSFET for cycle-by-cycle overcurrent protection at 0.65A minimum trip threshold.

Operation includes pulse-skipping mode under light load to reduce gate-driving and switching losses, achieving ≤3µA shutdown current. The internal 0.8V reference and feedback amplifier support adjustable output (0.8V–0.9·VIN) or fixed 3.3V/5V variants via external resistor divider or factory-trimmed versions.

Key Specifications

Pinout & Package

MPQ2451DT-LF-Z is packaged in SOT23-6L - a 6-pin, surface-mount, lead-free, RoHS-compliant package measuring 2.9mm × 1.6mm × 1.1mm, optimized for automated assembly and thermal performance up to 0.57W dissipation 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 TPS62825RVL, MPQ2451DT-LF-Z uniquely balances AEC-Q100 qualification, full 3.3V–36V operation, and zero-external-compensation design-making it optimal for cost- and space-constrained automotive and industrial modules where input voltage range and qualification supersede raw current capability.

Availability

MPQ2451DT-LF-Z is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial sensor nodes, ADAS camera modules, and smart actuator control boards requiring stable component supply with AEC-Q100 compliance and long-lifecycle support.

Supply support for MPQ2451DT-LF-Z 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 mixed-signal ICs for power management, motion control, and automotive applications.

The MPQ2451 belongs to MPS's automotive-qualified buck converter product line, engineered specifically for robust, compact, and efficient power conversion in harsh environments-from engine compartments to factory floors-without external compensation or current-sense components.

FAQ

What is the maximum allowable input voltage for MPQ2451DT-LF-Z?

The absolute maximum input voltage is +40V, but the recommended operating range is 3.3V to 36V. Exceeding 36V may trigger internal UVLO or cause premature stress on the integrated MOSFET-designs targeting 36V nominal input should include margin for load-dump transients per ISO 7637-2.

Can MPQ2451DT-LF-Z operate with only ceramic capacitors on input and output?

Yes-MPQ2451DT-LF-Z is internally compensated and stable with ceramic output capacitors as low as 10µF. For input, a 4.7µF X5R/X7R ceramic capacitor placed within 2mm of VIN and GND pins meets ESR and ESL requirements for reliable 2MHz operation.

How does the bootstrap circuit function, and what capacitor value is required?

The BST pin requires a 0.1µF ceramic capacitor connected between BST and SW to charge the high-side driver. During low-side conduction, VIN charges this capacitor through the internal bootstrap diode; insufficient capacitance causes gate drive collapse and erratic switching above 50% duty cycle.

Is MPQ2451DT-LF-Z pin-compatible with other MPQ2451 variants like MPQ2451DG-LF-Z?

No-MPQ2451DT-LF-Z uses SOT23-6L packaging with pin 1 = BST, while MPQ2451DG-LF-Z uses QFN-6L with inverted pin mapping (BST = pin 6). Layouts and thermal pads are not interchangeable; migration requires PCB redesign and revalidation of thermal performance.

What is the purpose of the EN pin's hysteresis, and how should it be driven?

The EN pin has 400mV hysteresis (1.35V rising, 0.95V falling) to prevent oscillation during slow-rising enable signals. It should be driven by a clean logic signal or RC-filtered microcontroller GPIO-floating EN disables the device via internal pull-down, making it safe for unpowered states.

Does MPQ2451DT-LF-Z support adjustable output voltage, and how is it configured?

Yes-output voltage is set using a resistive divider from VOUT to FB. With internal 0.794V reference, R1 = 124kΩ and R2 = 23.7kΩ yields 5V; R2 = 40.2kΩ yields 3.3V. The FB pin draws only 0.05–1.0µA bias current, ensuring minimal divider power loss.

What thermal derating applies when operating in SOT23-6L package at 85°C ambient?

With θ_JA = 220°C/W, maximum power dissipation at 85°C ambient is (125°C − 85°C)/220°C/W = 182mW. At 0.6A output and 12V input, typical losses are ~150mW-allowing full-load operation with 25°C safety margin before thermal shutdown activates.