Monolithic Power Systems Inc. MPQ2451DJ-AEC1-LF-Z

Overview

MPQ2451DJ-AEC1-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 a 3.3V–36V input range, fixed 2MHz switching frequency, and 130µA quiescent current-designed for automotive body control modules requiring robust start-stop operation.

For engineers reviewing the MPQ2451DJ-AEC1-LF-Z datasheet, MPQ2451DJ-AEC1-LF-Z pinout, MPQ2451DJ-AEC1-LF-Z application, or MPQ2451DJ-AEC1-LF-Z equivalent, key selection criteria include its TSOT23-6L package thermal performance (θJA = 220°C/W), precision 0.794V feedback reference, internal soft-start timing (0.5–1ms), and pulse-skipping mode efficiency optimization below 100mA load.

Technical Context

The MPQ2451DJ-AEC1-LF-Z implements current-mode PWM control with cycle-by-cycle overcurrent protection and internal compensation, enabling stable regulation without external loop components. Its 2MHz fixed-frequency architecture supports compact filter design using ≤3.3µH inductors and ceramic output capacitors.

Operation includes UVLO (2.7V rise / 2.3V fall), thermal shutdown at 150°C, and bootstrap-driven high-side gate drive with dedicated BST-to-SW capacitor charging path. Pulse-skipping mode activates when COMP voltage drops below sleep threshold, reducing IQ to 3µA in shutdown and sustaining >90% efficiency at light loads.

Key Specifications

Pinout & Package

MPQ2451DJ-AEC1-LF-Z uses the TSOT23-6L package (1.6mm × 2.9mm × 0.9mm), optimized for automotive thermal cycling reliability and board-level reflow compatibility. Pin mapping is identical to SOT23-6L and QFN-6L variants but with enhanced moisture sensitivity level (MSL3) and AEC-Q100 stress screening.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ2451DG-AEC1-LF-Z, the DJ variant trades thermal headroom for footprint reduction and assembly compatibility; versus LM61480-Q1, it sacrifices peak current and ultra-low IQ for plug-and-play simplicity, smaller solution size, and superior startup safety.

Availability

MPQ2451DJ-AEC1-LF-Z is available at Aetrix Electronics and suitable for automotive body electronics, ADAS camera modules, and infotainment systems requiring stable component supply with full AEC-Q100 documentation and PPAP support.

Supply support for MPQ2451DJ-AEC1-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-efficiency analog and power ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MPQ2451 product line targets automotive and industrial DC/DC conversion where high input voltage tolerance, AEC-Q100 compliance, and minimal external component count are critical-enabling compact, reliable power solutions for next-generation E/E architectures.

FAQ

What is the maximum recommended PCB copper area for thermal relief with MPQ2451DJ-AEC1-LF-Z in TSOT23-6L?

For continuous 0.6A operation at 85°C ambient, use ≥80mm² of 2oz copper connected directly to GND pin via ≥4 thermal vias (0.3mm diameter). This achieves ~110°C junction temp per θJA=220°C/W, staying within Grade 1 limits. Avoid placing copper under BST/SW pins to prevent coupling.

Can MPQ2451DJ-AEC1-LF-Z regulate 3.3V output with only two external resistors?

Yes. Connect R1=124kΩ between VOUT and FB, and R2=40.2kΩ between FB and GND. This sets VOUT = 0.794V × (1 + 124kΩ/40.2kΩ) ≈ 3.3V. The 1% tolerance resistors ensure output accuracy within ±2.5%, meeting automotive sensor supply requirements.

Does the internal soft-start time change with input voltage or temperature?

No. Soft-start time is fixed at 0.5–1ms (typical 0.75ms) across -40°C to +125°C and 3.3V–36V VIN. It is generated by an internal current source charging a capacitor, making it independent of external conditions-ensuring consistent startup behavior during cold cranking or hot soak.

Is an external bootstrap diode required for reliable operation at 90% duty cycle?

Yes. When VOUT/VIN > 0.65 (e.g., 12V→5V = 42%, but 5V→3.3V = 66%), BST capacitor recharge time shrinks. At >90% duty cycle (e.g., 5V→4.5V), add BAT54 or IN4148 from 5V rail to BST to maintain ≥4.5V gate drive and prevent high-side FET dropout.

How does pulse-skipping mode affect output voltage ripple compared to forced PWM?

In pulse-skipping mode, ripple increases to ~20–30mVpp (vs. 5–10mVpp in PWM) due to burst-mode operation, but RMS noise remains low. For noise-sensitive analog circuits, use a ferrite-bead + RC filter on VOUT rather than disabling pulse-skipping, which would raise IQ to 130µA and reduce battery life.

What failure modes trigger thermal shutdown, and how quickly does recovery occur?

Thermal shutdown activates at 150°C junction temperature and holds until die cools to ~135°C (15°C hysteresis). Recovery time depends on PCB thermal mass: on 2-layer FR4 with 80mm² copper, recovery takes ~1.2 seconds after overload removal. No latch-up occurs-operation resumes automatically.

Can EN pin be driven directly from a 3.3V microcontroller GPIO without level shifting?

Yes. The EN pin's 1.35–1.8V high threshold and 400mV hysteresis are compatible with standard 3.3V CMOS outputs (VOH ≥ 2.4V). Pull-up to 3.3V is unnecessary-direct GPIO control enables precise sequencing with µs-level enable/disable timing.