Monolithic Power Systems Inc. MPQ2451GG-33-Z

Overview

MPQ2451GG-33-Z from Monolithic Power Systems is a 36V, 2.2MHz, 0.6A asynchronous step-down DC/DC converter with integrated high-side MOSFET (R_DS(ON) = 500mΩ), fixed 3.3V output, AEC-Q100 Grade 1 qualification, and 130µA quiescent current - designed for automotive power rails requiring stable low-noise 3.3V supply under wide input (3.3–36V) and extended temperature (−40°C to +125°C) conditions.

For engineers reviewing the MPQ2451GG-33-Z datasheet, MPQ2451GG-33-Z pinout, MPQ2451GG-33-Z application, or MPQ2451GG-33-Z equivalent, key selection criteria include its AEC-Q100 qualification, QFN-6L thermal performance (θ_JA = 80°C/W), pulse-skipping light-load efficiency mode, internal soft-start, and absence of external compensation components.

Technical Context

This regulator employs peak-current-mode control with fixed 2.2MHz switching frequency and internal compensation, enabling stable operation with ceramic output capacitors without external loop components. Its current-limit threshold (0.75A typ.) is set internally without sense resistors, and UVLO features 2.9V rising / 2.6V falling hysteresis.

The device integrates a bootstrap driver with dedicated UVLO (2.4V rising), supports external bootstrap diode enhancement for high-duty-cycle operation, and implements thermal shutdown at 150°C with automatic recovery. Startup includes 50µs noise blanking and reference-first sequencing to ensure robust power-on behavior.

Key Specifications

Pinout & Package

MPQ2451GG-33-Z is housed in a thermally enhanced 2mm × 2mm QFN-6L package with exposed thermal pad, supporting 1.56W continuous power dissipation at 25°C ambient and θ_JA = 80°C/W on standard 4-layer PCB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ2451GG-33-Z, the SOT23-6L variant trades thermal headroom for footprint reduction, while the LMQ66430QRNXTQ1 adds current capacity and configurability at the cost of BOM complexity and board area - making MPQ2451GG-33-Z optimal for fixed 3.3V, AEC-Q100-compliant, space- and efficiency-sensitive 0.6A applications.

Availability

MPQ2451GG-33-Z is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC power supplies, and battery-powered telematics requiring stable component supply with AEC-Q100 assurance and long-term production continuity.

Supply support for MPQ2451GG-33-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 power ICs, with core expertise in DC/DC conversion, motor drivers, and LED lighting controllers.

The MPQ2451 product line delivers compact, AEC-Q100-qualified buck converters targeting automotive subsystems where reliability, small footprint, and wide-input operation are essential - particularly for 3.3V and 5V domain controllers.

FAQ

What is the minimum input voltage required for MPQ2451GG-33-Z to regulate 3.3V output?

The device regulates down to 3.3V input per datasheet specifications, enabled by its internal 2.6V regulator and optimized gate drive. At VIN = 3.3V, the duty cycle approaches 100%, and bootstrap charging relies on residual voltage headroom (VIN – VOUT > 3V recommended). Operation is guaranteed across the full −40°C to +125°C junction range at this minimum input.

Does MPQ2451GG-33-Z require an external bootstrap diode?

No external bootstrap diode is required for standard operation. The IC includes an internal bootstrap regulator that charges the BST–SW capacitor from VIN. An external diode (e.g., BAT54) is optional only for VIN ≤ 6V, high-duty-cycle (>65%) applications, or to improve efficiency when a clean 5V rail is available - per Figure 2 in the datasheet.

How does pulse-skipping mode affect output voltage ripple and EMI profile?

In pulse-skipping mode, switching becomes irregular and low-frequency, increasing low-frequency output ripple (typically <10kHz) but reducing high-frequency harmonics. This lowers average switching losses and improves light-load efficiency, though designers should verify ripple compliance with downstream loads and consider adding post-filtering if sensitive analog circuits are powered from this rail.

Can MPQ2451GG-33-Z be used without the EN pin connected?

Yes - the EN pin has an internal pull-down to GND, so leaving it unconnected disables the device. To enable operation, EN must be pulled above 1.35V (typical VIH). For systems requiring default-on behavior, connect EN to VIN through a resistor divider or direct tie if VIN stays within 1.35–5.0V range.

What is the maximum achievable output current with MPQ2451GG-33-Z on a standard 4-layer PCB?

At 25°C ambient, the QFN-6L package supports up to 0.6A continuous output based on thermal limits (1.56W P_D max, θ_JA = 80°C/W). At 70°C ambient, derating yields ~0.45A; at 105°C, ~0.25A. Performance assumes proper thermal via array under the exposed pad and adequate copper pour on inner layers.

Is the 3.3V output voltage trimmed or factory-fixed?

The 3.3V output is factory-trimmed and fixed - no external resistors are used or supported. Electrical characteristics specify ±3.6% tolerance (3.168–3.432V) over full input voltage (3.3–36V), temperature (−40°C to +125°C), and load (0–0.6A), with tighter ±1.5% typical variation at 25°C.

How does thermal shutdown behave during sustained overload?

When junction temperature exceeds 150°C, the device shuts down completely - disabling switching, pulling COMP low, and disconnecting the bootstrap charging path. It remains latched off until die temperature falls below ~135°C (typical hysteresis), then automatically resumes normal operation without requiring EN toggling or power cycle.