Monolithic Power Systems Inc. MPQ2451GG-5-Z

Overview

MPQ2451GG-5-Z from Monolithic Power Systems is a 36V, 2.2MHz, 0.6A asynchronous step-down converter with integrated high-side MOSFET (R_DS(ON) = 500mΩ), fixed 5V output, AEC-Q100 Grade 1 qualification, and 130µA quiescent current-designed for automotive power rails in engine control units and ADAS camera modules.

For engineers reviewing the MPQ2451GG-5-Z datasheet, MPQ2451GG-5-Z pinout, MPQ2451GG-5-Z application, or MPQ2451GG-5-Z equivalent, this page delivers verified package mapping (QFN-6L), validated thermal performance (θ_JA = 80°C/W), confirmed pulse-skipping light-load operation, and real-world design constraints including bootstrap charging headroom (VIN − VOUT > 3V) and EN threshold hysteresis (400mV).

Technical Context

This IC implements peak-current-mode control with internal compensation and a dedicated error amplifier driving the COMP node. Its 2.2MHz fixed-frequency PWM operation transitions to pulse-skipping mode below ~10mA load to reduce gate-driving and switching losses while maintaining regulation.

The device integrates a floating high-side driver powered by an external BST capacitor, with internal bootstrap regulation targeting ~5V between BST and SW pins. Thermal shutdown activates at 150°C junction temperature, and UVLO ensures operation only above VIN = 2.7V (rising) with 0.4V hysteresis.

Key Specifications

Pinout & Package

MPQ2451GG-5-Z uses a thermally enhanced 2mm × 2mm QFN-6L package with exposed thermal pad, offering θ_JA = 80°C/W on a 4-layer PCB - significantly lower than SOT23-6L (220°C/W) for higher power density in space-constrained automotive modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ2451GG-5-Z, the SOT23 variant trades thermal performance for footprint reduction, while the LM61480QPWRQ1 offers scalability at the cost of design simplicity and component count - making MPQ2451GG-5-Z optimal for cost-sensitive, space-limited 0.6A automotive rails where fixed 5V and AEC-Q100 are mandatory.

Availability

MPQ2451GG-5-Z is available at Aetrix Electronics and suitable for automotive engine control units, ADAS camera modules, and infotainment displays requiring stable component supply with AEC-Q100 traceability and long-term lifecycle support.

Supply support for MPQ2451GG-5-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 over 20 years of leadership in DC/DC conversion and motor drive solutions.

The MPQ2451 product line delivers AEC-Q100-qualified, high-frequency buck converters optimized for automotive subsystems demanding ultra-low quiescent current, wide input range, and minimal external components.

FAQ

What is the minimum input voltage required for reliable startup?

The MPQ2451GG-5-Z features under-voltage lockout (UVLO) with a rising threshold of 2.7V and 0.4V hysteresis. Reliable startup occurs when VIN exceeds 2.7V and remains above 2.3V during operation. Below 2.3V, the device shuts down to protect internal circuitry and prevent erratic behavior during battery brownout conditions.

Can MPQ2451GG-5-Z operate without an external bootstrap capacitor?

No. The BST pin requires a 100nF ceramic capacitor connected between BST and SW to power the floating high-side gate driver. Omitting this capacitor prevents proper MOSFET turn-on, resulting in no output voltage and potential damage due to uncontrolled switching. Layout guidelines specify placement within 2mm of the IC pins.

How does pulse-skipping mode affect output voltage ripple?

In pulse-skipping mode (active below ~10mA load), the regulator reduces switching frequency dynamically, causing variable off-times and higher low-frequency ripple (typically <10kHz). This increases peak-to-peak output ripple versus fixed-frequency PWM but improves light-load efficiency by >30%. A 22µF ceramic output capacitor limits ripple to <25mV under these conditions.

Is the EN pin internally pulled down when left floating?

Yes. The EN pin has an internal pull-down to GND, ensuring the device remains disabled when unconnected. This fail-safe behavior prevents unintended power-up during assembly or handling. To enable operation, drive EN to ≥1.35V with a current-sourcing signal; floating EN guarantees shutdown with ≤1µA supply current.

What is the maximum recommended duty cycle for reliable bootstrap charging?

For reliable BST capacitor charging, the duty cycle (VOUT/VIN) must remain below 65%. At higher duty cycles, the SW node voltage remains elevated too long, reducing the VIN–VSW headroom needed to charge the BST capacitor via the internal PMOS pass transistor. If exceeding 65%, add an external 5V-fed bootstrap diode as shown in Figure 2 of the datasheet.

Does MPQ2451GG-5-Z require external compensation components?

No. The MPQ2451GG-5-Z is fully internally compensated, eliminating the need for external RC networks on the COMP pin. This simplifies design, improves production yield, and ensures consistent loop response across temperature and process variations - verified by MPS across −40°C to +125°C operating range.

How is thermal performance affected by PCB layout?

Thermal resistance θ_JA = 80°C/W assumes a 4-layer PCB with ≥6 thermal vias (15mil barrel, 40mil pitch) under the exposed pad connected to a solid inner ground plane. Reducing via count or omitting the ground plane increases θ_JA to >120°C/W, limiting max continuous current to 0.35A at 85°C ambient - underscoring strict adherence to the recommended land pattern.