Monolithic Power Systems Inc. MPQ2420GF-AEC1-Z

Overview

MPQ2420GF-AEC1-Z from Monolithic Power Systems is an AEC-Q100 Grade 1 qualified synchronous step-down converter integrating high- and low-side 75V MOSFETs, delivering up to 0.3A output with 1.2Ω/0.45Ω R_DS(on), 4.5–75V input range, and integrated window watchdog for automotive safety-critical power rails.

For engineers reviewing the MPQ2420GF-AEC1-Z datasheet, MPQ2420GF-AEC1-Z pinout, MPQ2420GF-AEC1-Z application, or MPQ2420GF-AEC1-Z equivalent, key selection criteria include its 5μA shutdown current, programmable short/long watchdog window modes, TSSOP-16 EP thermal performance (θ_JA = 45°C/W), and FB voltage tolerance of ±2% over temperature.

Technical Context

The MPQ2420GF-AEC1-Z implements a current-mode PWM control architecture with zero-current detection (ZCD) for discontinuous conduction mode (DCM) operation, enabling light-load efficiency scaling via frequency reduction. Its internal 1V reference (±2% over –40°C to +125°C) feeds a precision error amplifier that regulates output via external resistive divider on FB.

Watchdog functionality operates independently of the DC/DC core: TIMER pin sets timeout period (e.g., 880μs with 51kΩ), MODE selects short (15/10 cycle) or long (1500/1000 cycle) windows, and WDI/WDO provide bidirectional MCU synchronization with reset pulse width of 4 cycles. Power-on reset triggers at VCC = 4.6V with 10-cycle delay.

Key Specifications

Pinout & Package

TSSOP-16 EP package with exposed thermal pad soldered to PCB ground plane for optimal thermal dissipation (θ_JA = 45°C/W, θ_JC = 10°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck converter with watchdog applications.

Compared with MPQ2420GF-AEC1-Z, the MPQ2420GJ-AEC1-Z trades thermal performance for smaller footprint, while the TPS63060-Q1 offers wider input range and higher current but omits the integrated watchdog-requiring additional components for ASIL-B compliance.

Availability

MPQ2420GF-AEC1-Z is available at Aetrix Electronics and suitable for automotive body electronics, ADAS camera modules, and telematics control units requiring stable component supply with AEC-Q100 qualification and long-term production support.

Supply support for MPQ2420GF-AEC1-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 design centers in the US, China, and Taiwan.

The MPQ2420 product line targets automotive power conversion with integrated safety features, designed specifically for ASIL-B–capable subsystems requiring watchdog supervision and extended temperature operation.

FAQ

What is the purpose of the BIAS pin, and how should it be connected?

The BIAS pin supplies power to the internal low-side MOSFET driver and bias circuitry. For optimal efficiency, connect BIAS to the regulated output voltage (2.9–5.5V). When output voltage falls outside this range, use an external 3–5.5V supply. Connecting BIAS reduces VIN supply current and improves light-load efficiency by bypassing the internal VIN-regulated bias path.

How does the watchdog timer period scale with the TIMER resistor value?

The watchdog timeout period T (in μs) is calculated as T = 15.75 × R_TIMER(kΩ) + 73.5. For example, a 51kΩ resistor yields T ≈ 880μs. This linear relationship allows precise tuning of watchdog window timing without firmware changes, supporting both fast-response (short mode) and robust (long mode) MCU supervision.

Can the MPQ2420GF-AEC1-Z operate with input voltages below 4.5V?

No. The device has a fixed UVLO rising threshold of 4.2V (typical) and falling threshold of 3.75V. Operation below 4.5V violates the recommended operating condition and will cause the regulator to remain disabled. For sub-4.5V inputs, consider alternative regulators such as the MPQ4312 or external UVLO circuitry.

What is the maximum allowable output voltage, and how is it set?

The maximum output voltage is 0.9 × VIN, limited by internal circuitry. It is set using a resistive divider from VOUT to FB, where R1/R2 = (VOUT/VREF) – 1 and VREF = 1.0V. For a 12V output with VIN ≥13.3V, use R1 = 1200kΩ and R2 = 109kΩ. Feedback resistor values in the MΩ range minimize no-load current draw.

Is the /WD_DIS pin active-high or active-low, and what happens when it's left unconnected?

The /WD_DIS pin is active-low: pulling it low disables the watchdog, while pulling it high enables it. The pin has a weak internal pull-up, so leaving it unconnected defaults to watchdog enabled. This behavior ensures fail-safe operation-watchdog remains active unless explicitly disabled by system design.

How does the soft-start function interact with short-circuit recovery?

During short-circuit recovery, the SS voltage tracks FB voltage downward. When the short is removed, SS ramps up from its tracked level-not from zero-preventing output overshoot. This dynamic tracking ensures controlled re-establishment of regulation without requiring manual reset or external intervention.

What thermal derating applies when operating at 125°C junction temperature?

At T_J = 125°C, the maximum continuous power dissipation is reduced to PD(MAX) = (150°C – 125°C)/45°C/W = 0.56W. With typical 75V input and 5V output at 0.3A, power loss is ~2.1W-exceeding this limit. Therefore, full 0.3A load requires heatsinking, airflow, or lower ambient temperature to maintain T_J ≤125°C.