Monolithic Power Systems Inc. MP2040DQ-LF-Z

Overview

MP2040DQ-LF-Z from Monolithic Power Systems is a dual-supply, very low dropout linear regulator delivering up to 3A output current with 150mV dropout at full load, 0.9V–3.3V adjustable output, ±2% output voltage accuracy, and fast transient response optimized for post-regulation of switching supplies in DSP/ASIC/μC power rails.

For engineers reviewing the MP2040DQ-LF-Z datasheet, MP2040DQ-LF-Z pinout, MP2040DQ-LF-Z application, or MP2040DQ-LF-Z equivalent, key selection criteria include dual-supply architecture (VIN + BIAS), ultra-low ESR capacitor stability (≥1µF ceramic), open-drain PGOOD signaling, thermal/current protection, and QFN-10 (3×3 mm) package compatibility with high-density PCB layouts.

Technical Context

The MP2040 employs a dual-rail architecture: BIAS (3.3–5.5V) powers internal reference and control circuitry, while VIN (1.1–5.5V) supplies the NMOS pass device's drain-enabling regulation with VIN as low as VOUT + 0.2V. This decouples bias integrity from input headroom constraints.

It features a 0.51V FB threshold with resistive divider programming, 40dB PSRR at 100kHz, 80µVRMS output noise (10Hz–100kHz), and 280µs soft-start. Protection includes thermal shutdown (135°C, 15°C hysteresis), current limiting (~3.6A), and UVLO on BIAS (2.35V).

Key Specifications

Pinout & Package

MP2040DQ-LF-Z uses a 10-pin QFN package (3mm × 3mm, exposed thermal pad). Pin functions are validated per Monolithic Power Systems MP2040 Rev. 1.01 datasheet.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-supply LDO applications.

Compared with TPS7A8300RGRT and ADM7172ACPZ-R7, MP2040DQ-LF-Z uniquely delivers 3A current with dual-supply architecture enabling sub-200mV dropout-critical for high-efficiency post-regulation where VIN is tightly constrained by upstream converter design.

Availability

MP2040DQ-LF-Z is available at Aetrix Electronics and suitable for telecom baseband processing, DSP core voltage regulation, and ASIC I/O bank supply requiring stable component supply across extended temperature ranges (–40°C to +85°C) and long production lifecycles.

Supply support for MP2040DQ-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 power management ICs, with expertise in DC/DC converters, LDOs, and motor drivers for industrial, telecom, and computing markets.

The MP2040 belongs to MPS's high-current, fast-transient LDO product line-designed specifically for post-regulation of switching supplies powering DSPs, ASICs, and μCs where low noise, tight accuracy, and minimal dropout are mandatory.

FAQ

What is the minimum required voltage difference between BIAS and VOUT?

The BIAS supply must be at least 2.5V higher than the regulated output voltage (VOUT) to ensure proper operation of the internal NMOS gate drive and reference circuitry. For example, setting VOUT = 1.2V requires BIAS ≥ 3.7V. This constraint is specified in the datasheet's "Maximum Output Voltage and Load Current" section and verified across –40°C to +85°C.

Can MP2040DQ-LF-Z operate with VIN equal to VOUT?

No-VIN must exceed VOUT by at least the dropout voltage (150mV at 3A). The NMOS pass device requires sufficient V_GS headroom, and the datasheet specifies a minimum VIN of 1.1V and maximum VOUT of 3.3V only when BIAS ≥ 5.8V. Operation with VIN = VOUT violates absolute maximum ratings and causes regulation failure.

How is output voltage adjusted using the FB pin?

VOUT is set via a resistive divider from VOUT to FB, where FB regulates to 0.51V. Using R2 = 10kΩ to ground, R1 = R2 × (VOUT − 0.51)/0.51. For 1.8V output, R1 = 25.5kΩ (standard 1% value). The datasheet confirms this ratio-based method and specifies R2 ≤ 100kΩ for bias current error minimization.

Is an external capacitor required on the BYPASS pin?

Yes-a 1nF capacitor must be connected from BYPASS to GND. The datasheet explicitly states "Connect a 1nF to this pin. Do not load this pin resistively." This capacitor sets soft-start timing (280µs), stabilizes the internal reference, and prevents oscillation during startup or fault recovery.

What thermal derating applies to the QFN-10 package at 85°C ambient?

With θ_JA = 50°C/W, maximum power dissipation at T_A = 85°C is PD_MAX = (135°C − 85°C)/50°C/W = 1.0W. At 3A output and 150mV dropout, power dissipation is 0.45W-well within safe limits. No heatsink is required unless ambient exceeds 85°C or power loss exceeds 1.0W.

Does PGOOD assert before or after soft-start completion?

PGOOD asserts only after VOUT reaches ≥90% of its final regulated value and remains stable-occurring after the 280µs soft-start period. The datasheet defines PGOOD delay as 80µs from that 90% threshold crossing, ensuring reliable power sequencing for downstream logic that requires settled voltage before initialization.

Can EN be left floating?

No-EN must be actively driven. The datasheet states: "If not used then connect this pin to VBIAS." Floating EN risks undefined behavior due to internal leakage and noise susceptibility. Connecting EN to BIAS ensures guaranteed startup; tying to GND forces shutdown with <1µA quiescent current.