Monolithic Power Systems Inc. MP2249DQT-LF-Z

Overview

MP2249DQT-LF-Z from Monolithic Power Systems is a 1MHz, 3A synchronous step-down DC/DC converter optimized for single-cell Li-ion battery-powered portable electronics. It integrates high-side and low-side MOSFETs, supports 2.5V–6V input, delivers adjustable output from 0.6V to VIN, and operates at 100% duty cycle in dropout - enabling stable 1.8V core supply for smartphones and MP3 players.

For engineers reviewing the MP2249DQT-LF-Z datasheet, MP2249DQT-LF-Z pinout, MP2249DQT-LF-Z application, or MP2249DQT-LF-Z equivalent, key selection criteria include its 72mΩ NFET R_DS(on), 0.6V ±12mV feedback reference accuracy, integrated output discharge, power-good indicator, and thermal shutdown at 145°C - all critical for compact, battery-sensitive designs.

Technical Context

The MP2249DQT-LF-Z employs constant-frequency current-mode PWM control with slope compensation to ensure stability at >50% duty cycles and cycle-by-cycle overcurrent protection. Its internal 1MHz oscillator enables small external components while maintaining tight regulation across line and load variations.

It features an integrated 0.6V precision bandgap reference, 450kΩ internal EN pull-down resistor, open-drain PG output with 85–90% V_FB window detection, and automatic output discharge via internal MOSFET when disabled - eliminating need for external discharge circuitry in portable systems.

Key Specifications

Pinout & Package

MP2249DQT-LF-Z is housed in a thermally enhanced 3mm × 3mm TQFN-10 package with exposed pad for optimal PCB heat dissipation (θ_JA = 50°C/W on 4-layer board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS62231DRYT and RT7297BZSP, MP2249DQT-LF-Z uniquely combines 100% duty cycle, integrated output discharge, and open-drain PG in a 3mm×3mm TQFN - making it optimal for space-constrained, battery-critical portable systems requiring robust power sequencing.

Availability

MP2249DQT-LF-Z is available at Aetrix Electronics and suitable for smartphone core supplies, portable audio DACs, digital camera sensor rails, and wearable BLE SoC power management requiring stable component supply across high-volume production cycles.

Supply support for MP2249DQT-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 analog and power ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP2249 belongs to MPS's low-voltage DC/DC converter product line, engineered specifically for Li-ion–powered portable electronics demanding high efficiency, minimal footprint, and robust protection in thermally constrained environments.

FAQ

What is the maximum recommended PCB copper area for the exposed thermal pad of MP2249DQT-LF-Z?

The exposed pad (pins 2 and 3) must be soldered to a minimum 30mm² solid copper pour connected to ground plane via ≥4 thermal vias (0.3mm diameter, spaced ≤1mm apart). This achieves θ_JA ≤50°C/W per JEDEC MO-229 VEED-5 compliance and prevents junction temperature exceedance at 3A load.

Does MP2249DQT-LF-Z support pre-biased output startup?

No - MP2249DQT-LF-Z does not support true pre-bias startup. Its internal discharge MOSFET activates only after EN is deasserted; applying external voltage to VOUT while EN=LOW may cause reverse current flow exceeding 100mA, risking damage. External diode isolation is required for pre-bias applications.

How is output voltage accuracy affected by resistor divider tolerance?

With a 0.6V ±12mV reference, ±1% FB resistors contribute ±1% output error. For 1.8V output using 150kΩ/75kΩ divider, total error is ±1.2% (±21.6mV), dominated by resistor matching. Use 0.5% matched pairs to achieve ±0.7% total accuracy.

What happens during thermal shutdown, and how does recovery work?

At 145°C junction temperature, internal thermal shutdown disables both PFET and NFET, halting switching and pulling PG low. Recovery occurs only after junction cools to ~135°C hysteresis threshold and EN is cycled - no automatic restart. This prevents repeated tripping under sustained overload.

Can MP2249DQT-LF-Z operate with ceramic output capacitors below 22µF?

Yes - minimum recommended is 10µF X5R/X7R ceramic (e.g., 2×4.7µF or 1×10µF) for 1.8V/3A operation. Lower values increase output ripple beyond 20mV_PP and reduce phase margin; stability is maintained if ESR <5mΩ and C_OUT ≥10µF with proper loop compensation.

Is the EN pin compatible with 1.8V logic without level shifting?

Yes - EN has guaranteed 1.8V turn-on threshold (min 1.8V) and 0.4V turn-off threshold (max 0.4V), making it directly compatible with standard 1.8V GPIO outputs. The internal 450kΩ pull-down ensures reliable disable state when left floating or driven by open-drain sources.