Monolithic Power Systems Inc. MP2143DJ-LF-P

Overview

MP2143DJ-LF-P from Monolithic Power Systems is a synchronous step-down DC/DC converter IC with integrated 80mΩ high-side and 40mΩ low-side MOSFETs, delivering up to 3A continuous output current from a 2.5V–5.5V input while regulating output down to 0.6V. It employs constant-on-time (COT) control for fast transient response, features 40μA quiescent current, 1.2MHz switching frequency, and includes EN control, power-good (PG) indicator, cycle-by-cycle current limiting, and thermal shutdown-ideal for powering FPGA I/O rails and portable system core supplies.

For engineers reviewing the MP2143DJ-LF-P datasheet, MP2143DJ-LF-P pinout, MP2143DJ-LF-P application, or MP2143DJ-LF-P equivalent, key selection criteria include its TSOT23-8 package footprint, COT-based light-load efficiency behavior, ±10% PG threshold window, 50ns minimum off-time constraint, and compatibility with low-ESR ceramic output capacitors in space-constrained battery-powered designs.

Technical Context

The MP2143DJ-LF-P implements a constant-on-time (COT) control architecture with input-voltage feed-forward, enabling near-constant 1.2MHz switching across its 2.5V–5.5V input range and supporting stable regulation down to 0.6V output. Its internal power stage integrates complementary P-channel and N-channel MOSFETs with 80mΩ and 40mΩ R_DS(ON), respectively, eliminating external switch requirements.

Functional blocks include a 0.6V precision reference, open-drain PG output with 500kΩ internal pull-up and ±10% trip thresholds, soft-start (1.3ms) and soft-stop (1ms), hiccup-mode short-circuit protection, and auto-discharge during shutdown. The IC operates in forced PWM at full load and transitions to a proprietary light-load mode that suppresses switching-node ringing without entering discontinuous conduction mode (DCM).

Key Specifications

Pinout & Package

MP2143DJ-LF-P is housed in a thermally enhanced TSOT23-8 package (2.9mm × 1.6mm × 0.85mm), optimized for high-density portable PCBs with exposed thermal pad connected to PGND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with RT6203BGQW and TPS62231DRVR, MP2143DJ-LF-P uniquely combines COT-based transient response, integrated PG signaling, 100% duty cycle operation, and lowest quiescent current - making it optimal for battery-sensitive, sequenced, and dynamically loaded portable systems where reliability and footprint are critical.

Availability

MP2143DJ-LF-P is available at Aetrix Electronics and suitable for mobile baseband power, FPGA I/O rail supply, USB-C PD sink systems, and portable medical sensor hubs requiring stable component supply, RoHS-compliant packaging, and long-term lifecycle support.

Supply support for MP2143DJ-LF-P 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 MP2143 belongs to MPS's COT-based synchronous buck converter product line, engineered specifically for space-constrained, battery-powered applications demanding fast transient response, ultra-low quiescent current, and robust fault protection without external compensation.

FAQ

What is the minimum recommended output capacitance for stable operation?

The MP2143DJ-LF-P is stable with ≥10µF X5R/X7R ceramic output capacitors. Lower values may cause instability under heavy load transients. For 3A loads, 22µF is recommended to limit output ripple to <20mV peak-to-peak. Tantalum or electrolytic capacitors require careful ESR selection (20–50mΩ) and should be paralleled with 0.1µF ceramic for high-frequency filtering.

Does MP2143DJ-LF-P support forced PWM mode across all load conditions?

No - the MP2143DJ-LF-P automatically transitions from forced PWM at medium-to-heavy loads to a proprietary light-load mode that minimizes switching losses while suppressing switching-node ringing. It does not enter true discontinuous conduction mode (DCM) due to internal timing constraints, preserving regulation accuracy and noise performance at microamp loads.

How is the power-good (PG) signal asserted and what load conditions affect its accuracy?

PG is asserted high (pulled to VIN via internal 500kΩ resistor) only when the FB voltage remains within ±10% of 0.600V for ≥110µs. It deasserts immediately if FB deviates outside this window due to overvoltage, undervoltage, or excessive load transient. PG accuracy is unaffected by load current but depends on proper resistor divider tolerance (1% recommended) and PCB layout immunity to noise coupling.

Can MP2143DJ-LF-P operate with input voltage below 2.5V?

No - the absolute minimum operating input voltage is 2.5V per datasheet specifications. Below this, UVLO disables the device. The under-voltage lockout rising threshold is 2.2V ±0.2V, with 150mV hysteresis, ensuring clean startup from weak or aging batteries but preventing operation in marginal input conditions that could cause erratic regulation.

What is the thermal performance limitation in TSOT23-8 package at 3A output?

In a standard 4-layer PCB with 1-in² 2oz copper thermal pad, the MP2143DJ-LF-P reaches ~115°C junction temperature at 3A/1.2V output with 5V input. Derating to 2.5A is recommended for ambient temperatures >60°C or when thermal vias to inner ground planes are limited. θ_JA = 100°C/W and θ_JC = 55°C/W enable effective thermal management when the exposed pad is soldered to PGND.

Is the EN pin internally pulled down, and what happens if left floating?

Yes - the EN pin has an internal 1MΩ pull-down resistor to AGND. If left floating, the device remains disabled. To enable, apply ≥1.2V (typical) to EN; logic high threshold is guaranteed ≥1.2V over temperature. Leakage current is <2µA at 2V, allowing direct connection to GPIOs without external level-shifting.

How does the 50ns minimum off-time affect inductor selection at low output voltages?

At low V_OUT/V_IN ratios (e.g., 0.6V/5.5V), the theoretical off-time exceeds 50ns, so the minimum off-time does not constrain operation. However, at high V_OUT/V_IN (e.g., 3.3V/3.6V), off-time approaches 50ns - requiring inductors ≤1.0µH to maintain CCM and avoid unintended boundary-mode operation that impacts efficiency and noise.