Monolithic Power Systems Inc. MP6401DJ-18AD3-LF-P

Overview

MP6401DJ-18AD3-LF-P from Monolithic Power Systems is a 300mA low-dropout linear regulator with integrated push-pull active-low reset circuit, delivering 1.8V ±2% output at up to 300mA load current from 2.5V–5.5V input. It features 114mV dropout at full load, 80μA quiescent current, and 15μVRMS output noise-optimized for space-constrained portable electronics requiring stable voltage regulation and reliable microprocessor reset signaling.

For engineers reviewing the MP6401DJ-18AD3-LF-P datasheet, MP6401DJ-18AD3-LF-P pinout, MP6401DJ-18AD3-LF-P application, or MP6401DJ-18AD3-LF-P equivalent, key selection criteria include fixed 1.8V output, -7.5% reset threshold, 200ms reset delay, TSOT23-6 package compatibility, and integrated reverse-current protection for battery-backed memory retention.

Technical Context

The MP6401DJ-18AD3-LF-P integrates a precision LDO regulator core with an independent reset comparator monitoring the regulated output. Its internal reference (1.229V) enables ±2% output accuracy across -40°C to +85°C, while the reset circuit asserts when VOUT falls below 92.5% of nominal (i.e., 1.665V for 1.8V output), with fixed 200ms deassertion delay after recovery.

It uses a PMOS pass device with thermal shutdown (150°C trip, 20°C hysteresis), short-circuit current limit (500mA), and reverse leakage protection that reduces OUT→IN current to ≤0.1μA when VIN < VOUT-enabling seamless backup-battery operation in memory-retention applications without external diodes.

Key Specifications

Pinout & Package

MP6401DJ-18AD3-LF-P is housed in a 6-pin TSOT23-6 package (1.0mm max height, 2.8mm × 2.9mm footprint) with exposed thermal pad for enhanced power dissipation. Pin 1 is bottom-left when reading top marking left-to-right.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO-with-reset applications.

Compared with TPS79918YZTT and MCP1825-1802E/DB, MP6401DJ-18AD3-LF-P uniquely combines 300mA delivery, 1.8V ±2% accuracy, and factory-configured 200ms reset delay in a single TSOT23-6 package-reducing design complexity and improving reliability in space-constrained portable systems.

Availability

MP6401DJ-18AD3-LF-P is available at Aetrix Electronics and suitable for smartphone baseband power, portable GPS receivers, wearable health sensor hubs, and industrial handheld terminals requiring stable component supply with guaranteed long-term sourcing.

Supply support for MP6401DJ-18AD3-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.

The MP6401 product line delivers integrated LDO regulators with embedded reset functionality for portable and battery-powered applications-designed to replace discrete regulator + supervisor combinations in space- and power-sensitive consumer electronics.

FAQ

What is the exact reset threshold voltage for MP6401DJ-18AD3-LF-P?

The "A" suffix indicates a -7.5% reset threshold relative to nominal output voltage. For the 1.8V version, this equals 1.665V (1.8V × 0.925). The reset asserts when VOUT drops below this level and deasserts after the fixed 200ms delay once VOUT recovers above 1.665V.

Can the ADJ pin be left unconnected in fixed-output mode?

No. In fixed-output mode, the ADJ pin must be connected to GND with low impedance (<50kΩ). Leaving it floating causes undefined regulation behavior and potential output instability. Direct solder connection to ground is recommended per MPS application guidance.

Does MP6401DJ-18AD3-LF-P support backup battery operation?

Yes. Its reverse-current protection blocks OUT→IN leakage to ≤0.1μA when VIN drops below VOUT, enabling seamless switchover to a backup battery on the OUT rail. This maintains SRAM data during main power interruption without external diodes or control logic.

What is the minimum output capacitor required for stability?

A minimum 3.3μF X5R or X7R ceramic capacitor is required on the OUT pin. Larger values (e.g., 10μF) improve transient response and PSRR. ESR must be ≤100mΩ; tantalum or aluminum electrolytics are not recommended due to ESR and reliability concerns.

How does the EN pin behave during shutdown?

When EN is pulled low (<0.3VIN), the regulator output shuts down and quiescent current drops to 0.1–1μA. The RESET output remains asserted (low) during shutdown. EN must never be left floating-it should be tied to IN for always-on operation or actively driven by system logic.

Is thermal derating required for continuous 300mA operation in TSOT23-6?

Yes. With θJA = 220°C/W, continuous 300mA at 5.5V input and 1.8V output (2.22W dissipation) exceeds safe junction limits. Derating is required: at TA = 60°C, maximum sustainable load is ~180mA. Use PCB copper pour under the exposed pad and minimize ambient temperature to sustain full load.

What failure protections are built into MP6401DJ-18AD3-LF-P?

It includes thermal shutdown (150°C trip), short-circuit current limiting (500mA), reverse-current blocking (<0.1μA), and input undervoltage lockout (2.05V typical). All protections are fully autonomous-no external components or configuration needed-and recover automatically when fault conditions clear.