Monolithic Power Systems Inc. MP6401DGT-33BD3-LF-Z

Overview

MP6401DGT-33BD3-LF-Z from Monolithic Power Systems is a 300mA low-dropout linear regulator with integrated push-pull active-low reset circuit, fixed 3.3V output (±2% accuracy), -12.5% reset threshold, and 200ms reset delay. It operates from 2.5V–5.5V input, delivers 114mV dropout at full load, and targets space-constrained portable electronics requiring reliable power sequencing and microprocessor supervision.

For engineers reviewing the MP6401DGT-33BD3-LF-Z datasheet, MP6401DGT-33BD3-LF-Z pinout, MP6401DGT-33BD3-LF-Z application, or MP6401DGT-33BD3-LF-Z equivalent, this device serves as a single-chip solution for regulated 3.3V supply generation and deterministic system reset assertion during brownout, power-up, or undervoltage events in battery-powered handheld devices.

Technical Context

The MP6401 integrates a PMOS pass transistor LDO with an independent voltage-monitoring comparator driving a push-pull RESET output. Its regulation loop maintains ±2% output accuracy across -40°C to +85°C, while the reset circuit samples VOUT continuously and asserts RESET within 30μs when voltage falls below 87.5% of nominal (3.3V → 2.8875V).

Four factory-set reset delays (3.125/25/200/1580ms) are selected via part number suffix; D3 denotes 200ms. The ADJ pin enables either fixed-output mode (GND-connected) or adjustable mode (external resistor divider), and EN provides active-high enable control with <1μA shutdown current.

Key Specifications

Pinout & Package

MP6401DGT-33BD3-LF-Z uses the 2mm×2mm TQFN6 package with exposed thermal pad (Mo-229 WCCC compliant), optimized for high-density PCB layouts and thermal performance in compact handheld enclosures.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS79933DBVR and MCP1826-3302E/DB, MP6401DGT-33BD3-LF-Z delivers verified 200ms reset timing, push-pull drive strength, and single-component integration-reducing design risk and PCB area in space-constrained portable applications where deterministic reset behavior is mandatory.

Availability

MP6401DGT-33BD3-LF-Z is available at Aetrix Electronics and suitable for smartphone baseband power, portable GPS receivers, wireless sensor nodes, and PDA application processor rails requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for MP6401DGT-33BD3-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 expertise in DC/DC converters, LDOs, motor drivers, and LED drivers for consumer, industrial, and automotive markets.

The MP6401 belongs to MPS's integrated power management portfolio designed specifically for portable electronics, emphasizing ultra-low quiescent current, small-footprint packaging, and system-level functions like reset supervision to reduce total solution size and cost.

FAQ

What is the exact reset threshold voltage for MP6401DGT-33BD3-LF-Z?

The "B" suffix indicates a -12.5% reset threshold relative to nominal output voltage. For the 3.3V variant, this equals 3.3V × 0.875 = 2.8875V. The datasheet specifies tolerance as 85%–90% of VOUT, so actual threshold ranges from 2.805V to 2.97V at TA = +25°C.

Can the ADJ pin be left unconnected in this fixed-voltage variant?

No. Per the datasheet, the ADJ pin must be connected to GND in fixed-output mode. Leaving it floating violates the absolute maximum rating (ADJ = –0.3V to 6V) and may cause regulation instability or unpredictable reset behavior due to internal node biasing errors.

Does MP6401DGT-33BD3-LF-Z support backup battery operation?

Yes. Its reverse current protection limits OUT-to-IN leakage to <0.1μA when VIN < VOUT, enabling seamless switchover to a backup battery connected at the OUT pin. The RESET output asserts during input removal, signaling the host to enter low-power state while maintaining RAM retention.

What is the recommended output capacitor type and value?

A minimum 3.3μF X5R or X7R ceramic capacitor is required for stability. The datasheet recommends 10μF for improved transient response and PSRR. ESR should be ≤10mΩ; avoid high-ESR electrolytics or tantalums which may cause oscillation or excessive overshoot.

How does thermal shutdown behave under continuous overload?

Thermal shutdown activates at TJ = 150°C (typical) and releases at TJ = 130°C (20°C hysteresis). During sustained overload, the device cycles between regulation and shutdown, limiting average power dissipation. For reliable operation, keep junction temperature ≤125°C using adequate copper pour on the exposed pad.

Is the RESET output truly push-pull, and what are its drive capabilities?

Yes. RESET is a true push-pull output: it sources up to 500μA (VOH ≥ 0.8×VOUT) and sinks up to 3.2mA (VOL ≤ 0.4V). This eliminates need for external pull-up resistors and ensures fast, rail-to-rail logic transitions compatible with all modern microcontroller reset inputs.

What is the minimum input voltage required to maintain regulation at 300mA load?

With 114mV typical dropout at 300mA and 3.3V nominal output, minimum input is 3.3V + 0.114V = 3.414V. At worst-case 220mV dropout (per datasheet max), VIN must be ≥3.52V to sustain full load without dropout-induced output collapse.