Monolithic Power Systems Inc. MP3021DQ-LF-P

Overview

MP3021DQ-LF-P from Monolithic Power Systems is a white LED backlight driver IC using an auto-adjusting 1x/1.5x/2x charge pump architecture to drive up to four WLEDs at 30mA each. It features 5-bit brightness control plus low-current mode, single-wire MPC™ serial interface, and thermal/under-voltage protection. Designed for compact portable displays, it operates from 2.7V to 5.5V input and delivers >90% efficiency at 4.2V with 30mA per LED.

For engineers reviewing the MP3021DQ-LF-P datasheet, MP3021DQ-LF-P pinout, MP3021DQ-LF-P application, or MP3021DQ-LF-P equivalent, key selection criteria include charge pump mode automation, 32-level current-controlled brightness, ISET resistor-based full-scale current setting (e.g., 30mA @ R1 = 4.17kΩ), soft-start inrush limiting, and QFN16 (3mm × 3mm) thermal performance (θJA = 60°C/W).

Technical Context

The MP3021DQ-LF-P implements a fully integrated switched-capacitor charge pump with automatic gain selection (1x, 1.5x, or 2x) based on input voltage and LED forward voltage, maintaining regulated current across varying battery conditions. Its internal 1.2 MHz oscillator drives synchronous switching, while the MPC™ protocol uses pulse-width encoding (1.5–3.5 µs short pulses, ≥8 µs long pulses) for register writes over a single DATA line.

Current regulation is achieved via a precision 1.25V reference applied to the ISET pin, with 100× current gain (ILED = 100 × VR1/R1). Each of the four LED outputs (LED0–LED3) provides independent current sinking with ±3% matching at 20mA and thermal shutdown activation at 150°C.

Key Specifications

Pinout & Package

MP3021DQ-LF-P is housed in a thermally enhanced 3mm × 3mm QFN-16 package with exposed thermal pad (connected to VSS, Pin 5). The package supports high-density layout and efficient heat dissipation (θJC = 12°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar WLED backlight driver applications.

Compared with MP1519DJ-LF-Z and RT9397BZSP, MP3021DQ-LF-P uniquely balances auto-gain charge pump efficiency, single-wire simplicity, and sub-mA dimming-making it optimal for cost-constrained, space-limited portable displays where design-in stability outweighs next-gen feature adoption.

Availability

MP3021DQ-LF-P is available at Aetrix Electronics and suitable for cellular phones, PDA phones, PDAs, and portable media players requiring stable component supply across extended production lifecycles.

Supply support for MP3021DQ-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 core expertise in DC/DC conversion, LED drivers, and motor control solutions.

The MP3021 belongs to MPS's WLED backlight driver product line, engineered specifically for space-constrained portable electronics needing high-efficiency, low-EMI, and minimal-component-count display illumination.

FAQ

What is the recommended external capacitor value for C1 and C2?

Monolithic Power specifies 1µF X5R ceramic capacitors for both C1 and C2, placed as close as possible to the respective pins (C1A/C1B and C2A/C2B). Using mismatched values or types degrades charge pump efficiency and may cause mode-switching instability-verified in the MP3021 Rev. 1.0 datasheet Figure 1 and Section "CP Pin".

How does the HC/LC bit affect brightness resolution?

The HC/LC bit selects between high-current (HC) and low-current (LC) scaling modes: in HC mode, the 5-bit register sets 30mA full-scale with ~0.94mA step size; in LC mode, full-scale is reduced to 3mA with ~0.1mA steps-enabling precise dimming below 1mA without PWM flicker, as shown in Table 2 of the datasheet.

Can MP3021DQ-LF-P drive LEDs in common-cathode configuration?

No-the MP3021DQ-LF-P is designed exclusively for common-anode WLED configurations, with LED0–LED3 functioning as current sinks referenced to VSS. Driving common-cathode LEDs would require external high-side switches and invalidate the internal current regulation loop, per the "Typical Application" schematic on page 1.

What happens if the DATA line is left floating during operation?

A floating DATA line violates the MPC™ protocol requirement for a 100kΩ pull-down resistor. This can cause unintended register writes due to noise coupling, leading to erratic brightness changes or unintended shutdown. The datasheet explicitly mandates this resistor in the "DATA" pin description (page 3) and Figure 2 waveform annotations.

Is the exposed thermal pad electrically isolated?

No-the exposed pad is internally connected to VSS (Pin 5) and must be soldered directly to the PCB ground plane. Leaving it unconnected or floating increases junction temperature by >25°C under full load, violating thermal limits and risking premature thermal shutdown, as confirmed in the "Package Information" section and θJA/θJC specifications.

Does MP3021DQ-LF-P support PWM dimming in addition to register-based control?

No-brightness is controlled solely via the 5-bit register and HC/LC bit; there is no dedicated PWM input or analog dimming pin. Attempting external PWM on the DATA line disrupts MPC™ communication and may corrupt register state, as the protocol relies on precise pulse-width timing (1.5–3.5 µs) defined in Table 1.

What is the maximum total output current capability?

The MP3021DQ-LF-P supports up to 30mA per channel across four outputs, yielding a maximum total output current of 120mA. This is validated under "Recommended Operating Conditions" (VIN = 2.7–5.5V, TA = –40°C to +85°C) and confirmed in the "Typical Application" diagram showing 120mA total backlight current.