Monolithic Power Systems Inc. MP2108DK-LF-P

Overview

MP2108DK-LF-P from Monolithic Power Systems is a 2A, 6V-input synchronous buck converter with 740kHz fixed-frequency operation, integrated 160mΩ/190mΩ power switches, and 0.9V to 5V adjustable output. It delivers >95% efficiency in compact MSOP-10 packaging and targets space-constrained portable power rails for digital cameras and handheld computers.

For engineers reviewing the MP2108DK-LF-P datasheet, MP2108DK-LF-P pinout, MP2108DK-LF-P application, or MP2108DK-LF-P equivalent, key selection criteria include input voltage range (2.6–6V), soft-start programmability via SS pin, internal 0.9V feedback reference, thermal shutdown at 160°C, and compatibility with ceramic output capacitors down to 22µF.

Technical Context

The MP2108DK-LF-P implements current-mode control using an internal transconductance error amplifier (450μA/V) and PWM comparator referenced to inductor current sensing. Its 740kHz oscillator enables small external LC filters while maintaining stable regulation across 0.01–2A load range.

It integrates a 2.4V internal LDO regulator (bypassed at VREF), cycle-by-cycle overcurrent protection (source limit 2.5–3.5A, sink limit 350mA), and undervoltage lockout with 100mV hysteresis. The bootstrap circuit (BST–LX) requires ≥10nF capacitor for high-side gate drive.

Key Specifications

Pinout & Package

MP2108DK-LF-P uses a RoHS-compliant 10-pin MSOP package (3mm × 4.9mm), optimized for thermal performance in space-limited applications. Exposed pad is absent; thermal resistance θ_JA = 150°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck converter applications.

Compared with RT8059GJ6F and TPS62231DRVR, MP2108DK-LF-P offers the only combination of 0.9V feedback reference, dedicated BST pin for high-duty-cycle operation, and MSOP-10 package-making it optimal for cost-sensitive, space-constrained 2A applications requiring design reuse of existing 0.9V FB networks.

Availability

MP2108DK-LF-P is available at Aetrix Electronics and suitable for digital camera power management, handheld computer core rails, and SOHO router PHY supplies requiring stable component supply and long-term industrial availability.

Supply support for MP2108DK-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, headquartered in Kirkland, WA, with global design and support centers.

The MP2108 belongs to MPS's mainstream synchronous buck converter product line, engineered for high-efficiency, low-noise DC-DC conversion in portable and embedded systems with stringent size and thermal constraints.

FAQ

What is the minimum recommended input capacitance for MP2108DK-LF-P?

A 10µF ceramic capacitor placed close to VIN and PGND is the minimum recommended value. For improved ripple suppression and reliability, combine it with a 0.1µF ceramic capacitor adjacent to the IC. Total RMS current rating must exceed half the DC load current (≥1A RMS for 2A output) to prevent capacitor overheating and premature failure.

Can MP2108DK-LF-P operate with a 1.2V input supply?

No. MP2108DK-LF-P has a minimum input voltage of 2.6V per its absolute maximum ratings and operating conditions. Operation below 2.6V will trigger undervoltage lockout (UVLO), disabling switching. For sub-2.6V inputs, consider a boost-buck or buck-boost topology such as the MP2451 or MP9486.

How is output voltage set, and what resistor tolerance is recommended?

Output voltage is set using a resistive divider from VOUT to FB, referenced to the internal 0.9V bandgap. With R1 = 10kΩ (low-side), R2 = 10kΩ × ((VOUT / 0.9V) − 1). Use 1% tolerance metal-film resistors to maintain output accuracy within ±1.5%, as FB bias current (±100nA) introduces negligible error at this level.

Does MP2108DK-LF-P require an external bootstrap diode?

An external bootstrap diode (e.g., IN4148) is optional and recommended only when VOUT ≥ 3.3V and duty cycle exceeds 65% (i.e., VOUT/VIN > 0.65). It improves high-side gate drive margin and efficiency under these conditions but is unnecessary for typical 1.2V–2.5V outputs from 3.3V–5V inputs.

What is the purpose of the VREF pin, and can it power external circuitry?

VREF provides a buffered 2.4V output from the internal LDO used to power internal circuitry. It must be bypassed with ≥10nF to SGND but cannot supply external current-any load will degrade regulation accuracy and may cause instability. External circuits requiring 2.4V must use a separate regulator.

How does thermal performance differ between MSOP-10 and QFN-10 packages?

The QFN-10 (3mm × 3mm) package has θ_JA = 50°C/W versus 150°C/W for MSOP-10, enabling ~100°C lower junction temperature at 2A load with identical PCB copper area. QFN is recommended for continuous 2A operation; MSOP-10 suits intermittent or <1.5A applications where board space favors narrow-body packaging.

Is MP2108DK-LF-P pin-compatible with other MP2108 variants?

Yes. MP2108DK-LF-P (MSOP-10) shares identical pinout and functionality with MP2108DQ-LF-P (QFN-10). Both use the same 10-pin assignment and electrical specifications; only package dimensions and thermal characteristics differ. Layout redesign is required for package substitution, but schematic and BOM remain unchanged.