Monolithic Power Systems Inc. MP2104DJ-1.8-LF-Z

Overview

MP2104DJ-1.8-LF-Z from Monolithic Power Systems is a 1.7MHz synchronous step-down DC/DC converter delivering 600mA output current with fixed 1.8V output, operating from 2.5V–6V input. It integrates high-side PFET and low-side NFET switches, supports 100% duty cycle for low-dropout operation, and uses TSOT23-5 packaging for space-constrained Li+-battery-powered portable electronics.

For engineers reviewing the MP2104DJ-1.8-LF-Z datasheet, MP2104DJ-1.8-LF-Z pinout, MP2104DJ-1.8-LF-Z application, or MP2104DJ-1.8-LF-Z equivalent, key selection criteria include fixed 1.8V output accuracy (±3% over –40°C to +85°C), 0.1μA shutdown current, thermal fault protection, and compatibility with compact 10μH inductors and ceramic input/output capacitors.

Technical Context

The MP2104DJ-1.8-LF-Z employs constant-frequency current-mode PWM control with slope compensation to ensure stability at >50% duty cycles and provide cycle-by-cycle current limiting. Its internal feedback reference is trimmed to 0.6V, enabling precise regulation of the fixed 1.8V output via an internal resistor divider connected to the OUT pin.

It features integrated PFET (0.44Ω typical R_DS(on)) and NFET (0.29Ω typical R_DS(on)) power switches, eliminating external Schottky diodes. Short-circuit protection reduces oscillator frequency and lowers PFET current limit during fault conditions, recovering automatically when FB voltage returns to 0.6V.

Key Specifications

Pinout & Package

MP2104DJ-1.8-LF-Z is housed in a 5-pin TSOT23-5 package (1.0mm height, 2.9mm × 1.6mm footprint) with exposed pad omitted - thermal dissipation relies on PCB copper area under pins 2 (GND) and 4 (IN). Pin 1 (EN) enables logic-level control; Pin 3 (SW) drives the external inductor; Pin 5 (OUT) connects to internal feedback divider for fixed 1.8V regulation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP2104DJ-1.8-LF-Z, the TPS62231DRYR trades higher EMI risk for smaller passives, while the ADP2302ARMZ-1.8-R7 sacrifices battery compatibility for industrial input flexibility - neither matches the 2.5V start-up, 0.1μA shutdown, and 1.7MHz/TSOT23-5 balance of the MP2104DJ-1.8-LF-Z.

Availability

MP2104DJ-1.8-LF-Z is available at Aetrix Electronics and suitable for portable medical devices, battery-powered imaging modules, Bluetooth LE sensor nodes, and wearable audio systems requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for MP2104DJ-1.8-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 design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP2104 product line targets space- and efficiency-critical portable electronics, delivering integrated synchronous buck conversion in ultra-small packages optimized for single-cell Li-ion battery systems.

FAQ

What is the minimum input voltage required for MP2104DJ-1.8-LF-Z to regulate 1.8V output?

The device starts switching at VIN ≥2.27V (UVLO rising threshold) and maintains regulation down to VIN = VOUT + I_LOAD × (R_{DS(on)_P} + R_{DS(on)_N} + R_DCR). At 600mA load with typical 0.44Ω/0.29Ω FETs and 100mΩ inductor DCR, regulation holds to ~2.5V - matching its rated 2.5V–6V input range.

Can MP2104DJ-1.8-LF-Z be used with ceramic output capacitors only?

Yes - the device is fully compatible with X5R/X7R ceramic output capacitors. A 10μF value is recommended for stability and ripple suppression; ESR is not required for loop compensation since internal Type-II compensation is optimized for low-ESR ceramics.

Does MP2104DJ-1.8-LF-Z require an external feedback resistor divider?

No - unlike the adjustable MP2104DJ variant, the MP2104DJ-1.8-LF-Z uses an internal resistor divider connected to the OUT pin to set 1.8V output. The FB pin is unused; OUT must be connected directly to the output capacitor.

How does the 100% duty-cycle mode function during dropout?

When VIN drops near VOUT, the controller extends the high-side PFET on-time until it remains continuously on. Output voltage then equals VIN minus I_LOAD × (R_{DS(on)_P} + R_DCR), enabling regulation down to ~2.5V input at full 600mA load.

Is thermal derating required for continuous 600mA operation in TSOT23-5 package?

At TA = +85°C, θ_JA = 220°C/W limits continuous power dissipation to ~0.3W. With typical 0.25V total drop at 600mA, power loss is ~150mW - well within safe margin. No derating needed below +85°C ambient with standard 1oz copper.

What PCB layout practices maximize efficiency and stability?

Place input capacitor ≤2mm from IN/GND pins; keep SW trace short and away from FB/EN; connect GND pins to large copper pour; avoid routing sensitive traces under the IC; replicate EV2104DJ-00A evaluation board layout for optimal performance.

Does MP2104DJ-1.8-LF-Z support forced PWM or power-save mode?

No - it operates exclusively in PWM mode at 1.7MHz. There is no pulse-frequency modulation (PFM) or discontinuous conduction mode (DCM) transition; light-load efficiency is maintained via low 400μA quiescent current and synchronous rectification.