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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

Monolithic Power Systems Inc. MP3120DJ-LF-Z

Name: MP3120DJ-LF-Z
Brand: Monolithic Power Systems Inc.
SKU: MP3120DJ-LF-Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MP3120DJ-LF-Z

Manufacturer:: Monolithic Power Systems Inc.

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: SOT-23-6 Thin, TSOT-23-6

Datasheet:: MP3120DJ-LF-Z.pdf

Description:: IC REG BOOST ADJ 1.2A TSOT23-6

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MP3120DJ-LF-Z from Monolithic Power Systems is a synchronous boost converter IC with 1.2A switch current, 1.1MHz fixed-frequency operation, and true output disconnect via integrated P-MOS. It starts up from 0.8V input, supports 2.5–5V adjustable output, and delivers up to 96% efficiency in portable battery-powered systems such as wireless mice and audio recorders.

For engineers reviewing the MP3120DJ-LF-Z datasheet, MP3120DJ-LF-Z pinout, MP3120DJ-LF-Z application, or MP3120DJ-LF-Z equivalent, key selection criteria include low-voltage startup capability, inrush current limiting, short-circuit protection, internal compensation, and TSOT23-6 thermal performance under 100mA–500mA load conditions.

Technical Context

The MP3120DJ-LF-Z implements current-mode PWM control with internal slope compensation and a transconductance error amplifier referenced to a 1.2V internal bandgap. Its dual-MOSFET architecture enables VOUT regulation even when VIN exceeds VOUT, though efficiency drops significantly above that threshold.

Startup uses an independent oscillator at ~65% duty cycle until VOUT reaches 2.3V, then transitions to closed-loop operation powered by VOUT-not VIN-enabling continued function as battery voltage falls below 0.8V. Thermal shutdown activates at 160°C with recovery hysteresis of ~20°C.

Key Specifications

Parameter	Value and Actual Design Meaning
Switch Current Limit	1.2A typical; sets maximum inductor peak current regardless of input/output voltage
Feedback Voltage	1.2V ±30mV; defines output voltage setpoint via external resistor divider (VOUT = 1.2V × [1 + R1/R2])
Startup Input Voltage	0.8V min; enables operation from deeply discharged single-cell alkaline or NiMH batteries
Quiescent Current (Active)	470–600μA; determines no-load power draw during regulation, critical for battery runtime
Shutdown Current	0.1–1μA; ensures near-zero battery drain when EN is low and output fully disconnected
Switching Frequency	1.1MHz nominal (865–1155kHz); enables compact 4.7μH inductor and 10μF ceramic capacitors
N-MOS R_DS(on)	290mΩ max; limits conduction loss during boost phase, directly impacting efficiency at medium loads
P-MOS R_DS(on)	530mΩ max; governs forward drop and power dissipation during output disconnect and VOUT > VIN mode

Pinout & Package

MP3120DJ-LF-Z is housed in a 6-lead TSOT23-6 package (2.9mm × 1.6mm × 0.85mm), optimized for high-density portable PCB layouts with exposed thermal pad (GND-connected).

Pin/Terminal	Circuit Role	Design Meaning
1 SW	Switch node	Drain connection of internal N-MOS and P-MOS; connects directly to inductor; high dv/dt node requiring tight layout
2 GND	Power and signal ground	Primary return path for switch current and feedback reference; must be low-impedance plane tie point
3 FB	Feedback input	Senses resistor-divider voltage; 0.9–100nA input bias enables high-impedance dividers without loading error
4 EN	Enable control	Logic-level input: >0.7V enables regulator; <0.15V disables with full output disconnect and <1μA off-current
5 OUT	Regulated output	Source of internal P-MOS; connects to output capacitor; body-diode isolation prevents backfeed during shutdown
6 IN	Input supply	Connects to battery or DC source; powers startup circuit and internal logic before VOUT takeover

Key Features

Feature	Design Value
True output disconnect	Internal P-MOS blocks reverse current and discharges VOUT to 0V during shutdown, eliminating leakage paths
Inrush current limiting	Soft-start time of 0.7–2.6ms prevents input surge during startup, protecting weak batteries and input caps
Low-voltage start-up	Operates from 0.8V input-enables use with single-cell alkaline/NiMH down to end-of-life voltage
Integrated synchronous rectifier	Eliminates external Schottky diode, reducing BOM count and improving efficiency by ~5–8% at light loads
Short-circuit protection	Combines current limit reduction, thermal regulation at 125°C, and hard shutdown at 160°C to survive sustained shorts
VOUT > VIN regulation	Maintains stable output even when input exceeds output (e.g., USB charging while battery active), with controlled dropout

Applications

Wireless Peripherals

Portable Audio Devices

Use Scenario: Wireless optical mouse powered by single AA alkaline cell with intermittent 500mA peak RF transmission bursts.

IC Role / Device Role / Timing Role: Boost converter providing regulated 3.3V rail to MCU and 2.4GHz transceiver; manages battery voltage sag during transmit.

Use Value: 0.8V startup extends usable battery life by >20% vs. 1.8V-start competitors; 1.1MHz switching minimizes inductor size for thin-profile housing.

Use Scenario: Flash-based voice recorder using single NiMH cell with variable 10–200mA load during recording/playback.

IC Role / Device Role / Timing Role: Synchronous step-up regulator delivering stable 3.3V to codec and microSD interface; handles dynamic load steps without brownout.

Use Value: Internal soft-start prevents audio pop on power-up; true disconnect eliminates standby drain, enabling >1-year shelf life.

USB-Powered Accessories

Low-Power IoT Sensors

Use Scenario: USB-to-serial adapter with Li-ion backup, requiring 5V output from 3.3V system rail during host disconnect.

IC Role / Device Role / Timing Role: Bidirectional boost controller maintaining 5V VBUS during USB suspend; switches seamlessly between USB and battery sources.

Use Value: VOUT > VIN operation allows 5V output from 3.3V rail without external LDO or charge pump; P-MOS R_DS(on) limits dropout to <150mV at 100mA.

Use Scenario: Battery-operated environmental sensor node transmitting BLE packets every 5 seconds, drawing 15mA peak for 5ms.

IC Role / Device Role / Timing Role: High-efficiency boost stage powering 3.3V MCU and radio; shuts down completely between transmissions to minimize quiescent draw.

Use Value: 0.1–1μA shutdown current enables >2-year battery life on CR2032; 1.2A current limit supports fast capacitor charging for RF burst.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TPS610992DRCR	0.7V startup, 1.2A switch, but no true output disconnect; relies on external MOSFET for isolation	Lacks integrated P-MOS disconnect; requires additional FET and gate driver for zero-VOUT shutdown	Prefer MP3120DJ-LF-Z when board space is constrained and full output discharge is required
RT9086AGQW	1.1MHz, 1.2A, 0.85V startup, but only 92% max efficiency and no thermal foldback below 125°C	No thermal regulation before shutdown; less robust under sustained overload or poor heatsinking	MP3120DJ-LF-Z offers superior short-circuit survivability and higher efficiency across 10–500mA loads

Compared with TPS610992DRCR and RT9086AGQW, MP3120DJ-LF-Z uniquely integrates both N- and P-channel MOSFETs with true disconnect, delivers higher efficiency at light loads due to lower quiescent current, and provides graded thermal protection instead of abrupt shutdown-critical for unattended portable devices.

Availability

MP3120DJ-LF-Z is available at Aetrix Electronics and suitable for wireless peripherals, portable audio devices, USB-powered accessories, and low-power IoT sensors requiring stable component supply with guaranteed long-term availability.

Supply support for MP3120DJ-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.

The MP3120 belongs to MPS's low-voltage synchronous boost converter product line, engineered specifically for energy-constrained portable electronics where battery life, board area, and reliability under transient overload are primary design constraints.

FAQ

What is the minimum input voltage required for MP3120DJ-LF-Z to start switching?

The MP3120DJ-LF-Z starts switching at 0.7V minimum (typical 0.85V) with no load and VOUT=0V. This ultra-low startup voltage is enabled by a dedicated oscillator circuit and allows operation from nearly depleted single-cell alkaline or NiMH batteries before the main control loop engages.

Does MP3120DJ-LF-Z require an external Schottky diode?

No. The MP3120DJ-LF-Z integrates both N-channel and P-channel MOSFETs, eliminating the need for an external Schottky diode. The internal synchronous rectifier improves efficiency by 5–8% at light loads and enables true output disconnect-provided no external diode is placed between SW and OUT pins.

How does MP3120DJ-LF-Z behave when input voltage exceeds output voltage?

When VIN > VOUT, the internal P-MOS operates in linear mode rather than switching, causing increased power dissipation. Output remains regulated, but efficiency drops sharply. Maximum continuous output current must be reduced to avoid exceeding 125°C junction temperature-refer to thermal derating curves in the datasheet.

What is the purpose of the RC snubber recommended for 5V output applications?

The RC snubber (R=5.1Ω, C=1nF) from SW to GND suppresses voltage spikes caused by parasitic inductance during MOSFET turn-off. At 5V output and 1.1MHz switching, these spikes can exceed 7V and risk damaging the internal N-MOS-making the snubber essential for reliability in high-VOUT designs.

Can MP3120DJ-LF-Z drive a 500mA load continuously at 3.3V output from a 1.5V alkaline cell?

Yes-under TA=25°C with proper PCB layout and thermal management. Efficiency peaks near 85% at 500mA/3.3V from 1.5V input, yielding ~425mW dissipation. With θJA=220°C/W, this results in ~94°C junction rise-within the 125°C limit. Derating is required above 60°C ambient or with poor copper area.

Is the feedback pin (FB) compatible with high-impedance resistor dividers?

Yes. FB input bias current is only 0.9–100nA, enabling use of megaohm-level dividers (e.g., 1MΩ/640kΩ for 3.3V) without significant voltage error. This reduces quiescent current draw from the output rail and improves light-load regulation accuracy.

What happens during short-circuit events at the output?

During output short, MP3120DJ-LF-Z reduces current limit, activates thermal regulation starting at 125°C, and triggers hard shutdown at 160°C. Unlike basic boost converters, it survives sustained shorts due to coordinated current limiting, thermal foldback, and automatic restart after cooldown-no latch-up occurs.

MP3120DJ-LF-Z Specifications

Product attributes: Attribute value

Manufacturer:: Monolithic Power Systems Inc.

Series:: -

Package/Case:: SOT-23-6 Thin, TSOT-23-6

Packaging:: Tape & Reel (TR)

Product Status:: Active

Function:: Step-Up

Output Configuration:: Positive

Topology:: Boost

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 0.8V

Voltage - Input (Max):: 5V

Voltage - Output (Min/Fixed):: 2.5V

Voltage - Output (Max):: 5V

Current - Output:: 1.2A

Frequency - Switching:: 1.05MHz

Synchronous Rectifier:: Yes

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: TSOT-23-6

MP3120DJ-LF-Z FAQ

1.How can I place an order for MP3120DJ-LF-Z through Aetrix?

Please submit a Request for Quotation (RFQ) for MP3120DJ-LF-Z on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MP3120DJ-LF-Z reliable?

The price and inventory of MP3120DJ-LF-Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MP3120DJ-LF-Z is usually 5 days.

3.What payment methods are accepted for MP3120DJ-LF-Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MP3120DJ-LF-Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MP3120DJ-LF-Z?

MP3120DJ-LF-Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MP3120DJ-LF-Z order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MP3120DJ-LF-Z?

For technical support, including MP3120DJ-LF-Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MP3120DJ-LF-Z requirements.

6.How does Aetrix verify that MP3120DJ-LF-Z is sourced from the original manufacturer or authorized distributors?

All MP3120DJ-LF-Z products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MP3120DJ-LF-Z meets industry standards.

7.What is the process for return or replacement of MP3120DJ-LF-Z?

All MP3120DJ-LF-Z units undergo pre-shipment inspection (PSI). If there is an issue with MP3120DJ-LF-Z, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MP3120DJ-LF-Z part is unused and in its original packaging.

Return procedure for MP3120DJ-LF-Z:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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