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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Diodes Incorporated AP139-33WG-7

Name: AP139-33WG-7
Brand: Diodes Incorporated
SKU: AP139-33WG-7
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AP139-33WG-7

Manufacturer:: Diodes Incorporated

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: SC-74A, SOT-753

Datasheet:: AP139-33WG-7.pdf

Description:: IC REG LINEAR 3.3V 300MA SOT25

Quantity:: RFQ Add To RFQ list

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Product details

Overview

AP139-33WG-7 from Diodes Incorporated is a 3.3V, 300mA low-noise CMOS LDO regulator in SOT25 package, featuring 45μA typical quiescent current, 0.45V max dropout at 300mA, ±2% output voltage accuracy, and integrated thermal shutdown/current limiting-designed for battery-powered portable electronics requiring stable, low-power regulation.

For engineers reviewing the AP139-33WG-7 datasheet, AP139-33WG-7 pinout, AP139-33WG-7 application, or AP139-33WG-7 equivalent, key selection criteria include dropout performance at full load, PSRR (75dB @1kHz with 10nF bypass), EN pin threshold (1.7V), stability with ≥1.0μF low-ESR output capacitors, and automotive-grade availability via AEC-Q100-qualified variants.

Technical Context

The AP139-33WG-7 employs a pMOS pass transistor architecture enabling ultra-low dropout and near-zero gate-drive current draw, supporting operation down to VIN = VOUT + 0.45V. Its error amplifier compares feedback from internal resistor divider (R1/R2) against a precision bandgap reference, delivering ±2% output accuracy over temperature and line/load variation.

Enable functionality is implemented as an active-low digital control input (VEN < 0.8V disables regulator; IQ drops to <2μA), while the BYP pin accepts a 10nF capacitor to enhance PSRR by stabilizing internal reference noise-critical for RF-sensitive or audio subsystems where supply ripple must be suppressed below 100kHz.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 3.3V ±2% at 1mA–300mA load ensures compatibility with 3.3V logic rails and microcontrollers.
Max Output Current	Guaranteed 300mA continuous output supports moderate-power peripherals like sensors, displays, or BLE radios.
Dropout Voltage	≤0.45V at 300mA enables operation from single-cell Li-ion (3.0V min) or two-cell alkaline (3.2V min).
Quiescent Current	45μA typ / 60μA max extends battery life in always-on IoT nodes or standby modes.
PSRR	75dB @1kHz (with 10nF BYP cap) suppresses switching noise from upstream DC/DC converters.
Thermal Shutdown	Activates at +130°C with +20°C hysteresis, protecting PCB layout under sustained high-power dissipation.
Input Voltage Range	2.7V to 5.5V covers USB, coin-cell, and multi-cell battery inputs without external regulators.

Pinout & Package

SOT25 (5-pin, lead-free, RoHS-compliant, "Green" halogen/antimony-free) surface-mount package measuring 2.9mm × 1.6mm × 1.1mm, optimized for space-constrained handheld devices.

Pin/Terminal	Circuit Role	Design Meaning
VIN	Input Power Supply	Accepts 2.7–5.5V unregulated input; requires ≥0.1μF ceramic decoupling close to pin.
GND	Ground Reference	Common return path for all internal circuits; must connect to low-impedance PCB ground plane.
EN	Enable Control Input	Active-low logic input; pulling ≤0.8V disables regulator and reduces IQ to <2μA for system-level power gating.
BYP	Bypass Capacitor Terminal	Connects to 10nF capacitor to ground to reduce reference noise and improve PSRR above 1kHz.
VOUT	Regulated Output	Delivers stable 3.3V ±2%; requires ≥1.0μF low-ESR ceramic capacitor directly at pin for stability.

Key Features

Feature	Design Value
Low Dropout Operation	0.45V max at 300mA enables efficient regulation from marginal input sources like aging batteries.
Ultra-Low Quiescent Current	45μA typ allows >1-year runtime on CR2032 in always-on sensor nodes with 10μA average load.
High PSRR with Bypass	75dB @1kHz using 10nF BYP capacitor mitigates noise coupling into analog/RF sections.
Robust Protection	Integrated current limit (300–450mA) and thermal shutdown (+130°C) prevent failure during short-circuit or overload.
Stability with Low-ESR Caps	Guaranteed stable with ≥1.0μF ceramic output capacitor-eliminates need for costly tantalum or polymer types.

Applications

Wearable Health Monitor

USB-Powered Peripheral

Use Scenario: Continuous ECG signal acquisition powered by coin-cell battery with strict 5-year shelf life requirement.

IC Role / Device Role / Timing Role: Primary 3.3V supply for analog front-end and BLE SoC, enabling low-noise ADC biasing and RF transmission stability.

Use Value: 45μA IQ and 0.45V dropout extend usable battery voltage range down to 3.0V, adding ~18% operational time vs. higher-IQ LDOs.

Use Scenario: Compact USB-C hub providing 3.3V rail to HDMI level-shifter and USB PD controller logic.

IC Role / Device Role / Timing Role: Local post-regulator isolating sensitive logic from noisy 5V USB bus; BYP pin used to suppress 1MHz switching artifacts.

Use Value: 75dB PSRR @1kHz with 10nF BYP capacitor reduces conducted noise on 3.3V rail to <1mVpp, preventing HDMI timing jitter.

Smart Home Sensor Node

Industrial Handheld Scanner

Use Scenario: Battery-operated Zigbee temperature/humidity node deployed in HVAC ducts with -40°C to +85°C ambient range.

IC Role / Device Role / Timing Role: Main 3.3V regulator powering MCU, radio, and precision sensor interface; EN pin controlled by MCU sleep mode.

Use Value: ±2% output accuracy and 50ppm/°C tempco ensure consistent ADC reference across full operating temperature range.

Use Scenario: Ruggedized barcode scanner using dual AA batteries with frequent drop-induced load transients.

IC Role / Device Role / Timing Role: Load-switched 3.3V supply for imager and decode ASIC; thermal shutdown prevents latch-up during extended scanning bursts.

Use Value: Current limit (300–450mA) and fast thermal response (+130°C trip) protect against momentary shorts caused by connector arcing or ESD events.

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
AP7343-33SG-7	Successor device: 300mA, 40μA IQ, 0.35V dropout, same SOT25 footprint, AEC-Q100 qualified.	Supports automotive-grade qualification and longer product lifecycle; identical pinout and electrical behavior.	Select for new designs requiring long-term supply assurance and IATF 16949 manufacturing traceability.
MCP1700-3302E/TO	300mA, 1.6μA IQ, 600mV dropout, TO-92 through-hole package; no EN or BYP pins.	Limited to low-power, non-battery-critical applications; lacks enable control and noise-reduction bypass capability.	Use only in cost-sensitive, non-portable industrial controls where ultra-low IQ outweighs dropout and feature trade-offs.

Compared with AP139-33WG-7, AP7343-33SG-7 offers lower dropout and automotive qualification but identical form/fit/function, while MCP1700-3302E/TO sacrifices EN/BYP functionality and dropout performance for extreme quiescent current reduction in fixed-mount applications.

Availability

AP139-33WG-7 is available at Aetrix Electronics and suitable for battery-powered wearables, USB peripherals, smart home sensors, and industrial handheld scanners requiring stable component supply with known end-of-life status.

Supply support for AP139-33WG-7 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

Diodes Incorporated is a global semiconductor manufacturer specializing in discrete, analog, and mixed-signal solutions, with design centers in Asia, Europe, and the U.S., and manufacturing in IATF 16949-certified facilities.

The AP139 belongs to Diodes' low-noise, low-IQ LDO family targeting portable and battery-constrained applications-engineered for minimal voltage overhead, high accuracy, and robust protection in space-limited environments.

FAQ

What is the minimum input voltage required for AP139-33WG-7 to maintain regulation at 300mA load?

The minimum input voltage is calculated as VOUT + VDROPOUT = 3.3V + 0.45V = 3.75V. However, per Recommended Operating Conditions, VIN must be ≥2.7V, and functional regulation is guaranteed only when VIN ≥ VOUT + VDROPOUT. At 300mA, 3.75V is the practical minimum; operation below this causes output droop or dropout.

Can AP139-33WG-7 operate without the 10nF bypass capacitor on the BYP pin?

Yes, it will regulate without the BYP capacitor, but PSRR degrades significantly-dropping from 75dB to ~40dB at 1kHz. The datasheet specifies the 10nF capacitor as necessary for low-noise operation; omitting it compromises noise-sensitive applications like RF receivers or precision ADCs.

Is AP139-33WG-7 pin-compatible with AP7343-33SG-7?

Yes-both use identical SOT25 pinout (VIN, GND, EN, BYP, VOUT), share the same footprint and thermal pad layout, and have functionally equivalent electrical characteristics. AP7343-33SG-7 is a direct replacement with improved specs and automotive qualification, recommended for new designs.

Does AP139-33WG-7 require an input capacitor, and what value is recommended?

Yes-an input capacitor is required for stability and transient suppression. The datasheet recommends ≥0.1μF ceramic placed close to the VIN and GND pins. For best EMI performance and load-step response, a 1μF X7R ceramic capacitor is commonly used alongside the mandatory output capacitor.

AP139-33WG-7 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: SC-74A, SOT-753

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 5.5V

Voltage - Output (Min/Fixed):: 3.3V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 0.45V @ 300mA

Current - Output:: 300mA

Current - Quiescent (Iq):: 60 µA

Current - Supply (Max):: -

PSRR:: 75dB ~ 30dB (1KHz ~ 100KHz)

Control Features:: Enable

Protection Features:: Over Current, Over Temperature, Short Circuit

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-25

AP139-33WG-7 FAQ

1.How can I place an order for AP139-33WG-7 through Aetrix?

Please submit a Request for Quotation (RFQ) for AP139-33WG-7 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 AP139-33WG-7 reliable?

The price and inventory of AP139-33WG-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP139-33WG-7 is usually 5 days.

3.What payment methods are accepted for AP139-33WG-7?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP139-33WG-7 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AP139-33WG-7?

AP139-33WG-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AP139-33WG-7 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 AP139-33WG-7?

For technical support, including AP139-33WG-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP139-33WG-7 requirements.

6.How does Aetrix verify that AP139-33WG-7 is sourced from the original manufacturer or authorized distributors?

All AP139-33WG-7 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 AP139-33WG-7 meets industry standards.

7.What is the process for return or replacement of AP139-33WG-7?

All AP139-33WG-7 units undergo pre-shipment inspection (PSI). If there is an issue with AP139-33WG-7, 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 AP139-33WG-7 part is unused and in its original packaging.

Return procedure for AP139-33WG-7:

1.Submit a request within 90 days.

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

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