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

Diodes Incorporated AP7381-33Y-13

Name: AP7381-33Y-13
Brand: Diodes Incorporated
SKU: AP7381-33Y-13
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AP7381-33Y-13

Manufacturer:: Diodes Incorporated

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

Package:: TO-243AA

Datasheet:: AP7381-33Y-13.pdf

Description:: IC REG LINEAR 3.3V 150MA SOT89

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Product details

Overview

AP7381-33Y-13 from Diodes Incorporated is a fixed-output 3.3V, 150mA ultra-low dropout (ULDO) linear regulator with 40V maximum input voltage, 1000mV dropout at 100mA, ±2% output voltage accuracy, and 2.5µA quiescent current - designed for USB-powered and battery-operated portable electronics requiring stable low-noise supply under wide input variation.

For engineers reviewing the AP7381-33Y-13 datasheet, AP7381-33Y-13 pinout, AP7381-33Y-13 application, or AP7381-33Y-13 equivalent, key selection considerations include dropout performance at full load, thermal shutdown threshold (+160°C), compatibility with 1µF/2.2µF ceramic capacitors, and SOT89 package thermal resistance (125°C/W).

Technical Context

The AP7381-33Y-13 integrates a precision voltage reference, error amplifier, resistor network for fixed 3.3V output, current-limit protection (150mA), chip enable control, and thermal shutdown circuitry. It operates across -40°C to +125°C junction temperature with no external feedback components required.

Its architecture supports stable regulation with low-ESR ceramic input (1µF) and output (2.2µF) capacitors, delivers 0.05%/V line regulation and 0.5% load regulation, and achieves 60dB PSRR at 1kHz - enabling clean power delivery in noise-sensitive analog and mixed-signal subsystems.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 3.3V ±2% - ensures compatible logic-level supply for 3.3V microcontrollers and peripherals without external resistive divider.
Max Input Voltage	40V - supports direct connection to unregulated 24V industrial rails or automotive battery systems with transient margin.
Dropout Voltage	1000mV @ 100mA - enables regulation down to VIN = 4.3V while maintaining 3.3V output, critical for battery discharge tracking.
Quiescent Current	2.5µA @ zero load - minimizes standby power loss in always-on IoT sensor nodes and energy-harvesting applications.
Thermal Shutdown	+160°C with +20°C hysteresis - provides robust overtemperature protection during sustained high-load or poor PCB heatsinking conditions.
PSRR	60dB @ 1kHz - suppresses ripple from upstream switching converters, reducing need for additional LC filtering in mixed-power domains.
Current Limit	150mA - protects internal pass transistor and downstream circuitry during short-circuit or overload events.

Pinout & Package

The AP7381-33Y-13 is packaged in SOT89 - a thermally enhanced 3-pin surface-mount package with exposed tab for improved heat dissipation (θ_JA = 125°C/W on JEDEC High-K board). Pin 1 = VIN, Pin 2 = GND, Pin 3 = VOUT.

Pin/Terminal	Circuit Role	Design Meaning
1	VIN	Main input supply connection; accepts up to 40V DC with internal overvoltage clamp and ESD protection (4kV HBM).
2	GND	Power ground reference for regulator core and feedback loop; must be low-impedance path to minimize noise coupling.
3	VOUT	Stable 3.3V regulated output; requires 2.2µF ceramic capacitor placed within 3mm of pin for stability and transient response.

Key Features

Feature	Design Value
Wide input range support	Operates from 3.3V to 40V input - eliminates need for pre-regulation stages in multi-rail industrial sensors.
Ultra-low quiescent current	2.5µA at zero load - extends battery life in coin-cell–powered meters and wearables beyond 5 years.
Ceramic capacitor compatibility	Stable with 1µF input / 2.2µF output ceramic caps - reduces BOM cost and board area vs. tantalum or electrolytic alternatives.
Integrated protection	Thermal shutdown + short-circuit current limit - removes need for external foldback or thermal monitoring circuits.
High accuracy output	±2% output tolerance over -40°C to +125°C - ensures reliable operation of ADC references and PLL power domains.

Applications

Smart Electricity Meters

USB-Powered Portable Instruments

Use Scenario: Powering metrology ICs, RTC, and RF transceivers in Class 0.5S utility meters operating from 12–36V DC auxiliary supply.

IC Role / Device Role / Timing Role: Primary 3.3V LDO supplying precision analog front-end and secure MCU core.

Use Value: 0.5% load regulation and ±100ppm/°C tempco ensure consistent ADC reference stability across temperature and battery aging.

Use Scenario: Regulating power for handheld multimeters, oscilloscopes, and thermal imagers powered via USB-C PD negotiation (5–20V input).

IC Role / Device Role / Timing Role: Post-regulator converting variable USB PD voltage to clean 3.3V for microcontroller, display driver, and sensor interface.

Use Value: 60dB PSRR rejects switching noise from upstream buck converter, preventing measurement drift in µV-range analog inputs.

Industrial Wireless Sensors

Laptop Subsystem Power

Use Scenario: Supplying LoRaWAN or NB-IoT modules in battery-operated condition-monitoring nodes deployed in remote locations.

IC Role / Device Role / Timing Role: Low-quiescent LDO powering radio SoC and MEMS accelerometer during deep-sleep cycles.

Use Value: 2.5µA I_Q enables >10-year battery life on CR2032 when paired with duty-cycled transmission.

Use Scenario: Providing auxiliary 3.3V rail for embedded controller (EC), keyboard backlight, and USB hub logic in thin-and-light notebooks.

IC Role / Device Role / Timing Role: Secondary LDO supporting always-on functions independent of main CPU VRM.

Use Value: 1000mV dropout allows operation down to 4.3V input - sustaining functionality during 5V rail sag during peak GPU loads.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MCP1703T-3302E/MB	250mA rating, 600mV dropout @ 250mA, 3µA I_Q, SOT23-5 package	Higher current capacity but larger dropout voltage margin required at full load	Select when >150mA peak load or space-constrained SOT23 layout is mandatory
TPS7A2033PDBVR	300mA rating, 170mV dropout @ 300mA, 25µA I_Q, 1.5% accuracy, SOT23-5	Lower dropout and higher accuracy, but 10× higher quiescent current	Select for ultra-low-drop applications where battery runtime is secondary to regulation tightness

Compared with MCP1703T-3302E/MB and TPS7A2033PDBVR, the AP7381-33Y-13 offers optimal balance of ultra-low I_Q, 40V input tolerance, and SOT89 thermal performance - making it preferred for long-life, wide-input industrial and portable designs where 150mA suffices.

Availability

AP7381-33Y-13 is available at Aetrix Electronics and suitable for smart metering, USB-powered instrumentation, industrial wireless sensors, and laptop subsystem power requiring stable component supply with full traceability and lifecycle continuity.

Supply support for AP7381-33Y-13 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 manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.

The AP7381 belongs to Diodes' wide-input ULDO regulator product line, engineered specifically for battery-backed and unregulated supply environments where low quiescent current, high input voltage tolerance, and ceramic capacitor compatibility are essential design requirements.

FAQ

What is the minimum input voltage required for regulation at 3.3V output?

The AP7381-33Y-13 requires VIN ≥ VOUT + VDROP. With typical dropout of 1000mV at 100mA, minimum functional input is 4.3V. At light loads (<1mA), dropout drops below 200mV, allowing regulation from as low as 3.5V - verified per Electrical Characteristics table at TJ = +25°C.

Can the AP7381-33Y-13 be used with aluminum polymer capacitors instead of ceramic?

No - the AP7381-33Y-13 is optimized for low-ESR ceramic capacitors (1µF input, 2.2µF output). Aluminum polymer capacitors typically exhibit higher ESR (>20mΩ) and may cause instability or oscillation. The datasheet explicitly specifies ceramic compatibility and does not characterize performance with polymer or electrolytic types.

Does the AP7381-33Y-13 include an enable pin?

No - the AP7381-33Y-13 has no dedicated enable (EN) pin. It operates continuously when VIN is within specification. For on/off control, external series FET or power switch is required. This differs from the AP7380 variant, which includes an active-high EN pin - confirmed in Pin Descriptions and Ordering Information sections.

Is the SOT89 package of AP7381-33Y-13 RoHS-compliant and lead-free?

Yes - the AP7381-33Y-13 is fully RoHS 3 compliant (2015/863/EU), totally lead-free, halogen-free, and antimony-free per Diodes' "Green" definition (<900ppm Br, <900ppm Cl, <1000ppm Sb). This is documented in Features section and Notes 1–3 of the datasheet, with plating specified as matte tin.

AP7381-33Y-13 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: TO-243AA

Packaging:: Tape & Reel (TR)

Product Status:: Not For New Designs

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 40V

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

Voltage - Output (Max):: -

Voltage Dropout (Max):: 1V @ 100mA

Current - Output:: 150mA

Current - Quiescent (Iq):: 2.5 µA

Current - Supply (Max):: 25 µA

PSRR:: -

Control Features:: -

Protection Features:: Current Limit, Thermal Shutdown

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-89-3

AP7381-33Y-13 FAQ

1.How can I place an order for AP7381-33Y-13 through Aetrix?

Please submit a Request for Quotation (RFQ) for AP7381-33Y-13 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 AP7381-33Y-13 reliable?

The price and inventory of AP7381-33Y-13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP7381-33Y-13 is usually 5 days.

3.What payment methods are accepted for AP7381-33Y-13?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP7381-33Y-13 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AP7381-33Y-13?

AP7381-33Y-13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AP7381-33Y-13 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 AP7381-33Y-13?

For technical support, including AP7381-33Y-13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP7381-33Y-13 requirements.

6.How does Aetrix verify that AP7381-33Y-13 is sourced from the original manufacturer or authorized distributors?

All AP7381-33Y-13 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 AP7381-33Y-13 meets industry standards.

7.What is the process for return or replacement of AP7381-33Y-13?

All AP7381-33Y-13 units undergo pre-shipment inspection (PSI). If there is an issue with AP7381-33Y-13, 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 AP7381-33Y-13 part is unused and in its original packaging.

Return procedure for AP7381-33Y-13:

1.Submit a request within 90 days.

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

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