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

Diodes Incorporated AP7381-28V-A

Name: AP7381-28V-A
Brand: Diodes Incorporated
SKU: AP7381-28V-A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AP7381-28V-A

Manufacturer:: Diodes Incorporated

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

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: AP7381-28V-A.pdf

Description:: IC REG LIN 2.8V TO92 AMMO 2K

Quantity:: RFQ Add To RFQ list

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Inventory:3,446

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Product details

Overview

AP7381-28V-A from Diodes Incorporated is a fixed-output 2.8V ultra-low dropout (ULDO) linear regulator IC designed for space-constrained, battery-powered systems. It delivers up to 150mA output current with 1000mV dropout at 100mA, ±2% output voltage accuracy, and only 2.5µA ground current at zero load - enabling long runtime in portable USB devices and e-meters.

For engineers reviewing the AP7381-28V-A datasheet, AP7381-28V-A pinout, AP7381-28V-A application, or AP7381-28V-A equivalent, key selection criteria include wide 3.3–40V input range compatibility, thermal shutdown at +160°C, short-circuit protection, low-ESR ceramic capacitor support, and TO92 (Ammo Packing) package suitability for legacy cost-sensitive designs.

Technical Context

The AP7381-28V-A integrates an error amplifier, precision voltage reference, resistor network for fixed 2.8V output, current-limit circuitry, and chip-enable logic - all operating within a -40°C to +125°C junction temperature range. Its architecture supports stable regulation under fast load transients and maintains ±0.5% load regulation across 1–150mA output current.

It features dual protection mechanisms: thermal shutdown activation at +160°C with +20°C hysteresis and internal current limiting set at 150mA. The device achieves 60dB PSRR at 1kHz and exhibits ±100ppm/°C output voltage temperature coefficient over full operating temperature range.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 2.8V ±2% - ensures stable supply for 2.8V logic rails and analog sensors without external feedback.
Input Voltage Range	3.3V to 40V - supports direct connection to automotive batteries, industrial 24V rails, and multi-cell Li-ion packs.
Dropout Voltage	1000mV @ 100mA - enables regulation down to VIN = 3.8V, critical for brownout resilience in battery discharge cycles.
Ground Current	2.5µA @ IOUT = 0mA - minimizes quiescent power loss in always-on monitoring circuits.
Thermal Shutdown	+160°C with +20°C hysteresis - prevents latch-up during sustained overload while allowing safe recovery.
PSRR	60dB @ 1kHz - suppresses ripple from noisy DC-DC pre-regulators feeding the ULDO input.
Load Regulation	±0.5% from 1mA to 150mA - maintains tight voltage stability across dynamic load profiles in portable instruments.

Pinout & Package

AP7381-28V-A is supplied in TO92 (Ammo Packing) package - a through-hole, three-terminal plastic case measuring 4.3–4.7mm width × 12.5–14.5mm length × 3.3–3.8mm height, rated for 165°C/W thermal resistance and suitable for wave-soldered legacy PCBs.

Pin/Terminal	Circuit Role	Design Meaning
VIN (Pin 1)	Input Supply Terminal	Accepts 3.3–40V unregulated input; requires ≥1µF low-ESR ceramic bypass capacitor placed near pin.
GND (Pin 2)	Ground Reference	Common return path for internal reference, error amplifier, and output stage; must connect to low-impedance system ground plane.
VOUT (Pin 3)	Regulated Output	Delivers stable 2.8V ±2%; requires ≥2.2µF ceramic output capacitor for loop stability and transient response.

Key Features

Feature	Design Value
Ultra-low quiescent current	2.5µA at zero load - extends battery life in metering and remote sensor applications where standby dominates duty cycle.
Wide input voltage capability	Supports 3.3–40V input - eliminates need for pre-regulation in 12V/24V industrial or automotive subsystems powering 2.8V peripherals.
Low-ESR ceramic capacitor compatibility	Stable with ≥2.2µF X5R/X7R ceramics - reduces board area and cost vs. tantalum or electrolytic alternatives.
Integrated short-circuit protection	Current limit clamps at 150mA - prevents damage during output faults without requiring external foldback circuitry.
High accuracy over temperature	±2% initial tolerance and ±100ppm/°C drift - meets precision analog supply requirements for ADC references and sensor biasing.

Applications

Smart Electricity Meters

Portable Medical Sensors

Use Scenario: Powering metrology ICs, RTCs, and RF transceivers in Class 0.2 smart meters operating from 3-phase AC rectified rails or backup Li-SOCl₂ cells.

IC Role / Device Role / Timing Role: Primary 2.8V ULDO supplying precision analog front-end and real-time clock circuitry with minimal voltage drift.

Use Value: Maintains ±0.5% load regulation across 1–150mA loads and withstands 40V surges per IEC 61000-4-5, ensuring metrology accuracy during grid transients.

Use Scenario: Providing clean 2.8V bias to low-power ECG amplifiers, pulse oximeter LEDs, and BLE SoCs in handheld diagnostic tools.

IC Role / Device Role / Timing Role: Low-noise, low-quiescent LDO delivering regulated supply to analog signal chain and wireless MCU core.

Use Value: 2.5µA ground current extends single-CR2032 battery life beyond 12 months in intermittent-use clinical devices.

Industrial Handheld Terminals

USB-Powered Test Probes

Use Scenario: Powering ARM Cortex-M microcontrollers, capacitive touch controllers, and 2.8V display drivers in ruggedized field service terminals.

IC Role / Device Role / Timing Role: Main system LDO converting 5V USB or 12V PoE-derived input to stable 2.8V logic rail.

Use Value: 1000mV dropout allows operation down to 3.8V input - sustaining functionality during USB cable voltage drop or battery sag.

Use Scenario: Regulating 5V USB power to precise 2.8V for high-accuracy multimeter front-ends and calibration reference circuits.

IC Role / Device Role / Timing Role: Precision voltage source for 24-bit delta-sigma ADC reference and op-amp biasing.

Use Value: ±2% output accuracy and ±100ppm/°C tempco ensure <0.01% measurement error across 0–50°C ambient range.

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low dropout linear regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MCP1703T-2802E/MB	250mA output, 600mV dropout @ 250mA, 3µA IQ, SOT23 package only	Lacks TO92 option; higher current rating suits newer designs needing headroom	Select when >150mA load margin or surface-mount assembly is required.
TPS7A2028PDQNR	300mA output, 170mV dropout @ 300mA, 25µA IQ, 1.5% accuracy, WSON-6 package	Lower dropout and higher accuracy but 10× higher IQ; no through-hole option	Choose for ultra-low-drop applications with ample board space and no legacy TO92 constraint.

Compared with MCP1703T-2802E/MB and TPS7A2028PDQNR, the AP7381-28V-A uniquely balances TO92 through-hole compatibility, 2.5µA ultra-low IQ, and 40V input range - making it irreplaceable in cost-sensitive, repairable, or wave-soldered metering hardware where footprint and legacy process compatibility are mandatory.

Availability

AP7381-28V-A is available at Aetrix Electronics and suitable for smart electricity meters, portable medical sensors, and industrial handheld terminals requiring stable component supply with long-term manufacturability and RoHS-compliant through-hole packaging.

Supply support for AP7381-28V-A 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 across Asia, Europe, and the US, serving industrial, computing, consumer, and automotive markets.

The AP7381 series belongs to Diodes' high-voltage ULDO regulator product line, engineered specifically for battery-powered and wide-input industrial equipment where low quiescent current, robust protection, and extended input range are non-negotiable.

FAQ

What is the maximum input voltage the AP7381-28V-A can safely handle?

The AP7381-28V-A has an absolute maximum input voltage rating of 45V, but its recommended operating range is 3.3V to 40V. Operation above 40V risks exceeding thermal limits even at light loads due to increased power dissipation in dropout mode. For sustained reliability, keep VIN ≤ 40V with adequate PCB copper pour for heat sinking in TO92 package.

Does the AP7381-28V-A require an external enable signal?

No - the AP7381-28V-A has no enable pin and operates continuously when valid input voltage is applied. It lacks active control logic; regulation begins automatically once VIN exceeds VOUT + VDROP. This simplifies design in always-on applications like utility meters but precludes software-controlled power sequencing.

Can the AP7381-28V-A be used with aluminum polymer capacitors instead of ceramic?

While the datasheet specifies stability with ≥2.2µF low-ESR ceramic capacitors, aluminum polymer capacitors with ESR < 50mΩ and capacitance ≥3.3µF may function but are not characterized or guaranteed. Ceramic capacitors ensure optimal phase margin and transient response; polymer types risk instability or overshoot under load steps due to higher ESR and ESL variations.

Is the TO92 package of AP7381-28V-A still recommended for new designs?

No - Diodes explicitly marks the TO92 (Ammo Packing) variant as "Not Recommend For New Design" in the datasheet. It remains available for legacy repair and cost-driven volume production but lacks modern thermal performance and assembly compatibility. New designs should use SOT23 or SOT89 packages for better efficiency, smaller footprint, and automated placement support.

AP7381-28V-A Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Tape & Box (TB)

Product Status:: Active

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 40V

Voltage - Output (Min/Fixed):: 2.8V

Voltage - Output (Max):: -

Voltage Dropout (Max):: -

Current - Output:: 150mA

Current - Quiescent (Iq):: -

Current - Supply (Max):: 25 µA

PSRR:: -

Control Features:: -

Protection Features:: Current Limit, Short Circuit, Thermal Shutdown

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92

AP7381-28V-A FAQ

1.How can I place an order for AP7381-28V-A through Aetrix?

Please submit a Request for Quotation (RFQ) for AP7381-28V-A 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 AP7381-28V-A reliable?

The price and inventory of AP7381-28V-A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP7381-28V-A is usually 5 days.

3.What payment methods are accepted for AP7381-28V-A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP7381-28V-A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AP7381-28V-A?

AP7381-28V-A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AP7381-28V-A 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 AP7381-28V-A?

For technical support, including AP7381-28V-A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP7381-28V-A requirements.

6.How does Aetrix verify that AP7381-28V-A is sourced from the original manufacturer or authorized distributors?

All AP7381-28V-A 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 AP7381-28V-A meets industry standards.

7.What is the process for return or replacement of AP7381-28V-A?

All AP7381-28V-A units undergo pre-shipment inspection (PSI). If there is an issue with AP7381-28V-A, 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 AP7381-28V-A part is unused and in its original packaging.

Return procedure for AP7381-28V-A:

1.Submit a request within 90 days.

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

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