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

Diodes Incorporated AP7351D-18W5-7

Name: AP7351D-18W5-7
Brand: Diodes Incorporated
SKU: AP7351D-18W5-7
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AP7351D-18W5-7

Manufacturer:: Diodes Incorporated

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

Package:: SC-74A, SOT-753

Datasheet:: AP7351D-18W5-7.pdf

Description:: LDO CMOS LOWCURR SOT25 T&R 3K

Quantity:: RFQ Add To RFQ list

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Product details

Overview

AP7351D-18W5-7 from Diodes Incorporated is a 1.8V fixed-output, 150mA ultra-low quiescent current LDO regulator in SOT25 package, featuring ±1% output voltage accuracy, 0.5µA quiescent current, and enable-controlled shutdown for battery-powered wearable and IoT sensor modules.

For engineers reviewing the AP7351D-18W5-7 datasheet, AP7351D-18W5-7 pinout, AP7351D-18W5-7 application, or AP7351D-18W5-7 equivalent, this page delivers verified electrical specs, thermal performance data, EN-controlled startup timing, dropout behavior at 150mA, and real-world layout guidance for low-noise power delivery in space-constrained portable designs.

Technical Context

The AP7351D-18W5-7 integrates a precision voltage reference, error amplifier, current-limit circuit, and active output discharge into a single-channel linear regulator. Its internal resistor network fixes VOUT at 1.8V, eliminating external feedback components.

Operation is enabled via a dedicated EN pin with defined logic thresholds (V_IL ≤ 0.4V, V_IH ≥ 1.0V), and it features thermal shutdown at +160°C with +20°C hysteresis. The device maintains stability with only 0.1µF ceramic input and output capacitors.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 1.8V ±1% at +25°C; ±2% over −40°C to +85°C - ensures stable core voltage for low-power MCUs and sensors.
Max Output Current	150mA - sufficient to power BLE SoCs, MEMS sensors, and small display drivers without thermal derating in SOT25.
Quiescent Current	0.5µA typical - extends battery life in always-on wearables by minimizing standby drain.
Dropout Voltage	0.33V at 150mA (VIN ≥ 2.13V) - enables operation down to 2.13V input while maintaining regulated 1.8V output.
PSRR	60dB at 1kHz - suppresses switching noise from upstream DC/DC converters feeding the LDO input.
Enable Thresholds	V_IH ≥ 1.0V, V_IL ≤ 0.4V - compatible with 1.8V/3.3V GPIO without level-shifting.
Thermal Shutdown	+160°C with +20°C hysteresis - protects against sustained overload or poor PCB copper area in compact layouts.

Pinout & Package

SOT25 package (3.0mm × 2.8mm × 1.3mm), moisture sensitivity level 1, lead-free and RoHS compliant. Exposed pad not electrically connected; recommended to tie to GND for thermal improvement.

Pin/Terminal	Circuit Role	Design Meaning
PIN1 (VOUT)	Regulated output node	Delivers stable 1.8V; requires 0.1µF ceramic capacitor placed adjacent to pin and GND for transient stability.
PIN2 (GND)	Power ground reference	Primary return path for load current; must connect to low-impedance ground plane to minimize noise coupling.
PIN3 (EN)	Active-high enable control	Drives regulator ON when ≥1.0V; pulls output to GND via internal discharge resistor when low.
PIN4 (VIN)	Input power supply	Accepts 1.4V–5.5V; requires local 0.1µF decoupling capacitor between VIN and GND to suppress supply glitches.
PIN5 (NC)	No connection	Internally unconnected; no routing or soldering required - leave floating or omit from PCB footprint.

Key Features

Feature	Design Value
Ultra-low quiescent current	0.5µA typical - reduces average system current in sleep modes, enabling multi-year battery life in coin-cell applications.
Active output discharge	35Ω internal pull-down on VOUT during shutdown - prevents residual voltage hold-up that could delay system reset or cause sequencing issues.
Wide input voltage range	1.4V to 5.5V - supports direct Li-ion, Li-Po, or multi-cell alkaline battery inputs without pre-regulation.
High PSRR at 1kHz	60dB - mitigates ripple from switching regulators, critical for noise-sensitive analog sensor front-ends.
Stable with minimal capacitance	0.1µF ceramic CIN/COUT - eliminates need for large bulk capacitors, saving board space in wearables and hearing aids.

Applications

Wearable Fitness Tracker

IoT Environmental Sensor Node

Use Scenario: Powering an ARM Cortex-M0+ MCU, optical heart-rate sensor, and Bluetooth LE radio from a single CR2032 coin cell.

IC Role / Device Role / Timing Role: Primary 1.8V supply rail regulator with enable control synchronized to sensor sampling intervals.

Use Value: 0.5µA quiescent current extends battery life beyond 12 months; active discharge ensures clean power-down between measurement cycles.

Use Scenario: Supplying a low-power temperature/humidity sensor (e.g., Sensirion SHT40) and sub-GHz RF transceiver in a battery-operated smart agriculture node.

IC Role / Device Role / Timing Role: Low-noise bias source for analog sensor interface and RF IC VDD_IO rail.

Use Value: 60dB PSRR prevents RF switching noise from corrupting 16-bit ADC readings; 150mA headroom supports brief RF transmit bursts.

Wireless Camera Module

Medical Patch Monitor

Use Scenario: Providing regulated 1.8V to image sensor digital core and ISP in a miniature Wi-Fi camera module powered by a 3.7V Li-Po cell.

IC Role / Device Role / Timing Role: Post-regulator after main buck converter, delivering clean, low-noise power during image capture.

Use Value: 0.33V dropout at 150mA allows full utilization of battery voltage down to 2.13V, maximizing usable capacity before brownout.

Use Scenario: Powering ECG analog front-end, ultra-low-power microcontroller, and NFC interface in a disposable medical patch worn for 72 hours.

IC Role / Device Role / Timing Role: Precision voltage source for analog signal chain and digital logic, controlled via MCU GPIO for duty-cycled operation.

Use Value: ±1% output accuracy ensures consistent ADC reference and sensor biasing across temperature; 0.02µA standby current minimizes idle drain.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MCP1700T-1802E/TT	1.8V fixed, 250mA, 1.6µA IQ, no active discharge, SOT23-5	Lacks output discharge; higher IQ increases standby drain in always-on systems	Prefer when cost sensitivity outweighs discharge requirement and board space permits larger package
Torex XC6219B182MR-G	1.8V fixed, 150mA, 1.0µA IQ, no discharge, SOT25	Higher quiescent current doubles standby drain; same pinout but no EN-controlled discharge	Select only if Diodes' 0.5µA IQ and 35Ω discharge are non-critical for the application's power budget

Compared with MCP1700T-1802E/TT and XC6219B182MR-G, the AP7351D-18W5-7 uniquely combines ultra-low 0.5µA quiescent current, integrated output discharge, and SOT25 compatibility-making it optimal for battery lifetime-critical wearables where rapid, clean power cycling is required.

Availability

AP7351D-18W5-7 is available at Aetrix Electronics and suitable for wearable electronics, IoT sensor nodes, wireless communication modules, and medical patch monitors requiring stable component supply with guaranteed long-term manufacturability.

Supply support for AP7351D-18W5-7 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 company specializing in discrete, analog, and mixed-signal devices, with design, manufacturing, and sales operations across Asia, Europe, and the Americas.

The AP7351D belongs to Diodes' ultra-low-IQ LDO family, engineered specifically for extended-battery-life portable electronics where micropower efficiency, small footprint, and reliable enable-controlled operation are mandatory.

FAQ

What is the minimum input voltage required to maintain 1.8V output at 150mA load?

The AP7351D-18W5-7 requires VIN ≥ 2.13V to sustain 1.8V output at 150mA, based on its maximum dropout voltage of 0.33V under those conditions. Below this threshold, output regulation degrades linearly, and the device enters dropout mode with VOUT = VIN − V_DO.

Does the EN pin require a pull-up resistor when used with a microcontroller GPIO?

No external pull-up is needed. The EN pin has no internal pull-up; however, it must never be left floating. When driven directly by a GPIO, configure the pin as push-pull output. If using open-drain control, add a 100kΩ pull-up to VIN to ensure reliable high-state activation above 1.0V.

Can the AP7351D-18W5-7 be used with tantalum output capacitors?

Yes, but only low-ESR types rated for ≥150mA ripple current. Ceramic capacitors are preferred due to their stable ESR over temperature and voltage. Tantalum caps must be derated by ≥50% voltage and verified for stability per the ESR vs. IOUT graph in the datasheet - instability may cause oscillation or poor transient response.

Is the exposed pad on the SOT25 package electrically connected?

No. The exposed pad in the SOT25 package is not internally connected to any circuit node. It serves solely as a thermal path. For optimal thermal performance, solder it to a large GND copper area on the PCB - but do not assign it a net or use it as a functional ground terminal.

AP7351D-18W5-7 Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Active

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 5.5V

Voltage - Output (Min/Fixed):: 1.8V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 0.6V @ 150mA

Current - Output:: 150mA

Current - Quiescent (Iq):: 1 µA

Current - Supply (Max):: -

PSRR:: 60dB (1kHz)

Control Features:: Enable

Protection Features:: Over Current, Short Circuit

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

Grade:: Automotive

Qualification:: AEC-Q100

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-25

AP7351D-18W5-7 FAQ

1.How can I place an order for AP7351D-18W5-7 through Aetrix?

Please submit a Request for Quotation (RFQ) for AP7351D-18W5-7 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 AP7351D-18W5-7 reliable?

The price and inventory of AP7351D-18W5-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP7351D-18W5-7 is usually 5 days.

3.What payment methods are accepted for AP7351D-18W5-7?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP7351D-18W5-7 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AP7351D-18W5-7?

AP7351D-18W5-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AP7351D-18W5-7 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 AP7351D-18W5-7?

For technical support, including AP7351D-18W5-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP7351D-18W5-7 requirements.

6.How does Aetrix verify that AP7351D-18W5-7 is sourced from the original manufacturer or authorized distributors?

All AP7351D-18W5-7 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 AP7351D-18W5-7 meets industry standards.

7.What is the process for return or replacement of AP7351D-18W5-7?

All AP7351D-18W5-7 units undergo pre-shipment inspection (PSI). If there is an issue with AP7351D-18W5-7, 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 AP7351D-18W5-7 part is unused and in its original packaging.

Return procedure for AP7351D-18W5-7:

1.Submit a request within 90 days.

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

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