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

Diodes Incorporated AP2121AK-3.2TRE1

Name: AP2121AK-3.2TRE1
Brand: Diodes Incorporated
SKU: AP2121AK-3.2TRE1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AP2121AK-3.2TRE1

Manufacturer:: Diodes Incorporated

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

Package:: SC-74A, SOT-753

Datasheet:: AP2121AK-3.2TRE1.pdf

Description:: IC REG LINEAR 3.2V 200MA SOT23-5

Quantity:: RFQ Add To RFQ list

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Inventory:4,353

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Product details

Overview

AP2121AK-3.2TRE1 from Diodes Incorporated is a high-speed, extremely low-noise 3.2V fixed-output LDO regulator in SOT-23-3 package, delivering up to 200mA output current with 150mV typical dropout at 100mA, 30µV_rms output noise (10Hz–100kHz), and ±2% output voltage accuracy. It serves as a precision local power rail for noise-sensitive analog and RF circuitry in portable battery-powered systems.

For engineers reviewing the AP2121AK-3.2TRE1 datasheet, AP2121AK-3.2TRE1 pinout, AP2121AK-3.2TRE1 application, or AP2121AK-3.2TRE1 equivalent, key selection criteria include dropout performance under 200mA load, RMS noise floor in audio/RF biasing contexts, CE input logic thresholds, thermal resistance in SOT-23-3, and compatibility with 1µF ceramic output capacitors.

Technical Context

The AP2121AK-3.2TRE1 employs a CMOS-based error amplifier architecture with internal voltage reference and current-limit protection, optimized for fast line and load transient response. Its enable circuit operates with 1.5V minimum CE "high" threshold and 0.25V maximum CE "low" threshold, supporting low-power shutdown modes.

Designed for stable operation with 1µF ceramic output capacitors (ESR 0.01Ω–100Ω), it achieves 70dB PSRR at 1kHz and maintains ±12mV load regulation across 1–80mA output range. The device is rated for –40°C to +85°C ambient operation with 250°C/W junction-to-ambient thermal resistance in SOT-23-3.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	3.2V ±2% - ensures stable bias for 3.3V-tolerant analog ICs without external trimming
Max Output Current	200mA - sufficient for powering single-core microcontrollers or RF front-end ICs
Dropout Voltage	150mV typ. @ 100mA - enables regulation from 3.35V input when V_IN ≥ 3.35V
RMS Noise	30µV_rms (10Hz–100kHz) - critical for low-phase-noise VCOs and high-SNR ADC references
PSRR	70dB @ 1kHz - suppresses switching noise from upstream DC/DC converters
Quiescent Current	25µA typ. - extends battery life in always-on sensor nodes
Enable Threshold	V_CE(HI) ≥ 1.5V, V_CE(LO) ≤ 0.25V - compatible with 1.8V/3.3V GPIO control without level shifters

Pinout & Package

SOT-23-3 package: ultra-compact 2.9mm × 1.6mm footprint with 0.95mm height, optimized for space-constrained PCB layouts in handheld devices.

Pin/Terminal	Circuit Role	Design Meaning
1 (VIN)	Input voltage supply	Accepts 2V–6V input; requires ≥1µF ceramic input capacitor for stability
2 (GND)	Ground reference	Common return path for input, output, and internal circuitry; must be low-impedance
3 (VOUT)	Regulated output	Delivers 3.2V ±2% at up to 200mA; stable with ≥1µF ceramic output capacitor

Key Features

Feature	Design Value
Low-noise regulation	30µV_rms output noise enables clean power for RF synthesizers and precision ADCs
Fast transient response	Excellent line/load transient behavior minimizes output voltage dip during burst-mode MCU operation
Ceramic capacitor compatibility	Stable with 1µF ceramic output caps (ESR 0.01–100Ω), reducing BOM count vs. tantalum alternatives
Ultra-low quiescent current	25µA I_Q supports >1-year battery life in coin-cell–powered IoT endpoints
High PSRR at 1kHz	70dB rejection of DC/DC ripple allows co-location with switching regulators on same PCB

Applications

Mobile Phone Baseband Power

Wireless Audio Codec Supply

Use Scenario: Providing clean 3.2V bias to baseband processor I/O banks and PLL circuits in LTE/5G handsets.

IC Role / Device Role / Timing Role: Local LDO regulator delivering low-noise, tightly regulated voltage for digital core and clock generation blocks.

Use Value: 30µV_rms noise prevents phase jitter degradation in RF synthesizers; ±2% accuracy ensures reliable I/O voltage margining.

Use Scenario: Powering stereo audio DAC/ADC and Class-D amplifier bias rails in Bluetooth earbuds.

IC Role / Device Role / Timing Role: Low-noise post-regulator for analog signal chain components requiring minimal power-supply-induced distortion.

Use Value: 70dB PSRR at 1kHz suppresses switching noise from buck converter supplying main SoC, preserving THD+N < 0.01%.

Portable Medical Sensor Node

Industrial Handheld Scanner

Use Scenario: Supplying 3.2V to ultra-low-power ECG front-end amplifiers and SAR ADCs in wearable biosensors.

IC Role / Device Role / Timing Role: Precision analog rail generator with sub-50µV noise floor and <25µA quiescent draw.

Use Value: Enables >100dB SNR in biopotential measurement; 200mA capacity supports simultaneous BLE radio wake-up bursts.

Use Scenario: Regulating 3.2V for CMOS image sensor interface, laser driver, and decode ASIC in rugged barcode scanners.

IC Role / Device Role / Timing Role: High-reliability local regulator tolerant of battery voltage sag during motor actuation.

Use Value: 150mV dropout ensures continuous operation down to 3.35V input; ±2% accuracy guarantees consistent sensor exposure timing.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
AP7343-33WG-7	3.3V output, 300mA rating, 250mV dropout @ 300mA, 22µV_rms noise, SOT-23-5 with CE pin	Requires board redesign for 5-pin layout and 0.1V higher output; better noise but no direct pinout match	Select when upgrading to higher current or lower noise is acceptable and CE control is required
MCP1700-3302E/TO	3.3V output, 250mA rating, 600mV dropout @ 250mA, 30µV_rms noise, TO-92 package	Larger through-hole package; higher dropout limits use in low-V_IN scenarios; no CE function	Choose only for legacy TO-92 designs where SOT-23-3 rework is prohibited

Compared with AP2121AK-3.2TRE1, AP7343-33WG-7 offers lower noise and higher current but requires layout change and delivers 3.3V instead of 3.2V; MCP1700-3302E/TO provides identical noise performance but lacks enable control and suffers from significantly higher dropout, limiting its utility in battery-voltage–sensitive designs.

Availability

AP2121AK-3.2TRE1 is available at Aetrix Electronics and suitable for mobile phone baseband power, wireless audio codec supply, portable medical sensor node, and industrial handheld scanner applications requiring stable component supply and long-term sourcing continuity.

Supply support for AP2121AK-3.2TRE1 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-performance power management, signal integrity, and protection solutions for consumer, industrial, and automotive markets.

The AP2121 series belongs to Diodes' high-speed LDO product line, engineered specifically for battery-powered portable electronics demanding ultra-low noise, fast transient response, and ceramic-capacitor compatibility.

FAQ

What is the minimum input voltage required for AP2121AK-3.2TRE1 to maintain regulation at 200mA?

The AP2121AK-3.2TRE1 requires VIN ≥ VOUT + VDROP. At 200mA, typical dropout is 250mV (per DS46506 Rev. 3–3, p.7–13), so minimum VIN = 3.2V + 0.25V = 3.45V. Absolute max dropout is 500mV, so design for VIN ≥ 3.7V to ensure margin across temperature and process variation.

Can AP2121AK-3.2TRE1 be used with a 0.47µF output capacitor?

No. The datasheet specifies a minimum 1µF ceramic output capacitor for stability (DS46506 Rev. 3–3, p.2). Using 0.47µF risks oscillation or poor transient response due to insufficient phase margin, especially with ESR < 100Ω. Always use ≥1µF X5R/X7R ceramic with 0.01–100Ω ESR.

Does AP2121AK-3.2TRE1 have built-in reverse polarity protection?

No. The AP2121AK-3.2TRE1 lacks reverse-voltage protection. Applying reversed input voltage (e.g., VIN < GND) may damage the IC. External protection-such as a series Schottky diode or dedicated reverse-polarity MOSFET circuit-is required in applications where incorrect battery insertion is possible.

Is AP2121AK-3.2TRE1 qualified for automotive applications per AEC-Q100?

No. While Diodes offers AEC-Q100–qualified variants in the AP2121 family (e.g., AP2121Wxx series), the AP2121AK-3.2TRE1 is not automotive-qualified. Its datasheet states automotive-grade parts require specific change control and PPAP capability-this part number is intended for commercial/industrial use only.

AP2121AK-3.2TRE1 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):: 6V

Voltage - Output (Min/Fixed):: 3.2V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 0.5V @ 200mA

Current - Output:: 200mA

Current - Quiescent (Iq):: 50 µA

Current - Supply (Max):: -

PSRR:: 70dB (1kHz)

Control Features:: Enable

Protection Features:: Over Current

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-5

AP2121AK-3.2TRE1 FAQ

1.How can I place an order for AP2121AK-3.2TRE1 through Aetrix?

Please submit a Request for Quotation (RFQ) for AP2121AK-3.2TRE1 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 AP2121AK-3.2TRE1 reliable?

The price and inventory of AP2121AK-3.2TRE1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP2121AK-3.2TRE1 is usually 5 days.

3.What payment methods are accepted for AP2121AK-3.2TRE1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP2121AK-3.2TRE1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AP2121AK-3.2TRE1?

AP2121AK-3.2TRE1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AP2121AK-3.2TRE1 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 AP2121AK-3.2TRE1?

For technical support, including AP2121AK-3.2TRE1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP2121AK-3.2TRE1 requirements.

6.How does Aetrix verify that AP2121AK-3.2TRE1 is sourced from the original manufacturer or authorized distributors?

All AP2121AK-3.2TRE1 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 AP2121AK-3.2TRE1 meets industry standards.

7.What is the process for return or replacement of AP2121AK-3.2TRE1?

All AP2121AK-3.2TRE1 units undergo pre-shipment inspection (PSI). If there is an issue with AP2121AK-3.2TRE1, 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 AP2121AK-3.2TRE1 part is unused and in its original packaging.

Return procedure for AP2121AK-3.2TRE1:

1.Submit a request within 90 days.

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

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