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Diodes Incorporated AP2121AK-3.3TRG1
- Part No.:
- AP2121AK-3.3TRG1
- Manufacturer:
- Diodes Incorporated
- Package:
- SC-74A, SOT-753
- Datasheet:
-
AP2121AK-3.3TRG1.pdf
- Description:
- IC REG LINEAR 3.3V 200MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:32,996
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Product details
Overview
AP2121AK-3.3TRG1 from Diodes Incorporated is a high-speed, extremely low-noise 3.3V fixed-output LDO regulator in SOT-23-5 package, delivering up to 200mA output current with 150mV typical dropout at 100mA, 30µVrms output noise (10Hz–100kHz), and ±2% output voltage accuracy. It integrates chip-enable control, supports ceramic capacitors as low as 1µF, and targets power-sensitive analog and RF circuitry in portable electronics.
For engineers reviewing the AP2121AK-3.3TRG1 datasheet, AP2121AK-3.3TRG1 pinout, AP2121AK-3.3TRG1 application, or AP2121AK-3.3TRG1 equivalent, key selection criteria include dropout performance under 200mA load, sub-1µA standby current, 70dB PSRR at 1kHz, and compatibility with space-constrained SOT-23-5 layouts requiring precise 3.3V rail regulation.
Technical Context
The AP2121AK-3.3TRG1 uses a CMOS-based error amplifier architecture with internal voltage reference and resistor network for fixed 3.3V output. Its current-limit circuit provides short-circuit protection up to 50mA, while the active-high CE pin enables full shutdown with 0.1µA typical standby current.
Designed for stability with low-ESR ceramic capacitors (≥1µF), it achieves excellent transient response-both line and load-with minimal external components. Thermal resistance is 250°C/W (Junction-to-Ambient, SOT-23-5), and junction temperature is rated to +150°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 3.3V ±2% - ensures stable logic-level supply for 3.3V microcontrollers and interface ICs across temperature and load. |
| Max Output Current | 200mA continuous - sufficient for powering small DSPs, sensors, or RF front-end bias rails without thermal derating. |
| Dropout Voltage | 150mV typ. @ 100mA - enables operation from 3.45V input (e.g., single Li-ion cell post-regulation) while maintaining regulation. |
| Output Noise | 30µVrms (10Hz–100kHz) - critical for noise-sensitive analog circuits like ADC references or RF synthesizer VCO supplies. |
| PSRR | 70dB typ. @ 1kHz - suppresses switching noise from upstream DC/DC converters feeding the LDO input. |
| Quiescent Current | 25µA typ. - minimizes battery drain in always-on subsystems such as real-time clocks or wake-up controllers. |
| Enable Threshold | CE "High" ≥1.5V - compatible with 1.8V/3.3V GPIO logic without level-shifting. |
Pinout & Package
SOT-23-5 package: 2.9mm × 1.6mm × 1.1mm body, surface-mount, RoHS-compliant, thermal pad not present. Pin 1 marked with dot; pin numbering follows standard top-view counterclockwise convention.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CE) | Chip Enable | Active-high digital control input; pulls down internally via 2.5–10MΩ resistor when unconnected, defaulting to enabled state. |
| 2 (GND) | Ground Reference | Primary return path for output current and internal bias; must be connected to low-impedance system ground plane. |
| 3 (VIN) | Input Supply | Accepts 2V to 6V input; requires ≥1µF ceramic capacitor placed within 2mm of pin for EMI suppression and stability. |
| 4 (NC) | No Connection | Internally unconnected; must remain floating-no external tie or routing permitted. |
| 5 (VOUT) | Regulated Output | Delivers 3.3V ±2%; requires ≥1µF ceramic output capacitor with ESR 0.01–100Ω for loop stability. |
Key Features
| Feature | Design Value |
|---|---|
| Low-noise regulation | 30µVrms output noise enables clean power for precision analog signal chains and RF local oscillators. |
| Ultra-low quiescent current | 25µA typical IQ allows >1-year battery life in coin-cell-powered IoT endpoints with periodic wake-up cycles. |
| High PSRR at audio frequencies | 70dB rejection at 1kHz mitigates ripple from buck converter switching harmonics entering sensitive analog stages. |
| Fast load transient response | Stable recovery from 10–90% load steps within microseconds-critical for burst-mode digital processors. |
| Single-ceramic-capacitor support | Stable with ≥1µF X5R/X7R ceramic output cap eliminates need for bulk electrolytic, reducing board area and cost. |
Applications
| Mobile Baseband Power | RF Front-End Bias |
|---|---|
|
Use Scenario: Powering baseband processor I/O and memory interfaces in smartphones and feature phones. IC Role / Device Role / Timing Role: Primary 3.3V LDO supplying core logic voltage for application processors and PMIC-controlled peripherals. Use Value: ±2% output accuracy ensures reliable digital signaling margins; 150mV dropout extends usable battery range during discharge. |
Use Scenario: Providing clean bias voltage to LNAs, mixers, and VCOs in cellular/Wi-Fi transceivers. IC Role / Device Role / Timing Role: Low-noise post-regulator decoupling switching DC/DC output to meet RF spectral purity requirements. Use Value: 30µVrms noise prevents phase noise degradation in VCOs; 70dB PSRR suppresses switching artifacts at IF frequencies. |
| Portable Imaging Sensors | Wearable Health Monitoring |
|
Use Scenario: Supplying image sensor analog core and ADC reference in compact cameras and video recorders. IC Role / Device Role / Timing Role: Dedicated low-noise LDO isolating sensor analog domain from noisy digital subsystems. Use Value: Sub-50µV noise floor preserves dynamic range in 12-bit+ image pipelines; fast transient response prevents frame corruption during exposure changes. |
Use Scenario: Regulating power for optical heart-rate sensors and bio-potential amplifiers in fitness trackers. IC Role / Device Role / Timing Role: Always-on 3.3V rail supporting ultra-low-power analog front-end during sleep and activity modes. Use Value: 0.1µA standby current enables multi-week operation on small Li-Po cells; ±2% accuracy maintains consistent sensor gain calibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AP7343-33SAG-7 | Successor device: 300mA output, 120mV dropout @ 200mA, 25µVrms noise, same SOT-23-5 footprint. | Higher current capability and lower noise; qualified for automotive AEC-Q100 Grade 2 (−40°C to +105°C). | Select for new designs requiring extended temperature range or higher load headroom. |
| MCP1700-3302E/TO | Microchip part: 250mA output, 175mV dropout @ 250mA, 35µVrms noise, TO-92 package (through-hole). | Through-hole mounting only; lacks enable pin; wider operating temperature (−40°C to +125°C) but no CE control. | Use only where through-hole assembly is mandated and enable functionality is unnecessary. |
Compared with AP2121AK-3.3TRG1, AP7343-33SAG-7 offers improved current drive and noise performance in identical packaging, while MCP1700-3302E/TO trades enable control and SMT compatibility for ruggedized through-hole construction and broader temp range.
Availability
AP2121AK-3.3TRG1 is available at Aetrix Electronics and suitable for mobile phone power management, RF transceiver biasing, portable imaging systems, and wearable health monitoring requiring stable component supply and long-term obsolescence planning.
Supply support for AP2121AK-3.3TRG1 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-efficiency power management, signal integrity, and protection solutions for consumer, industrial, and automotive markets.
The AP2121 series belongs to Diodes' high-performance LDO portfolio, designed specifically for battery-powered devices demanding ultra-low noise, low dropout, and minimal quiescent current in compact packages.
FAQ
What is the recommended input capacitor for AP2121AK-3.3TRG1?
A minimum 1µF X5R or X7R ceramic capacitor is required at the VIN pin, placed within 2mm of the package. This capacitor stabilizes the input impedance, filters high-frequency noise from upstream sources, and prevents oscillation during fast load transients. Larger values (e.g., 2.2µF) improve ripple rejection but are not mandatory for basic stability.
Can AP2121AK-3.3TRG1 be used without connecting the CE pin?
Yes-the CE pin has an internal pull-down resistor (2.5–10MΩ), so leaving it unconnected defaults the device to enabled mode. However, for deterministic startup/shutdown control in systems with noisy or floating GPIOs, it is strongly recommended to tie CE to a defined logic level (e.g., MCU GPIO or pull-up to VIN) rather than relying on the internal resistor alone.
Is AP2121AK-3.3TRG1 qualified for automotive applications?
No-AP2121AK-3.3TRG1 is not AEC-Q100 qualified. Diodes Incorporated explicitly states that automotive-grade variants require specific change control and PPAP capability, and directs users to contact their representative for qualified alternatives such as the AP7343 series, which meets AEC-Q100 Grade 2 requirements.
Why does the datasheet state "NOT RECOMMENDED FOR NEW DESIGNS"?
This notice indicates Diodes has introduced the AP7343 as a functional and pin-compatible successor with enhanced specs: higher output current (300mA vs. 200mA), lower dropout (120mV vs. 150mV @ 200mA), and reduced noise (25µVrms vs. 30µVrms). While AP2121AK-3.3TRG1 remains fully supported and available, new designs should adopt AP7343-33SAG-7 for improved performance and long-term roadmap alignment.
AP2121AK-3.3TRG1 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):
- 3.3V
- 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-3.3TRG1 FAQ
1.How can I place an order for AP2121AK-3.3TRG1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AP2121AK-3.3TRG1 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-3.3TRG1 reliable?
The price and inventory of AP2121AK-3.3TRG1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP2121AK-3.3TRG1 is usually 5 days.
3.What payment methods are accepted for AP2121AK-3.3TRG1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP2121AK-3.3TRG1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AP2121AK-3.3TRG1?
AP2121AK-3.3TRG1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AP2121AK-3.3TRG1 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-3.3TRG1?
For technical support, including AP2121AK-3.3TRG1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP2121AK-3.3TRG1 requirements.
6.How does Aetrix verify that AP2121AK-3.3TRG1 is sourced from the original manufacturer or authorized distributors?
All AP2121AK-3.3TRG1 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-3.3TRG1 meets industry standards.
7.What is the process for return or replacement of AP2121AK-3.3TRG1?
All AP2121AK-3.3TRG1 units undergo pre-shipment inspection (PSI). If there is an issue with AP2121AK-3.3TRG1, 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-3.3TRG1 part is unused and in its original packaging.
Return procedure for AP2121AK-3.3TRG1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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