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Diodes Incorporated AP2121AK-2.5TRE1
- Part No.:
- AP2121AK-2.5TRE1
- Manufacturer:
- Diodes Incorporated
- Package:
- SC-74A, SOT-753
- Datasheet:
-
AP2121AK-2.5TRE1.pdf
- Description:
- IC REG LINEAR 2.5V 200MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,281
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Product details
Overview
AP2121AK-2.5TRE1 from Diodes Incorporated is a high-speed, extremely low-noise 2.5V 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 1µF ceramic input/output capacitors, and targets precision power rails in battery-powered portable electronics.
For engineers reviewing the AP2121AK-2.5TRE1 datasheet, AP2121AK-2.5TRE1 pinout, AP2121AK-2.5TRE1 application, or AP2121AK-2.5TRE1 equivalent, key selection criteria include ultra-low noise performance for RF/analog circuitry, tight load/line regulation (12mV/4mV typ), high PSRR (70dB @ 1kHz), and enable-controlled shutdown with 0.1µA standby current.
Technical Context
The AP2121AK-2.5TRE1 employs a CMOS-based error amplifier architecture with internal voltage reference and resistor network for fixed 2.5V output. Its current-limit circuit provides short-circuit protection up to 50mA, while the CE pin enables active-high logic control of regulator operation.
Designed for stability with low-ESR ceramic capacitors ≥1µF, it achieves excellent transient response under load steps and maintains regulation across input voltages from 3.0V to 6.0V, with thermal resistance θJA = 250°C/W in SOT-23-5.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 2.5V ±2% - ensures stable biasing for ADC references and low-voltage logic cores |
| Max Output Current | 200mA - sufficient for powering single-core microcontrollers or sensor signal chains |
| Dropout Voltage | 150mV typ @ 100mA - enables operation from 2.65V input, extending battery runtime |
| Output Noise | 30µVrms (10Hz–100kHz) - minimizes interference in RF front-ends and precision analog stages |
| PSRR | 70dB @ 1kHz - suppresses switching noise from upstream DC/DC converters |
| Quiescent Current | 25µA typ - preserves battery life during active operation |
| Standby Current | 0.1µA typ - enables deep-sleep modes in portable devices |
Pinout & Package
SOT-23-5 package with exposed pad (thermal enhancement), 1.3mm × 2.9mm footprint, 1.45mm height, RoHS-compliant matte tin lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CE) | Chip Enable | Active-high digital control input; logic high ≥1.5V enables regulation, low ≤0.25V disables output |
| 2 (GND) | Ground Reference | Common return path for input, output, and internal circuitry; connects to PCB ground plane |
| 3 (VIN) | Input Supply | Accepts 3.0V–6.0V unregulated input; requires ≥1µF ceramic capacitor for stability |
| 4 (NC) | No Connection | Internally unconnected; must be left floating or tied to GND per layout best practice |
| 5 (VOUT) | Regulated Output | Delivers 2.5V ±2% output; requires ≥1µF ceramic capacitor with ESR 0.01Ω–100Ω |
Key Features
| Feature | Design Value |
|---|---|
| Low-noise regulation | 30µVrms output noise enables clean power for RF transceivers and audio codecs |
| Enable-controlled shutdown | 0.1µA standby current allows system-level power gating without external switches |
| Ceramic capacitor compatibility | Stable with ≥1µF low-ESR ceramics - eliminates need for bulk tantalum or electrolytic caps |
| High PSRR at 1kHz | 70dB rejection of ripple from switching regulators - reduces need for additional filtering stages |
| Precision output accuracy | ±2% over -40°C to +85°C - eliminates post-production calibration for most embedded applications |
Applications
| Wireless Sensor Node | Portable Medical Monitor |
|---|---|
|
Use Scenario: Powering BLE SoC and analog front-end in compact wearable sensors. IC Role / Device Role / Timing Role: Primary 2.5V LDO supplying RF transceiver and ADC reference voltage. Use Value: 30µVrms noise prevents SNR degradation in sub-1Vpp sensor signals; 0.1µA shutdown extends multi-year battery life. |
Use Scenario: Regulating power for ECG analog signal chain and low-power MCU in handheld diagnostics. IC Role / Device Role / Timing Role: Clean 2.5V rail for instrumentation amplifier and 12-bit SAR ADC reference. Use Value: ±2% output accuracy ensures consistent gain calibration; 70dB PSRR rejects noise from display backlight DC/DC. |
| Industrial Handheld Terminal | Smart Camera Module |
|
Use Scenario: Providing stable core voltage to ARM Cortex-M4 MCU and RS-485 transceiver in rugged field device. IC Role / Device Role / Timing Role: Secondary LDO generating 2.5V for I/O buffer and communication interface logic. Use Value: 150mV dropout allows operation down to 2.65V input - extends usable battery range by >12% versus higher-dropout alternatives. |
Use Scenario: Powering image sensor analog block and ISP core in battery-operated surveillance camera. IC Role / Device Role / Timing Role: Low-noise 2.5V supply for CIS pixel array bias and analog video processing stage. Use Value: Excellent load transient response prevents image artifacts during rapid scene changes; 1µF ceramic support simplifies compact PCB layout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AP7343-25SAG-7 | Successor device: same 2.5V output, 300mA rating, 250mV dropout @ 300mA, 25µVrms noise, improved PSRR (75dB @ 1kHz) | Pin-compatible SOT-23-5 replacement with enhanced thermal performance (θJA = 200°C/W) and AEC-Q100 qualification option | Select for new designs requiring longer product lifecycle, automotive-grade variants, or higher output current headroom |
| MCP1700-2502E/TO | Microchip 2.5V LDO: 250mA output, 178mV dropout @ 250mA, 35µVrms noise, 60dB PSRR @ 1kHz, 1.6µA quiescent current | Higher IQ limits battery life in always-on sensing; lower PSRR increases sensitivity to upstream ripple | Consider only if legacy design reuse or specific Microchip ecosystem alignment is required |
Compared with AP2121AK-2.5TRE1, AP7343-25SAG-7 offers higher current capability and automotive qualification readiness, while MCP1700-2502E/TO trades noise/PSRR performance for slightly lower cost and broader distributor availability - neither matches the original's balance of ultra-low noise, low dropout, and sub-1µA standby in a single SOT-23-5 solution.
Availability
AP2121AK-2.5TRE1 is available at Aetrix Electronics and suitable for wireless sensor nodes, portable medical monitors, industrial handheld terminals, and smart camera modules requiring stable component supply and long-term obsolescence management.
Supply support for AP2121AK-2.5TRE1 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 industrial, computing, and consumer markets.
The AP2121 series belongs to Diodes' precision LDO portfolio, engineered specifically for battery-powered portable electronics where ultra-low noise, low quiescent current, and small-footprint packaging are critical design constraints.
FAQ
What is the recommended input capacitor for AP2121AK-2.5TRE1?
A minimum 1µF ceramic capacitor with X5R or X7R dielectric is required at the VIN pin, placed as close as possible to pins 3 (VIN) and 2 (GND). This capacitor stabilizes the input supply against source impedance and prevents oscillation during load transients. Tantalum or aluminum electrolytic capacitors are not recommended due to higher ESR and potential instability.
Can AP2121AK-2.5TRE1 operate with a 2.7V input voltage?
No - the AP2121AK-2.5TRE1 requires a minimum input voltage of 3.0V per Recommended Operating Conditions. At 2.7V input, the device falls below its specified operating range and cannot maintain 2.5V output regulation, especially under load. The absolute minimum VIN is 2.0V, but functional regulation begins only at 3.0V for the 2.5V version.
Is the NC pin (Pin 4) required to be grounded?
Pin 4 is internally unconnected and must not be soldered to any net. Diodes Incorporated specifies it as "No Connection" - leaving it floating is correct. Grounding Pin 4 may cause unpredictable behavior or damage due to unintended internal coupling; PCB layout should isolate this pad with solder mask and avoid copper pour underneath.
Why does the datasheet state "not recommended for new designs"?
Diodes Incorporated has designated AP2121AK-2.5TRE1 as legacy due to the introduction of the AP7343 series, which offers improved specifications (higher current, better thermal performance, AEC-Q100 option) and ongoing long-term supply assurance. While AP2121AK-2.5TRE1 remains fully functional and supported for existing designs, new projects should evaluate AP7343-25SAG-7 as the direct upgrade path.
AP2121AK-2.5TRE1 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):
- 2.5V
- 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-2.5TRE1 FAQ
1.How can I place an order for AP2121AK-2.5TRE1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AP2121AK-2.5TRE1 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-2.5TRE1 reliable?
The price and inventory of AP2121AK-2.5TRE1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP2121AK-2.5TRE1 is usually 5 days.
3.What payment methods are accepted for AP2121AK-2.5TRE1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP2121AK-2.5TRE1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AP2121AK-2.5TRE1?
AP2121AK-2.5TRE1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AP2121AK-2.5TRE1 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-2.5TRE1?
For technical support, including AP2121AK-2.5TRE1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP2121AK-2.5TRE1 requirements.
6.How does Aetrix verify that AP2121AK-2.5TRE1 is sourced from the original manufacturer or authorized distributors?
All AP2121AK-2.5TRE1 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-2.5TRE1 meets industry standards.
7.What is the process for return or replacement of AP2121AK-2.5TRE1?
All AP2121AK-2.5TRE1 units undergo pre-shipment inspection (PSI). If there is an issue with AP2121AK-2.5TRE1, 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-2.5TRE1 part is unused and in its original packaging.
Return procedure for AP2121AK-2.5TRE1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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