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Diodes Incorporated AP2121AK-1.8TRE1
- Part No.:
- AP2121AK-1.8TRE1
- Manufacturer:
- Diodes Incorporated
- Package:
- SC-74A, SOT-753
- Datasheet:
-
AP2121AK-1.8TRE1.pdf
- Description:
- IC REG LINEAR 1.8V 200MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,990
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Product details
Overview
AP2121AK-1.8TRE1 from Diodes Incorporated is a high-speed, extremely low-noise 1.8 V fixed-output LDO regulator in SOT-23-5 package, delivering up to 200 mA output current with 150 mV typical dropout at 100 mA, 30 µVrms output noise (10 Hz–100 kHz), and ±2% output voltage accuracy. It integrates an active-high enable pin, current-limit protection, and supports ceramic output capacitors as low as 1 µF - ideal for powering noise-sensitive analog circuitry in portable battery-powered systems.
For engineers reviewing the AP2121AK-1.8TRE1 datasheet, AP2121AK-1.8TRE1 pinout, AP2121AK-1.8TRE1 application, or AP2121AK-1.8TRE1 equivalent, key selection criteria include dropout performance at 100 mA load, RMS noise floor under 30 µV, CE logic threshold compatibility (1.5 V high / 0.25 V low), thermal resistance (θJA = 250 °C/W), and AEC-Q100 eligibility status for automotive use cases.
Technical Context
The AP2121AK-1.8TRE1 employs a CMOS-based error amplifier architecture with internal voltage reference and resistor network for precise 1.8 V regulation. Its high PSRR of 70 dB at 1 kHz enables effective suppression of switching noise from upstream DC/DC converters feeding its VIN rail.
It features fast line and load transient response due to optimized control loop dynamics, and includes thermal shutdown and short-circuit current limiting (50 mA typical). The CE pin allows system-level power sequencing and ultra-low standby current (0.1 µA typical) during shutdown.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 1.8 V ±2% - ensures stable biasing for 1.8 V I/O domains in microcontrollers and sensors |
| Max Output Current | 200 mA - sufficient for powering RF transceivers, ADCs, or small FPGA I/O banks |
| Dropout Voltage | 150 mV typ. @ 100 mA - enables operation from 1.95 V input, extending battery runtime in single-cell Li-ion/Li-poly systems |
| Output Noise | 30 µVrms (10 Hz–100 kHz) - preserves SNR in precision analog signal chains and audio codecs |
| PSRR | 70 dB @ 1 kHz - rejects ripple from switching regulators without requiring additional LC filtering |
| Quiescent Current | 25 µA typ. - minimizes standby power loss in always-on sensor nodes and wearables |
| Enable Threshold | VCE(HI) = 1.5 V min., VCE(LO) = 0.25 V max. - compatible with 1.8 V GPIO and open-drain logic interfaces |
Pinout & Package
SOT-23-5 package: 5-pin surface-mount plastic package with 0.95 mm pitch, exposed pad optional, θJA = 250 °C/W, rated for -40 °C to +85 °C ambient operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CE) | Chip Enable | Active-high digital control input; pulls down internally via 5 MΩ resistor when unconnected - enables clean power sequencing |
| 2 (VIN) | Input Supply | Accepts 2 V to 6 V input; requires ≥1 µF ceramic input capacitor for stability and EMI reduction |
| 3 (GND) | Ground Reference | Common return path for input, output, and internal circuitry; must be low-impedance for noise immunity |
| 4 (NC) | No Connection | Internally unconnected; must remain floating - no external tie or routing allowed |
| 5 (VOUT) | Regulated Output | Delivers 1.8 V ±2%; requires ≥1 µF ceramic output capacitor with ESR 0.01–100 Ω for loop stability |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low noise regulation | 30 µVrms output noise enables direct powering of PLLs, VCOs, and high-resolution ADCs without added filtering |
| Low dropout with high current | 150 mV dropout at 100 mA allows efficient operation from partially discharged batteries or tightly regulated intermediate rails |
| Fast transient response | Excellent line and load transient behavior maintains output stability during sudden current steps in wireless baseband processors |
| Low-power enable control | 0.1 µA standby current and defined CE thresholds simplify integration with low-voltage microcontroller GPIOs |
| Ceramic capacitor compatibility | Stable with 1 µF ceramic output caps eliminates need for bulk tantalum or electrolytic capacitors, reducing board area and cost |
Applications
| Mobile RF Front-End | Digital Camera Sensor Bias |
|---|---|
Use Scenario: Powering 1.8 V LNA and mixer stages in LTE/5G handset front-end modules. IC Role / Device Role / Timing Role: Low-noise local regulation stage isolating sensitive RF analog blocks from noisy system supply rails. Use Value: 30 µVrms noise prevents reciprocal mixing degradation and maintains receiver sensitivity below –100 dBm. | Use Scenario: Supplying image sensor analog core and column ADC in compact digital cameras. IC Role / Device Role / Timing Role: Precision voltage source for sensor pixel bias and analog signal chain reference. Use Value: ±2% output accuracy and low temperature drift (±100 ppm/°C) ensure consistent exposure calibration across operating temperatures. |
| Wearable Biometric SoC | Industrial IoT Edge Node |
Use Scenario: Regulating power to ultra-low-power ARM Cortex-M based biometric processing SoC with integrated ADC and BLE radio. IC Role / Device Role / Timing Role: Primary 1.8 V domain regulator enabling simultaneous analog sensing and digital computation. Use Value: 25 µA quiescent current and 0.1 µA shutdown current extend coin-cell battery life beyond 12 months in continuous monitoring mode. | Use Scenario: Providing clean 1.8 V supply to isolated RS-485 transceiver and low-power microcontroller in factory automation node. IC Role / Device Role / Timing Role: Secondary LDO stage decoupling communication interface from noisy 3.3 V system rail. Use Value: 70 dB PSRR at 1 kHz suppresses switching noise from adjacent DC/DC converters, preventing data corruption on differential bus lines. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AP7343-18SAG-7 | Successor device: lower 12 µA IQ, 120 mV dropout @ 150 mA, same SOT-23-5 footprint, AEC-Q100 qualified | Designed for automotive-grade reliability and extended temperature range (–40 °C to +125 °C) | Preferred for new designs requiring longer product lifecycle support and automotive qualification |
| MCP1700-1802E/TO | Higher 6 µA IQ but only 250 mA max output; no CE pin; TO-92 package; ±0.4% initial accuracy | Limited to low-complexity, cost-sensitive consumer devices without enable control requirements | Only suitable where CE functionality and SMT assembly are not required |
Compared with AP7343-18SAG-7, the AP2121AK-1.8TRE1 offers identical pinout but higher quiescent current and lacks AEC-Q100 qualification; versus MCP1700-1802E/TO, it provides enable control and SMT packaging at the cost of slightly lower accuracy and higher IQ.
Availability
AP2121AK-1.8TRE1 is available at Aetrix Electronics and suitable for mobile RF front-end modules, digital camera sensor biasing, wearable biometric SoCs, and industrial IoT edge nodes requiring stable component supply with known legacy design support.
Supply support for AP2121AK-1.8TRE1 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 ICs, with manufacturing certified to IATF 16949 and quality systems aligned to AEC-Q standards.
The AP2121 series belongs to Diodes' high-performance LDO portfolio targeting battery-powered and noise-sensitive applications, emphasizing low dropout, ultra-low noise, and fast transient response for portable and industrial electronics.
FAQ
What is the minimum input voltage required for stable 1.8 V output at 100 mA?
The AP2121AK-1.8TRE1 requires VIN ≥ VOUT + VDROP = 1.8 V + 0.15 V = 1.95 V minimum for 100 mA load. At 200 mA, dropout rises to 250 mV typ., so VIN ≥ 2.05 V is recommended. Operation below 2.0 V risks regulation loss and increased noise.
Can the NC pin (Pin 4) be grounded or left floating?
Pin 4 is internally unconnected and must remain floating - grounding or tying it to any voltage violates the absolute maximum ratings and may cause unpredictable behavior or latch-up. PCB layout must isolate this pad with no copper or solder mask bridge.
Is AP2121AK-1.8TRE1 qualified for automotive applications?
No - the AP2121AK-1.8TRE1 is not AEC-Q100 qualified. Diodes explicitly states that automotive-grade variants require specific change control and PPAP capability; for such use, the AP7343-18SAG-7 (AEC-Q100 Grade 1) is the designated replacement.
What output capacitor ESR range ensures stability?
Stability is guaranteed with ceramic output capacitors having ESR between 0.01 Ω and 100 Ω. A 1 µF X5R/X7R ceramic capacitor (e.g., 0603 or 0805) meets both capacitance and ESR requirements and is recommended over tantalum or aluminum electrolytics.
AP2121AK-1.8TRE1 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):
- 1.8V
- 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-1.8TRE1 FAQ
1.How can I place an order for AP2121AK-1.8TRE1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AP2121AK-1.8TRE1 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-1.8TRE1 reliable?
The price and inventory of AP2121AK-1.8TRE1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP2121AK-1.8TRE1 is usually 5 days.
3.What payment methods are accepted for AP2121AK-1.8TRE1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP2121AK-1.8TRE1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AP2121AK-1.8TRE1?
AP2121AK-1.8TRE1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AP2121AK-1.8TRE1 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-1.8TRE1?
For technical support, including AP2121AK-1.8TRE1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP2121AK-1.8TRE1 requirements.
6.How does Aetrix verify that AP2121AK-1.8TRE1 is sourced from the original manufacturer or authorized distributors?
All AP2121AK-1.8TRE1 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-1.8TRE1 meets industry standards.
7.What is the process for return or replacement of AP2121AK-1.8TRE1?
All AP2121AK-1.8TRE1 units undergo pre-shipment inspection (PSI). If there is an issue with AP2121AK-1.8TRE1, 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-1.8TRE1 part is unused and in its original packaging.
Return procedure for AP2121AK-1.8TRE1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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