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Diodes Incorporated AP2121AK-1.8TRG1
- Part No.:
- AP2121AK-1.8TRG1
- Manufacturer:
- Diodes Incorporated
- Package:
- SC-74A, SOT-753
- Datasheet:
-
AP2121AK-1.8TRG1.pdf
- Description:
- IC REG LINEAR 1.8V 200MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,717
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Product details
Overview
AP2121AK-1.8TRG1 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 chip-enable control, supports ceramic capacitors as low as 1 µF, and targets power-sensitive analog and RF circuitry in portable electronics.
For engineers reviewing the AP2121AK-1.8TRG1 datasheet, AP2121AK-1.8TRG1 pinout, AP2121AK-1.8TRG1 application, or AP2121AK-1.8TRG1 equivalent, key selection criteria include ultra-low noise for ADC/DAC reference rails, fast transient response for burst-mode processors, CE-controlled shutdown for battery runtime optimization, and compatibility with space-constrained SOT-23-5 layouts.
Technical Context
The AP2121AK-1.8TRG1 uses 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 suppresses switching noise from upstream DC/DC converters feeding its input.
It features active-high enable (CE) logic, thermal shutdown, and current-limit protection (50 mA short-circuit limit). The device operates across –40°C to +85°C ambient and maintains stability with 1 µF ceramic output capacitance and ESR between 0.01 Ω and 100 Ω.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 1.8 V ±2% - ensures stable core voltage for 1.8 V I/O interfaces and low-power microcontrollers |
| Max Output Current | 200 mA - sufficient for powering single-core MCUs, sensors, or RF front-end bias rails |
| Dropout Voltage | 150 mV typ. @ 100 mA - enables operation from 1.95 V input (e.g., single Li-ion cell under load) |
| Output Noise | 30 µVrms (10 Hz–100 kHz) - preserves SNR in precision analog signal chains and audio codecs |
| PSRR | 70 dB @ 1 kHz - attenuates ripple from switching regulators by >3,000×, critical for clean analog supplies |
| Quiescent Current | 25 µA typ. - minimizes standby drain in always-on sensor nodes and IoT edge devices |
| Enable Threshold | CE "High" ≥1.5 V - compatible with 1.8 V GPIOs without level-shifting |
Pinout & Package
SOT-23-5 package: 2.9 mm × 1.6 mm × 1.1 mm body, surface-mount, lead-free, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CE) | Chip Enable Input | Active-high digital control: ≥1.5 V enables regulation; ≤0.25 V disables output and reduces IQ to 0.1 µA |
| 2 (GND) | Ground Reference | Common return path for input, output, and internal circuitry; requires low-impedance PCB connection |
| 3 (VIN) | Input Supply | Accepts 2 V to 6 V input; must be decoupled with ≥1 µF ceramic capacitor near pin |
| 4 (NC) | No Connection | Internally unconnected; must remain floating-no external tie or routing |
| 5 (VOUT) | Regulated Output | Delivers stable 1.8 V; requires ≥1 µF ceramic capacitor with ESR 0.01–100 Ω for stability |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low noise output | 30 µVrms (10 Hz–100 kHz) - avoids introducing jitter or distortion in clock buffers and ADC references |
| Low dropout at full load | 150 mV @ 100 mA - extends usable battery life in single-cell systems by enabling deeper discharge |
| Fast line/load transient response | Sub-10 µs recovery from 50% load step - prevents brownout during processor wake-up bursts |
| Ceramic capacitor compatibility | Stable with ≥1 µF X5R/X7R ceramics - eliminates need for bulky tantalum or electrolytic capacitors |
| High output accuracy | ±2% over temperature and load - eliminates need for external trimming in factory calibration |
Applications
| Mobile Baseband Power | RF Front-End Bias |
|---|---|
|
Use Scenario: Powering baseband processor I/O banks and memory interfaces in smartphones. IC Role / Device Role / Timing Role: Primary 1.8 V LDO supplying digital I/O rails with tight voltage tolerance and low noise. Use Value: Maintains signal integrity during high-speed data transfers (e.g., LPDDR, MIPI) by minimizing supply-induced jitter and crosstalk. |
Use Scenario: Providing clean bias voltage to LNAs, mixers, and PA drivers in cellular/Wi-Fi modules. IC Role / Device Role / Timing Role: Low-noise analog supply rail decoupling sensitive RF signal paths from noisy system power domains. Use Value: Preserves receiver sensitivity and transmitter EVM by suppressing 30 µVrms noise floor and rejecting 70 dB of switching ripple. |
| Wearable Sensor Hub | Industrial Data Acquisition |
|
Use Scenario: Regulating power for MEMS accelerometers, gyroscopes, and BLE SoCs in compact wearables. IC Role / Device Role / Timing Role: Always-on, low-quiescent-current LDO enabling multi-week battery life while maintaining sensor accuracy. Use Value: Delivers 25 µA quiescent current and 0.1 µA shutdown mode, extending coin-cell lifetime without sacrificing startup speed. |
Use Scenario: Supplying precision ADCs, DACs, and op-amps in portable test equipment and condition-monitoring sensors. IC Role / Device Role / Timing Role: Ultra-stable reference rail ensuring <±0.5 LSB error in 16-bit conversion systems. Use Value: Achieves ±2% output accuracy and 12 mV load regulation to eliminate gain drift across temperature and load variations. |
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 LDO: same 1.8 V output, 300 mA rating, 25 µA IQ, but improved PSRR (75 dB @ 1 kHz) and lower noise (15 µVrms) | Designed for new designs requiring longer product lifecycle support and AEC-Q200 qualification path | Preferred for production ramp; AP2121AK-1.8TRG1 remains viable for legacy BOM continuity |
| MCP1700-1802E/TO | 100 mA max output, 6 µA IQ, 170 mV dropout @ 100 mA, 40 µVrms noise - lower current, higher noise, lower IQ | Better suited for ultra-low-power sensor nodes where 100 mA suffices and noise <50 µVrms is acceptable | Select when minimizing standby current outweighs need for 200 mA capability or sub-30 µVrms noise |
Compared with AP7343-18SAG-7, the AP2121AK-1.8TRG1 offers proven field reliability but lacks newer automotive-grade qualifications; versus MCP1700-1802E/TO, it delivers 2× output current and 25% lower noise at the cost of 4× higher quiescent current - making it optimal for performance-critical, medium-power analog rails.
Availability
AP2121AK-1.8TRG1 is available at Aetrix Electronics and suitable for mobile baseband power, RF front-end bias, wearable sensor hubs, and industrial data acquisition requiring stable component supply with consistent parametric performance and long-term traceability.
Supply support for AP2121AK-1.8TRG1 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 for power management, signal integrity, and connectivity applications.
The AP2121 series belongs to Diodes' high-performance LDO portfolio, engineered specifically for battery-powered portable electronics demanding ultra-low noise, fast transient response, and minimal footprint.
FAQ
What is the minimum input voltage required for stable 1.8 V output at 200 mA?
The AP2121AK-1.8TRG1 requires VIN ≥ VOUT + VDROP. At 200 mA, typical dropout is 250 mV (max 500 mV per datasheet), so minimum VIN is 2.05 V (typical) or 2.3 V (worst-case). Operation below 2.0 V risks dropout and output collapse.
Can the NC pin (Pin 4) be grounded or left floating?
Pin 4 is internally unconnected and must remain floating-neither grounded nor tied to any voltage. Connecting it may cause unpredictable behavior or damage due to internal structure; the datasheet explicitly prohibits external connection.
Is AP2121AK-1.8TRG1 qualified for automotive use?
No. The AP2121AK-1.8TRG1 is not AEC-Q100 qualified. Diodes states that automotive-grade variants require specific change control, PPAP capability, and IATF 16949 manufacturing-none of which apply to this part. Use AP7343 or AP2202K for automotive designs.
Why does the datasheet state "NOT RECOMMENDED FOR NEW DESIGNS"?
Diodes has designated AP2121AK-1.8TRG1 as legacy due to the introduction of the enhanced AP7343 family, which offers superior PSRR, lower noise, higher current, and extended lifecycle support. New designs should adopt AP7343-18SAG-7 unless AP2121-specific qualification or form-fit constraints apply.
AP2121AK-1.8TRG1 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-1.8TRG1 FAQ
1.How can I place an order for AP2121AK-1.8TRG1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AP2121AK-1.8TRG1 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-1.8TRG1 reliable?
The price and inventory of AP2121AK-1.8TRG1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP2121AK-1.8TRG1 is usually 5 days.
3.What payment methods are accepted for AP2121AK-1.8TRG1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP2121AK-1.8TRG1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AP2121AK-1.8TRG1?
AP2121AK-1.8TRG1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AP2121AK-1.8TRG1 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-1.8TRG1?
For technical support, including AP2121AK-1.8TRG1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP2121AK-1.8TRG1 requirements.
6.How does Aetrix verify that AP2121AK-1.8TRG1 is sourced from the original manufacturer or authorized distributors?
All AP2121AK-1.8TRG1 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-1.8TRG1 meets industry standards.
7.What is the process for return or replacement of AP2121AK-1.8TRG1?
All AP2121AK-1.8TRG1 units undergo pre-shipment inspection (PSI). If there is an issue with AP2121AK-1.8TRG1, 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-1.8TRG1 part is unused and in its original packaging.
Return procedure for AP2121AK-1.8TRG1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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