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Diodes Incorporated AP2121N-1.8TRE1
- Part No.:
- AP2121N-1.8TRE1
- Manufacturer:
- Diodes Incorporated
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
AP2121N-1.8TRE1.pdf
- Description:
- IC REG LINEAR 1.8V 200MA SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,217
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Product details
Overview
AP2121N-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 and supports ceramic output capacitors as low as 1 µF, making it suitable for powering noise-sensitive analog circuitry in portable battery-powered systems.
For engineers reviewing the AP2121N-1.8TRE1 datasheet, AP2121N-1.8TRE1 pinout, AP2121N-1.8TRE1 application, or AP2121N-1.8TRE1 equivalent, key selection criteria include its ultra-low noise performance, high PSRR (70 dB @ 1 kHz), sub-1 µA standby current, and compatibility with low-ESR ceramic capacitors in space-constrained designs.
Technical Context
The AP2121N-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 stems from optimized internal compensation and low-noise biasing, enabling stable operation under fast line/load transients.
It features an active-high chip-enable input (CE) that reduces quiescent current to 0.1 µA in shutdown mode, and includes current-limit protection (50 mA short-circuit limit) and thermal shutdown. The device operates across –40 °C to +85 °C ambient temperature with input voltage range of 2.0 V to 6.0 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 1.8 V ±2% - ensures stable core supply for 1.8 V logic and RF ICs without external feedback. |
| Max Output Current | 200 mA continuous - sufficient for powering microcontrollers, sensors, or RF front-ends in portable devices. |
| Dropout Voltage | 150 mV typ. @ 100 mA - enables regulation from 1.95 V input, extending battery runtime in single-cell Li-ion or NiMH systems. |
| RMS Output Noise | 30 µVrms (10 Hz–100 kHz) - minimizes phase jitter in clocked analog circuits like ADCs and RF synthesizers. |
| PSRR | 70 dB @ 1 kHz - suppresses switching noise from upstream DC/DC converters feeding the LDO input. |
| Quiescent Current | 25 µA typ. - maintains efficiency during light-load operation in always-on subsystems. |
| Standby Current | 0.1 µA typ. - enables ultra-low-power system sleep modes when CE = low. |
| Input Voltage Range | 2.0 V to 6.0 V - supports direct connection to single-cell Li-ion (2.7–4.2 V), dual-cell alkaline, or regulated 3.3/5 V rails. |
Pinout & Package
SOT-23-5 package: 5-pin surface-mount, 1.6 mm × 2.9 mm footprint, 1.1 mm height, lead-free and RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - CE | Enable control input | Active-high logic signal; drives internal pass transistor gate. Pull-down resistance 2.5–10 MΩ ensures defined OFF state if left floating. |
| 2 - VIN | Input voltage supply | Accepts 2.0–6.0 V; requires ≥1 µF ceramic input capacitor for stability and transient response. |
| 3 - GND | Power ground reference | Common return path for input, output, and internal circuitry; must be low-impedance connection to minimize noise coupling. |
| 4 - NC | No connection | Internally unconnected; must remain unconnected on PCB to avoid parasitic leakage or ESD paths. |
| 5 - VOUT | Regulated output | Delivers 1.8 V ±2%; requires ≥1 µF ceramic output capacitor (ESR 0.01–100 Ω) for loop stability and load transient suppression. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low noise regulation | 30 µVrms output noise enables clean power for precision ADCs, audio codecs, and RF receivers without additional filtering. |
| High PSRR at 1 kHz | 70 dB rejection of ripple from switching regulators allows co-location with DC/DC converters on compact PCBs. |
| Low dropout at full load | 150 mV dropout at 100 mA permits operation down to 1.95 V input, maximizing usable battery capacity in 2.0 V–3.6 V systems. |
| Sub-microamp standby mode | 0.1 µA shutdown current extends shelf life and enables long-term battery-backed memory retention or real-time clock operation. |
| Ceramic capacitor compatibility | Stable with ≥1 µF X5R/X7R ceramics (ESR ≥0.01 Ω) - eliminates need for bulky tantalum or electrolytic capacitors. |
| Precision output accuracy | ±2% over temperature and load ensures reliable operation of 1.8 V I/O interfaces and core logic without margining overhead. |
Applications
| Mobile Phone Baseband Power | Wireless Sensor Node MCU Supply |
|---|---|
|
Use Scenario: Powers baseband processor I/O banks and auxiliary analog blocks in LTE/5G handsets where RF sensitivity demands ultra-clean 1.8 V rails. IC Role / Device Role / Timing Role: Primary low-noise post-regulator downstream of a buck converter, providing isolated, ripple-free 1.8 V for mixed-signal SoC domains. Use Value: 30 µVrms noise and 70 dB PSRR prevent digital switching noise from degrading receiver SNR and adjacent-channel selectivity. |
Use Scenario: Supplies 1.8 V to ultra-low-power MCUs (e.g., ARM Cortex-M0+) and environmental sensors in battery-operated IoT nodes with 10-year lifetime targets. IC Role / Device Role / Timing Role: Main system LDO with CE-controlled shutdown, enabling deep-sleep current <1 µA while maintaining regulated rail readiness. Use Value: 0.1 µA standby current and ceramic-capacitor compatibility reduce BOM cost and board area versus legacy LDOs requiring tantalum caps. |
| Digital Camera Image Sensor Bias | Portable Medical Pulse Oximeter Analog Front-End |
|
Use Scenario: Provides low-noise 1.8 V bias to CMOS image sensor I/O and timing controller in compact digital cameras and action cams. IC Role / Device Role / Timing Role: Dedicated analog-domain LDO decoupling sensor interface from noisy digital supply rails, minimizing pixel-level fixed-pattern noise. Use Value: ±2% output accuracy and excellent load regulation (<12 mV) ensure consistent sensor gain calibration across battery discharge cycles. |
Use Scenario: Powers op-amps, ADC drivers, and photodiode transimpedance stages in handheld pulse oximeters requiring clinical-grade signal integrity. IC Role / Device Role / Timing Role: Precision analog LDO supplying critical analog signal chain components, rejecting noise from display backlight drivers and Bluetooth radios. Use Value: 30 µVrms noise directly translates to <0.1 LSB noise floor in 12-bit medical ADCs operating at 1 kSPS. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-noise LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AP7343-18SAG-7 | Successor part: same 1.8 V output, 300 mA rating, 25 µA IQ, but improved 25 µVrms noise and AEC-Q100 Grade 2 qualification. | Supports automotive infotainment and ADAS modules requiring extended temperature and PPAP compliance. | Select for new designs requiring longer product lifecycle, higher reliability, or automotive qualification. |
| MCP1700-1802E/TO | 100 mA max output, 6 µA IQ, 40 µVrms noise, TO-92 package - lower current, higher noise, through-hole mounting. | Suitable for low-cost, low-density consumer electronics where PCB space and noise are less critical. | Choose only for legacy through-hole assembly or ultra-low-quiescent-current needs below 100 mA load. |
Compared with AP2121N-1.8TRE1, AP7343-18SAG-7 offers superior noise performance and automotive qualification for future-proofing, while MCP1700-1802E/TO trades output capability and noise for ultra-low IQ and through-hole compatibility in cost-sensitive, low-power applications.
Availability
AP2121N-1.8TRE1 is available at Aetrix Electronics and suitable for mobile phone baseband power, wireless sensor node MCU supply, digital camera image sensor bias, and portable medical pulse oximeter analog front-end applications requiring stable component supply and proven field reliability.
Supply support for AP2121N-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 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, designed specifically for battery-powered portable electronics demanding ultra-low noise, high PSRR, and minimal quiescent current in miniature packages.
FAQ
What is the minimum input voltage required for AP2121N-1.8TRE1 to maintain regulation?
The AP2121N-1.8TRE1 requires VIN ≥ (VOUT + VDROP). At 100 mA load, typical dropout is 150 mV, so minimum input is 1.95 V. At 200 mA, dropout rises to ≤500 mV per datasheet, requiring VIN ≥ 2.3 V for guaranteed regulation. Input must stay within 2.0–6.0 V absolute ratings.
Can AP2121N-1.8TRE1 be used with a 0.47 µF output capacitor?
No. The datasheet specifies a minimum 1 µF ceramic output capacitor (ESR 0.01–100 Ω) for stability. Using 0.47 µF risks oscillation, poor load transient response, and potential output overshoot. Always use ≥1 µF X5R/X7R ceramic with appropriate voltage rating.
Is AP2121N-1.8TRE1 qualified for automotive applications?
No. AP2121N-1.8TRE1 is not AEC-Q100 qualified. Diodes explicitly states that automotive-grade variants require specific change control and PPAP capability - the recommended replacement is AP7343-18SAG-7, which is AEC-Q100 Grade 2 qualified and manufactured in IATF 16949 certified facilities.
What happens to output voltage when CE pin is left floating?
The CE pin has an internal 2.5–10 MΩ pull-down resistor. When left floating, it defaults to logic low, placing the device in shutdown mode with VOUT disabled and quiescent current reduced to 0.1 µA. To enable regulation, CE must be actively driven ≥1.5 V.
AP2121N-1.8TRE1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- -
- Protection Features:
- Over Current
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
AP2121N-1.8TRE1 FAQ
1.How can I place an order for AP2121N-1.8TRE1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AP2121N-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 AP2121N-1.8TRE1 reliable?
The price and inventory of AP2121N-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 AP2121N-1.8TRE1 is usually 5 days.
3.What payment methods are accepted for AP2121N-1.8TRE1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP2121N-1.8TRE1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AP2121N-1.8TRE1?
AP2121N-1.8TRE1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AP2121N-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 AP2121N-1.8TRE1?
For technical support, including AP2121N-1.8TRE1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP2121N-1.8TRE1 requirements.
6.How does Aetrix verify that AP2121N-1.8TRE1 is sourced from the original manufacturer or authorized distributors?
All AP2121N-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 AP2121N-1.8TRE1 meets industry standards.
7.What is the process for return or replacement of AP2121N-1.8TRE1?
All AP2121N-1.8TRE1 units undergo pre-shipment inspection (PSI). If there is an issue with AP2121N-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 AP2121N-1.8TRE1 part is unused and in its original packaging.
Return procedure for AP2121N-1.8TRE1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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