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Diodes Incorporated AP2125K-4.2TRE1
- Part No.:
- AP2125K-4.2TRE1
- Manufacturer:
- Diodes Incorporated
- Package:
- SC-74A, SOT-753
- Datasheet:
-
AP2125K-4.2TRE1.pdf
- Description:
- IC REG LINEAR 4.2V 300MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,136
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Product details
Overview
AP2125K-4.2TRE1 from Diodes Incorporated is a 300mA, fixed-output 4.2V CMOS low-dropout linear regulator in SC-70-5 package, featuring 50µVRMS output noise, 65mV dropout at 100mA (3.3V version), ±2% output voltage accuracy, and active-high enable control. It delivers stable power to RF-sensitive circuits in battery-powered handheld instruments and portable information appliances.
For engineers reviewing the AP2125K-4.2TRE1 datasheet, AP2125K-4.2TRE1 pinout, AP2125K-4.2TRE1 application, or AP2125K-4.2TRE1 equivalent, key selection criteria include ultra-low noise performance for analog/RF stages, thermal shutdown at +160°C, compatibility with low-ESR ceramic capacitors, and standby current of 0.01µA in shutdown mode.
Technical Context
The AP2125K-4.2TRE1 integrates a precision voltage reference, error amplifier, resistor network for fixed 4.2V output, chip-enable circuit, current-limit protection, and over-temperature shutdown (OTSD). Its CMOS process enables low quiescent current (60µA typical) and high PSRR (65dB at 1kHz).
It operates across input voltages from (VOUT + 0.5)V to 6V, supports –40°C to +85°C ambient range, and maintains load regulation within 13mV over 1–300mA output current. The device uses internal compensation and requires only 1µF input/output ceramic capacitors for stability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 4.2V ±2% - ensures precise biasing for lithium-ion charging management and 3.3V/1.8V logic rails requiring tight tolerance. |
| Max Output Current | 300mA minimum - sufficient to power microcontrollers, sensors, and RF front-ends in compact portable devices. |
| Dropout Voltage | 65mV at 100mA (3.3V version); 10mV typ. at 10mA - enables operation with minimal headroom, extending battery runtime in single-cell systems. |
| Output Noise | 50µVRMS (10Hz–100kHz) - critical for noise-sensitive analog signal chains and RF receivers where LDO ripple directly impacts SNR. |
| PSRR | 65dB at 1kHz - suppresses switching noise from upstream DC/DC converters, protecting downstream analog circuits. |
| Quiescent Current | 60µA typical - minimizes idle power loss in always-on subsystems such as real-time clocks or wake-up controllers. |
| Standby Current | 0.01µA typical - enables nanowatt-level shutdown for long-term storage or deep-sleep modes in IoT endpoints. |
| Enable Threshold | VCE(HI) = 1.5V min., VCE(LO) = 0.4V max. - compatible with 1.8V/3.3V GPIOs without level-shifting. |
Pinout & Package
AP2125K-4.2TRE1 is housed in a 5-pin SC-70-5 package (2.0mm × 1.25mm × 0.9mm), optimized for space-constrained PCB layouts in portable electronics.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VIN | Input supply pin - accepts 4.7V to 6V input; must be decoupled with ≥1µF ceramic capacitor close to pin. |
| 2 | GND | Analog ground reference - shared return path for internal reference, error amp, and output stage; requires low-impedance connection to PCB ground plane. |
| 3 | NC | No connection - internally unconnected; must remain floating per datasheet; no external tie required. |
| 4 | CE | Active-high enable input - logic high (≥1.5V) enables regulation; logic low (≤0.4V) places IC in ultra-low-power shutdown (0.01µA). |
| 5 | VOUT | Regulated 4.2V output - supplies load; requires ≥1µF low-ESR ceramic capacitor; ESR < 1Ω ensures stability across full load range. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low noise | 50µVRMS output noise enables clean power for ADCs, PLLs, and RF transceivers without additional filtering. |
| Low dropout | 65mV dropout at 100mA allows operation from partially discharged Li-ion cells (down to ~4.25V input) while maintaining regulation. |
| High PSRR | 65dB rejection at 1kHz prevents switching noise from DC/DC converters from coupling into sensitive analog sections. |
| Thermal protection | Over-temperature shutdown at +160°C with +25°C hysteresis prevents permanent damage during sustained overload or poor heatsinking. |
| Ceramic capacitor compatible | Stable with 1µF input/output ceramic capacitors - eliminates need for larger, costlier tantalum or aluminum electrolytics. |
| Green RoHS compliance | Fully lead-free, halogen-free, and antimony-free per Diodes Inc. "Green" definition (<900ppm Br/Cl, <1000ppm Sb). |
Applications
| Battery-Powered Handheld Instruments | Portable Information Appliances |
|---|---|
Use Scenario: Digital multimeters and portable oscilloscopes powered by single-cell Li-ion batteries. IC Role / Device Role / Timing Role: Primary 4.2V rail regulator supplying analog front-end, ADC reference, and microcontroller core. Use Value: 50µVRMS noise preserves measurement accuracy; 0.01µA shutdown extends shelf life during storage. |
Use Scenario: E-readers and handheld POS terminals with always-on display controllers and touch interfaces. IC Role / Device Role / Timing Role: Stable 4.2V supply for display driver ICs and USB PHY circuitry requiring low ripple. Use Value: 65dB PSRR isolates display timing from noisy system DC/DC converters; SC-70-5 footprint saves board area. |
| CDMA/GSM Cellular Handsets | Laptops & Notebook Computers |
Use Scenario: Powering RF transceiver bias rails and audio codec analog sections in legacy 2G/3G handsets. IC Role / Device Role / Timing Role: Low-noise post-regulator for PA driver stages and RF synthesizer VCO supplies. Use Value: 4.2V output matches Li-ion cell voltage profile; 65mV dropout maximizes usable battery capacity. |
Use Scenario: Standby power rail for embedded controller (EC), keyboard controller, and battery fuel gauge ICs. IC Role / Device Role / Timing Role: Always-on 4.2V supply enabling fast wake-from-sleep and real-time battery monitoring. Use Value: 0.01µA standby current minimizes battery drain during suspend-to-RAM; CE pin enables coordinated system power sequencing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MCP1700T-4202E/TT | 250mA max output, 175mV dropout at 250mA, 30µVRMS noise, SOT-23-3 package (3-pin, no enable) | Lacks enable pin and thermal shutdown; lower current rating limits use in higher-power peripherals. | Select when board space is extremely constrained and enable control is handled externally; verify thermal margin at 300mA. |
| TPS7A2042PDBVR | 300mA, 4.2V fixed, 12µVRMS noise, 165mV dropout at 300mA, SOT-23-5 with enable, but higher IQ (6.5µA typ. in active mode) | Superior noise performance but higher dropout reduces usable battery range; higher cost and longer lead times. | Prefer for ultra-low-noise RF applications where 12µVRMS justifies trade-offs in efficiency and supply voltage headroom. |
Compared with MCP1700T-4202E/TT, AP2125K-4.2TRE1 adds enable control and thermal protection at identical noise level; versus TPS7A2042PDBVR, it trades 38µVRMS higher noise for 100mV lower dropout and broader temperature-rated operation.
Availability
AP2125K-4.2TRE1 is available at Aetrix Electronics and suitable for battery-powered handheld instruments, portable information appliances, CDMA/GSM cellular handsets, and laptops requiring stable component supply with guaranteed green compliance and long-lifecycle support.
Supply support for AP2125K-4.2TRE1 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-reliability power management, signal integrity, and protection solutions for industrial, computing, and consumer markets.
The AP2125 series belongs to Diodes' precision LDO portfolio, designed specifically for noise-critical, battery-operated applications where ultra-low quiescent current, high PSRR, and small-footprint packaging are essential.
FAQ
What is the minimum input voltage required for AP2125K-4.2TRE1 to maintain regulation?
The AP2125K-4.2TRE1 requires VIN ≥ (VOUT + 0.5V) = 4.7V under all operating conditions per Recommended Operating Conditions. At 300mA load, dropout is ≤300mV, so 4.5V input may sustain regulation transiently-but 4.7V is the guaranteed minimum for stable operation across temperature and process variation.
Can AP2125K-4.2TRE1 be used with ceramic output capacitors smaller than 1µF?
No. The datasheet specifies 1µF minimum for both CIN and COUT using X5R/X7R ceramic capacitors. Using smaller values risks instability, increased output ripple, and degraded transient response-verified via ESR vs. output current plots showing stable operation only above ~1µF.
Does the NC pin on AP2125K-4.2TRE1 require any PCB layout treatment?
Pin 3 (NC) is internally unconnected and must remain electrically floating. Do not tie to GND, VIN, or VOUT. Maintain standard solder mask clearance and avoid routing traces or vias beneath it to prevent parasitic coupling or mechanical stress-induced shorts in the SC-70-5 package.
How does thermal shutdown behave during continuous overload?
When junction temperature reaches +160°C, the AP2125K-4.2TRE1 shuts down output and holds VOUT at 0V until temperature drops by ≥25°C hysteresis. During shutdown, quiescent current remains at 60µA-not 0.01µA-because the CE pin is still active; full standby (0.01µA) requires pulling CE low.
AP2125K-4.2TRE1 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):
- 4.2V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.3V @ 300mA
- Current - Output:
- 300mA
- Current - Quiescent (Iq):
- 90 µA
- Current - Supply (Max):
- -
- PSRR:
- 65dB (100Hz ~ 1kHz)
- Control Features:
- Enable
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
AP2125K-4.2TRE1 FAQ
1.How can I place an order for AP2125K-4.2TRE1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AP2125K-4.2TRE1 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 AP2125K-4.2TRE1 reliable?
The price and inventory of AP2125K-4.2TRE1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AP2125K-4.2TRE1 is usually 5 days.
3.What payment methods are accepted for AP2125K-4.2TRE1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AP2125K-4.2TRE1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AP2125K-4.2TRE1?
AP2125K-4.2TRE1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AP2125K-4.2TRE1 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 AP2125K-4.2TRE1?
For technical support, including AP2125K-4.2TRE1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AP2125K-4.2TRE1 requirements.
6.How does Aetrix verify that AP2125K-4.2TRE1 is sourced from the original manufacturer or authorized distributors?
All AP2125K-4.2TRE1 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 AP2125K-4.2TRE1 meets industry standards.
7.What is the process for return or replacement of AP2125K-4.2TRE1?
All AP2125K-4.2TRE1 units undergo pre-shipment inspection (PSI). If there is an issue with AP2125K-4.2TRE1, 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 AP2125K-4.2TRE1 part is unused and in its original packaging.
Return procedure for AP2125K-4.2TRE1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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