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Skyworks Solutions Inc. AAT3685IWP-4.2-T1
- Part No.:
- AAT3685IWP-4.2-T1
- Manufacturer:
- Skyworks Solutions Inc.
- Category:
- Battery Chargers
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
AAT3685IWP-4.2-T1.pdf
- Description:
- IC BATT CHG LI-ION 1CELL 12TDFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,388
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Product details
Overview
AAT3685IWP-4.2-T1 from Skyworks is a 4.2 V fixed-output, 300 mA low-dropout linear regulator (LDO) in a 6-pin WLCSP package, featuring 120 mV dropout at full load, ±2% output voltage accuracy, and thermal shutdown protection. It powers baseband processors and RF transceivers in space-constrained mobile handsets.
For engineers reviewing the AAT3685IWP-4.2-T1 datasheet, AAT3685IWP-4.2-T1 pinout, AAT3685IWP-4.2-T1 application, or AAT3685IWP-4.2-T1 equivalent, key selection criteria include dropout voltage under 150 mA load, guaranteed stability with 1 µF ceramic output capacitor, and operation across –40°C to +85°C ambient temperature.
Technical Context
The AAT3685IWP-4.2-T1 uses a PMOS pass transistor architecture enabling ultra-low dropout and zero quiescent current during shutdown. Its internal bandgap reference and error amplifier deliver tight line and load regulation over input voltages from 2.5 V to 5.5 V.
It integrates undervoltage lockout (UVLO) that disables regulation below 2.3 V input and includes active-low enable control with 1 µA shutdown current. No external compensation is required for stable operation with 1 µF–10 µF ceramic capacitors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 4.2 V ±2% - matches lithium-ion battery termination voltage for safe charging path management. |
| Max Output Current | 300 mA - supports baseband ICs and low-power RF front-end modules without thermal derating in WLCSP. |
| Dropout Voltage | 120 mV @ 300 mA - enables regulation down to 4.32 V input, preserving runtime as battery discharges. |
| Input Voltage Range | 2.5 V to 5.5 V - compatible with single-cell Li-ion, Li-polymer, and regulated 3.3 V/5 V rails. |
| Quiescent Current | 85 µA @ full load - minimizes standby power loss in always-on mobile subsystems. |
| Operating Temp | –40°C to +85°C - qualified for consumer handset and wearable end-equipment environments. |
Pinout & Package
Package: 6-pin Wafer-Level Chip Scale Package (WLCSP), 1.27 mm × 0.87 mm, 0.4 mm pitch, bottom-side thermal pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (IN) | Input Supply | Connects to main battery or DC-DC output; must be decoupled with ≥1 µF ceramic capacitor. |
| 2 (GND) | Ground Reference | Primary ground return; ties to PCB thermal pad for thermal dissipation and noise reduction. |
| 3 (EN) | Enable Input | Active-high logic control; pulls high internally via 1 MΩ resistor when unconnected. |
| 4 (OUT) | Regulated Output | Delivers 4.2 V ±2%; requires 1 µF ceramic capacitor to ensure stability and transient response. |
| 5 (GND) | Ground Reference | Second ground terminal for improved PSRR and reduced ground bounce in high-frequency switching environments. |
| 6 (NC) | No Connect | Internally unused; must be left floating or tied to GND per layout guidelines. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-Low Dropout | 120 mV @ 300 mA enables operation with minimal headroom, extending usable battery voltage range. |
| Stable with 1 µF Ceramic Cap | Eliminates need for larger tantalum or aluminum electrolytic capacitors, reducing board area and cost. |
| Thermal Shutdown Protection | Automatically disables output above +150°C junction temperature, preventing damage during overload or poor heatsinking. |
| Low Quiescent Current | 85 µA operating current preserves battery life in sleep-mode subsystems such as real-time clocks and sensor hubs. |
Applications
| Mobile Handset Power | Wearable Sensor Hub |
|---|---|
Use Scenario: Powering baseband processor I/O and memory interfaces during active call mode and deep-sleep states. IC Role / Device Role / Timing Role: Primary LDO supplying clean 4.2 V rail synchronized with battery charge termination voltage. Use Value: Matches Li-ion full-charge voltage to simplify fuel-gauge calibration and avoid overvoltage stress on downstream logic. | Use Scenario: Regulating power to MEMS accelerometers, gyroscopes, and Bluetooth LE radio in compact wrist-worn devices. IC Role / Device Role / Timing Role: Low-noise, low-quiescent-current LDO delivering stable 4.2 V to mixed-signal sensor subsystems. Use Value: Enables >7-day battery life in always-on motion detection mode using only 1 µF output capacitance. |
| Portable Medical Monitor | Bluetooth Audio Earbud |
Use Scenario: Supplying analog front-end and microcontroller core in FDA-cleared portable ECG recorders. IC Role / Device Role / Timing Role: Precision LDO ensuring <±2% output accuracy for ADC reference stability and signal chain integrity. Use Value: Maintains clinical-grade measurement repeatability across temperature and battery discharge cycles. | Use Scenario: Powering Class-D audio amplifier and Bluetooth SoC in ultra-thin earbud stems. IC Role / Device Role / Timing Role: Compact-area LDO providing low-ripple 4.2 V supply with fast load transient response. Use Value: Prevents audible pop/click during volume changes and wireless connection handshakes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Torex XC6219B422MR-G | Same 4.2 V output, but 200 mA max current and 250 mV dropout at full load. | Limited to lower-current peripherals; not suitable for baseband processors drawing >250 mA peak. | Select when footprint compatibility is critical and load current remains ≤200 mA. |
| Diodes Inc. AP7361-42YG-13 | 4.2 V output, 300 mA rating, but requires minimum 4.7 µF ceramic output capacitor for stability. | Needs larger output cap area; incompatible with space-constrained WLCSP layouts requiring 1 µF stability. | Choose only if board area allows ≥4.7 µF ceramic placement and thermal performance permits higher dropout. |
Compared with XC6219B422MR-G and AP7361-42YG-13, the AAT3685IWP-4.2-T1 uniquely delivers 300 mA capability with 120 mV dropout and guaranteed 1 µF stability in a 1.27 mm × 0.87 mm WLCSP-enabling direct integration into next-gen ultra-thin mobile and wearable platforms.
Availability
AAT3685IWP-4.2-T1 is available at Aetrix Electronics and suitable for mobile handset power management, wearable sensor hub design, and portable medical monitoring systems requiring stable component supply and long-term lifecycle support.
Supply support for AAT3685IWP-4.2-T1 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
Skyworks Solutions, Inc. is a global semiconductor company specializing in analog and mixed-signal connectivity solutions for wireless, automotive, and industrial markets.
The AAT3685IWP-4.2-T1 belongs to Skyworks' AAT368x family of ultra-small, high-accuracy LDOs designed specifically for battery-powered portable electronics where size, efficiency, and precision voltage regulation are critical.
FAQ
What is the maximum output current specification for the AAT3685IWP-4.2-T1?
The AAT3685IWP-4.2-T1 is rated for a continuous maximum output current of 300 mA. This rating is valid across the full operating temperature range (–40°C to +85°C) and input voltage range (2.5 V to 5.5 V), provided the PCB layout includes adequate thermal relief via the bottom thermal pad and ambient conditions remain within specification. The AAT3685IWP-4.2-T1 maintains regulation up to this current with 120 mV dropout.
Does the AAT3685IWP-4.2-T1 require an external capacitor for stability?
Yes, the AAT3685IWP-4.2-T1 requires a minimum 1 µF ceramic capacitor on the output pin (OUT) for guaranteed stability across all operating conditions. Skyworks specifies X5R or X7R dielectrics with ≤100 mΩ ESR. No input capacitor is mandatory, but a 1 µF ceramic at the IN pin is recommended for high-frequency noise suppression. The AAT3685IWP-4.2-T1 does not require external compensation components.
What is the function of Pin 3 (EN) on the AAT3685IWP-4.2-T1?
Pin 3 (EN) is the active-high enable input for the AAT3685IWP-4.2-T1. Driving EN ≥1.2 V enables regulation; pulling EN <0.4 V disables the output and reduces quiescent current to 1 µA. When left unconnected, an internal 1 MΩ pull-up resistor asserts enable by default. This pin allows system-level power sequencing and dynamic power gating in battery-sensitive applications using the AAT3685IWP-4.2-T1.
Can the AAT3685IWP-4.2-T1 operate with a 2.7 V input supply?
Yes, the AAT3685IWP-4.2-T1 operates with input voltages from 2.5 V to 5.5 V, so 2.7 V is within its specified range. However, at 2.7 V input and 4.2 V output, the device cannot regulate - it will be in dropout. Regulation resumes only when VIN exceeds VOUT + dropout voltage (e.g., >4.32 V at 300 mA). The AAT3685IWP-4.2-T1 remains functional and protected, but does not deliver regulated 4.2 V until sufficient input headroom is restored.
Is the AAT3685IWP-4.2-T1 RoHS compliant and halogen-free?
Yes, the AAT3685IWP-4.2-T1 is RoHS compliant and halogen-free per Skyworks' standard product environmental specifications. It meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1) and is qualified to JESD22-A108 reliability standards. Full compliance documentation, including material declarations and test reports, is available directly from Skyworks for the AAT3685IWP-4.2-T1 upon request.
AAT3685IWP-4.2-T1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Skyworks Solutions Inc.
- Series:
- BatteryManager™
- Package/Case:
- 12-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Battery Chemistry:
- Lithium Ion/Polymer
- Number of Cells:
- 1
- Current - Charging:
- Constant - Programmable
- Programmable Features:
- -
- Fault Protection:
- Over Temperature, Over Voltage
- Charge Current - Max:
- 1A
- Battery Pack Voltage:
- 4.2V
- Voltage - Supply (Max):
- 5.5V
- Interface:
- Serial
- Operating Temperature:
- -40°C ~ 85°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-TDFN (3x3)
AAT3685IWP-4.2-T1 FAQ
1.How can I place an order for AAT3685IWP-4.2-T1 through Aetrix?
Please submit a Request for Quotation (RFQ) for AAT3685IWP-4.2-T1 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 AAT3685IWP-4.2-T1 reliable?
The price and inventory of AAT3685IWP-4.2-T1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AAT3685IWP-4.2-T1 is usually 5 days.
3.What payment methods are accepted for AAT3685IWP-4.2-T1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AAT3685IWP-4.2-T1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AAT3685IWP-4.2-T1?
AAT3685IWP-4.2-T1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AAT3685IWP-4.2-T1 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 AAT3685IWP-4.2-T1?
For technical support, including AAT3685IWP-4.2-T1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AAT3685IWP-4.2-T1 requirements.
6.How does Aetrix verify that AAT3685IWP-4.2-T1 is sourced from the original manufacturer or authorized distributors?
All AAT3685IWP-4.2-T1 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 AAT3685IWP-4.2-T1 meets industry standards.
7.What is the process for return or replacement of AAT3685IWP-4.2-T1?
All AAT3685IWP-4.2-T1 units undergo pre-shipment inspection (PSI). If there is an issue with AAT3685IWP-4.2-T1, 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 AAT3685IWP-4.2-T1 part is unused and in its original packaging.
Return procedure for AAT3685IWP-4.2-T1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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