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onsemi FAN48685UC08X
- Part No.:
- FAN48685UC08X
- Manufacturer:
- onsemi
- Package:
- 9-UFBGA, WLCSP
- Datasheet:
-
FAN48685UC08X.pdf
- Description:
- IC REG BOOST PROG 800MA 9WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:3,081
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Product details
Overview
FAN48685UC08X from onsemi is a fixed-output synchronous TinyBoost regulator designed to generate stable 3.6 V, 5.0 V, or 5.45 V from single-cell Li-ion batteries (2.5–5.5 V input), delivering up to 800 mA output current with forced pass-through mode support and 2.5 MHz switching frequency. It targets NFC module power rails where EMI-sensitive operation near 13.56 MHz requires precise frequency placement and low output ripple.
For engineers reviewing the FAN48685UC08X datasheet, pinout, applications, or equivalent options, key selection criteria include output voltage programmability via MODE pins, WLCSP-9 package thermal performance, pass-through transition behavior under line/load transients, and compatibility with minimal external components (0603 inductor + two 0402 capacitors).
Technical Context
The FAN48685UC08X implements a peak-current-mode PWM controller with automatic transition between boost and 100% duty-cycle pass-through modes when PVIN approaches VOUT within ~150 mV. Its MODE[1:0] pins configure three regulated outputs (3.6 V, 5.0 V, 5.45 V) or force immediate pass-through (MODE = 00).
It integrates synchronous power MOSFETs, features 90 mA linear-mode soft-start current limiting, UVLO thresholds of 2.15 V (rising) and 2.05 V (falling), and includes short-circuit protection during automatic pass-through mode triggered by >300 mV PVIN–VOUT differential sustained for 10 µs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5 V to 5.5 V - supports full discharge curve of Li-ion cells down to 2.5 V while maintaining regulation. |
| Output Voltage Options | 3.6 V / 5.0 V / 5.45 V - selected by MODE[1:0]; enables single BOM for multiple system rail requirements. |
| Max Output Current | 800 mA - delivered with <93% efficiency at 5.45 V/500 mA, enabling compact NFC power delivery without external LDO post-regulation. |
| Switching Frequency | 2.5 MHz typical - placed away from NFC subcarrier (13.56 MHz ± 200 kHz) to avoid interference; reduces required inductor size. |
| Package | WLCSP-9, 0.4 mm pitch, 1.22 × 1.22 × 0.38 mm - ultra-small footprint ideal for space-constrained NFC modules and wearables. |
| Quiescent Current (Pass-Through) | 3–10 µA - enables ultra-low standby power in battery-backed NFC readers during idle periods. |
| Output Ripple | 15–30 mV peak-to-peak - measured at 5.45 V/550 mA, meeting tight noise budgets for analog RF front-ends. |
Pinout & Package
Package: Wafer-Level Chip-Scale Package (WLCSP), 9-bump, 0.4 mm pitch, 1.22 mm × 1.22 mm × 0.38 mm body height (Case 567QW). Thermal resistance θJA = 50°C/W on 4-layer JEDEC-compliant board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1, A2 | VOUT | Dual parallel output pads reduce IR drop and improve current sharing; connect directly to both COUT terminals. |
| A3 | PVIN | Main input power terminal; connects to battery anode and CIN - shortest possible trace required for stability. |
| B1, B2 | SW | Switching node shared across internal high-side and synchronous rectifier FETs; drives external 470 nH inductor. |
| B3, C3 | MODE 0 / MODE 1 | Digital configuration inputs with internal 300 kΩ pull-downs; logic levels define output voltage or force pass-through mode. |
| C1, C2 | PGND | Power ground return for both input and output capacitors; must be tied with minimum inductance to minimize switching noise coupling. |
Key Features
| Feature | Design Value |
|---|---|
| Forced Pass-Through Mode | Enables direct PVIN-to-VOUT conduction (MODE = 00), eliminating switching loss and EMI when input voltage exceeds target output - critical for NFC burst-mode efficiency. |
| Three-Point Output Programmability | Single device supports 3.6 V (NFC analog supply), 5.0 V (legacy interface), and 5.45 V (optimized for 5 V USB charging compliance) without hardware change. |
| Ultra-Low External Component Count | Only four passive components required: one 0603 inductor, one 0402 input cap, two 0402 output caps - reduces BOM cost and PCB area in miniaturized modules. |
| Integrated Short-Circuit Protection | Auto-shutdown if PVIN–VOUT > 300 mV for 10 µs during pass-through mode - protects IC and external circuitry during load faults or hot-plug events. |
| Thermal Shutdown with Hysteresis | Disables switching at 150°C junction temperature with 15°C hysteresis - prevents thermal runaway in sealed NFC enclosures with limited airflow. |
Applications
| NFC Reader Power Supply | Wearable Biometric Sensor Hub |
|---|---|
Use Scenario: Powers ISO/IEC 14443-A/B RF front-end and secure element in contactless payment wristbands. IC Role / Device Role / Timing Role: Primary boost regulator providing clean, low-noise 3.6 V rail synchronized to NFC field activation timing. Use Value: 2.5 MHz switching avoids 13.56 MHz interference; <30 mV ripple ensures stable RF amplifier bias; forced pass-through extends battery life during idle polling. |
Use Scenario: Supplies 5.0 V to optical heart-rate sensor and BLE SoC in ultra-thin fitness trackers. IC Role / Device Role / Timing Role: System power manager delivering regulated rail from coin-cell or micro-LiPo battery with dynamic voltage scaling. Use Value: MODE-selectable outputs allow firmware-driven rail optimization; 800 mA capability supports simultaneous LED flash and sensor burst acquisition. |
| Smart Card Emulation Module | Industrial RFID Tag Programmer |
Use Scenario: Enables host device to emulate MIFARE DESFire or NTAG in mobile accessories using embedded secure element. IC Role / Device Role / Timing Role: Fast-transient boost converter supporting rapid VOUT transitions between 3.6 V (secure element) and 5.45 V (interface buffer) during protocol handshakes. Use Value: <200 µs VOUT settling time (95%) from pass-through to boost mode ensures compliant NFC-A frame timing; dual VOUT pads lower impedance for pulsed current demands. |
Use Scenario: Powers programmable RFID tag writer in handheld industrial tools operating from 3.7 V Li-ion packs. IC Role / Device Role / Timing Role: High-efficiency DC-DC stage enabling 5.45 V programming voltage generation with minimal heat dissipation in confined tool housings. Use Value: 93% efficiency at 500 mA reduces thermal load; WLCSP-9 package allows placement adjacent to antenna coil without compromising RF performance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61291DRVR | Fixed 5.0 V output only; no MODE-pin programmability; 1.2 MHz switching; higher IQ (1.2 µA vs. 3 µA in pass-through) | Lacks multi-voltage flexibility and NFC-optimized frequency placement; better suited for general-purpose 5 V boost where EMI is less critical | Select when only 5.0 V is needed and layout space permits larger 2 mm × 2 mm DSBGA package |
| MAX17222ETA+T | Adjustable output (0.6–5.25 V) via feedback resistor; 2.5 MHz switching; 500 mA max output; no forced pass-through mode | Requires external resistors for voltage setting; cannot achieve zero-loss conduction path; less suitable for NFC burst efficiency | Choose when fine-grained output tuning is required and pass-through operation is unnecessary |
Compared with TPS61291DRVR and MAX17222ETA+T, the FAN48685UC08X uniquely combines triple-output programmability, forced pass-through mode, and NFC-optimized 2.5 MHz switching in a 1.22 mm² WLCSP - making it the only option that simultaneously satisfies strict EMI, efficiency, and footprint requirements in next-generation contactless modules.
Availability
FAN48685UC08X is available at Aetrix Electronics and suitable for NFC reader power supplies, wearable biometric sensor hubs, smart card emulation modules, and industrial RFID tag programmers requiring stable component supply with guaranteed long-term manufacturability.
Supply support for FAN48685UC08X 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient innovation for automotive, industrial, cloud, medical, and IoT applications.
The FAN48685UC08X belongs to onsemi's TinyBoost family of ultra-compact, low-noise boost regulators engineered specifically for EMI-sensitive, space-constrained portable electronics - especially NFC, wearables, and secure authentication systems.
FAQ
What output voltages does the FAN48685UC08X support, and how are they selected?
The FAN48685UC08X supports three regulated output voltages: 3.6 V, 5.0 V, and 5.45 V. These are selected using the MODE[1:0] pins per Table 8 in the datasheet: MODE[1:0] = 10 sets 3.6 V, 01 sets 5.0 V, and 11 sets 5.45 V. Setting MODE[1:0] = 00 forces immediate pass-through mode (VOUT ≈ PVIN). All configurations are verified across −40°C to +85°C ambient.
Does the FAN48685UC08X require external compensation components?
No, the FAN48685UC08X is internally compensated and requires no external compensation network. Stability is ensured with the recommended external components: a 470 nH 0603 inductor and two 22 µF 0402 output capacitors. The minimum effective output capacitance is 5 µF (voltage-derated), validated for all three output voltages and load conditions up to 800 mA.
How does the FAN48685UC08X behave during input voltage droop, such as near end-of-life battery discharge?
When PVIN drops below the regulated VOUT minus ~200 mV, the FAN48685UC08X automatically transitions into automatic pass-through mode to maintain regulation - provided PVIN remains above the 2.05 V UVLO falling threshold. Under deep discharge (PVIN < 2.5 V), it sustains 800 mA load at VOUT = 3.6 V until UVLO triggers shutdown, ensuring maximum usable battery capacity.
What is the thermal performance of the FAN48685UC08X in its WLCSP-9 package?
The FAN48685UC08X has a typical junction-to-ambient thermal resistance (θJA) of 50°C/W when mounted on a 4-layer JEDEC-standard board with thermal vias. At 800 mA output and 5.45 V, power dissipation remains below 300 mW under typical conditions, keeping junction temperature well within the 125°C max operating limit - even in sealed NFC module enclosures without forced airflow.
Can the FAN48685UC08X be used without a load during startup?
Yes, the FAN48685UC08X is designed to start up with no load. Its linear-mode soft-start limits inrush current to 90 mA (typical), preventing brown-out in low-capacity batteries. Startup time to full VOUT is ≤2 ms under no-load conditions, and fault timeout (1.5 ms to reach PVIN) applies only if regulation fails - confirmed across all MODE configurations and temperature ranges.
FAN48685UC08X Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- TinyBoost®
- Package/Case:
- 9-UFBGA, WLCSP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Programmable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 3.6V, 5V, 5.45V
- Voltage - Output (Max):
- -
- Current - Output:
- 800mA
- Frequency - Switching:
- 2.5MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 9-WLCSP (1.22x1.22)
FAN48685UC08X FAQ
1.How can I place an order for FAN48685UC08X through Aetrix?
Please submit a Request for Quotation (RFQ) for FAN48685UC08X 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 FAN48685UC08X reliable?
The price and inventory of FAN48685UC08X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FAN48685UC08X is usually 5 days.
3.What payment methods are accepted for FAN48685UC08X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FAN48685UC08X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FAN48685UC08X?
FAN48685UC08X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FAN48685UC08X 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 FAN48685UC08X?
For technical support, including FAN48685UC08X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FAN48685UC08X requirements.
6.How does Aetrix verify that FAN48685UC08X is sourced from the original manufacturer or authorized distributors?
All FAN48685UC08X 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 FAN48685UC08X meets industry standards.
7.What is the process for return or replacement of FAN48685UC08X?
All FAN48685UC08X units undergo pre-shipment inspection (PSI). If there is an issue with FAN48685UC08X, 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 FAN48685UC08X part is unused and in its original packaging.
Return procedure for FAN48685UC08X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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