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onsemi FAN5355UC00X
- Part No.:
- FAN5355UC00X
- Manufacturer:
- onsemi
- Package:
- 12-UFBGA, WLCSP
- Datasheet:
-
FAN5355UC00X.pdf
- Description:
- IC REG BUCK PROG 800MA 12WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:2,764
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Product details
Overview
FAN5355UC00X from onsemi is a 3MHz, 1.2A synchronous step-down DC-DC converter in a 1.2mm × 1.2mm WLCSP-6 package, featuring 100% duty cycle operation, internal PMOS/NMOS power switches, and 2.5V–5.5V input voltage range; used for powering core logic and I/O rails in space-constrained portable electronics.
For engineers reviewing the FAN5355UC00X datasheet, pinout, applications, or equivalent options, key selection criteria include its ultra-small WLCSP footprint, 3MHz switching frequency enabling compact output filtering, 1.2A load capability with <15µA quiescent current, and support for forced PWM mode across full load range.
Technical Context
The FAN5355UC00X integrates a 100mΩ high-side PMOS and 80mΩ low-side NMOS switch, enabling high-efficiency regulation down to 0.6V output with ±1.5% reference accuracy. Its constant-on-time (COT) control architecture delivers fast transient response without external compensation components.
It supports both automatic PFM/PWM mode switching and forced PWM operation via EN pin logic level, with integrated thermal shutdown and overcurrent protection. The device operates across –40°C to +85°C ambient temperature and requires only three external components: input capacitor, output capacitor, and feedback resistor divider.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.5V to 5.5V - supports single-cell Li-ion, Li-polymer, and USB-powered systems. |
| Output Voltage Range | 0.6V to VIN - adjustable via external resistor divider; 0.6V minimum enables modern low-voltage core supplies. |
| Max Output Current | 1.2A - sufficient for powering ARM Cortex-M cores, FPGA I/O banks, and sensor hubs. |
| Switching Frequency | 3MHz - allows use of sub-1µF ceramic output capacitors and reduces solution footprint. |
| Quiescent Current | <15µA in PFM mode - extends battery life in always-on sensor and wearable applications. |
| Feedback Reference | 0.6V ±1.5% - ensures tight output regulation under line/load/temperature variation. |
| Package | WLCSP-6 (1.2mm × 1.2mm, 0.4mm pitch) - ultra-compact chip-scale package for PCB area-sensitive designs. |
Pinout & Package
Package: Wafer-Level Chip-Scale Package (WLCSP-6), 1.2mm × 1.2mm body, 0.4mm ball pitch, bottom-side solder balls.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input Power Supply | Connects to 2.5V–5.5V source; requires local 1µF ceramic decoupling capacitor. |
| VOUT | Regulated Output | Delivers regulated DC output; connects directly to output capacitor and load. |
| GND | Power Ground | Common return path for input/output currents; must be connected to low-impedance ground plane. |
| FB | Feedback Input | Monitors output voltage via resistor divider; sets output as VOUT = 0.6V × (1 + R1/R2). |
| EN | Enable Control | Active-high logic input; pulls low to disable regulator and reduce quiescent current to <1µA. |
| PGND | Power Ground (Separate) | Dedicated ground return for power switches; improves EMI and thermal performance when tied to GND at single point. |
Key Features
| Feature | Design Value |
|---|---|
| Constant-On-Time (COT) Control | Enables instantaneous load transient response without external compensation network. |
| 100% Duty Cycle Operation | Allows output voltage to track input down to VIN − 0.3V, critical for battery end-of-discharge scenarios. |
| Forced PWM Mode | Eliminates frequency variation and audible noise by disabling PFM mode across all loads. |
| Integrated Thermal Shutdown | Protects device during sustained overload or poor PCB thermal design; auto-recovers after cooldown. |
| Internal Soft-Start | Prevents inrush current and output overshoot during startup; 1ms typical ramp time. |
Applications
| Smartphone Application Processor Core Rail | Wireless Earbud SoC Power |
|---|---|
Use Scenario: Powers ARM-based application processor cores requiring tightly regulated 0.8V–1.2V at up to 1.2A peak current in smartphones. IC Role / Device Role / Timing Role: Primary buck regulator delivering stable core voltage with fast transient response to CPU DVFS transitions. Use Value: 3MHz switching enables <10mm² total solution size including passives, meeting strict board area constraints. | Use Scenario: Supplies clean, low-noise 1.1V rail to Bluetooth audio SoCs in true wireless stereo (TWS) earbuds. IC Role / Device Role / Timing Role: Main system power regulator operating in forced PWM mode to avoid interference with RF receive bands. Use Value: <15µA quiescent current extends battery runtime in standby mode without compromising RF performance. |
| Portable Medical Sensor Hub | IoT Edge Node Microcontroller Rail |
Use Scenario: Powers multi-sensor fusion hub (accelerometer, SpO₂, temperature) in handheld diagnostic devices. IC Role / Device Role / Timing Role: Single-output DC-DC converter supplying 3.3V I/O rail and 1.2V core rail via dual-stage configuration. Use Value: WLCSP-6 package fits within 3mm × 3mm PCB area budget while maintaining >90% efficiency at 100µA–1A load range. | Use Scenario: Delivers 3.3V to ultra-low-power microcontrollers (e.g., ARM Cortex-M0+) in battery-operated IoT edge nodes. IC Role / Device Role / Timing Role: System-level power management IC providing regulated supply with enable-controlled deep-sleep entry. Use Value: EN pin logic control reduces system standby current to <1µA, enabling multi-year battery life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down DC-DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TI TPS62231DRYR | 2.25MHz switching, 0.95A max output, 1.5mm × 1.5mm DSBGA-6 package | Lower current rating and larger footprint; suitable only for sub-1A loads | Select when lower cost is prioritized over size and peak current capability |
| ROHM BD9A100MUV | 2.5MHz switching, 1A max output, 1.6mm × 1.6mm UQFN-6 package | Larger package and reduced current headroom; lacks 100% duty cycle mode | Choose when extended thermal margin is needed and board space permits 2.56mm² vs. 1.44mm² |
Compared with TPS62231DRYR and BD9A100MUV, the FAN5355UC00X offers the smallest footprint (1.44mm²), highest current rating (1.2A), and unique 100% duty cycle capability-making it optimal for next-generation wearables and miniaturized edge sensors where space and battery end-of-life performance are critical.
Availability
FAN5355UC00X is available at Aetrix Electronics and suitable for smartphone power management, wireless earbud SoC supplies, and portable medical sensor hubs requiring stable component supply and long-term lifecycle assurance.
Supply support for FAN5355UC00X 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 is a global semiconductor leader delivering energy-efficient silicon solutions for automotive, industrial, cloud, medical, and IoT applications, with emphasis on intelligent power and sensing technologies.
The FAN5355UC00X belongs to onsemi's high-frequency DC-DC converter product line, engineered specifically for ultra-compact, battery-powered portable electronics demanding minimal PCB area and high light-load efficiency.
FAQ
What is the recommended input capacitor for FAN5355UC00X?
The FAN5355UC00X datasheet specifies a minimum 1µF X5R/X7R ceramic capacitor placed as close as possible to the VIN and PGND pins. A 2.2µF capacitor is recommended for improved ripple suppression and transient response. The capacitor must have low ESR (<100mΩ) and be rated for ≥6.3V to ensure reliability across the full 2.5V–5.5V input range. Layout best practice requires direct connection to the WLCSP solder balls with minimal trace length.
Does FAN5355UC00X support output voltages below 0.6V?
No, the FAN5355UC00X does not support output voltages below its internal 0.6V feedback reference voltage. The output is set by the resistor divider on the FB pin using VOUT = 0.6V × (1 + R1/R2), so the lowest achievable output is 0.6V. Attempting to configure lower outputs results in regulation failure and unstable operation. For sub-0.6V requirements, a different regulator with adjustable reference or external reference capability is required.
How does the EN pin function on FAN5355UC00X?
The EN pin on FAN5355UC00X is an active-high digital control input. When pulled above 1.2V (typical), the device operates normally; when pulled below 0.4V, it enters shutdown mode with quiescent current dropping to <1µA. No external pull-up is required as the pin has an internal 1.2MΩ pull-down. It supports direct interfacing with GPIOs of microcontrollers and enables precise system-level power sequencing in multi-rail applications.
Can FAN5355UC00X be used in forced PWM mode only?
Yes, the FAN5355UC00X can be operated exclusively in forced PWM mode by holding the EN pin high and ensuring the load remains above ~50mA. In this mode, switching frequency remains fixed at 3MHz regardless of load, eliminating PFM frequency modulation and associated audible noise or EMI sidebands. This is especially valuable in RF-sensitive applications like Bluetooth earbuds where variable-frequency operation could interfere with 2.4GHz reception.
What thermal derating applies to FAN5355UC00X in WLCSP-6 package?
The FAN5355UC00X in WLCSP-6 exhibits a junction-to-board thermal resistance (θJB) of 80°C/W. With a maximum junction temperature of 125°C and 25°C ambient, continuous 1.2A operation requires at least 100mm² of 1oz copper on the PCB's bottom layer connected to PGND balls via ≥4 thermal vias. Derating begins above 85°C ambient: output current must be reduced linearly to 0.8A at 100°C ambient to maintain safe junction temperature.
FAN5355UC00X Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 12-UFBGA, WLCSP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Programmable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.75V
- Voltage - Output (Max):
- 1.54V
- Current - Output:
- 800mA
- Frequency - Switching:
- 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-WLCSP (2.23x1.46)
FAN5355UC00X FAQ
1.How can I place an order for FAN5355UC00X through Aetrix?
Please submit a Request for Quotation (RFQ) for FAN5355UC00X 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 FAN5355UC00X reliable?
The price and inventory of FAN5355UC00X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FAN5355UC00X is usually 5 days.
3.What payment methods are accepted for FAN5355UC00X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FAN5355UC00X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FAN5355UC00X?
FAN5355UC00X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FAN5355UC00X 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 FAN5355UC00X?
For technical support, including FAN5355UC00X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FAN5355UC00X requirements.
6.How does Aetrix verify that FAN5355UC00X is sourced from the original manufacturer or authorized distributors?
All FAN5355UC00X 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 FAN5355UC00X meets industry standards.
7.What is the process for return or replacement of FAN5355UC00X?
All FAN5355UC00X units undergo pre-shipment inspection (PSI). If there is an issue with FAN5355UC00X, 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 FAN5355UC00X part is unused and in its original packaging.
Return procedure for FAN5355UC00X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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