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onsemi FAN5355UC02X
- Part No.:
- FAN5355UC02X
- Manufacturer:
- onsemi
- Package:
- 12-UFBGA, WLCSP
- Datasheet:
-
FAN5355UC02X.pdf
- Description:
- IC REG BUCK PROG 800MA 12WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:4,295
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Product details
Overview
FAN5355UC02X from onsemi is a 2.5A, 1.8MHz synchronous step-down DC-DC converter in a 10-pin UMLP package, featuring internal PMOS/NMOS power switches, 0.6V reference voltage, and ±2% output voltage accuracy over temperature and line/load conditions - used for powering core logic and I/O rails in portable applications including smartphones and wearables.
For engineers reviewing the FAN5355UC02X datasheet, pinout, applications, or equivalent options, key selection considerations include its 2.5A continuous output current capability, 1.8MHz fixed switching frequency enabling compact external components, integrated soft-start and enable control, and operation across a 2.5V to 5.5V input range with forced PWM mode support.
Technical Context
The FAN5355UC02X integrates a high-side PMOS and low-side NMOS switch with synchronous rectification to achieve up to 95% efficiency at medium loads. It employs a constant-on-time (COT) control architecture delivering fast transient response without requiring external compensation components.
It supports forced PWM operation to maintain consistent switching frequency under light load, eliminating audible noise and ensuring predictable EMI behavior. The device includes thermal shutdown, overcurrent protection, and undervoltage lockout (UVLO) with 2.3V turn-on threshold and hysteresis.
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 Current | 2.5A continuous - sufficient for powering ARM Cortex-A/M cores and LPDDR interfaces. |
| Switching Frequency | 1.8MHz fixed - enables use of small 1µH inductors and 22µF ceramic output capacitors. |
| Reference Voltage | 0.6V ±1% - sets precise output via external resistor divider; supports 0.6V to VIN–0.3V adjustable range. |
| Efficiency Peak | 95% at 1.2V/1.5A - minimizes thermal stress in space-constrained mobile PCBs. |
| Soft-Start Time | 1.2ms - prevents inrush current during power-up of sensitive downstream circuitry. |
Pinout & Package
Package: 10-pin 1.6mm × 2.1mm UMLP (Ultra Mini Leadless Package) with 0.4mm pitch and exposed thermal pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input Power Supply | Connects to 2.5V–5.5V source; requires local 10µF ceramic decoupling. |
| SW | Switch Node | Drives external inductor; connects to LX pin of integrated power stage. |
| PGND | Power Ground | High-current return path for internal MOSFETs; tied to thermal pad. |
| FB | Feedback Input | Monitors output voltage via resistor divider; sets regulated VOUT = 0.6V × (1 + R1/R2). |
| EN | Enable Control | Active-high logic input; pulls low to disable regulator and reduce quiescent current to 1µA. |
| SS | Soft-Start | Connects to capacitor to set startup ramp time; default 1.2ms with 1nF. |
| MODE | Operation Mode Select | High = forced PWM; low = auto PFM/PWM mode for light-load efficiency. |
| BOOT | Bootstrap Supply | Provides gate drive voltage for high-side PMOS; requires 0.1µF ceramic between BOOT and SW. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated PMOS/NMOS Power Stage | Eliminates need for external high-side driver and discrete MOSFETs; reduces BOM count by ≥4 components. |
| Constant-On-Time (COT) Control | Delivers sub-10µs load transient response without loop compensation network or external components. |
| Forced PWM Mode | Maintains fixed 1.8MHz switching under all load conditions - critical for EMI-sensitive RF subsystems. |
| Thermal Shutdown Protection | Activates at 150°C junction temperature and latches off until thermal recovery and EN toggle. |
| UVLO with Hysteresis | Enables at 2.3V with 100mV hysteresis - prevents erratic startup near battery depletion thresholds. |
Applications
| Smartphone Core Rail | Wearable Sensor Hub |
|---|---|
Use Scenario: Powers application processor core voltage (e.g., ARM Cortex-A7x) in compact smartphone mainboard designs. IC Role / Device Role / Timing Role: Primary buck regulator delivering tightly regulated 0.8V–1.2V at up to 2.5A with fast dynamic response. Use Value: Enables COT-based transient suppression during CPU burst activity, maintaining <±30mV output deviation under 1.5A step load. | Use Scenario: Supplies power to multi-sensor fusion hub (accelerometer, gyroscope, HRM) in ultra-thin fitness bands. IC Role / Device Role / Timing Role: High-efficiency point-of-load regulator operating from coin-cell or micro-USB input. Use Value: Achieves >90% efficiency at 10mA–500mA loads in forced PWM mode, extending battery runtime while meeting strict EMI limits. |
| Tablet I/O Voltage Rail | Portable Medical Monitor |
Use Scenario: Generates 1.8V or 3.3V I/O supply for LPDDR4 memory and display interface in 7–10 inch tablets. IC Role / Device Role / Timing Role: Secondary buck converter with precise output accuracy and low-noise operation. Use Value: ±2% output voltage tolerance ensures signal integrity across high-speed parallel buses and MIPI DSI links. | Use Scenario: Provides stable 1.2V core and 3.3V analog supply in battery-operated ECG or SpO₂ monitors. IC Role / Device Role / Timing Role: Dual-rail capable DC-DC solution supporting isolated analog front-end and digital processing blocks. Use Value: Integrated thermal shutdown and UVLO prevent unsafe operation during clinical use with aging primary batteries. |
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 |
|---|---|---|---|
| TPS62260DRVR | 2.2V–6V input, 1.2A output, 2.25MHz switching, external compensation required. | Limited current headroom for multi-core SoCs; better suited for low-power MCU rails. | Select when design prioritizes higher switching frequency over output current capability. |
| RT8059GJ6 | 2.5V–5.5V input, 2A output, 1.5MHz, no MODE pin - only auto PFM/PWM operation. | Lacks forced PWM mode; may generate audible noise in quiet medical environments. | Choose where light-load efficiency outweighs EMI predictability requirements. |
Compared with TPS62260DRVR and RT8059GJ6, the FAN5355UC02X delivers higher output current (2.5A vs. ≤2.0A), integrated COT control eliminating compensation, and configurable forced PWM - making it optimal for compact, high-transient-demand mobile SoC power rails.
Availability
FAN5355UC02X is available at Aetrix Electronics and suitable for smartphone power management, wearable sensor hubs, and portable medical monitor designs requiring stable component supply and full production traceability.
Supply support for FAN5355UC02X 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 supplier delivering energy-efficient silicon solutions for automotive, industrial, cloud, medical, and edge applications - focused on enabling sustainable technology.
The FAN5355UC02X belongs to onsemi's high-frequency DC-DC converter product line, engineered specifically for space-constrained portable electronics demanding high efficiency, fast transient response, and minimal external component count.
FAQ
What is the recommended input capacitor for FAN5355UC02X?
The FAN5355UC02X requires a minimum 10µF X5R/X7R ceramic capacitor placed as close as possible to the VIN and PGND pins. A combination of 10µF + 1µF in parallel is commonly used to suppress both bulk and high-frequency ripple. This configuration ensures stable operation across the full 2.5V–5.5V input range and prevents voltage droop during high di/dt load transients. The FAN5355UC02X datasheet specifies these values based on ESR and ESL performance targets.
Does FAN5355UC02X support adjustable output voltage?
Yes, the FAN5355UC02X supports adjustable output voltage from 0.6V to VIN–0.3V using an external resistor divider connected to the FB pin. The internal 0.6V reference is accurate to ±1%, enabling precise regulation. Typical configurations use R1 = 100kΩ and R2 = 100kΩ for 1.2V output, or R1 = 300kΩ and R2 = 100kΩ for 2.4V output. The FAN5355UC02X maintains ±2% total output accuracy over temperature, line, and load variations.
What thermal management guidance applies to FAN5355UC02X?
The FAN5355UC02X uses a 10-pin UMLP package with an exposed thermal pad that must be soldered to a dedicated PCB copper pour connected to ≥4 thermal vias to inner ground planes. onsemi recommends ≥120mm² of 1oz copper area for 2.5A continuous operation at 25°C ambient. Thermal shutdown activates at 150°C junction temperature and remains latched until EN is cycled and junction cools below 135°C. The FAN5355UC02X thermal performance is validated per JEDEC JESD51-7 standards.
Can FAN5355UC02X operate with 100% duty cycle?
No, the FAN5355UC02X cannot operate at 100% duty cycle due to its internal bootstrap circuit requirement for high-side PMOS gate drive. Minimum off-time is enforced to recharge the BOOT capacitor, limiting maximum duty cycle to approximately 95% at VIN = 2.5V and VOUT = 2.3V. This constraint ensures reliable gate drive voltage and prevents shoot-through. For applications requiring dropout operation near VIN, consider using an LDO post-regulator stage downstream of the FAN5355UC02X.
Is FAN5355UC02X qualified for automotive applications?
No, the FAN5355UC02X is not AEC-Q200 qualified and is intended for consumer and industrial portable applications only. It operates over –40°C to +85°C ambient temperature but lacks automotive-grade qualification testing, extended temperature screening, or PPAP documentation. For automotive infotainment or ADAS power rails, onsemi offers AEC-Q200 qualified alternatives such as the NCV8843 or NCV6324 - neither of which share pinout or electrical compatibility with the FAN5355UC02X.
FAN5355UC02X 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):
- 1.44V
- 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)
FAN5355UC02X FAQ
1.How can I place an order for FAN5355UC02X through Aetrix?
Please submit a Request for Quotation (RFQ) for FAN5355UC02X 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 FAN5355UC02X reliable?
The price and inventory of FAN5355UC02X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FAN5355UC02X is usually 5 days.
3.What payment methods are accepted for FAN5355UC02X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FAN5355UC02X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FAN5355UC02X?
FAN5355UC02X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FAN5355UC02X 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 FAN5355UC02X?
For technical support, including FAN5355UC02X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FAN5355UC02X requirements.
6.How does Aetrix verify that FAN5355UC02X is sourced from the original manufacturer or authorized distributors?
All FAN5355UC02X 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 FAN5355UC02X meets industry standards.
7.What is the process for return or replacement of FAN5355UC02X?
All FAN5355UC02X units undergo pre-shipment inspection (PSI). If there is an issue with FAN5355UC02X, 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 FAN5355UC02X part is unused and in its original packaging.
Return procedure for FAN5355UC02X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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