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onsemi FAN53555UC24X
- Part No.:
- FAN53555UC24X
- Manufacturer:
- onsemi
- Package:
- 20-UFBGA, WLCSP
- Datasheet:
-
FAN53555UC24X.pdf
- Description:
- IC REG BUCK PROG 4A 20WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:4,717
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Product details
Overview
FAN53555UC24X from onsemi is a digitally programmable 4 A synchronous step-down DC-DC regulator with I²C interface, 2.4 MHz fixed switching frequency, and 0.603–1.420 V output voltage range in 12.967 mV steps-designed for core power delivery in Li-ion-powered handheld devices including smartphones and tablets.
For engineers reviewing the FAN53555UC24X datasheet, pinout, applications, or equivalent options, key selection criteria include its 4 A RMS current rating (vs. 5 A in other variants), register-reset-on-EN behavior, WLCSP-20 package footprint, and support for dynamic voltage scaling with programmable slew rate control.
Technical Context
The FAN53555UC24X employs a proprietary non-linear fixed-frequency PWM modulator with synchronous rectification to deliver fast load transient response while maintaining stable 2.4 MHz operation across input voltages (2.5–5.5 V) and load currents (0–4 A). Its architecture eliminates ESR dependency, enabling use of low-ESR ceramic capacitors.
It operates in auto PFM/PWM mode-switching to pulse-frequency modulation below ~100 mA for quiescent current as low as 60 µA-while supporting forced PWM via I²C register control. The device integrates input UVLO (2.45 V threshold), thermal shutdown (150 °C), and input OVP (6.15 V rising).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 4 A RMS maximum - defines PCB copper area, thermal pad design, and inductor selection (e.g., 470 nH preferred per Table 5) |
| Switching Frequency | 2.4 MHz nominal - enables compact 0603/0402 external components (330–470 nH inductor, 22 µF ×2 X5R 0603 output caps) |
| Input Voltage Range | 2.5 V to 5.5 V - supports single-cell Li-ion (3.0–4.2 V) and USB-powered systems without pre-regulation |
| I²C Interface Speed | Up to 3.4 Mbps (High-Speed Mode) - enables rapid DVS transitions during processor DVFS events |
| Output Voltage Range | 0.603 V to 1.420 V in 12.967 mV steps - matches ARM Cortex-A series core voltage requirements with <±2.0% DC accuracy |
| Quiescent Current | 60 µA typical in PFM mode - extends battery runtime in standby without sacrificing transient response |
| Package | 20-bump WLCSP, 1.6 mm × 2.0 mm - ultra-compact footprint for space-constrained mobile applications |
Pinout & Package
Package: 20-bump Wafer-Level Chip Scale Package (WLCSP), 1.6 mm × 2.0 mm, 0.4 mm pitch, bottom-side solder bumps.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1 | VSEL | Voltage select input: LOW selects VSEL0 register value; HIGH selects VSEL1 - enables dual-voltage configuration without I²C writes |
| A2 | EN | Hardware enable: LOW forces shutdown (<0.5 µA); HIGH enables regulation - resets all registers to defaults on rising edge for FAN53555UC24X |
| A3 | SCL | I²C clock input - supports High-Speed Mode (3.4 Mbps) with ≤400 pF bus capacitance |
| A4 | VOUT | Output voltage sense node - must connect directly to COUT anode with minimal trace length to ensure regulation accuracy |
| B1 | SDA | I²C data bidirectional line - requires pull-up resistor; supports standard/fast/fast-plus/high-speed modes |
| B2–B3, C1–C4 | GND | Power ground return for low-side MOSFET and input/output capacitors - critical for EMI control and current-loop minimization |
| B4 | AGND | Analog ground reference for internal circuitry - must be isolated from high-dV/dt digital paths to avoid noise coupling |
| D1–D2, E1–E2 | VIN | Main input power supply (2.5–5.5 V) - connects to CIN with shortest possible path to minimize input ripple and EMI |
| D3–D4, E3–E4 | SW | Switching node - connects to inductor; high di/dt path requiring tight layout and thermal relief for 4 A peak currents |
Key Features
| Feature | Design Value |
|---|---|
| Digitally programmable output voltage | Configurable via I²C (0.603–1.420 V in 12.967 mV steps) or hardware VSEL pin - enables dynamic voltage scaling for ARM-based SoCs |
| Programmable slew rate | Eight selectable rates (0.5–64 mV/µs) via CONTROL register - prevents overshoot/undershoot during DVS transitions under varying load conditions |
| Auto PFM/PWM mode | Seamless transition between 60 µA quiescent current (PFM) and 2.4 MHz fixed-frequency operation (PWM) - maintains efficiency from 10 mA to 4 A |
| Internal soft-start | Ramped reference startup with synchronous rectification inhibited - allows safe start into pre-biased outputs up to 1.42 V |
| Input UVLO & OVP protection | UVLO at 2.45 V (350 mV hysteresis); OVP shutdown at 6.15 V - safeguards against brown-out and accidental 5 V/USB overvoltage |
| Thermal shutdown | Activates at 150 °C with 17 °C hysteresis - protects die during sustained 4 A loads in compact WLCSP layout |
Applications
| Smartphone Core Power | Tablet GPU Voltage Scaling |
|---|---|
|
Use Scenario: Powers ARM Cortex-A7/A53/A72 CPU cores in battery-operated smartphones with aggressive DVFS policies. IC Role / Device Role / Timing Role: Primary core voltage regulator delivering dynamically adjusted 0.6–1.4 V at up to 4 A with sub-100 ns load transient response. Use Value: Enables >20% battery life extension via PFM-mode 60 µA IQ and reduces board area by 30% vs. discrete buck solutions using 0603 passives. |
Use Scenario: Supplies graphics processing unit (GPU) voltage rails in Android tablets requiring rapid voltage changes during gaming workloads. IC Role / Device Role / Timing Role: Digitally controlled buck converter with programmable slew rate for glitch-free GPU voltage transitions. Use Value: Eliminates need for external DAC + LDO by providing 12.967 mV DVS steps and 0.5–64 mV/µs slew control - cuts BOM cost by $0.18/unit. |
| Ultra-Mobile PC SoC Rail | Li-ion-Powered Gaming Handheld |
|
Use Scenario: Delivers core voltage to Intel Atom or Qualcomm Snapdragon SoCs in fanless ultra-mobile PCs with thermal constraints. IC Role / Device Role / Timing Role: High-efficiency 2.4 MHz buck regulator with thermal shutdown (150 °C) and UVLO for reliable operation under variable ambient conditions. Use Value: Maintains >82% efficiency at 1.2 V/2 A (VIN = 3.6 V), reducing thermal dissipation by 1.2 W vs. legacy 1 MHz converters. |
Use Scenario: Powers application processor and display controller in portable gaming devices with single-cell Li-ion battery input. IC Role / Device Role / Timing Role: Compact WLCSP-20 DC-DC regulator supporting 2.5–5.5 V input and 0.6–1.42 V output with integrated soft-start. Use Value: 1.6 × 2.0 mm footprint enables placement directly under SoC BGA - reduces interconnect inductance and improves PSRR above 100 kHz. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar digitally programmable buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62864DRLR | 3 A max output, 2.5–5.5 V input, I²C interface, 0.4–1.95 V output in 10 mV steps, 2.0 mm × 1.5 mm DSBGA | Lower current rating; lacks programmable slew rate and PFM/PWM auto-transition logic | Choose for lower-cost designs where 3 A suffices and DVS timing control is not required |
| RTQ2132BGQW | 4 A max, 2.7–5.5 V input, I²C interface, 0.5–1.52 V output in 10 mV steps, 1.6 × 2.1 mm WLCSP, 2.2 MHz switching | No register reset-on-EN; fixed 10 mV DVS step (vs. 12.967 mV); no PFM disable option | Prefer when consistent 10 mV granularity and absence of EN-triggered register reset are acceptable |
Compared with TPS62864DRLR and RTQ2132BGQW, the FAN53555UC24X uniquely combines 4 A capability with register-reset-on-EN behavior, 12.967 mV DVS resolution matching specific SoC VDD requirements, and programmable slew rate - making it optimal for smartphone/tablet platforms requiring precise, repeatable boot-time voltage configuration.
Availability
FAN53555UC24X is available at Aetrix Electronics and suitable for smartphone core power, tablet GPU voltage scaling, and ultra-mobile PC SoC rail applications requiring stable component supply, full lifecycle support, and traceable sourcing.
Supply support for FAN53555UC24X 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 (Nasdaq: ON) is a global semiconductor leader delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The FAN53555UC24X belongs to onsemi's TinyBuck® family of ultra-compact, high-current DC-DC regulators designed specifically for space- and power-constrained mobile processors and SoCs.
FAQ
What is the maximum continuous output current rating for the FAN53555UC24X?
The FAN53555UC24X is rated for 4 A RMS continuous output current, as confirmed in Table 4 ("FAN53555−24, −08, and −09 REDUCED OUTPUT CURRENT") and Table 8 ("RECOMMENDED OPERATING CONDITIONS"). This is lower than the 5 A rating of base FAN53555 variants due to optimized thermal performance in its compact WLCSP-20 package. Exceeding 4 A may trigger current limit or thermal shutdown.
Does the FAN53555UC24X reset its I²C registers when the EN pin is toggled?
Yes - the FAN53555UC24X resets all I²C registers to default values when the EN pin is pulled LOW, as explicitly stated in Table 1 ("Ordering Information") and the "Enable and Soft-Start" section: "The 04, 24, and 042 options reset all registers to default values when EN pin is LOW." This behavior distinguishes it from variants like FAN53555UC05X, which retain register values during shutdown.
What output voltage range and step size does the FAN53555UC24X support?
The FAN53555UC24X supports an output voltage range of 0.603 V to 1.420 V in 12.967 mV increments, as defined in Table 1 and Equation 6 ("VOUT = 0.603 V + NSELx × 12.967 mV"). This step size is implemented via its 6-bit DAC and matches voltage requirements of modern ARM-based application processors requiring fine-grained dynamic voltage scaling.
Can the FAN53555UC24X operate with a 330 nH inductor, or is 470 nH required?
The FAN53555UC24X supports both 330 nH and 470 nH inductors. Table 5 lists "470 or 330 nH, 2016 case size" for −08/−09/−24 variants, and Figure 17/18 show stable operation across load and input conditions with either value. However, 470 nH is preferred for reduced peak current and improved light-load efficiency in lower-current mobile applications.
What is the purpose of the AGND pin on the FAN53555UC24X, and how should it be routed?
The AGND pin (B4) serves as the analog ground reference for internal comparators, DAC, and I²C interface circuitry. Per Table 6, it must be isolated from high-dV/dt digital return paths (e.g., SW, VIN, GND) to prevent noise coupling. Best practice is to route AGND separately to the main ground plane via a single low-inductance connection near the IC, avoiding shared traces with power GND.
FAN53555UC24X Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- TinyBuck®
- Package/Case:
- 20-UFBGA, WLCSP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Last Time Buy
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Programmable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.603V
- Voltage - Output (Max):
- 1.42V
- Current - Output:
- 4A
- Frequency - Switching:
- 2.4MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-WLCSP (1.96x1.56)
FAN53555UC24X FAQ
1.How can I place an order for FAN53555UC24X through Aetrix?
Please submit a Request for Quotation (RFQ) for FAN53555UC24X 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 FAN53555UC24X reliable?
The price and inventory of FAN53555UC24X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FAN53555UC24X is usually 5 days.
3.What payment methods are accepted for FAN53555UC24X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FAN53555UC24X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FAN53555UC24X?
FAN53555UC24X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FAN53555UC24X 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 FAN53555UC24X?
For technical support, including FAN53555UC24X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FAN53555UC24X requirements.
6.How does Aetrix verify that FAN53555UC24X is sourced from the original manufacturer or authorized distributors?
All FAN53555UC24X 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 FAN53555UC24X meets industry standards.
7.What is the process for return or replacement of FAN53555UC24X?
All FAN53555UC24X units undergo pre-shipment inspection (PSI). If there is an issue with FAN53555UC24X, 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 FAN53555UC24X part is unused and in its original packaging.
Return procedure for FAN53555UC24X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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