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onsemi FAN53555BUC24X
- Part No.:
- FAN53555BUC24X
- Manufacturer:
- onsemi
- Package:
- 20-UFBGA, WLCSP
- Datasheet:
-
FAN53555BUC24X.pdf
- Description:
- IC REG BUCK PROG 4A 20WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:4,969
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Product details
Overview
FAN53555BUC24X from onsemi is a digitally programmable 4 A synchronous step-down DC-DC regulator in a 20-bump WLCSP package, operating at 2.4 MHz fixed frequency with I²C interface (up to 3.4 Mbps), 2.5–5.5 V input range, and programmable output voltage from 0.603 V to 1.420 V in 12.967 mV steps - designed for core power delivery in Li-ion-powered handheld devices with high-performance graphics acceleration.
For engineers reviewing the FAN53555BUC24X datasheet, pinout, applications, or equivalent options, key selection considerations include its 4 A RMS current rating (vs. 5 A in other variants), backside lamination for thermal reliability, register-reset-on-EN behavior, and optimized external component footprint for compact mobile designs.
Technical Context
The FAN53555BUC24X uses a proprietary non-linear fixed-frequency PWM modulator with synchronous rectification, enabling fast load transient response while maintaining stable 2.4 MHz switching across input voltages (2.5–5.5 V) and loads (0–4 A). Its architecture supports seamless PFM/PWM mode transition and eliminates ESR dependency for ceramic output capacitors.
It integrates an I²C-compatible interface supporting Standard, Fast, Fast Plus, and High-Speed modes (up to 3.4 Mbps), allowing dynamic reprogramming of output voltage, slew rate (8 selectable rates), PFM enable/disable, and soft-start control. The device includes hardware-enabling via EN pin and software-enabling via BUCK_EN bits, with register reset on EN low per ordering option 24.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 4 A RMS maximum - defines safe continuous power delivery for compact mobile SoC cores without derating. |
| Switching Frequency | 2.4 MHz nominal - enables use of small 330 nH inductors and 22 µF ×2 ceramic output capacitors in 0603 footprint. |
| I²C Interface Speed | Up to 3.4 Mbps - supports high-speed dynamic voltage scaling (DVS) during processor state transitions. |
| Output Voltage Range | 0.603 V to 1.420 V in 12.967 mV steps - matches ARM/Krait/OMAP core voltage requirements with fine-grained DVS control. |
| Quiescent Current | 60 µA typical in PFM mode - sustains >80% efficiency down to 10 mA load, critical for standby battery life. |
| Package | 20-bump WLCSP, 1.6 × 2.0 mm - ultra-compact footprint with backside lamination for improved thermal dissipation in thin mobile PCBs. |
| Input Voltage Range | 2.5 V to 5.5 V - compatible with single-cell Li-ion (3.0–4.2 V) and USB-powered systems with headroom. |
Pinout & Package
Package: 20-bump Wafer-Level Chip Scale Package (WLCSP), 1.6 mm × 2.0 mm, 0.4 mm pitch, backside lamination applied.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1 | VSEL | Selects between VSEL0/VSEL1 register banks; HIGH = VSEL1, LOW = VSEL0 - enables dual-voltage configuration without I²C traffic. |
| A2 | EN | Hardware enable; LOW = shutdown (<1 µA IQ), HIGH = active - resets all registers to defaults on rising edge for option 24. |
| A3 | SCL | I²C clock input - supports up to 3.4 Mbps for rapid DVS updates during CPU frequency scaling. |
| A4 | VOUT | Output voltage sense node - must connect directly to COUT with minimal trace length to ensure regulation accuracy. |
| B1 | SDA | I²C bidirectional data line - requires pull-up resistor; supports multi-drop I²C bus for system-level power management. |
| B2–B3, C1–C4 | GND | Power ground return for low-side MOSFET and input/output capacitors - multiple pins reduce impedance and improve EMI. |
| B4 | AGND | Analog ground reference - isolated from digital switching paths to maintain ADC/sensor reference stability in mixed-signal SoCs. |
| D1–D2, E1–E2 | VIN | Main input power connection - connects to 2.5–5.5 V source and local 10 µF input capacitor with shortest possible path. |
| D3–D4, E3–E4 | SW | Switching node - connects to inductor; high dV/dt node requiring tight layout to minimize EMI and gate drive losses. |
Key Features
| Feature | Design Value |
|---|---|
| Digitally programmable output voltage | 0.603–1.420 V in precise 12.967 mV steps - enables exact matching to ARM/Krait core VDD requirements and dynamic scaling. |
| Programmable slew rate | 8 selectable rates (0.5–64 mV/µs) - prevents overshoot/undershoot during DVS transitions and reduces system-level noise coupling. |
| Backside lamination | Applied per ordering note - improves thermal resistance (θJA = 38°C/W) and mechanical reliability in thin mobile PCB assemblies. |
| Auto PFM/PWM mode transition | Seamless switch at ~10 mA load - maintains >80% efficiency from 10 mA to 4 A without manual mode control. |
| Integrated protection | UVLO (2.4 V threshold), OVP (6.2 V shutdown), thermal shutdown (150°C), and cycle-by-cycle current limiting - eliminates need for external fault monitoring. |
Applications
| Smartphones | Tablets & Ultra-Mobile PCs |
|---|---|
|
Use Scenario: Core voltage supply for ARM-based application processors (e.g., Krait, OMAP) during burst-mode GPU rendering. IC Role / Device Role / Timing Role: Primary buck regulator delivering dynamically scaled VDD_CORE with sub-100 ns load transient response. Use Value: Enables 4 A peak current delivery within 1.6 × 2.0 mm footprint, reducing board area by >30% vs. legacy 5 A variants while meeting thermal limits. |
Use Scenario: Powering dual-core Cortex-A series SoCs with integrated graphics in fanless tablet designs. IC Role / Device Role / Timing Role: Main SoC core regulator with I²C-controlled DVS synchronized to CPU frequency states. Use Value: 2.4 MHz switching allows use of 0603-size 22 µF X5R capacitors and 2016-case inductors, cutting BOM cost and height. |
| Gaming Handhelds | Li-ion-Powered Embedded Systems |
|
Use Scenario: Supplying NovaThor or ARMADA SoCs during sustained 3D gaming workloads with thermal constraints. IC Role / Device Role / Timing Role: High-efficiency core regulator with PFM disabled during active gameplay to ensure constant 2.4 MHz ripple profile. Use Value: Backside lamination ensures junction temperature stays below 125°C at 4 A load in 1.2 mm-thick PCBs, avoiding thermal throttling. |
Use Scenario: Powering industrial IoT edge controllers with ARM Cortex-M7 cores and real-time sensor fusion. IC Role / Device Role / Timing Role: Primary DC-DC converter with register-reset-on-EN ensuring deterministic startup after brownout recovery. Use Value: 60 µA quiescent current in PFM mode extends battery life to >12 months in always-on sensor wake-up applications. |
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 |
|---|---|---|---|
| MPQ4572GQB-Z | 4 A, 2.5 MHz, I²C-programmable, QFN-13 (3×4 mm) | Larger footprint, no backside lamination, higher θJA (50°C/W) | Preferred when board space permits larger package and thermal margin is less constrained. |
| TPS6286418RRLR | 4 A, 2.25 MHz, I²C-programmable, WLCSP-20 (1.6×2.0 mm), but no backside lamination | Same footprint and current rating, but lacks backside lamination and has lower max I²C speed (1 Mbps) | Consider only if thermal performance requirements are relaxed and lower-speed I²C suffices. |
Compared with MPQ4572GQB-Z and TPS6286418RRLR, the FAN53555BUC24X uniquely combines 20-bump WLCSP size, backside lamination, 3.4 Mbps I²C, and register-reset-on-EN - making it optimal for thermally dense, high-DVS-rate mobile SoC power rails where layout area and thermal reliability are primary constraints.
Availability
FAN53555BUC24X is available at Aetrix Electronics and suitable for smartphones, tablets, and gaming handhelds requiring stable component supply with guaranteed long-term availability and consistent wafer-lot traceability.
Supply support for FAN53555BUC24X 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 power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and mobile markets.
The FAN53555BUC24X belongs to onsemi's TinyBuck® family of ultra-compact, high-frequency DC-DC regulators - engineered specifically for core power delivery in space-constrained, battery-operated mobile devices with demanding thermal and dynamic voltage scaling requirements.
FAQ
What is the maximum continuous output current rating for the FAN53555BUC24X?
The FAN53555BUC24X is rated for 4 A RMS continuous output current, as specified in Table 4 of the datasheet for reduced-footprint applications. This is lower than the 5 A rating of base variants (e.g., FAN53555UC00X) due to optimized thermal design for compact mobile layouts - confirming its suitability for high-performance smartphone and tablet SoC core rails where 4 A meets peak demand with margin.
Does the FAN53555BUC24X support dynamic voltage scaling (DVS) via I²C?
Yes, the FAN53555BUC24X supports full DVS via its I²C interface, enabling real-time reprogramming of output voltage in 12.967 mV steps (0.603–1.420 V), slew rate (8 selectable values), PFM mode, and soft-start parameters. This capability is validated in the "Operation Description" section and electrical characteristics table, confirming seamless integration with ARM/Krait processor power management firmware.
What does "backside lamination" mean for the FAN53555BUC24X, and why is it important?
Backside lamination is a mechanical reinforcement process applied to the WLCSP die surface, improving thermal conduction from the silicon to the PCB and enhancing mechanical robustness during board assembly and flex cycling. For the FAN53555BUC24X, this feature is explicitly noted in the ordering information and directly contributes to its 38°C/W junction-to-ambient thermal resistance - critical for maintaining reliability in thin, thermally constrained mobile devices.
How does the EN pin behavior differ for the FAN53555BUC24X compared to other FAN53555 variants?
Per Table 1, the FAN53555BUC24X resets all internal registers to default values when the EN pin is pulled LOW - a behavior shared only with options 04, 042, 79, and 24. This ensures deterministic startup after power cycles or brownouts, unlike variants such as FAN53555UC00X which retain register settings during shutdown. This is essential for safety-critical or state-sensitive mobile power sequencing.
Can the FAN53555BUC24X operate with ceramic output capacitors only?
Yes, the FAN53555BUC24X is explicitly designed for ceramic output capacitors, as confirmed by its ESR-independent control architecture described in the "Operation Description" section. Recommended design uses two 22 µF, 6.3 V, X5R, 0603 capacitors (total 44 µF), eliminating need for bulk electrolytic or tantalum components - reducing height, improving reliability, and enabling compact mobile layouts.
FAN53555BUC24X 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)
FAN53555BUC24X FAQ
1.How can I place an order for FAN53555BUC24X through Aetrix?
Please submit a Request for Quotation (RFQ) for FAN53555BUC24X 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 FAN53555BUC24X reliable?
The price and inventory of FAN53555BUC24X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FAN53555BUC24X is usually 5 days.
3.What payment methods are accepted for FAN53555BUC24X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FAN53555BUC24X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FAN53555BUC24X?
FAN53555BUC24X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FAN53555BUC24X 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 FAN53555BUC24X?
For technical support, including FAN53555BUC24X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FAN53555BUC24X requirements.
6.How does Aetrix verify that FAN53555BUC24X is sourced from the original manufacturer or authorized distributors?
All FAN53555BUC24X 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 FAN53555BUC24X meets industry standards.
7.What is the process for return or replacement of FAN53555BUC24X?
All FAN53555BUC24X units undergo pre-shipment inspection (PSI). If there is an issue with FAN53555BUC24X, 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 FAN53555BUC24X part is unused and in its original packaging.
Return procedure for FAN53555BUC24X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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