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onsemi FAN53555BUC79X
- Part No.:
- FAN53555BUC79X
- Manufacturer:
- onsemi
- Package:
- 20-UFBGA, WLCSP
- Datasheet:
-
FAN53555BUC79X.pdf
- Description:
- IC REG BUCK PROG 5A 20WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
FAN53555BUC79X from onsemi is a 5 A, 2.4 MHz synchronous buck converter in WLCSP20 package with I²C interface, PGOOD output, and programmable VOUT (0.85 V fixed via internal VSEL mapping). It delivers up to 5 A continuous output current from 2.5–5.5 V input, supports PFM/PWM auto-mode operation, and targets core voltage regulation for mobile SoCs including ARM-based processors.
For engineers reviewing the FAN53555BUC79X datasheet, pinout, applications, or equivalent options, key selection criteria include its fixed 0.85 V output, PGOOD monitoring capability, 20-ball WLCSP footprint, I²C programmability (3.4 Mbps), and thermal performance in high-density portable designs.
Technical Context
The FAN53555BUC79X integrates dual MOSFETs (RDS(on) = 28 mΩ high-side, 17 mΩ low-side) and operates with a fixed 2.4 MHz switching frequency, enabling compact 330 nH inductor and low-ESR ceramic capacitor designs. Its control loop supports automatic transition between PFM (60 µA quiescent current) and PWM modes based on load conditions.
I²C register access enables dynamic VOUT adjustment (though FAN53555BUC79X is factory-configured to 0.85 V), slew rate control (0.5–64 mV/s), and status monitoring via PGOOD. The device includes UVLO (2.35–2.45 V), OVP (6.15 V), thermal shutdown (150 °C), and current-limit protection (6.3–8.5 A peak).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 5 A continuous - supports CPU/GPU core rail loads in smartphones and tablets |
| Input Voltage Range | 2.5 V to 5.5 V - compatible with single-cell Li-ion/Li-poly battery and USB-powered systems |
| Fixed Output Voltage | 0.85 V - factory-programmed via VSEL pins (ID1 DIE_ID = 0010), no external resistor required |
| Switching Frequency | 2.4 MHz ±15% - enables use of small 330 nH inductors and minimizes EMI in RF-sensitive layouts |
| I²C Interface Speed | Up to 3.4 Mbps - supports high-speed configuration and telemetry in fast-boot systems |
| PGOOD Output | Active-high open-drain - provides system-level power-good signaling for sequencer coordination |
| Package | WLCSP20 (2.015 × 1.615 × 0.586 mm) - ultra-compact chip-scale package for space-constrained mobile PCBs |
Pinout & Package
Package: WLCSP20 (2.015 mm × 1.615 mm × 0.586 mm), ball pitch 0.4 mm, case 567QK/567SH/567SK.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1 | PGOOD | Power-good status indicator - asserts high when VOUT is within ±3% of 0.85 V and all fault conditions cleared |
| A2 | EN | Enable input - active-high; logic threshold 1.1 V min, 0.4 V max; internal pull-down when floating |
| A3 | SCL | I²C clock input - supports standard (100 kHz), fast (400 kHz), and high-speed (3.4 Mbps) modes |
| A4 | VOUT | Regulated output - connects directly to load (e.g., CPU core); requires local 44 µF ceramic output capacitance |
| B1 | SDA | I²C data bidirectional line - open-drain, requires external pull-up; supports ACK/NACK handshaking |
| B2–B3, C1–C4 | GND | Power ground - multiple dedicated balls minimize ground impedance and improve PSRR |
| B4 | AGND | Analog ground - isolated reference for internal feedback and comparator circuitry |
| D1–D2, E1–E2 | VIN | Input supply - accepts 2.5–5.5 V; requires 10 µF ceramic input capacitance near package |
| D3–D4, E3–E4 | SW | Switch node - connects to external 330 nH inductor; high dV/dt node requiring tight layout |
Key Features
| Feature | Design Value |
|---|---|
| Integrated MOSFETs with low RDS(on) | 28 mΩ (HS) / 17 mΩ (LS) at 5 V VIN - reduces conduction loss and improves full-load efficiency (>88% at 3.6 V → 0.85 V, 2 A) |
| Auto-mode PFM/PWM operation | 60 µA quiescent current in PFM, seamless transition to PWM above ~100 mA - extends battery life without sacrificing transient response |
| PGOOD with comprehensive fault coverage | Monitors EN assertion, I²C communication, UVLO, OVP, thermal shutdown, and soft-start completion - enables robust system power sequencing |
| I²C programmable slew rate | Configurable 0.5–64 mV/s output ramp rate - prevents inrush current and meets SoC-specific voltage ramp requirements |
| Thermal and overcurrent protection | 150 °C thermal shutdown with 17 °C hysteresis; peak current limit 6.3–8.5 A depending on variant - ensures safe operation under overload or short-circuit |
| Ultra-small WLCSP20 footprint | 2.015 mm × 1.615 mm area - saves >50% board space vs. comparable QFN packages, critical for slim mobile form factors |
Applications
| Smartphone Application Processor Core Rail | Tablet SoC DVFS Power Domain |
|---|---|
|
Use Scenario: Powers ARM Cortex-A series CPU cores in flagship smartphones requiring dynamic voltage scaling across 0.6–1.2 V range. IC Role / Device Role / Timing Role: Primary buck regulator delivering tightly regulated 0.85 V at up to 5 A, synchronized to SoC's DVFS commands via I²C. Use Value: Enables precise voltage control during frequency transitions, minimizing dynamic power while maintaining timing margins under 100 ns load steps. |
Use Scenario: Supplies GPU and multimedia accelerator rails in Android tablets where thermal density and battery runtime are critical. IC Role / Device Role / Timing Role: High-efficiency point-of-load converter operating in PFM mode at light loads (<10 mA) and PWM at full load. Use Value: Achieves >86% efficiency at 10 mA (PFM) and >90% at 3 A (PWM), extending video playback time by 12+ minutes per charge cycle. |
| Wearable System-on-Chip Core Supply | IoT Edge Device AI Accelerator Rail |
|
Use Scenario: Regulates core voltage for low-power wearable MCUs (e.g., Ambiq Apollo series) in always-on health monitors. IC Role / Device Role / Timing Role: Ultra-low-IQ buck converter with PGOOD signaling to MCU for brown-out detection and graceful shutdown. Use Value: 60 µA quiescent current in PFM mode extends coin-cell battery life to 18+ months in sleep mode without compromising wake-up responsiveness. |
Use Scenario: Powers neural network accelerator blocks in battery-operated IoT gateways performing local inference. IC Role / Device Role / Timing Role: Fast-transient buck regulator supporting 1.5–6 A load steps with <±40 mV output deviation (COUT = 88 µF). Use Value: Maintains stable 0.85 V under 100 ns, 3 A load transients - prevents inference errors during burst-mode AI computation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS628641RQYR | 4 A, 2.5 V–5.5 V, fixed 0.85 V, 2.2 MHz, 16-pin WQFN (2.0 × 2.0 mm) | Higher thermal resistance (θJA = 52°C/W vs. 38°C/W), no PGOOD, no I²C | Choose for cost-sensitive designs where programmability and fault reporting are not required |
| RTQ2132BGQW | 5 A, 2.7 V–5.5 V, adjustable 0.6–1.8 V, 2.2 MHz, 20-pin WQFN (3.0 × 3.0 mm) | Larger footprint, external feedback resistors needed for 0.85 V, no integrated PGOOD | Choose when adjustable output or higher input voltage margin (2.7 V min) is mandatory |
Compared with TPS628641RQYR and RTQ2132BGQW, the FAN53555BUC79X offers superior thermal performance in minimal area, built-in PGOOD for system sequencing, and I²C configurability - making it optimal for space- and intelligence-constrained mobile SoC rails.
Availability
FAN53555BUC79X is available at Aetrix Electronics and suitable for smartphone processor core rails, tablet SoC DVFS domains, and wearable MCU power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for FAN53555BUC79X 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 edge applications.
The FAN53555 family is designed specifically for high-current, ultra-compact DC-DC conversion in mobile and portable electronics, emphasizing low quiescent current, fast transient response, and minimal PCB footprint.
FAQ
What is the fixed output voltage of the FAN53555BUC79X?
The FAN53555BUC79X is factory-configured to deliver a fixed 0.85 V output voltage, verified by its DIE_ID = 0010 in register ID1 (address 0x03). This eliminates the need for external feedback resistors and simplifies layout for core voltage rails in ARM-based SoCs.
Does the FAN53555BUC79X support I²C programming despite its fixed output?
Yes, the FAN53555BUC79X retains full I²C functionality including register read/write access for slew rate control, MODE selection, and status monitoring (e.g., PGOOD, thermal flag). While VOUT is fixed at 0.85 V, I²C enables dynamic configuration of other critical parameters in the FAN53555BUC79X.
What is the purpose of the PGOOD pin on the FAN53555BUC79X?
The PGOOD pin on the FAN53555BUC79X is an active-high open-drain output that signals when the output voltage is within ±3% of 0.85 V and all fault conditions (UVLO, OVP, thermal shutdown) have cleared. It interfaces directly with SoC power sequencers or PMICs to coordinate system boot and reset sequences in the FAN53555BUC79X.
What inductor value is recommended for the FAN53555BUC79X?
The FAN53555BUC79X is optimized for a 330 nH shielded power inductor (e.g., MMD−04ABNR33M or VLC5020T−R47M), as specified in the datasheet for 2.4 MHz operation. Using this value ensures stable CCM/PFM boundary operation, minimal output ripple (<20 mVpp), and optimal efficiency across the 0–5 A load range in the FAN53555BUC79X.
Is the FAN53555BUC79X pin-compatible with other variants in the FAN53555 family?
Yes, all FAN53555 variants-including FAN53555BUC79X-share identical WLCSP20 (2.015 × 1.615 mm) packaging and pinout. This allows direct substitution across the family (e.g., FAN53555BUC13X, FAN53555BUC23X) without PCB changes, provided the application's VOUT, current, and feature requirements align with the FAN53555BUC79X specifications.
FAN53555BUC79X Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- 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):
- 0.6V
- Voltage - Output (Max):
- 1.23V
- Current - Output:
- 5A
- 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 (2.02x1.62)
FAN53555BUC79X FAQ
1.How can I place an order for FAN53555BUC79X through Aetrix?
Please submit a Request for Quotation (RFQ) for FAN53555BUC79X 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 FAN53555BUC79X reliable?
The price and inventory of FAN53555BUC79X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FAN53555BUC79X is usually 5 days.
3.What payment methods are accepted for FAN53555BUC79X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FAN53555BUC79X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FAN53555BUC79X?
FAN53555BUC79X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FAN53555BUC79X 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 FAN53555BUC79X?
For technical support, including FAN53555BUC79X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FAN53555BUC79X requirements.
6.How does Aetrix verify that FAN53555BUC79X is sourced from the original manufacturer or authorized distributors?
All FAN53555BUC79X 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 FAN53555BUC79X meets industry standards.
7.What is the process for return or replacement of FAN53555BUC79X?
All FAN53555BUC79X units undergo pre-shipment inspection (PSI). If there is an issue with FAN53555BUC79X, 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 FAN53555BUC79X part is unused and in its original packaging.
Return procedure for FAN53555BUC79X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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