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onsemi FAN49103AUC34AX
- Part No.:
- FAN49103AUC34AX
- Manufacturer:
- onsemi
- Package:
- 20-UFBGA, WLCSP
- Datasheet:
-
FAN49103AUC34AX.pdf
- Description:
- BUCK-BOOST REGULATOR, 2.5 A, 1.8
- Quantity:
- Payment:
- Shipping:
Inventory:1,275
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Product details
Overview
FAN49103AUC34AX from onsemi is a synchronous buck-boost DC-DC regulator delivering up to 2.5 A at 3.4 V output, supporting input voltages from 2.5 V to 5.5 V. It uses full-bridge architecture with I²C programmability and seamless mode transitions, designed for Li-ion battery-powered portable devices requiring stable rail generation across varying battery voltage.
For engineers reviewing the FAN49103AUC34AX datasheet, pinout, applications, or equivalent options, key selection considerations include its 1.8 MHz PWM switching frequency, 24 µA PFM quiescent current, ±5% total output accuracy under load transients, and WLCSP-20 package compatibility with space-constrained mobile power designs.
Technical Context
The FAN49103AUC34AX implements a four-switch full-bridge topology enabling true buck, boost, and buck-boost operation - Q1/Q2 active in boost, Q3/Q4 in buck, and all four switches phased in buck-boost. Its current-mode modulator ensures smooth PFM-to-PWM transition at ~300 mA load, maintaining high efficiency across light to heavy loads.
I²C interface supports Standard, Fast, Fast Plus, and HS modes (up to 3.4 MHz), with slave address 0xE0 (7-bit 0x71 for this variant per ordering table). Register 01 (VOUT_REF) enables precise output programming from 2.5 V to 4.0 V in 25–50 mV steps, while register 02 controls forced PWM, pass-through mode, and safety behavior.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.4 V (factory-programmed default; programmable via I²C from 2.5 V to 4.0 V) |
| Max Continuous Output Current | 2.5 A at VIN = 3.0 V, VOUT = 3.4 V - defines thermal and PCB layout requirements for sustained load |
| Input Voltage Range | 2.5 V to 5.5 V - supports full Li-ion battery discharge curve (3.0–4.2 V nominal + tolerance) |
| Switching Frequency | 1.8 MHz nominal in PWM mode - enables use of compact 1 µH inductor and low-ESR ceramic capacitors |
| Quiescent Current | 24 µA in PFM mode - extends battery life in standby/sleep states of portable systems |
| Output Accuracy | ±5% total (DC + load transient) - ensures reliable operation of downstream logic and RF circuitry |
| Package | 20-bump WLCSP, 1.615 mm × 2.015 mm, 0.4 mm pitch - ultra-compact footprint for thin mobile PCBs |
Pinout & Package
Package: 20-ball Wafer-Level Chip-Scale Package (WLCSP), 1.615 mm × 2.015 mm, 0.4 mm ball pitch, 0.586 mm height (Case 567QK).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A3, A4 | PVIN | Main power input - connects directly to input capacitor; must be routed with minimal impedance to handle peak currents |
| A1 | AVIN | Analog supply - ties to same node as PVIN/CIN for noise-sensitive control circuitry reference |
| A2 | EN | Enable control - active-high logic input; can be tied to VIN or driven by GPIO for system-level power sequencing |
| B3, B4 | SW1 | Switch node 1 - connects to one end of inductor L1; requires short, wide trace to minimize EMI and conduction loss |
| E1 | AGND | Analog ground - reference for internal control circuits; must be shorted to PGND at COUT ground pad to avoid noise coupling |
| B1, C1–C4, D1 | PGND | Power ground - return path for high-current MOSFETs; multiple balls reduce ground inductance and thermal resistance |
| D2 | SDA | I²C bidirectional data line - open-drain; requires external pull-up to VOUT for communication during regulation |
| D3, D4 | SW2 | Switch node 2 - connects to opposite end of inductor L1; forms full-bridge switching pair with SW1 |
| E2 | PG | Power good open-drain flag - pulled low on fault (OCP, OTP, UVLO) or startup failure; signals system readiness |
| B2 | SCL | I²C clock input - must be pulled high externally; timing compliant with Fast Mode (400 kHz) and HS Mode (3.4 MHz) |
| E3, E4 | VOUT | Regulated output - supplies load and output capacitor; dual balls reduce IR drop and improve current sharing |
Key Features
| Feature | Design Value |
|---|---|
| Seamless buck/boost/buck-boost transition | Eliminates output voltage disturbance during battery voltage sag or surge - critical for uninterrupted RF PA and NFC operation |
| Programmable output voltage (2.5–4.0 V) | Enables dynamic rail scaling via I²C without hardware change - supports multi-voltage SoC subsystems |
| Internal soft-start and output discharge | Prevents inrush current at enable and safely discharges VOUT via 230 Ω internal resistor when disabled - protects downstream components |
| Integrated safety protections | UVLO (2.0 V threshold), OTP (150°C shutdown), SCP/OCP - eliminates need for external fault management circuitry |
| Pass-through mode | VOUT tracks PVIN with minimal dropout (RDS(on)-based) - extends battery runtime when input > output and load is light |
Applications
| Smartphone Power Management | NFC Reader Module Supply |
|---|---|
Use Scenario: Regulating stable 3.4 V rail from declining Li-ion battery (3.6 V → 2.8 V) to power application processor I/O and memory interfaces. IC Role / Device Role / Timing Role: Primary buck-boost regulator providing continuous, ripple-controlled output during battery discharge cycle. Use Value: Maintains ±5% output accuracy and <45 mV load transient deviation - prevents logic errors and memory corruption during CPU burst activity. | Use Scenario: Supplying 3.4 V to NFC controller and antenna driver IC in contactless payment terminals. IC Role / Device Role / Timing Role: High-efficiency, low-noise power source with fast line/load transient response for RF-sensitive analog front-end. Use Value: 1.8 MHz fixed-frequency PWM minimizes interference in 13.56 MHz NFC band; <22 mV PFM ripple avoids signal integrity degradation. |
| 2G/3G/4G Power Amplifier Bias | Portable Medical Sensor Hub |
Use Scenario: Delivering 2.5–3.4 V bias voltage to cellular RF power amplifiers with rapid envelope tracking demands. IC Role / Device Role / Timing Role: Dynamic voltage regulator adapting to PA supply requirements across modulation schemes (GSM, WCDMA, LTE). Use Value: Seamless mode transition and <125 mV load transient deviation at 2 A step ensure clean PA output without spectral regrowth or ACLR degradation. | Use Scenario: Powering mixed-signal sensor hub (ECG, SpO₂, temperature) from single-cell Li-ion in wearable health monitors. IC Role / Device Role / Timing Role: Ultra-low-quiescent (24 µA) regulator enabling multi-week standby with periodic sensor wake-up. Use Value: PFM mode sustains >90% efficiency at 50 mA load - maximizes battery life while meeting medical-grade voltage stability specs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2155GQ-Z | Fixed 3.3 V output; no I²C interface; 2.2 MHz switching; 2 A max output | Lacks programmability and higher current capability - suitable only for static-rail, lower-power designs | Select when I²C control and >2 A load are unnecessary; verify thermal performance at 2 A in same PCB area |
| TPS63802DLAR | 3.3 V default; I²C programmable (2.5–5.5 V); 2 A max; 2.4 MHz; integrated load switch | Lower current rating and different I²C register map - requires firmware adaptation and layout review for thermal derating | Choose for TI-ecosystem designs needing integrated load switch; confirm 2 A limit meets peak PA or sensor burst requirements |
Compared with MP2155GQ-Z and TPS63802DLAR, the FAN49103AUC34AX delivers higher output current (2.5 A), tighter output accuracy (±5% total), and optimized WLCSP footprint for ultra-thin mobile PCBs - making it preferred for next-gen smartphones and NFC-enabled wearables where size, efficiency, and programmability are co-constrained.
Availability
FAN49103AUC34AX is available at Aetrix Electronics and suitable for smartphone power management, NFC reader modules, 4G power amplifier biasing, and portable medical sensor hubs requiring stable component supply with consistent WLCSP packaging and I²C configurability.
Supply support for FAN49103AUC34AX 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 specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and portable electronics.
The FAN49103AUC34AX belongs to onsemi's TinyPower™ family of ultra-compact, high-efficiency DC-DC regulators engineered specifically for space- and battery-life-constrained mobile devices operating across wide input voltage ranges.
FAQ
What is the factory-default output voltage of the FAN49103AUC34AX?
The FAN49103AUC34AX is factory-programmed to deliver 3.4 V as its default regulated output voltage. This value is set in the VOUT_REF register (address 0x01) and can be reconfigured via I²C to any value between 2.5 V and 4.0 V in 25–50 mV increments. The device marking "MQ" and part number suffix "34AX" explicitly denote the 3.4 V configuration per onsemi's ordering information table.
Does the FAN49103AUC34AX support I²C high-speed mode?
Yes, the FAN49103AUC34AX supports I²C high-speed (HS) mode up to 3.4 MHz, in addition to Standard (100 kHz), Fast (400 kHz), and Fast Plus (1 MHz) modes. Its SCL and SDA pins comply with I²C bus specifications, and the slave address is 0xE0 (7-bit 0x71 for this variant). HS mode activation requires the master to send the HS master code (0x08) followed by a repeated START condition.
How does the FAN49103AUC34AX handle transitions between buck and boost operation?
The FAN49103AUC34AX uses a full-bridge four-switch architecture to achieve automatic and seamless transitions between buck, boost, and buck-boost modes. When PVIN > VOUT, Q3 remains on and Q4 off (buck mode); when PVIN < VOUT, Q1 stays on and Q2 off (boost mode); near VOUT, all four switches operate in a three-phase sequence to maintain inductor volt-second balance - eliminating output glitches during battery voltage crossing.
What protection features are integrated into the FAN49103AUC34AX?
The FAN49103AUC34AX integrates UVLO (2.0 V threshold), over-temperature protection (150°C shutdown with 20°C hysteresis), over-current protection (OCP triggered at ~5.2 A peak), and short-circuit protection. All are internally set and require no external components. During fault conditions - including startup failure, OCP timeout, or OTP activation - the device enters FAULT state, disables switching, and pulls PG low to signal system-level intervention.
Can the FAN49103AUC34AX operate in pass-through mode, and how is it enabled?
Yes, the FAN49103AUC34AX supports pass-through (PT) mode where VOUT follows PVIN minus resistive drop across internal MOSFETs. PT mode is enabled by writing '1' to bit 3 (i2c_pt_in) of the CONTROL register (0x02) via I²C. In PT mode, only UVLO and OTP remain active; OCP is disabled, and the device draws minimal quiescent current - ideal for extending battery life when input voltage exceeds required output.
FAN49103AUC34AX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- TinyPower™
- Package/Case:
- 20-UFBGA, WLCSP
- Packaging:
- Bulk
- Product Status:
- Discontinued at Digi-Key
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck-Boost
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 3.4V
- Voltage - Output (Max):
- -
- Current - Output:
- 2.5A
- Frequency - Switching:
- 1.8MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-WLCSP (1.62x2.02)
FAN49103AUC34AX FAQ
1.How can I place an order for FAN49103AUC34AX through Aetrix?
Please submit a Request for Quotation (RFQ) for FAN49103AUC34AX 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 FAN49103AUC34AX reliable?
The price and inventory of FAN49103AUC34AX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FAN49103AUC34AX is usually 5 days.
3.What payment methods are accepted for FAN49103AUC34AX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FAN49103AUC34AX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FAN49103AUC34AX?
FAN49103AUC34AX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FAN49103AUC34AX 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 FAN49103AUC34AX?
For technical support, including FAN49103AUC34AX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FAN49103AUC34AX requirements.
6.How does Aetrix verify that FAN49103AUC34AX is sourced from the original manufacturer or authorized distributors?
All FAN49103AUC34AX 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 FAN49103AUC34AX meets industry standards.
7.What is the process for return or replacement of FAN49103AUC34AX?
All FAN49103AUC34AX units undergo pre-shipment inspection (PSI). If there is an issue with FAN49103AUC34AX, 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 FAN49103AUC34AX part is unused and in its original packaging.
Return procedure for FAN49103AUC34AX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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