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onsemi FAN48623UC35X
- Part No.:
- FAN48623UC35X
- Manufacturer:
- onsemi
- Package:
- 16-UFBGA, WLCSP
- Datasheet:
-
FAN48623UC35X.pdf
- Description:
- IC REG BOOST PROG 2.5A 16WLCSP
- Quantity:
- Payment:
- Shipping:
Inventory:5,074
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Product details
Overview
FAN48623UC35X from Fairchild Semiconductor is a 2500 mA synchronous TinyBoost® DC-DC boost regulator with true bypass mode, designed for Li-ion battery-powered portable systems requiring 3.5 V / 3.7 V fixed output. It operates from 2.5 V to 4.5 V input, delivers up to 97% efficiency at 3.5 V output, and integrates synchronous rectification and load disconnect for low-quiescent-current operation in smartphones and RF power amplifier supplies.
For engineers reviewing the FAN48623UC35X datasheet, pinout, applications, or equivalent options, key selection criteria include its 16-bump WLCSP package (1.81 mm × 1.81 mm, 0.4 mm pitch), forced/automatic bypass capability, ±1.0% to ±4.0% output voltage accuracy under load, 2.5 MHz CCM switching, and integrated short-circuit and thermal protection.
Technical Context
The FAN48623UC35X implements current-mode control with valley-current limiting and dynamically transitions between Linear Startup (LIN), Soft-Start (SS), Boost (BST), and Bypass (BPS) operating states based on VIN–VOUT relationship and load conditions. Its modulator supports both Continuous Conduction Mode (CCM) at moderate-to-heavy loads and Discontinuous Conduction Mode (DCM) at light loads to sustain high efficiency across wide load ranges.
Bypass activation is hysteresis-controlled: automatic entry occurs when VIN ≥ VOUT_TARGET + 30 mV, and exit triggers at VOUT_TARGET − 50 mV; forced bypass is enabled via logic-low BYP pin, disabling internal bias circuits to achieve ≤12 µA quiescent current. Power Good (PG) provides open-drain fault signaling tied to soft-start completion and die temperature monitoring.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.5 V / 3.7 V (dual-option per VSEL configuration) |
| Max Continuous Output Current | 2500 mA at VIN = 2.5 V → VOUT = 3.5 V; enables direct powering of 3G/4G RF PAs |
| Efficiency | Up to 97% at 3.5 V output, 1 A load, VIN = 3.0 V - reduces thermal load in compact layouts |
| Input Voltage Range | 2.5 V to 4.5 V - supports full discharge curve of single-cell Li-ion batteries (2.7–4.2 V) |
| Quiescent Current | 6.0–12.0 µA in Forced Bypass Mode - extends battery runtime during system sleep |
| Switching Frequency | Typical 2.5 MHz in CCM - allows use of ultra-small 0.47 µH inductor (2520 case) and 0603 capacitors |
| Output Accuracy | ±1.0% to ±4.0% over 0–2500 mA load and temperature - ensures stable PMIC LDO input regulation |
Pinout & Package
Package: 16-bump Wafer-Level Chip-Scale Package (WLCSP), 1.81 mm × 1.81 mm, 0.4 mm pitch, bumps down. Thermal performance optimized via PGND pad array and recommended multi-layer PCB ground pour with thermal vias.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A1 EN | Enable control input | Active-high logic input (VIH ≥ 1.05 V); ties to GPIO for precise startup sequencing and system-level power management |
| A2 PG | Power Good open-drain output | Signals successful soft-start completion and asserts LOW on overload, UVLO, or >125°C die temperature |
| A3/A4 VIN | Main input power connection | Accepts 2.5–4.5 V battery source; requires 10 µF X5R 0603 input capacitor placed adjacent to pins |
| B1 VSEL | Output voltage select | Configures dual-output option (3.5 V / 3.7 V); logic level sets target VOUT before boost activation |
| B3/B4 VOUT | Regulated output node | Delivers fixed 3.5 V / 3.7 V; requires two 22 µF X5R 0603 output caps placed directly at PGND/VOUT pads |
| C1 BYP | Forced bypass mode control | Logic-low activation disables internal regulators and fully enhances Q1/Q3 for near-zero-drop conduction path |
| C3/C4 SW | Switching node | Connects to 0.47 µH inductor; high dI/dt node requiring shortest possible trace and tight coupling to PGND |
| D1 AGND | Analog reference ground | Signal ground reference for error amplifier and control logic; must connect to PGND at single point to avoid noise coupling |
| D2–D4 PGND | Power ground return | Primary return path for inductor current and output capacitor; connects to PCB ground plane via multiple thermal vias |
| B2/C2 NC | No internal connection | Bumps present but unconnected internally; must be tied to PGND for mechanical stability and thermal relief |
Key Features
| Feature | Design Value |
|---|---|
| True Bypass Operation | Enables zero-switching, ultra-low-IQ path when VIN > VOUT_TARGET - eliminates switching losses and EMI during battery-sufficient states |
| Synchronous Rectification | Integrated high-side and low-side MOSFETs replace external diode - improves efficiency by ~8% vs. asynchronous designs at 2 A load |
| Integrated Load Disconnect | Blocks reverse current from VOUT to VIN during shutdown or fault - prevents battery drain and protects against backfeed from auxiliary sources |
| Automatic Mode Transition Logic | Seamlessly shifts between LIN→SS→BST→BPS without external control - eliminates need for system MCU intervention during battery voltage sag/recovery |
| Short-Circuit Protection (SCP) | Detects >160 mV VIN–VOUT drop in bypass mode and triggers FAULT restart timer - safeguards against sustained overload or output short |
Applications
| Smartphone RF PA Supply | Li-ion Brownout Prevention |
|---|---|
Use Scenario: Delivering stable 3.5 V to 4G LTE power amplifiers during peak transmit bursts while battery voltage drops below 3.3 V. IC Role / Device Role / Timing Role: Primary boost regulator with pulse-load capability (3.5 A peak) and fast transient response (<100 µs recovery). Use Value: Maintains PA linearity and output power integrity across full battery discharge cycle without requiring larger battery or additional LDO stages. |
Use Scenario: Preventing system reset or brownout when single-cell Li-ion voltage falls below 3.3 V nominal during high-current system wake-up events. IC Role / Device Role / Timing Role: Standby-ready boost converter that auto-activates only when VIN dips below VOUT_TARGET − 30 mV. Use Value: Extends usable battery capacity by 8–12% versus fixed-LDO solutions, with no firmware overhead or polling required. |
| PMIC Auxiliary Rail Generation | Tablet System Power Management |
Use Scenario: Generating clean, regulated 3.5 V supply for PMIC internal LDOs and analog blocks from shared main battery rail. IC Role / Device Role / Timing Role: High-accuracy (±1.0%), low-noise auxiliary regulator with PG flag for PMIC enable sequencing. Use Value: Eliminates need for discrete boost + LDO cascade, reducing BOM count by 3 components and PCB area by >25 mm². |
Use Scenario: Dynamically powering display backlight drivers and USB PHYs in tablets where battery voltage varies from 4.2 V (full) to 2.8 V (low). IC Role / Device Role / Timing Role: Dual-mode regulator that switches to bypass above 3.5 V to cut IQ to <12 µA, then resumes boost as voltage sags. Use Value: Reduces average system quiescent current by 40% during screen-off periods, extending standby time by >3 hours. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61230ARNSR | 3.3 V fixed output; 2.5 A max; 2.5 MHz; WQFN-16 (3 mm × 3 mm) | Larger footprint (3×3 mm vs. 1.81×1.81 mm); no forced bypass mode; higher min. input (2.7 V) | Preferred when board space permits larger package and bypass functionality is not required |
| MAX8642AETE+T | 3.3 V fixed output; 2.2 A max; 2.25 MHz; 16-bump WLCSP (1.92 mm × 1.92 mm) | Lower efficiency (94% typ.); no VSEL pin; lacks PG output and automatic bypass hysteresis | Considered when cost sensitivity outweighs efficiency and smart mode transition requirements |
Compared with TPS61230ARNSR and MAX8642AETE+T, the FAN48623UC35X offers superior space efficiency (40% smaller footprint), integrated bypass hysteresis for seamless mode transitions, and lower quiescent current in forced bypass - making it optimal for ultra-thin mobile devices with aggressive battery life targets.
Availability
FAN48623UC35X is available at Aetrix Electronics and suitable for smartphone RF power amplifier supplies, Li-ion battery brownout prevention circuits, and PMIC auxiliary rail generation requiring stable component supply, consistent WLCSP packaging, and guaranteed long-term production continuity.
Supply support for FAN48623UC35X 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
Fairchild Semiconductor (now part of ON Semiconductor) is a global leader in power management ICs, known for high-efficiency, small-footprint DC-DC solutions targeting portable and battery-operated electronics.
The FAN48623UC35X belongs to Fairchild's TinyBoost® family, engineered specifically for space-constrained mobile devices needing high-current boost conversion with intelligent bypass behavior to maximize battery runtime and minimize thermal impact.
FAQ
What output voltage does the FAN48623UC35X deliver?
The FAN48623UC35X delivers a fixed dual-option output voltage of either 3.5 V or 3.7 V, selected via the VSEL pin logic state. This matches the ordering code "UC35X", where "35" denotes the primary 3.5 V option and "X" indicates the dual-voltage capability. The device maintains ±1.0% to ±4.0% accuracy across 0–2500 mA load and −40°C to +85°C ambient temperature, ensuring reliable operation for RF PA and PMIC rails.
How does the FAN48623UC35X enter and exit Bypass Mode?
The FAN48623UC35X enters Automatic Bypass Mode when VIN exceeds VOUT_TARGET + 30 mV and exits when VOUT falls below VOUT_TARGET − 50 mV - providing 80 mV total hysteresis to prevent oscillation. Forced Bypass Mode is activated by pulling the BYP pin LOW, which disables internal regulators and fully enhances both pass transistors for near-zero-drop conduction. The FAN48623UC35X remains in Forced Bypass until BYP is returned HIGH, initiating a controlled transition back to Boost Mode.
What is the minimum number of external components required for the FAN48623UC35X?
The FAN48623UC35X requires only four external components: one 0.47 µH inductor (2520 case), one 10 µF input capacitor (0603 X5R), and two 22 µF output capacitors (0603 X5R). No compensation network, feedback resistors, or external MOSFETs are needed due to its fully integrated synchronous architecture and factory-trimmed voltage reference. This minimal BOM reduces layout complexity and accelerates time-to-market for portable designs using the FAN48623UC35X.
Does the FAN48623UC35X provide reverse current protection?
Yes, the FAN48623UC35X provides true load disconnect and reverse current blocking. When disabled (EN = LOW) or in FAULT state, it presents a high-impedance path between VIN and VOUT, limiting reverse leakage to ≤1.0 µA (ILK) and ≤1.5 µA (ILK_OUT). During Forced Bypass Mode, reverse current is actively prevented by internal logic that delays entry until VOUT discharges below VIN. This ensures no battery drain from auxiliary sources or output bus faults - a critical feature for the FAN48623UC35X in multi-rail portable systems.
What thermal management guidance applies to the FAN48623UC35X in its WLCSP package?
The FAN48623UC35X uses a 16-bump WLCSP with θJA = 60°C/W on a 4-layer evaluation board. Effective thermal design requires tying all PGND bumps (D2–D4) and NC bumps (B2/C2) to a large internal ground plane via ≥6 thermal vias, maximizing copper pour on layers 2 (solid ground) and 3 (ground fill), and routing VOUT/VIN traces as wide/short as possible. Ambient temperature must remain ≤+85°C, and junction temperature must stay ≤+125°C continuous (≤+150°C absolute max) - verified by thermal simulation or IR imaging during FAN48623UC35X prototype validation.
FAN48623UC35X Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- TinyBoost®
- Package/Case:
- 16-UFBGA, WLCSP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Programmable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 3.5V
- Voltage - Output (Max):
- 3.7V
- Current - Output:
- 2.5A
- Frequency - Switching:
- 2.5MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-WLCSP (1.78x1.78)
FAN48623UC35X FAQ
1.How can I place an order for FAN48623UC35X through Aetrix?
Please submit a Request for Quotation (RFQ) for FAN48623UC35X 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 FAN48623UC35X reliable?
The price and inventory of FAN48623UC35X are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FAN48623UC35X is usually 5 days.
3.What payment methods are accepted for FAN48623UC35X?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FAN48623UC35X transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FAN48623UC35X?
FAN48623UC35X orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FAN48623UC35X 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 FAN48623UC35X?
For technical support, including FAN48623UC35X datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FAN48623UC35X requirements.
6.How does Aetrix verify that FAN48623UC35X is sourced from the original manufacturer or authorized distributors?
All FAN48623UC35X 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 FAN48623UC35X meets industry standards.
7.What is the process for return or replacement of FAN48623UC35X?
All FAN48623UC35X units undergo pre-shipment inspection (PSI). If there is an issue with FAN48623UC35X, 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 FAN48623UC35X part is unused and in its original packaging.
Return procedure for FAN48623UC35X:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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