onsemi FAN48630BUC34X

Overview

FAN48630BUC34X from onsemi is a synchronous boost regulator with forced bypass mode, designed for Li-ion battery-powered systems requiring stable 3.20 V / 3.40 V dual-output regulation. It delivers up to 1500 mA continuous load current at VIN = 2.6 V boosting to 3.5 V, operates at 2.5 MHz switching frequency, and features true bypass operation when VIN exceeds target VOUT. It is used in brownout prevention and USB OTG power delivery.

For engineers reviewing the FAN48630BUC34X datasheet, pinout, applications, or equivalent options, key selection considerations include its backside-laminated WLCSP16 package, low-IQ forced bypass mode (4–10 µA), ±2% output voltage accuracy, and integrated synchronous rectifier with 65 mΩ RDS(ON)P.

Technical Context

The FAN48630BUC34X implements current-mode control in Continuous Conduction Mode (CCM) at ~2.5 MHz, with automatic transition between Boost and Bypass modes based on VIN vs. VOUT_TARGET comparison. Its valley-current limiting architecture supports peak inductor currents up to 3.8 A during overload, while soft-start sequencing (FAST mode, 600 µs EN-to-regulation) prevents inrush.

Bypass entry is triggered when VIN > VOUT_TARGET + 25 mV (25 mV hysteresis), and exit occurs when VOUT reaches target; forced bypass activation via BYP pin disables most internal circuitry to achieve ultra-low quiescent current. Thermal protection activates at 150°C (T150T) with 20°C hysteresis (T150H), and PG fault signaling reports overload, thermal events (>120°C), or startup failure.

Key Specifications

Pinout & Package

Package: Wafer-Level Chip-Scale Package (WLCSP), 16-bump, 0.4 mm pitch, 1.78 mm × 1.78 mm × 0.586 mm body height (Case 567SY).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar boost regulator applications.

Compared with TPS61291DRVR and MAX17222ETA+T, the FAN48630BUC34X uniquely combines dual-voltage targeting (3.20 V / 3.40 V), forced bypass with sub-10 µA IQ, integrated PG and thermal fault signaling, and mechanically reinforced backside lamination - making it optimal for high-reliability portable power rails.

Availability

FAN48630BUC34X is available at Aetrix Electronics and suitable for USB OTG power delivery, brownout prevention in smartphones, and boosted audio amplifiers requiring stable component supply across production volumes.

Supply support for FAN48630BUC34X 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, sensors, and connectivity solutions.

The FAN48630BUC34X belongs to the TINYBOOST® family of high-frequency synchronous boost regulators, engineered specifically for space- and power-constrained portable electronics using advanced Li-ion battery chemistries.

FAQ

What is the output voltage configuration of the FAN48630BUC34X?

The FAN48630BUC34X is factory-configured for dual fixed output voltages: 3.20 V and 3.40 V. This dual-option setting is defined by the "UC34X" suffix and verified in Table 1 of the datasheet. The device does not support adjustable output via external resistors - voltage selection is implemented internally and accessed via the VSEL pin for dynamic stepping. No external feedback network is required for basic operation of FAN48630BUC34X.

Does the FAN48630BUC34X support true bypass mode, and how is it activated?

Yes, the FAN48630BUC34X supports true bypass mode both automatically and forcibly. Automatic bypass engages when VIN exceeds VOUT_TARGET + 25 mV (with hysteresis), turning on internal P-channel switches Q1 and Q3 to create a low-impedance path. Forced bypass is activated by pulling the BYP pin LOW, which disables switching and reduces quiescent current to 4–10 µA. In forced bypass, short-circuit protection remains active only in OCP-On variants - the FAN48630BUC34X uses Low IQ mode, deactivating OCP during bypass.

What package type and dimensions does the FAN48630BUC34X use?

The FAN48630BUC34X uses a 16-bump Wafer-Level Chip-Scale Package (WLCSP) with 0.4 mm pitch, measuring 1.78 mm × 1.78 mm × 0.586 mm (Case 567SY). It features backside lamination - a structural reinforcement explicitly confirmed for FAN48630BUC34X in the identity context - improving mechanical durability and thermal dissipation. The top marking is "JR", per Table 1 ordering information.

How does the FAN48630BUC34X handle thermal protection and fault reporting?

The FAN48630BUC34X incorporates dual thermal thresholds: die temperature shutdown triggers at 150°C (T150T) with 20°C hysteresis (T150H), and early-warning thermal flag pulls PG LOW when junction exceeds 120°C (T120A). PG is an open-drain output that also asserts LOW during overload or startup failure. After a fault, the device enters FAULT state, halts switching, and attempts automatic restart after 20 ms (tRST). These protections are fully active in boost mode and partially retained in forced bypass (Low IQ variant disables OCP and UVLO).

What are the key differences between the FAN48630BUC34X and the standard FAN48630UC34X?

The FAN48630BUC34X differs from FAN48630UC34X solely by inclusion of backside lamination - a mechanical enhancement confirmed in the identity context for this exact part number. Both share identical electrical specifications: 3.20 V / 3.40 V output, FAST soft-start, Low IQ forced bypass, and WLCSP16 packaging. Backside lamination improves board-level reliability under mechanical stress (e.g., flex or drop), making FAN48630BUC34X preferred for consumer handhelds, while FAN48630UC34X suits cost-sensitive, static-mount applications.