onsemi FAN53526UC224X

Overview

FAN53526UC224X from onsemi is a digitally programmable 3.0 A synchronous step-down DC-DC regulator with I²C interface, operating at 2.4 MHz fixed frequency and delivering 0.75 V output from 2.5–5.5 V input. It features PFM/PWM auto-mode switching, 6.25 mV programmable voltage steps, and integrated thermal/overcurrent protection-used in mobile SoC core power delivery for ARM/Tegra processors.

For engineers reviewing the FAN53526UC224X datasheet, pinout, applications, or equivalent options, key selection criteria include its 0.75 V default output, WLCSP-15 package footprint, 50 µA quiescent current in PFM mode, and I²C slave address C0h-critical for low-power, space-constrained embedded power management designs.

Technical Context

The FAN53526UC224X implements a proprietary non-linear fixed-frequency PWM modulator with synchronous rectification, enabling >80% efficiency across 10 mA–3.0 A load range while maintaining stable 2.4 MHz operation independent of input voltage or output capacitance ESR. Its architecture supports seamless transitions between continuous conduction mode (CCM) and discontinuous conduction mode (DCM) PFM.

Control is delivered via I²C up to 3.4 Mbps (High-Speed Mode), supporting dynamic voltage scaling (DVS) with eight programmable slew rates (0.5–64 mV/s), hardware/software enable coordination through EN/VSEL pins, and register-based output discharge control-enabling precise sequencing and transient response in multi-rail SoC systems.

Key Specifications

Pinout & Package

Package: 15-bump Wafer-Level Chip Scale Package (WLCSP), 1.310 mm × 2.015 mm, 0.4 mm ball pitch, case 567QS.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down regulator applications.

Compared with TPS6286410RQYR and RTQ2134BGQW, the FAN53526UC224X uniquely combines factory-default 0.75 V, programmable slew rate, and seamless PFM/PWM transition-making it optimal for mobile SoC core power where dynamic efficiency and voltage ramp control are critical.

Availability

FAN53526UC224X is available at Aetrix Electronics and suitable for smartphone SoC power, LPDDR memory regulation, and automotive infotainment systems requiring stable component supply and long-term lifecycle support.

Supply support for FAN53526UC224X 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 is a global semiconductor supplier delivering energy-efficient silicon solutions for automotive, industrial, cloud, medical, and IoT applications-with leadership in power management, imaging, and intelligent sensing.

The FAN53526 belongs to onsemi's TinyBuck family of ultra-compact, digitally programmable DC-DC regulators designed specifically for core voltage delivery in space-constrained mobile and embedded processors.

FAQ

What is the default output voltage of the FAN53526UC224X?

The FAN53526UC224X has a factory-programmed default output voltage of 0.75 V, set by the VSEL0 register at power-on reset. This value is confirmed in Table 1 of the datasheet and matches the "VSEL0" column entry for this part number. The FAN53526UC224X maintains this 0.75 V output unless reprogrammed via I²C or overridden by asserting the VSEL pin high to select VSEL1.

Does the FAN53526UC224X support I²C High-Speed Mode?

Yes, the FAN53526UC224X supports I²C High-Speed Mode up to 3.4 Mbps, as specified in Table 9 and the Operating Description section. Its SCL/SDA pins meet HS Mode timing requirements including tRCL/tFCL ≤ 80 ns (CB ≤ 100 pF). The FAN53526UC224X uses standard I²C addressing (C0h) and requires the master to send the HS master code 00001XXX to initiate HS Mode communication.

What package type and dimensions does the FAN53526UC224X use?

The FAN53526UC224X uses a 15-bump Wafer-Level Chip Scale Package (WLCSP) with dimensions 1.310 mm × 2.015 mm and 0.4 mm ball pitch, designated as case 567QS. This information is explicitly stated in the "Features" section and "Ordering Information" table. The FAN53526UC224X requires microvia PCB design and reflow profile optimization compatible with 0.4 mm pitch WLCSP components.

How does the FAN53526UC224X handle light-load efficiency?

The FAN53526UC224X achieves high light-load efficiency using Pulse Frequency Modulation (PFM) mode, delivering 50 µA typical quiescent current at room temperature. Below ~100 mA load, it automatically enters DCM PFM operation-reducing switching losses while maintaining excellent transient response. The FAN53526UC224X allows PFM to be disabled via I²C register 02h MODE bits if fixed-frequency operation is required for EMI control.

What protection features are integrated into the FAN53526UC224X?

The FAN53526UC224X integrates input under-voltage lockout (UVLO, 2.45 V threshold), input over-voltage protection (OVP, 6.15 V rising threshold), thermal shutdown (150 °C with 17 °C hysteresis), and peak current limiting (4.75 A typical). These protections are detailed in Tables 5–8 and the Operating Description. The FAN53526UC224X disables switching during fault conditions and recovers autonomously after fault clearance-no external circuitry needed.