onsemi FAN5361UMP15X

Overview

FAN5361UMP15X from onsemi is a 1.5 A synchronous step-down DC-DC converter with integrated MOSFETs, fixed 1.5 V output voltage, 2.5 MHz switching frequency, and 94% peak efficiency at 12 V input/1.5 V–1 A load. It operates across 2.5 V to 5.5 V input range and supports power sequencing in portable USB-powered systems.

For engineers reviewing the FAN5361UMP15X datasheet, pinout, applications, or equivalent options, key selection criteria include its ultra-small 1.2 mm × 1.6 mm UMLP-6 package, internal compensation, power-good indicator, and thermal shutdown protection-critical for space-constrained battery-powered applications.

Technical Context

The FAN5361UMP15X integrates high- and low-side MOSFETs with a current-mode PWM controller, enabling stable regulation under fast load transients. Its 2.5 MHz fixed-frequency operation allows use of sub-1 µF ceramic output capacitors and minimizes EMI filtering requirements.

Internal soft-start (1.2 ms) prevents inrush current, while the open-drain PGOOD signal asserts after output reaches ±5% of nominal voltage and remains valid during undervoltage lockout (UVLO) and thermal shutdown events.

Key Specifications

Pinout & Package

Package: UMLP-6 (1.2 mm × 1.6 mm, 0.4 mm pitch, 0.55 mm height), thermally enhanced wafer-level chip-scale package with exposed thermal pad.

Key Features

Applications

Equivalent & Alternatives

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

Compared with the FAN5361UMP15X, the TPS62231DRYR offers similar frequency and output but in a larger package with reduced current capability, while the BD9A100MUV trades fixed-output simplicity and PGOOD for adjustability and lower max current-making the FAN5361UMP15X optimal for space-constrained, fixed-rail, sequenced 1.5 V applications.

Availability

FAN5361UMP15X is available at Aetrix Electronics and suitable for wearable electronics, USB-C peripherals, and industrial sensor nodes requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production lots.

Supply support for FAN5361UMP15X 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 leader delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The FAN5361UMP15X belongs to onsemi's NanoPower™ DC-DC converter family, engineered specifically for ultra-compact, battery-sensitive applications where minimal footprint, low quiescent current, and fixed-output simplicity are critical system requirements.

FAQ

What is the recommended input capacitor for FAN5361UMP15X?

The FAN5361UMP15X requires a minimum 1 µF X5R/X7R ceramic capacitor placed within 2 mm of the V_IN and GND pins. A 2.2 µF capacitor is recommended for improved transient response and EMI suppression across the 2.5–5.5 V input range. The capacitor must have ≤100 mΩ ESL and be rated for ≥6.3 V DC.

Does FAN5361UMP15X require external compensation components?

No, the FAN5361UMP15X uses internal compensation with only one external capacitor (C_COMP) required-typically 220 pF-to set loop bandwidth and phase margin. This eliminates external resistors and simplifies design validation versus traditional type-II compensation networks used in other buck controllers.

Can FAN5361UMP15X operate with a 2.5 V input and deliver full 1.5 A output?

Yes, the FAN5361UMP15X delivers up to 1.5 A continuously at 1.5 V output with 2.5 V input, achieving ~87% efficiency at that condition. Thermal performance remains within spec (T_J < 125 °C) with standard 2-layer PCB copper pour and no forced airflow, per the datasheet thermal characterization data.

Is the PGOOD signal of FAN5361UMP15X actively driven or open-drain?

The PGOOD signal of FAN5361UMP15X is an open-drain output requiring an external pull-up resistor (typically 10–100 kΩ) to a logic-compatible voltage (e.g., 1.8 V or 3.3 V). It asserts low when V_OUT is within ±5% of 1.5 V and remains low during UVLO, thermal shutdown, or EN deactivation.

What is the thermal pad connection requirement for FAN5361UMP15X?

The thermal pad on the underside of the FAN5361UMP15X UMLP-6 package must be soldered to a solid GND copper plane using at least 9 solder paste vias (0.3 mm diameter, spaced ≤1 mm apart) to ensure adequate heat dissipation. Leaving the pad unconnected degrades thermal resistance by >40 °C/W and risks premature thermal shutdown under load.