onsemi FAN2106EMPX

Overview

FAN2106EMPX from ON Semiconductor (formerly Fairchild) is a fully integrated 6 A synchronous buck regulator with internal high- and low-side MOSFETs, operating from 3 V to 24 V input and delivering adjustable output from 0.8 V to 80% VIN. It features programmable 200–600 kHz switching frequency, 1% reference accuracy over temperature, and integrated protections including over-current, over-voltage, under-voltage, and thermal shutdown - deployed in server point-of-load and graphics card power delivery.

For engineers reviewing the FAN2106EMPX datasheet, pinout, applications, or equivalent options, key selection considerations include its 5×6 mm 25-pin MLP package with three exposed PGND pads, external loop compensation capability, pre-biased startup support, and lossless current-mode control architecture optimized for ceramic-output designs.

Technical Context

The FAN2106EMPX implements a summing current-mode PWM controller with voltage feedforward via the RAMP pin, enabling stable operation across its full 3–24 V input range. Its modulator sums an amplified current-sense signal with an internally generated ramp, compared against the error amplifier output to drive the high-side MOSFET.

It integrates both power MOSFETs and gate drivers on a single BiCMOS die within a thermally enhanced 5×6 mm MLP package, featuring internal bootstrap diode, soft-start circuitry, and open-drain PGOOD flag with ±10% VREF threshold accuracy. The IC supports external compensation (Type-2 or Type-3), programmable current limit via ILIM resistor, and fault auto-restart or latch-off configuration via EN pin biasing.

Key Specifications

Pinout & Package

Package: 5 mm × 6 mm, 25-pin Molded Leadless Package (MLP) with three exposed thermal pads (P1, P2, P3) for enhanced heat dissipation. Pin layout follows bottom-view configuration with dedicated SW, VIN, PGND, and AGND terminals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP2451DT-LF-Z and TPS54620RGYR, the FAN2106EMPX offers the only monolithic 6 A solution in a 5×6 mm MLP with pre-biased startup, lossless current sensing, and full protection set - making it optimal for cost-sensitive, space-constrained analog-controlled PoL designs.

Availability

FAN2106EMPX is available at Aetrix Electronics and suitable for server point-of-load regulation, graphics card core power, and industrial computing SoM power requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for FAN2106EMPX 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

ON Semiconductor is a global semiconductor supplier delivering energy-efficient silicon solutions for automotive, industrial, cloud computing, and IoT applications.

The FAN2106EMPX belongs to ON Semiconductor's integrated power management product line, designed specifically for high-current, space-constrained DC-DC conversion in computing and communications infrastructure where thermal performance and reliability are critical.

FAQ

What is the maximum input voltage rating for the FAN2106EMPX?

The FAN2106EMPX has an absolute maximum VIN-to-PGND rating of 28 V, with recommended operation up to 24 V. Exceeding 24 V risks violating safe operating area limits of internal MOSFETs and may trigger over-voltage protection or cause permanent damage. Designers should maintain ≥2 V margin below 28 V for transient spikes, especially in automotive or industrial environments where input ripple can exceed nominal ratings. The FAN2106EMPX datasheet specifies 3–24 V as the functional input range.

Does the FAN2106EMPX support startup into a pre-biased output?

Yes, the FAN2106EMPX supports startup into a pre-biased output by disabling full synchronous rectification until the internal soft-start ramp reaches ~95% of the 0.8 V reference (~0.76 V). This prevents the low-side MOSFET from discharging an existing output voltage during startup. Verified in Figure 16 of the FAN2106EMPX datasheet, this feature is essential for multi-rail systems where sequencing constraints prohibit rail collapse. No external components are required to enable this behavior.

What package type and thermal characteristics does the FAN2106EMPX use?

The FAN2106EMPX uses a 5 mm × 6 mm, 25-pin Molded Leadless Package (MLP) with three exposed thermal pads (P1, P2, P3). Its thermal resistance is specified as θJC = 4°C/W (P1 and P3) and 7°C/W (P2), and θJ-PCB = 35°C/W on a standard 4-layer, 2-oz copper PCB. These values enable 6 A continuous operation without external heatsinking when properly mounted with thermal vias. The FAN2106EMPX MLP package is RoHS-compliant and halogen-free.

How is the switching frequency programmed on the FAN2106EMPX?

The switching frequency of the FAN2106EMPX is programmed using an external resistor (RT) connected between the R(T) pin and AGND. The relationship is approximated by fSW (kHz) ≈ 135 / RT (kΩ) – 65, yielding 200–600 kHz across 24–50 kΩ. RT must not be left open, as the device will not start. Frequency accuracy varies ±15% over temperature and process; for tighter tolerance, select 1% metal-film resistors. The FAN2106EMPX datasheet provides Figure 6 showing measured frequency vs. RT.

What protections are built into the FAN2106EMPX?

The FAN2106EMPX integrates over-current (cycle-by-cycle and fault-latched), over-voltage (110–120% VOUT), under-voltage (68–78% VOUT), over-temperature (155°C trip, 30°C hysteresis), and VCC UVLO (4.1–4.5 V) protections. All protections except UVLO and under-voltage are active during soft-start. Fault responses include latched shutdown or auto-restart, configurable via EN pin biasing per Table 1 in the FAN2106EMPX datasheet. No external components are needed to activate these protections.