Renesas ISL6446AIAZ-TK

Overview

ISL6446AIAZ-TK from Renesas Electronics is a triple-output power controller integrating two 180° out-of-phase voltage-mode PWM buck controllers and one linear controller for broadband, DSL, and networking point-of-load regulation. It supports 4.5V–24V input, delivers regulated outputs down to 0.6V ±1.5%, operates at programmable switching frequencies from 100kHz to 2.5MHz, and reduces input ripple via interleaved operation - used in ATX power supplies and FPGA/DSP core voltage regulation.

For engineers reviewing the ISL6446AIAZ-TK datasheet, ISL6446AIAZ-TK pinout, ISL6446AIAZ-TK application, or ISL6446AIAZ-TK equivalent, this page provides verified technical context, confirmed pin functions, real-world application scenarios, validated alternative parts, and supply-chain support details specific to the ISL6446AIAZ-TK in 24-lead QSOP packaging.

Technical Context

The ISL6446AIAZ-TK implements dual synchronous buck converters with fixed 180° phase offset and independent voltage-mode control loops, each featuring a 0.6V reference, ±1.5% output tolerance over line/temperature, and lossless r_DS(ON)-based overcurrent sensing. Its third channel is a transconductance linear controller (g_m = 2A/V) driving external PNP or PMOS pass devices with 50mA sink capability and 0.57V–0.62V LCFB threshold.

Core timing and protection are tightly integrated: a single RT resistor sets oscillator frequency (100kHz–2.5MHz); SS1/EN1 and SS2/EN2 pins combine soft-start ramping (30µA current source, 3.12V top) with enable/disable logic; PGOOD asserts only after both PWM outputs settle within ±10% and linear output exceeds 75% of nominal - all monitored by dedicated comparators separate from OVP/UVP/OC fault circuits.

Key Specifications

Pinout & Package

ISL6446AIAZ-TK is housed in a 24-lead QSOP (RoHS-compliant, M24.15 package) with exposed pad thermal enhancement. Pin assignments follow standard ISL6446A topology: dual gate drivers (UGATE/LGATE/BOOT/PHASE), independent feedback (FB1/FB2) and compensation (COMP1/COMP2), shared control (RT, SGND, PGND), and dedicated linear control (LCFB, LCDR).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple-output controller applications.

Compared with MP8765GL-Z and TPS546D24RSAR, the ISL6446AIAZ-TK uniquely combines interleaved dual PWM, lossless current sensing, and an integrated linear controller in a single analog IC - delivering superior input ripple suppression, higher efficiency at medium loads, and simpler BOM for multi-rail embedded power systems.

Availability

ISL6446AIAZ-TK is available at Aetrix Electronics and suitable for ATX power supplies, FPGA point-of-load regulation, and industrial networking applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for ISL6446AIAZ-TK 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

Renesas Electronics is a global semiconductor leader specializing in microcontrollers, analog power management, and timing solutions for automotive, industrial, and communications markets.

The ISL6446AIAZ-TK belongs to Renesas' high-performance power controller product line, designed specifically for broadband, DSL, and networking equipment requiring compact, efficient, and highly integrated multi-rail DC/DC solutions.

FAQ

What input voltage ranges does the ISL6446AIAZ-TK support?

The ISL6446AIAZ-TK supports two distinct input configurations: 4.5V–5.5V applied directly to the VCC pin, or 5.5V–24V applied to the VIN pin, which powers an internal 5V linear regulator. This dual-input architecture allows flexible system-level power design - for example, using a clean 5V rail for bias and a higher-voltage bulk supply for the buck stages. The device automatically selects the appropriate internal path based on pin connection.

How does the ISL6446AIAZ-TK achieve lossless overcurrent protection?

The ISL6446AIAZ-TK implements lossless overcurrent protection by monitoring the voltage drop across the upper MOSFET's r_DS(ON) during conduction. An internal 110µA current source pulls down the OCSET pin, establishing a trip threshold relative to VIN. When the PHASE node voltage falls below this threshold while the upper gate is active, the controller terminates the pulse and increments a fault counter. After 32 consecutive cycles, it latches off - eliminating the need for external sense resistors and their associated power loss and board area.

Can the ISL6446AIAZ-TK soft-start into a prebiased output?

Yes, the ISL6446AIAZ-TK supports soft-start into prebiased loads on both PWM outputs. When the SS/EN pin voltage ramps up, the upper and lower FETs remain off until the ramp crosses the prebiased output voltage - then regulation resumes seamlessly. This behavior prevents reverse current flow and output collapse during hot-swap or partial-power-up scenarios. The linear controller does not have soft-start but may track its input supply's ramp if sourced from a PWM output.

What is the function of the PGOOD signal on the ISL6446AIAZ-TK?

The PGOOD signal on the ISL6446AIAZ-TK is an open-drain output that goes high only after all three regulated outputs meet defined thresholds: both PWM outputs must be within ±10% of their nominal values, and the linear output must exceed 75% of its nominal value. A built-in delay (e.g., 46ms at 1.4MHz) starts once these conditions are met. If any output violates its window, PGOOD immediately pulls low - providing reliable power sequencing feedback for host processors or supervisors.

What package type and thermal characteristics apply to the ISL6446AIAZ-TK?

The ISL6446AIAZ-TK is packaged in a 24-lead QSOP (M24.15 drawing) with RoHS-compliant matte tin plating. Its thermal resistance is θ_JA = 75°C/W and θ_JC = 36°C/W. The device incorporates thermal shutdown at +150°C with 20°C hysteresis. For reliable operation at full load, PCB layout must include adequate copper pour on the exposed pad (if present in variant) and minimize thermal resistance between the package and ambient - especially when operating at high VIN and high f_SW.