The ISL6424 is a highly integrated voltage regulator and interface IC, specifically designed for supplying power and control signals from advanced satellite set-top box (STB) modules to the low noise blocks (LNBs) of two antenna ports. The device is comprised of two independent current mode boost PWMs and two low-noise linear regulators along with the circuitry required for 22kHz tone generation, modulation and I2C device interface. The device makes the total LNB supply design simple, efficient and compact with low external component count.

Two independent current-mode boost converters provide the linear regulators with input voltages that are set to the final output voltages, plus typically 1.2V to insure minimum power dissipation across each linear regulator. This maintains constant voltage drops across each linear pass element while permitting adequate voltage range for tone injection.

Features

• Single Chip Power Solution

   - True Dual Operation for 2-Tuner/2-Dish Applications

   - Both Outputs May be Enabled Simultaneously at Maximum Power

   - Integrated DC-DC Converter and I2C Interface

• Switch-Mode Power Converter for Lowest Dissipation

   - Boost PWMs with > 92% Efficiency

   - Selectable 13V or 18V Outputs

   - Digital Cable Length Compensation (1V)

• I2C Compatible Interface for Remote Device Control

   - Registered Slave Address 0001 00XX

   - Full 3.3V/5V Operation up to 400kHz

• External Pins to Select 13V/18V Option

• DSQIN1&2 and SEL18V1&2 pins 2.5V Logic Compatible

• Built-In Tone Oscillator Factory Trimmed to 22kHz

   - Facilitates DiSEqC (EUTELSAT) Encoding

• Internal Over-Temperature Protection and Diagnostics

• Internal Overload and Overtemp Flags (Visible on I2C)

• LNB Short-Circuit Protection and Diagnostics

• QFN Package

   - Compliant to JEDEC PUB95 MO-220 QFN - Quad Flat No Leads - Product Outline

   - Near Chip-Scale Package Footprint

• Pb-Free Plus Anneal Available (RoHS Compliant)

Applications

• LNB Power Supply and Control for Satellite Set-Top Box