1

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FN6412.1

ISL6423B

Single Output LNB Supply and Control

Advanced Satellite Set-Top Box Designs

The ISL6423B 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 singe antenna

ports. The device consists of a current-mode boost PWM

and a low-noise linear regulator along with the circuitry

device interface. The device makes the total LNB supply

design simple, efficient and compact with low external

component count.

The current-mode boost converters provides the linear

regulator with input voltage that is set to the final output

voltages, plus typically 0.8V to insure minimum power

dissipation across each linear regulator. This maintains

constant voltage drop across the linear pass element while

permitting adequate voltage range for tone injection.

The final regulated output voltage is available at output

terminals to support the operation of an antenna port for

single tuners. The outputs for each PWM can be controlled

switch to higher range i.e., 18V/19V, with the SELVTOP pin.

writing 8 bits words onto the System Registers (SR). The

the diagnostic status. Separate enable command sent on the

linear combination, disabling the output and forcing a shutdown

mode. The output channel is capable of providing 750mA of

continuous current. The overcurrent limit can be digitally

programmed to four levels.

The External modulation input EXTM can accept a

modulated Diseqc command and transfer it symmetrically to

the output. Alternatively the EXTM pin can be used to

modulate the continuos internal tone.

The FLT pin serves as an interrupt for the processor when

any condition turns OFF the LNB controller (Over

Temperature, Overcurrent, Disabled). The nature of the

Features

• Single Chip Power solution

- Operation for 1-Tuner/1-Dish Applications

• Switch-Mode Power Converter for Lowest Dissipation

- Boost PWMs with >92% Efficiency

- Selectable 13.3V or 18.3V Outputs

- Digital Cable Length Compensation (1V)

• Output Back Bias Capability of 28V

• Registered Slave Address 0001 00XX

• 2.5V, 3.3V, 5V Logic Compatible

• External Pin to Toggle Between V and H Polarization

• Built-In Tone Oscillator Factory Trimmed to 22kHz

- Facilitates DiSEqC (EUTELSAT) Encoding

- External Modulation Input

• Internal Over-Temperature Protection and Diagnostics

• Internal OV, UV, Overload and Overtemp Flags

•FLT signal

• LNB Short-Circuit Protection and Diagnostics

• QFN, EPTSSOP Packages

• Pb-Free Available (RoHS Compliant)

Applications

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

Ordering Information

PART

NUMBER*

PART

MARKING

TEMP.

(°C)

PACKAGE

PKG.

DWG. #

ISL6423BERZ

(Note)

6423BERZ

-20 to +85 24 Ld 4x4 QFN

(Pb-free)

L24.4x4D

ISL6423BEVEZ

(Note)

ISL6423BEVEZ -20 to +85 28 Ld EPTSSOP

(Pb-free)

M28.173B

NOTE: Intersil Pb-free plus anneal products employ special Pb-free

material sets; molding compounds/die attach materials and 100% matte

tin plate termination finish, which are RoHS compliant and compatible

with both SnPb and Pb-free soldering operations. Intersil Pb-free

products are MSL classified at Pb-free peak reflow temperatures that

meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.

Add “-T” suffix for tape and reel.

Data Sheet

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 1-888-468-3774

Copyright Intersil Americas Inc. 2006, 2007. All Rights Reserved

All other trademarks mentioned are the property of their respective owners.

April 10, 2007