1
FN6486.2
ISL6422B
Dual Output LNB Supply and Control
Voltage Regulator with I
2
C Interface for
Advanced Satellite Set-Top Box Designs
The ISL6422B 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 consists of two independent current-
mode boost PWMs and two low-noise linear regulators along
with the circuitry required for 22kHz tone generation,
modulation and I
2
C 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 0.8V 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.
The final regulated output voltages are available at two
output terminals to support simultaneous operation of two
antenna ports for dual tuners. The outputs for each PWM
can be controlled in two ways, full control from I
2
C using the
VTOP1, VTOP2 and VBOT1, VBOT2 bits or set the I
2
C to
the lower range ie 13V/14V and switch to higher range ie
18V/19V with the SELVTOP1, SELVTOP2 pins. All the
functions on this IC are controlled via the I
2
C bus by writing
8 bits words onto the System Registers (SR). The same
register can be read back, and four bits per output will report
the diagnostic status. Separate enable commands sent on the
I
2
C bus provide independent standby mode control for each
PWM and linear combination, disabling the output into
shutdown mode. Each output channel is capable of providing
750mA of continuous current. The overcurrent limit can be
digitally programmed.
The External modulation input EXTM1, EXTM2 can accept a
modulated DiSEqC command and transfer it symetrically to
the output. Alternatively the EXTM1, EXTM2 pins can be
used to modulate the continuous internal tone.
The FLT
pin serves as an interrupt for the processor when any
condition turns OFF the LNB controller (Over- Temperature,
Overcurrent, Disable). The nature of the fault can be read of
the I
2
C registers.
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 I
2
C Interface
• Switch-Mode Power Converter for Lowest Dissipation
- Boost PWMs with >92% Efficiency
- Selectable 13.3V or 18.3V Outputs
- Digital Cable Length Compensation (1V)
-I
2
C and Pin Controllable Output
• Output Back Bias Capability of 28V
•I
2
C Compatible Interface for Remote Device Control
• Four level Slave Address 0001 00XX
• 2.5V/3.3V/5V Logic Compatible
• External Pins 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 (Visible on
I
2
C)
•FLT
Signal
• LNB Short-Circuit Protection and Diagnostics
• QFN and EPTSSOP Packages
• Pb-Free Plus Anneal Available (RoHS Compliant)
Applications
• LNB Power Supply and Control for Satellite Set-Top Box
Ordering Information
PART NUMBER
(Note)
PART
MARKING
TEMP.
RANGE
(°C)
PACKAGE
(Pb-Free)
PKG.
DWG. #
ISL6422BERZ* 6422B ERZ -20 to +85 40 Ld 6x6 QFN L40.6x6
ISL6422BEVEZ*
(No longer
available,
Recommended
Replacement
ISL6422BERZ)
6422B EVEZ -20 to +85 38 Ld EPTSSOP M38.173B
*Add “-T” suffix for tape and reel.
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.
Data Sheet
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
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September 8, 2015
