ISL6422 Datasheet, PDF (1/19 Pages) Intersil Corporation – Dual Output LNB Supply and Control Voltage Regulator with I2C Interface for Advanced Satellite Set-Top Box Designs

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Data Sheet
April 10, 2007
ISL6422
FN9190.1
Dual Output LNB Supply and Control
Voltage Regulator with I²C Interface for
Advanced Satellite Set-Top Box Designs
The ISL6422 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 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 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 I²C using the VTOP1, VTOP2, VBOT1,
and VBOT12 bits, or
• Set the I²C to the lower range (13V/14V) and switch to the
higher range (18V/19V) with the SELVTOP1 or
SELVTOP2 pin.
All the functions on this IC are controlled via the I²C bus by
writing 8-bit 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 I²C 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 EXTM1/2 can accept a
modulated Diseqc command and transfer it symmetrically to
the output. Alternatively, the EXTM1 or EXTM2 pin can be
used to modulate the continuous internal tone.
The FLT pin serves as an interrupt for the processor when
an over temperature, overcurrent or backwards overcurrent
fault conditions is detected by the LNB controller or when
both channels are disabled by the I²C EN bits set low. The
nature of the fault can be read of the I²C 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 I²C 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)
- I²C and Pin controllable output
• Output Back Bias Capability of 28V
• I²C 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.
• Supports DiSEqC 2.0 Protocol
• 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 I²C)
• FLT Signal
• LNB Short-Circuit Protection and Diagnostics
• QFN, EPTSSOP Packages
• Pb-Free Plus Anneal Available (RoHS Compliant)
Applications
• LNB Power Supply and Control for Satellite Set-Top Box
Ordering Information
PART NUMBER PART
(Note)
MARKING
TEMP.
RANGE
(°C)
PACKAGE
(Pb-free)
PKG.
DWG. #
ISL6422ERZ ISL6422ERZ -20 to +85 40 Ld 6x6 QFN L40.6x6
ISL6422ERZ-T ISL6422ERZ -20 to +85 40 Ld 6x6 QFN L40.6x6
(Tape and Reel)
ISL6422EVEZ ISL6422EVEZ -20 to+ 85 38 Ld EPTSSOP M38.173B
ISL6422EVEZ-T ISL6422EVEZ -20 to +85 38 Ld EPTSSOP M38.173B
(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.
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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