ISL9492_1103 Datasheet, PDF (1/21 Pages) Intersil Corporation – Single Output LNB Supply and Control Voltage Regulator

Single Output LNB Supply and Control Voltage Regulator
with I²C Interface for Satellite Set-Top Box Designs
ISL9492
The ISL9492 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 (LNB) of a single antenna port. It also supports
DiSEqC tone generation and modulation with diagnostic status
read-back. Controlling the ISL9492 is simple via the I²C bus by
writing 8 bit words onto the System Registers (SR).
The device design makes the total LNB supply design simple,
efficient and compact with low external component count by
integrating Boost power MOSFET, current-mode boost PWM and
a low-noise linear regulator. The current-mode boost converters
provide the linear regulator with input voltage that is set to the
final output voltages, plus typically 0.9V to insure minimum
power dissipation across each linear regulator.
The LNB output voltage can be controlled in two ways; by full control
from I²C using the VTOP and VBOT bits or by setting the I²C to the
lower range and switching to higher range with the select VTOP pin.
The External modulation input EXTM accepts a modulated DISEqC
command and transfers it symmetrically to the output. The EXTM
pin can be used to modulate the continuous internal tone. The fault
signal serves as an interrupt for the processor when any condition
turns OFF the LNB controller (over-temperature, overcurrent,
disable). The states of these flags to the faults can be thoroughly
examined through the I²C registers.
Features
• Single-Chip Power Solution
- Operation for 1-Tuner/1-Dish Applications
- Integrated DC/DC Converter and I²C Interface
• Integrated Boost MOSFET
• Switch-Mode Power Converter for Lowest Dissipation
- 490kHz Boost Switching Frequency
- Boost PWMs with > 92% Efficiency
- Selectable 13.5V or 18.5V Outputs
- I²C and Pin Controllable Output
• 31V Output Back-Bias Capability
• Built-in Tone Oscillator Factory
- Facilitates DiSEqC (EUTELSAT) Encoding
- Trimmed to 22kHz
- External Modulation Input
• DiSEqC 2.0 Support and Diagnostics
• Internal Overvoltage, Undervoltage, Overcurrent Protection,
Over-Temperature Flags Accessible through the I²C Interface
and Fault Signal Status Pin
• Short-Circuit Protection
Applications
• LNB Power Supply and Control for Satellite Set-Top Box
TXT
TDOUT
EXTM
C1
0.047µF
C2
1µF
C5
2.2nF
C3
1µF
FERRITE
BEAD
VIN
March 17, 2011
1
FN6547.1
27 _CPVOUT
28 _CPSWOUT
1 _CPSWIN
6 _VCC
20 _{LDO_SGND} ISL9492
25 _{LDO_SGND}
5 _ABYP
9 _PGND
FLT# ²¹
SCL ¹⁷
SDA ¹⁶
DBYP ¹⁰
TCAP ²²
NC ⁴
DGATE ²³
Cp
See pg 14
L1
10µH
C10
100µF
Rp
D1
100
CMS06
C7
100µF
R1
100k
C4
1µF
C8
0.22µF
C6
0.1µF
RL
100
Q1
NDS356AP
C9
C10
0.1µF
0.22µF
L3
L2
220µH
R2
1µH
15
C11
10µF
D4
CMS06
FLT#
3.3V
SCL
SDA
LNB
POWER
FIGURE 1. TYPICAL APPLICATION
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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