LNBS21 Datasheet, PDF (1/19 Pages) STMicroelectronics – LNB SUPPLY AND CONTROL IC WITH STEP-UP CONVERTER AND I2C INTERFACE

LNBS21
LNB SUPPLY AND CONTROL IC WITH
STEP-UP CONVERTER AND I²C INTERFACE
s COMPLETE INTERFACE BETWEEN LNB
AND I2CTM BUS
s BUILT-IN DC/DC CONTROLLER FOR
SINGLE 12V SUPPLY OPERATION
s ACCURATE BUILT-IN 22KHz TONE
OSCILLATOR
s SUITS WIDELY ACCEPTED STANDARDS
s FAST OSCILLATOR START-UP FACILITATES
DiSEqCTM ENCODING
s BUILT-IN 22KHz TONE DETECTOR
SUPPORTS BI-DIRECTIONAL DiSEqCTM
s LOOP-THROUGH FUNCTION FOR SLAVE
OPERATION
s LNB SHORT CIRCUIT PROTECTION AND
DIAGNOSTIC
s CABLE LENGTH DIGITAL COMPENSATION
s INTERNAL OVER TEMPERATURE
PROTECTION
DESCRIPTION
Intended for analog and digital satellite STB
receivers/SatTV, sets/PC cards, the LNBS21 is a
monolithic voltage regulator and interface IC,
SCHEMATIC DIAGRAM
PowerSO-20
assembled in PowerSO-20, specifically designed
to provide the power and the 13/18V, 22KHz tone
signalling to the LNB downconverter in the
antenna or to the multiswitch box. In this
application field, it offers a complete solution with
extremely low component count, low power
dissipation together with simple design and I²C^TM
standard interfacing.
This IC has a built in DC/DC step-up controller
that, from a single supply source ranging from 8 to
15V, generates the voltages that let the linear
Gate
Sense
LNBS21
Step-up
Controller
Feedback
Vup
Vcc
Byp
Preregul.+
U.V.lockout
+P.ON res.
SDA
SCL
ADDR
DSQIN
I²C
interf.
Enable
I Select
V Select
Linear Post-reg
+Modulator
+Protections
Diagnostics
22KHz
Oscill.
Tone
Detector
LT1
LT2
OUT
EXTM
DETIN
DSQOUT
November 2002
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