LNBH21 Datasheet, PDF (1/20 Pages) STMicroelectronics – LNB SUPPLY AND CONTROL IC WITH STEP-UP CONVERTER AND I2C INTERFACE

LNBH21
LNB SUPPLY AND CONTROL IC WITH
STEP-UP CONVERTER AND I²C INTERFACE
s COMPLETE INTERFACE BETWEEN LNB
AND I²C^TM BUS
s BUILT-IN DC/DC CONTROLLER FOR
SINGLE 12V SUPPLY OPERATION AND
HIGH EFFICIENCY (Typ. 94% @ 750mA)
s TWO SELECTABLE OUTPUT CURRENT
LIMIT (450mA / 750mA)
s BOTH COMPLIANT WITH EUTELSAT AND
DIRECT OUTPUT VOLTAGE
SPECIFICATION
s ACCURATE BUILT-IN 22KHz TONE
OSCILLATOR SUITS WIDELY ACCEPTED
STANDARDS
s FAST OSCILLATOR START-UP FACILITATES
DiSEqC^TM ENCODING
s BUILT-IN 22KHz TONE DETECTOR
SUPPORTS BI-DIRECTIONAL DiSEqC^TM2.0
s SEMI-LOWDROP POST REGULATOR AND
HIGH EFFICIENCY STEP-UP PWM FOR
LOW POWER LOSS: Typ. 0.56W @ 125mA
s TWO OUTPUT PINS SUITABLE TO BYPASS
THE OUTPUT R-L FILTER AND AVOID ANY
TONE DISTORSION (R-L FILTER AS PER
DiSEqC 2.0 SPECs, see application circuit on
pag. 5)
s CABLE LENGTH DIGITAL COMPENSATION
s OVERLOAD AND OVER-TEMPERATURE
INTERNAL PROTECTIONS
BLOCK DIAGRAM
PowerSO-20
s OVERLOAD AND OVER-TEMPERATURE I²C
DIAGNOSTIC BITs
s LNB SHORT CIRCUIT SOA PROTECTION
WITH I²C DIAGNOSTIC BIT
s +/- 4KV ESD TOLERANT ON INPUT/
OUTPUT POWER PINS
DESCRIPTION
Intended for analog and digital satellite STB
receivers/SatTV, sets/PC cards, the LNBH21 is a
monolithic voltage regulator and interface IC,
assembled in POWER SO-20, specifically
designed to provide the 13/18V power supply and
the 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.
Gate
Sense
LNBH21
Step-up PWM
Control ler
Vup-Feedback
VoTX
Vup
Vcc
Byp
Preregul.+
U.V.lockout
+P.ON res.
SDA
SCL
ADDR
DSQIN
V Select
I²C interf. ^Enable
TEN
VoRX
Linear Post-reg
+Modulator
+Protections
Diagnostics
22KHz
Oscill .
Tone
Detector
ISEL
EXTM
DETIN
DSQOUT
April 2004
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