LNBEH21 Datasheet, PDF (1/22 Pages) STMicroelectronics – LNB SUPPLY AND CONTROL IC WITH STEP-UP CONVERTER AND IC INTERFACE

LNBEH21
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 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^TM 2.0
s 13/18V CONTROL WORD
COMMUNICATION
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)
s CABLE LENGTH DIGITAL COMPENSATION
s OVERLOAD AND OVER-TEMPERATURE
INTERNAL PROTECTIONS I²C WITH
DIAGNOSTIC BITs
BLOCK DIAGRAM
PowerSO-20
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 LNBEH21 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. The LNBEH21 supports both methods of
communication currently used, 13/18V Control
Word Communication Mode and DiSEqC^TM
communication. 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.
July 2004
Gate
Sense
LNBEH21
Step-up PWM
Controller
Vup-Feedback
VoTX
Vup
Vcc
Byp
Preregul.+
U.V.lockout
+P.ON res.
Linear Post-reg
+Modulator
+Protections
SDA
SCL
ADDR
TEN/VSEL
V Select
I²C interf. ^Enable
22KHz
Oscill.
OM=low _{Tone control}
13/18V control
OM=High
Echo-pulses control
TRISE= TFALL = 500µs
Diagnostics
Tone
Detector
VoRX
ISEL
EXTM
DETIN
DSQOUT
Rev. 1
1/22