LNBH21
LNB SUPPLY AND CONTROL IC WITH
STEP-UP CONVERTER AND I2C INTERFACE
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COMPLETE INTERFACE BETWEEN LNB
AND I2CTM BUS
BUILT-IN DC/DC CONTROLLER FOR
SINGLE 12V SUPPLY OPERATION AND
HIGH EFFICIENCY (Typ. 94% @ 750mA)
TWO SELECTABLE OUTPUT CURRENT
LIMIT (450mA / 750mA)
BOTH COMPLIANT WITH EUTELSAT AND
DIRECT OUTPUT VOLTAGE
SPECIFICATION
ACCURATE BUILT-IN 22KHz TONE
OSCILLATOR SUITS WIDELY ACCEPTED
STANDARDS
FAST OSCILLATOR START-UP FACILITATES
DiSEqCTM ENCODING
BUILT-IN 22KHz TONE DETECTOR
SUPPORTS BI-DIRECTIONAL DiSEqCTM2.0
SEMI-LOWDROP POST REGULATOR AND
HIGH EFFICIENCY STEP-UP PWM FOR
LOW POWER LOSS: Typ. 0.56W @ 125mA
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)
CABLE LENGTH DIGITAL COMPENSATION
OVERLOAD AND OVER-TEMPERATURE
INTERNAL PROTECTIONS
PowerSO-20
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OVERLOAD AND OVER-TEMPERATURE I2C
DIAGNOSTIC BITs
LNB SHORT CIRCUIT SOA PROTECTION
WITH I2C DIAGNOSTIC BIT
+/- 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
I2CTM standard interfacing.
BLOCK DIAGRAM
LNBH21
Gate
Sense
Step-up PWM
Controller
Vup-Feedback
VoTX
Vup
VoRX
Vcc
Preregul.+
U.V.lockout
+P.ON res.
Byp
SDA
SCL
Linear Post-reg
+Modulator
+Protections
V Select
Diagnostics
Tone
Detector
TEN
April 2004
EXTM
I²C interf. Enable
ADDR
DSQIN
ISEL
DETIN
22KHz
Oscill.
DSQOUT
1/20
LNBH21
ORDERING CODES
TYPE
PowerSO-20
(Tube)
PowerSO-20
(Tape & Reel)
LNBH21
LNBH21PD
LNBH21PD-TR
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
VCC
DC Input Voltage
-0.3 to 16
V
VUP
DC Input Voltage
-0.3 to 25
V
IO
Output Current
Internally Limited
mA
DC Output Pins Voltage
-0.3 to 25
V
Logic Input Voltage (SDA, SCL, DSQIN, ISEL)
-0.3 to 7
V
Detector Input Signal Amplitude
-0.3 to 2
VPP
VOH
Logic High Output Voltage (DSQOUT)
-0.3 to 7
V
IGATE
Gate Current
± 400
mA
-0.3 to 1
V
VOTX/RX
VI
VDETIN
VSENSE
Current Sense Voltage
VADDRESS Address Pin Voltage
-0.3 to 7
V
Tstg
Storage Temperature Range
-40 to +150
°C
Top
Operating Junction Temperature Range
-40 to +125
°C
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is
not implied.
THERMAL DATA
Symbol
Rthj-case
Parameter
Thermal Resistance Junction-case
PIN CONFIGUARATION (top view)
2/20
Value
Unit
2
°C/W
LNBH21
TABLE A: PIN CONFIGURATIONS
PIN N°
SYMBOL
NAME
18
VCC
17
16
GATE
SENSE
19
VUP
2
VORX
12
SDA
Output Port during
22KHz Tone RX
Serial Data
13
SCL
Serial Clock
14
DSQIN
DiSEqC Input
9
DETIN
Tone Detector Input
Supply Input
External Switch Gate
Current Sense Input
Step-up Voltage
FUNCTION
8V to 15V IC supply. A 220µF bypass capacitor to GND with a 470nF
(ceramic) in parallel is recommended
External MOS switch Gate connection of the step-up converter
DC/DC Current Sense comparator input. Connected to current
sensing resistor
Input of the linear post-regulator. The voltage on this pin is monitored
by internal step-ut controller to keep a minimum dropout across the
linear pass transistor
RX Output to the LNB in DiSEqC 2.0 application. See truth tables for
voltage selections on page 8 and description on page 5.
Bidirectional data from/to I2C bus.
5
EXTM
1, 6, 10,
11, 20
8
3
GND
Ground
Clock from I2C bus.
When the TEN bit of the System Register is LOW, this pin will accept
the DiSEqC code from the main µcontroller. The LNBH21 will use this
code to modulate the internally generated 22kHz carrier. Set to GND
this pin if not used.
22kHz Tone Detector Input. Must be AC coupled to the DiSEcQ 2.0
bus.
Open drain output of the tone Detector to the main µcontroller for
DiSEcQ 2.0 data decoding. It is LOW when tone is detected.
External Modulation Input acts on VOTX. Needs DC decoupling to the
AC source. If not used, can be left open.
Pins Connected to Ground.
BYP
ISEL
Bypass Capacitor
Current Limit Select
Needed for internal preregulator filtering
Set high or floating for Iout
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