Datasheet

LNBH21
3/20
TABLE A: PIN CONFIGURATIONS
PIN N° SYMBOL NAME FUNCTION
18 V
CC
Supply Input 8V to 15V IC supply. A 220µF bypass capacitor to GND with a 470nF
(ceramic) in parallel is recommended
17 GATE External Switch Gate External MOS switch Gate connection of the step-up converter
16 SENSE Current Sense Input DC/DC Current Sense comparator input. Connected to current
sensing resistor
19 V
UP
Step-up Voltage 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
2V
O
RX Output Port during
22KHz Tone RX
RX Output to the LNB in DiSEqC 2.0 application. See truth tables for
voltage selections on page 8 and description on page 5.
12 SDA Serial Data
Bidirectional data from/to I
2
C bus.
13 SCL Serial Clock
Clock from I
2
C bus.
14 DSQIN DiSEqC Input 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.
9 DETIN Tone Detector Input 22kHz Tone Detector Input. Must be AC coupled to the DiSEcQ 2.0
bus.
15 DSQOUT DiSEqC Output Open drain output of the tone Detector to the main µcontroller for
DiSEcQ 2.0 data decoding. It is LOW when tone is detected.
5 EXTM External Modulator External Modulation Input acts on V
O
TX. Needs DC decoupling to the
AC source. If not used, can be left open.
1, 6, 10,
11, 20
GND Ground Pins Connected to Ground.
8 BYP Bypass Capacitor Needed for internal preregulator filtering
3 ISEL Current Limit Select Set high or floating for Iout<=750mA, connect to ground for
I
OUT
≤ 450mA.
4V
O
TX Output Port during
22KHz Tone TX
Output of the linear post-regulator/modulator to the LNB. See truth
tables for voltage selections.
7 ADDR Address Setting
Four I
2
C bus addresses available by setting the Address Pin level
voltage. See address pin characteristics table.