LNBEH21 datasheet(3/22 Pages) STMICROELECTRONICS

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LNBEH21

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Table 4: Pin Description

PIN N°

SYMBOL

NAME

FUNCTION

VCC

Supply Input

8V to 15V IC supply. A 220µF bypass capacitor to GND with a 470nF

(ceramic) in parallel is recommended

GATE

External Switch Gate

External MOS switch Gate connection of the step-up converter

SENSE

Current Sense Input

DC/DC Current Sense comparator input. Connected to current

sensing resistor

VUP

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.

2VORX

Output Port during

22KHz Tone RX

RX Output to the LNB in DiSEqC 2.0 application. See truth tables for

voltage selections and Communication Mode section for details.

SDA

Serial Data

Bidirectional data from/to I2C bus.

SCL

Serial Clock

Clock from I2C bus.

TEN/VSEL DiSEqC or 13/18V

TTL Logic Input

Depending on the value set for OM bit this pin enable/disable the

internal 22KHz tone generator (OM=0) or switch the output voltage

from 13V to 18V and vice versa (OM=1)

DETIN

Tone Detector Input

22kHz Tone Detector Input. Must be AC coupled to the DiSEqC 2.0

bus.

DSQOUT

DiSEqC Output

Open drain output of the tone Detector to the main

µcontroller for

DiSEqC 2.0 data decoding. It is set LOW when a 22 KHz tone is

detected.

EXTM

External Modulator

External Modulation Input acts on VOTX. 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. Also internally connected to the die frame

(exposed pad) for heat dissipation.

BYP

Bypass Capacitor

Needed for internal preregulator filtering

ISEL

Current Limit Select

Set high or floating for IO ≤ 750mA, connect to ground for IO ≤ 450mA.

4VOTX

Output Port during

22KHz Tone TX

Output of the linear post-regulator/modulator to the LNB. See truth

tables for voltage selections.

ADDR

Address Setting

Four I2C bus addresses available by setting the Address Pin level

voltage. See address pin characteristics table.

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