LNBEH21

10/22

Figure 7: DETIN/DSQOUT Circuit

Figure 8: DETIN/DSQOUT Waveform

13/18V Control Word mode, OM=1

control the TEN/VSEL pin function. According to the VOM selection TEN/VSEL will absolve two different

functions:

2)VOM=1 - TEN/VSEL pin controls only the post regulator output voltage while the DC/DC Converter

output voltage is forced in a steady state, at the high level, 22.7V typ. with LLC=1 and 21.7V typ. if LLC=0.

During normal operation, when no 13/18V control word is transmitted, the device must work with VOM=0

and TEN/VSEL pin is used to select the odd or even numbered transponder setting up the post regulator

Before the beginning of the 13/18V Control Word Communication, it is mandatory to set VOM at HIGH

and 19.5V of are fully controlled by the internal voltage reference and they are maintained on a typical

value of 575µs, this time is guaranteed with a maximum output capacitance of 330nF and a load current

in the range of 6 to 450mA. As soon as the communication has expired VOM bit must be set LOW to avoid

any additional power dissipation (See Thermal Design Note). Refer to 13/18V Control Word section in the

complete truth table on page 11 for detailed logic combination and corresponding function description.

Tone

Detector

DSQOUT

DETIN

C6

100nF

to DiSEqC bus

(LNB)

VDD

(5V)

PWK data out

R1

2.5K

Ω

Ω

Ω

Ω

LNBEH21

0

5V

CH1=22KHz Tone to DETIN, CH2=PWK data at DSQOUT