L8312

Preliminary

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

6 of 6

www.unisonic.com.tw

QW-R123-016.c



FUNCTIONAL INFORMATION

The UTC L8312 is specially designed integrated circuit for control satellite receiver front-end block switch, it

contains all the circuits necessary to detect the DC voltage and 22KHz signal on the supply input to the LNB switch.

The tone switch circuit incorporates an operational amplifier used as active filter, a rectifier /a comparator and an

output driver. Built-in feedback resistor included in operational amplifier, external component counts are thus

minimized. Therefore, low pass filter response can be achieved with a simple external RC.

The gain of operational amplifier must be adjusted with different supply voltage due to the threshold of

comparator is supply dependent. To optimize the system performance, the external RC values must be adjusted.

detection circuit allows the UTC L8312 to reliably detect tone signal. Each channel decodes tone polarization signals

to activate one of four outputs. Each of those outputs has the capability of sinking 5mA and sourcing 5mA, providing

the capability of driving directly signal routing pin diodes.

pins input signal have priority over tone polarization signals to control channel outputs.

Table 1 shows the logical output truth table.

Table1

Tone

S1A

S1B

S1C

S1D

≤0.7V

Low

Low

Low

Low

≥1.2V

<9.5V

Low

Low

Low

Low

≥1.2V

Off

≤14V

High

Low

Low

Low

≥1.2V

Off

≥15.5V

Low

High

Low

Low

≥1.2V

On

≤14V

Low

Low

High

Low

≥1.2V

On

≥15.5V

Low

Low

Low

High

Tone

S2A

S2B

S2C

S2D

≤0.7V

Low

Low

Low

Low

≥1.2V

<9.5V

Low

Low

Low

Low

≥1.2V

Off

≤14V

High

Low

Low

Low

≥1.2V

Off

≥15.5V

Low

High

Low

Low

≥1.2V

On

≤14V

Low

Low

High

Low

≥1.2V

On

≥15.5V

Low

Low

Low

High

UTC assumes no responsibility for equipment failures that result from using products at values that

exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or

other parameters) listed in products specifications of any and all UTC products described or contained

herein. UTC products are not designed for use in life support appliances, devices or systems where

malfunction of these products can be reasonably expected to result in personal injury. Reproduction in

whole or in part is prohibited without the prior written consent of the copyright owner. The information

presented in this document does not form part of any quotation or contract, is believed to be accurate

and reliable and may be changed without notice.