L9705 datasheet(4/8 Pages) STMICROELECTRONICS

Part #	L9705

Description	DOUBLE QUAD CONTACT INTERFACE CIRCUIT

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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FUNCTIONAL DESCRIPTION

The L9705 circuit monitors the status of the con-

tacts which are connected through the series ex-

ternal resistors RIN to the contact sense input

pins. The contacts equivalent circuit is supposed

to be as shown in fig.2 for GND connected con-

tacts (IN 1 to 4) and as shown in fig. 3 for VBAT

connected contacts (IN 5 to 8).

Figure 1: Typical application diagram for the L9705 circuit. The current flowing in the arrow direction is

assumed positive. The external capacitors CIN and COUT represent the total wiring

capacitance at the corresponding pins.

Figure 2: The contact sense input connection with the contact equivalent circuit for GND connected

contacts.

Figure 3: The contact sense input connection with the contact equivalent circuit for VBAT connected

contacts.

L9705

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L9705 Datasheet(PDF) 4 Page - STMicroelectronics