AN1280 - APPLICATION NOTE

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Figure 9A: PCB (not to scale)

Figure 9C: Schematic

Figure 9B : Silkscreen

4. The SHUTDOWN pin is an open drain CMOS/

TTL compatible output which should be tied to the

TTL compatible input of an eventual control block.

The absolute maximum rating of this output is 7V.

In the case of a visual alarm, a LED is likely to be

tied to the positive power supply which can be de-

structive for the Shutdown output if the power sup-

ply is over 7V. An easy way to eliminate this is to

add a 6V zener diode between the Shutdown out-

put and the Ground as shown on figure 10.

5. The time constant of the protection mode (given

by the charge of CTRIP

greater than the time constant of the restart at-

tempts (given by the charge of the C

capacitors). This condition can be described as

follows :

(C