Multitone FLA 872, Техническое руководство

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TLA 852/FLA 872
TM1205 Issue 2 Page 3 - 10
IC5 monitors the voltage of V
DD
and resets the decoder circuits if the voltage drops
to a level that would cause data corruption.
Transistor TR1, connected to pins 6 and 15 of IC3, detects the battery voltage. If
BAT1 is removed, the drop in B+ causes transistor TR1 to switch OFF which sets the
microprocessor to low-current mode. In this mode BAT2 supplies sufficient power
to keep the microprocessor and the SRAM operational for up to 60 minutes.
The 1 volt supply for the receiver circuits is provided by transistor TR406 and its
associated components. The circuit is a series regulator and is maintained within
specification by a control circuit in IC401.