FEDL7005-01

ML7005

19/25

FUNCTIONAL DESCRIPTION

Oscillation Circuit

The X1 and X2 should be connected by a 3.579545 MHz crystal.

When the load capacitance of the crystal is 16pF, X1 and GND should be connected by a 20 pF capacitor, and

X2 and GND also should be connected by a 20 pF capacitor.

If necessary, an external clock should be input to X1 via a 1000 pF capacitor, and X2 should be left open.

DTMF Receiver, CPT Detector Input Level Adjustment

Adjust the input level according to the method shown in the figure 8.

Determine the value of a usable resistor so that the levels of the outputs (DTIO, CPDIO) of each amplifier at a

maximum input level are less than the maximum detect level described in the AC Characteristics.