8.2.2 Application Curves

Figure 8-2 shows the tone generated from applying different resistance values on the REM pin. Applying

and removing a resistance to the REM pin simulates a button press event which is detected by the

CD326x. Recommended button resistor values can be found in Figure 7-4 and Section 5.5 (specifically button

boundaries). Additionally, there are three sets of resistances between each band where either the generated

tone is unstable, or where the device does not generate a tone (see Table 8-2).

REM Pin Resistance (k

)

2

4

6

8

10

12

14

16

18

20

22

0.45

0.5

0.55

0.6

0.65

0.7

0.75

0.8

0.85

0.9

Figure 8-2. Generated Tone from REM Resistance Value

Table 8-2. Deadband Ranges

Button Transition

Deadband Range

From

To

Low (kΩ)

High (kΩ)

Button 1

Button 2

7.85

7.95

Button 2

Button 3

10.60

11.00

Button 3

Button 4

15.50

15.90

For Figure 8-3 and Figure 8-4, active currents refer to the currents drawn by the VMIC and VSHUNT pins when

a tone is being generated as part of tone mode operation.

Ambient Temperature (

C)

-50

-25

0

25

50

75

100

20

22

24

26

28

30

32

Figure 8-3. Active Current into MIC Pin vs

Temperature

Ambient Temperature (

C)

-50

-25

0

25

50

75

100

94

95

96

97

98

99

100

Figure 8-4. Active Current into VSHUNT Pin vs

Temperature

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