4-48

† Timing is over recommended temperature & power supply voltages.

‡ Typical figures are at 25°C and for design aid only: not guaranteed and not subject to production testing.

NOTES: 1) dBm=decibels above or below a reference power of 1 mW into a 600 ohm load.

2) Digit sequence consists of all 16 DTMF tones.

3) Tone duration=40 ms. Tone pause=40 ms.

4) Nominal DTMF frequencies are used.

5) Both tones in the composite signal have an equal amplitude.

6) The tone pair is deviated by ±1.5%±2 Hz.

7) Bandwidth limited (3 kHz) Gaussian noise.

8) The precise dial tone frequencies are 350 and 440 Hz (±2%).

9) For an error rate of less than 1 in 10,000.

10) Referenced to the lowest amplitude tone in the DTMF signal.

11) Referenced to the minimum valid accept level.

12) For guard time calculation purposes.

Characteristics

Sym

Min

Max

Units

Notes*

28

Data hold time (write)

10

ns

29

Input Capacitance (data bus)

5pF

30

Output Capacitance (IRQ/CP)

5pF

31

D

T

M

F

C

L

K

Crystal/clock frequency

3.5759

3.5795

3.5831

MHz

32

Clock input rise time

110

ns

Ext. clock

33

Clock input duty cycle

110

ns

Ext. clock

34

Clock input duty cycle

40

50

60

%

Ext. clock

35

Capacitive load (OSC2)

30

pF