LOW POWER DTMF RECEIVER

S5T3170

5

NOTES:

1.

Digit sequence consists of all 16 DTMF tones.

2.

Tone duration = 40mS, Tone pause = 40mS.

3.

Nominal DTMF frequencies are used.

4.

Both tones in the composite signal have an equal amplitude.

5.

Tone pair is deviated by

± 1.5% ± 2Hz.

6.

Bandwidth limited (3KHz) Gaussian Noise.

7.

The precise dial tone frequencies are (350Hz and 440Hz)

± 2%.

8.

For an error rate of better than 1 in 10000.

9.

Referenced to lowest level frequency component in DTMF signal.

10. Minimum signal acceptance level is measured with specified maximum frequency deviation.

11. This item also applies to a third tone injected onto the power supply.

12. Referenced to Fig. 1 Input DTMF tone level at -28dBm.

Third Tone Tolerance

T3rd

−

−25

−16

−

dB

Noise Tolerance

TN

−

−

−12

−

dB

Dial Tone Tolerance

DT

−

18

22

−

dB

Crystal Clock Frequency

−

3.5759

3.5795 3.5831

MHz

Maximum Clock Input Rise Time

External Clock

−

−

110

nS

Maximum Clock Input Fall Time

External Clock

−

−

110

nS

Acceptable Clock Input Duty Cycle

External Clock

40

50

60

%

Acceptable Capacitive Load

OSC2 PIN

−

−

30

pF

Tone Present Detect Time

−

5

11

14

mS

Tone Absent Detect Time

−

0.5

4

8.5

mS

Minimum Tone Duration Accept

User Adjustable

−

−

40

mS

Minimum Tone Duration Reject

User Adjustable

20

−

−

mS

Acceptable Interdigit Pause

User Adjustable

−

−

40

mS

Rejectable Interdigit Pause

User Adjustable

20

−

−

mS

Propagation Delay Time SI to Q

OE = High

−

8

11

µS

Propagation Delay Time SI to DSO

OE = High

−

12

16

µS

Output Data Setup Q to DSO

OE = High

−

3.4

−

µS

Propagation Delay Time OE to Q

(Enable)

−

50

60

nS

Propagation Delay Time OE to Q

(Disable)

−

300

−

nS

ELECTRICAL CHARACTERISTICS (Continued)

Characteristic

Symbol

Test Conditions

Min.

Typ.

Max.

Unit