Page 6
M-8870
Teltone Corporation, 22121-20th Avenue SE, Bothell, WA 98021-4408 U.S.A
Phone: 800-426-3926 or 425-487-1515 Fax: 425-487-2288
40-406-00011, Rev. E
E-mail: info@teltone.com Internet: www.teltone.com
Parameter
Symbol
Min
Typ*
Max
Units
Notes
Valid input signal levels (each tone of com-
posite signal)
-29
+1
dBm
1,2,3,4,5,8
27.5
869
mVRMS
Positive twist accept
10
dB
2,3,4,8
Negative twist accept
10
dB
Frequency deviation accept limit
± 1.5% + 2 Hz
Nom.
2,3,5,8,10
Frequency deviation reject limit
±3.5%
Nom.
2,3,5
Third tone tolerance
-25
-16
dB
2,3,4,5,8,9,13,14
Noise tolerance
-12
dB
2,3,4,5,6,8,9
Dial tone tolerance
+18
+22
dB
2,3,4,5,7,8,9
Tone present detection time
tDP
5
8
14
ms
See Figure 8
Tone absent detection time
tDA
0.5
3
8.5
ms
Minimum tone duration accept
tREC
40
ms
User adjustable (see Figures 3
and 5)
Maximum tone duration reject
tREC
20
ms
Minimum interdigit pause accept
tID
40
ms
Maximum interdigit pause reject
tDO
20
ms
Propagation delay (St to Q)
tPQ
611
µs
OE = VDD
Propagation delay (St to StD)
tPStD
916
µs
Output data setup (Q to StD)
tQStD
4.0
ms
Propagation delay (OE to Q), enable
tPTE
50
60
ns
RL = 10 kΩ, CL = 50 pF
Propagation delay (OE to Q), disable
tPTD
300
ns
Crystal clock frequency
fCLK
3.5759
3.5795
3.5831
MHz
Clock output (OSC2), capacitive load
CLO
30
pF
All voltages referenced to VSS unless otherwise noted. For typical values VDD = 5.0 V, VSS = 0 V, TA = 25°C, fCLK = 3.579545 MHz.
*Typical figures are at 25°C and are 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
W 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, measured at GS.
5. Both tones in the composite signal have an equal amplitude.
6. Bandwidth limited (0 to 3 kHz) Gaussian noise.
7. The precise dial tone frequencies are (350 and 440 Hz)
± 2%.
8. For an error rate of better than 1 in 10,000.
9. Referenced to lowest level frequency component in DTMF signal.
10. Minimum signal acceptance level is measured with specified maximum frequency deviation.
11. Input pins defined as IN+, IN-, and OE.
12. External voltage source used to bias VREF.
13. This parameter also applies to a third tone injected onto the power supply.
14. Referenced to Figure 4. Input DTMF tone level at -28 dBm.
Table 6 AC Specifications