M-8870 Datasheet, PDF (6/8 Pages) Clare, Inc. – DTMF Receiver

M-8870
Table 6 AC Specifications
Parameter
Symbol
Min
Typ*
Max
Units
Notes
Valid input signal levels (each tone of com-
-29
posite signal)
27.5
+1
dBm
869
mVRMS
1,2,3,4,5,8
Positive twist accept
Negative twist accept
10
dB
10
dB
2,3,4,8
Frequency deviation accept limit
± 1.5% + 2 Hz Nom.
2,3,5,8,10
Frequency deviation reject limit
Third tone tolerance
±3.5%
-25
-16
Nom.
dB
2,3,5
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
Tone absent detection time
t_DP
5
8
t_DA
0.5
3
14
ms
8.5
ms
See Figure 8
Minimum tone duration accept
t_REC
40
ms
Maximum tone duration reject
t_REC
20
ms _{User adjustable (see Figures 3}
Minimum interdigit pause accept
t_ID
40
ms
and 5)
Maximum interdigit pause reject
t_DO
20
ms
Propagation delay (St to Q)
t_PQ
6
11
µs
Propagation delay (St to StD)
t_PStD
9
16
µs
OE = V_DD
Output data setup (Q to StD)
t_QStD
4.0
ms
Propagation delay (OE to Q), enable
t_PTE
Propagation delay (OE to Q), disable
t_PTD
50
60
300
ns
ns
R_L = 10 kΩ, C_L = 50 pF
Crystal clock frequency
f_CLK
3.5759 3.5795
3.5831
MHz
Clock output (OSC2), capacitive load
C_LO
30
pF
All voltages referenced to V_SS unless otherwise noted. For typical values V_DD = 5.0 V, V_SS = 0 V, T_A = 25°C, f_CLK = 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 V_REF.
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.
Teltone Corporation, 22121-20th Avenue SE, Bothell, WA 98021-4408 U.S.A
40-406-00011, Rev. E
Page 6
Phone: [phone] or 425-487-1515 Fax: [phone]
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