M-8870 Datasheet, PDF (6/9 Pages) Clare, Inc. – DTMF Receiver

M-8870
AC Characteristics
Parameter
Symbol Min
Typ*
Max
Units
Valid input signal levels (each tone
-
-29
-
+1
dBm
of composite signal)
-
27.5
-
869
mVRMS
Positive twist accept
-
-
-
10
dB
Negative twist accept
-
-
-
10
dB
Frequency deviation accept limit
-
-
- ± 1.5% + 2 Hz Nom.
Frequency deviation reject limit
-
±3.5%
-
-
Nom.
Third tone tolerance
-
-25
-16
-
dB
Noise tolerance
-
-
-12
-
dB
Dial tone tolerance
-
+18
+22
-
dB
Tone present detection time
t_DP
5
8
14
ms
Tone absent detection time
t_DA
0.5
3
8.5
ms
Minimum tone duration accept
t_REC
-
-
40
ms
Maximum tone duration reject
t_REC
20
-
-
ms
Minimum interdigit pause accept
t_ID
-
-
40
ms
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
Output data setup (Q to StD)
t_QStD
-
4.0
-
µs
Propagation delay (OE to Q), enable
t_PTE
-
50
60
ns
Propagation delay (OE to Q), disable
t_PTD
-
300
-
ns
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, TA = 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 600Ω 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 Single - Ended Input Configuration on page 3. Input DTMF tone level at -28 dBm.
Notes
1,2,3,4,5,8
2,3,4,8
2,3,5,8,10
2,3,5
2,3,4,5,8,9,13,14
2,3,4,5,6,8,9
2,3,4,5,7,8,9
See Timing Diagram on page 7
User adjustable (see Basic Steering
Circuit and Guard Time Adjustment
on pages 3 and 4.)
OE = VDD
R_L = 10 kΩ, C_L = 50 pF
-
-
6
www.clare.com
Rev. 3