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5 ELECTRICAL CHARACTERISTICS
5.7 Dual-Tone (CAS) Detection Circuit Characteristics
5.7.1 CAS AC Characteristics
Unless otherwise noted: V
Parameter
Carrier-detect sensitivity ∗1
(input level at TPI/RING)
Low tone frequency
High tone frequency
∗1 When the gain in the input amp is set to G
equation below.
(When the internal tone filter gain = –4 dB)
CD
[dBm] = -G
ONTONE
∗2 BT mode is selected by setting the mode register (address = 0h) bit 2 to 1. By this setting, the gain in each dual-
tone filter is raised +6 dB for adjustment to the British Telecom CD level.
5.7.2 CAS Switching Characteristics
Unless otherwise noted: V
Parameter
CAS detect capture time
CAS end → #DET rise
CAS width
N = TH0 × 16 + TL3 × 8 + TL2 × 4 + TL1 × 2 + TL0
22
=5.0/3.0V, V
=0V, f
DD
SS
CLK
Symbol
CD
V
=5V, Bellcore mode
ONTONE
DD
Input amp gain (G
Tone filter gain=-4dB
=5V, BT mode ∗2
V
DD
nput amp gain (G
Tone filter gain=-4dB
=3V, BT mode ∗2
V
DD
nput amp gain (G
Tone filter gain=-4dB
=3V, BT mode ∗2
V
DD
nput amp gain (G
Tone filter gain=-4dB
f
Bellcore (±0.5%)
LTONE
BT line disconnected
BT line connected (±0.6%)
f
Bellcore (±0.5%)
HTONE
BT line disconnected
BT line connected (±0.6%)
(dB), the CD
AMP
- 40.9 + 20log( V
DD
) [dBm],
AMP
5
=5.0/3.0V, V
=0V, f
DD
SS
CLK
Symbol
t
CASAQ
t
CASDH
t
CASW
CAS
#DET
t
CASAQ
Figure 5.7.1 CAS switching characteristics
=3.579545MHz, Ta=-20 to 70°C
Condition
)=-5dB
AMP
)=-5dB
AMP
)=-9.4dB
AMP
)=-9.4dB
AMP
value (Typ.) can be calculated from the
ONTONE
CD
[dBV] = -G
ONTONE
=3.579545MHz, Ta=-20 to 70°C, C
Min.
Typ.
2.8×(N+2)+16.9
2.8×(31-N)+13.1
75
t
CASW
t
CASDH
EPSON
Min.
Typ.
Max.
-39.9
-35.9
-31.9
-48.1
-44.1
-40.1
-39.9
-35.9
-31.9
-48.1
-44.1
-40.1
2119.35
2130
2140.65
2110
2130
2150
2117.22
2130
2142.78
2736.25
2750
2763.75
2720
2750
2780
2733.50
2750
2766.50
- 49.1 + 20log( V
DD
AMP
5
=50pF
L
Max.
80
85
S1C05251 TECHNICAL MANUAL
Unit
dBm
dBV
dBm
dBV
Hz
Hz
Hz
Hz
Hz
Hz
) [dBV]
Unit
msec
msec
msec
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