MT88E45B
Data Sheet
Line Reversal
‘Idle State Tone Alert Signal’
DT-AS
B
Ch. seizure
D
Mark
E
Data
F
Ring
A/B Wires
A
C
G
Note 4
PWDN
Note 6
50-150ms
Tip/Ring
CASen
Note 6
tDP
tDA
EST
tGP
tGA
VTGt
Note 1
Note 2
ST/GT
tREC
tABS Note 3
STD
Note 7
15±1ms
< 0.5mA (optional)
TE DC load
TE AC load
<120µAµ
20±5ms
Current wetting pulse (see SIN227)
Zss (Refer to SIN227)
Note 4
Note 5
FSKen
Note 6
tCP
tCA
A ≥ 100ms
B = 88-110ms
C ≥ 45ms (up to 5sec)
D = 80-262ms
CD
DR
Note 7
E = 45-75ms
F ≤ 2.5sec (typ. 500ms)
G > 200ms
DCLK
DATA
OSC2
..101010..
Data
Note:
All
values
tPU
tPD
obtained from SIN227
Issue 1
Figure 17 - Application Timing for BT Caller Display Service (CDS), e.g., CLIP
Notes:
1) The total recognition time is tREC = tGP + tDP , where tGP is the tone present guard time and tDP is the tone present detect time. VTGt
is the comparator threshold (refer to Figure 5 for details).
2) The total tone absent time is tABS = tGA + tDA , where tGA is the tone absent guard time and tDA is the tone absent detect time. VTGt
is the comparator threshold (refer to Figure 5 for details).
3) By choosing tGA=15ms, tABS will be 15-25ms so that the current wetting pulse and AC load can be applied right after the STD rising
edge.
4) SIN227 specifies that the AC and DC loads should be removed between 50-150ms after the end of the FSK signal, indicated by CD
returning to high. The MT88E45B may also be powered down at this time.
5) The MT88E45B should be taken out of FSK mode when FSK is not expected to prevent the FSK demodulator from reacting to other
in-band signals such as speech, DT-AS/CAS and DTMF tones.
6) PWDN, Tip/Ring CASen, FSKen are internal signals decoded from CB0/1/2.
7) This signal represents the mode of the DR/STD pin.
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