MT88E43B
Vdd
TIP / A
Data Sheet
Vdd
1N4003
22nF
5%
R
1
1N4003
R
4
MT88E43
IN+
V
DD
St/GT
ESt
StD
INT
CD
DR
DATA
DCLK
FSKen
PWDN
IC
R
3
R
2
1N914
TISP4180,
TISP5180,
TPA150A12 or
TPB150B12
Vdd
53K6
60K4
1N4003
22nF
5%
R
1
1N4003
R
4
Vdd
C
Vdd
RING / B
464K
IN-
GS
V
Ref
CAP
100K
20%
499K, 5%
100nF
1N914
5%
1N914
1N914
Vdd
150K
5%
TRIGin
TRIGRC
TRIGout
MODE
OSCin
499K, 5%
100nF
5%
1N914
200K
5%
220nF
100nF
301K
5%
OSCout
V
SS
NOTE: Resistors must have 1% tolerance and capacitors have 20%
tolerance unless otherwise specified.
: Crystal is 3.579545MHz, 0.1% frequency tolerance.
: For BT Application C=0.1µF
±5%,
R
3
=422kΩ
±1%,
R
2
=422kΩ
±1%
:
For applications where CAS speech immunity is required (e.g. CIDCW)
C=0.1µF
±5%,
R
3
=825kΩ
±1%,
R
2
=226kΩ
±1%
: R
1
= 430K, R
4
= 34K for V
DD
= 5V
±
10% (See Figure 10)
: R
1
= 620K, R
4
= 63K4 for V
DD
= 3V
±
10% (See Figure 10)
= To microcontroller
= From microcontroller
(FSK Interface Mode 0 selected)
Figure 9 - Application Circuit
Application Circuits
The circuits shown in Figures 9 and 11 are application circuits for the MT88E43. As supply voltage (V
DD
) is
decreased, the threshold of the device’s tone and FSK detectors will be reduced. Therefore, to meet the BT or
Bellcore tone reject level requirements the gain of the internal opamp should be reduced according to the graph in
Figure 10. For example when V
DD
=5V (+/- 10%), R
1
should equal 430 kΩ and R
4
should equal 34 kΩ; and if
V
DD
=3V (+/- 10%) R
1
should equal 620 kΩ and R
4
should equal 63.4 kΩ. Resistors R
1
and R
4
are shown in Figures
9 and 11.
The circuit shown in Figure 9 illustrates the use of the MT88E43 in a proprietary system that doesn’t need to meet
FCC, DOC, and UL approvals. It should be noted that if glitches on the tip/ring interface are of sufficient amplitude,
the circuit will falsely detect these signals as ringing or line reversal.
The circuit shown in Figure 11 will provide common mode rejection of signals received by the ringing circuit. This
circuit should pass safety related tests specified by FCC Part 68, DOC CS-03, UL 1459, and CSA C22.2. These
safety tests will simulate high voltage faults that may occur on the line. The circuit provides isolation from these high
voltage faults via R1 and the 12 k1Ω resistors as well as the 22 nF & 330 nF capacitors. IRC manufactures a
resistor (part number GS3) that should be used for R1. This resistor is a 3 W, 5%, 1 kV power resistor. The 12 k1
resistor is manufactured by IRC (part number FA8425F). This resistor is a 1.5 W, 5%, fuseable type resistor. The
22 nF and 330 nF capacitors have a 400 V rating.
See the application note "MSAN-164: Applications of the MT8843 Calling Number Identification Circuit 2" for
information on designing the MT88E43 into CID and CIDCW systems.
13
Zarlink Semiconductor Inc.
100nF
ZARLINK [ ZARLINK SEMICONDUCTOR INC ]
