MT88E45
Application Circuits
Advance Information
Tx+
Microphone
TIP
TIP
Telephone
Hybrid
or
Speech IC
(Symbolic)
Tx-
RING
RING
Rx+
Speaker
Rx-
R5
C1
R1
D1
R3
R6
MT88E45
V
REF
IN2+
IN2-
GS2
CB2
CB1
Vdd
CD
R11
R10
R8 C3
D2
D3
C2 R2
D4
= To Microcontroller
R4
IN1+
IN1-
R7
GS1
Vss
OSC1
Vss Xtal
R12
R9 C4
Vdd
= From Microcontroller
OSC2
CB0
DCLK
(FSK Interface Mode 1 selected)
C5
ST/GT
R13
EST
R14
DATA
DR/STD
D5
C6
R15 is required only if both FSK
interface mode 0 and power
down features are used.
R15
C6 should be
connected directly
across Vdd and Vss
pins
Unless stated otherwise, resistors are 1%, 0.1Watt; capacitors are 5%, 6.3V.
For 1000Vrms, 60Hz isolation from Tip to Earth and Ring to Earth:
R1,R2
430K, 0.5W, 5%, 475V min. C1,C2
2n2, 1332V min.
(e.g. IRC type GS-3)
If the 1000Vrms is handled by other methods then this circuit has to meet the FCC Part 68 Type B Ringer requirements:
R1,R2
432K, 0.1W, 1%, 56V min. C1,C2
2n2, 212V min.
Common to both sets of R1,R2:
R3,R4
34K
R8,R9
464K
R13
825K
R14
226K or 26K1
R15
100K, 20%
5V, 0dB gain
53K6
60K4
464K
3V, -3.5dB gain
35K7
40K2
309K
C3,C4
C5
C6
D1-D4
D5
Xtal
2n2
100n
100n, 20%
Diodes. 1N4148 or equivalent
Diode. 1N4148 or equivalent
3.579545MHz, 0.1% crystal
or ceramic resonator
R5,R10
R6,R11
R7,R12
Figure 7 - Application Circuit: Bellcore MEI Compatible Type 2 Telephone
12
MITEL [ MITEL NETWORKS CORPORATION ]
