MT8880C Datasheet, PDF (11/18 Pages) Mitel Networks Corporation – ISO2-CMOS Integrated DTMFTransceiver

DTMF/CP
INPUT
C1
R1
R2
X-tal
DTMF
OUTPUT
C4
R_L
ISO²-CMOS MT8880C/MT8880C-1
MT8880C/C-1
IN+
VDD
IN-
St/GT
GS
VRef
ESt
R3
D3
VSS
D2
OSC1
D1
OSC2
D0
TONE
IRQ/CP
R/W
Φ2
CS
RS0
V_DD
C3
C2
R4
To µP
or µC
Notes:
R1, R2 = 100 kΩ 1%
R3 = 374 Ω 1%
R4 = 3.3 kΩ 10%
R_L = 10 k Ω (min.)
C1 = 100 nF 5%
C2 = 100 nF 5%
C3 = 100 nF 10%*
C4 = 10 nF 10%
X-tal = 3.579545 MHz
* Microprocessor based systems can inject undesirable noise into
the supply rails. The performance of the MT8880 can be optimized
by keeping noise on the supply rails to a minimum. The decoupling
capacitor (C3) should be connected close to the device and ground
loops should be avoided.
Figure 13 - Application Circuit (Single-Ended Input)
MMD6150
(or equivalent)
TEST POINT
5.0 VDC
2.4 kΩ
130 pF
24 kΩ
MMD7000
(or equivalent)
TEST POINT
5.0 VDC
3 kΩ
70 pF
Test load for D0-D3 pins
Test load for IRQ/CP pin
Figure 14 - Test Circuit
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