MB86437 Datasheet, PDF (18/35 Pages) Fujitsu Component Limited. – 3 V Single Power Supply Audio Interface Unit (AIU)

MB86437
(3) Melody IC connection
A melody IC can be connected using AMP4. However, the level can be made to vary in the same way as the tone
if the MDI pin is used. MDI has an input impedance of approximately 140 kΩ and is not high impedance.
Melody
IC
(–14 dBv typ)
DUAL TONE
(–15 dB)
MDI SW16 Approximately ^–
140 kΩ
+
SGC
To EV4
(4) JEAR signal selection
JEAR can receive a signal from AMP4 or AMP5. This enables a range of applications to be implemented depending
on the AMP4 and AMP5 circuit structures.
• Example of switching EAR and JEAR
PTBO
TBO
TBI
SGC
–
+
AMP4
SGO
SGI
SGC
–
+
AMP5
To EAR
To JEAR
SW15
(5) Preventing a clicking sound when the electronic volume gain is changed or when muting
Changing the gain of the electronic volume or muting may result in a clicking sound due to fluctuation in the DC
level. In such cases, the following setting is recommended.
Set the mode in which powering down the speaker amplifier is not linked with SW6b, 7b, 8b, and 9b (ADDRESS:
10001, DATA: 10111) and mute using SW6b, 7b, 8b, and 9b.
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