as2521t austriamicrosystems, as2521t Datasheet - Page 13

• Manufacturer Part Number: as2521t
• Description: Telephone Speech Circuit With Loudhearing And Handsfree
• Manufacturer: austriamicrosystems

Preliminary
Application Diagramme
Applications Hints
Interface to Microcontroller
In off-hook condition the microcontroller can be supplied from V
MT) must be kept low until V
Radio Frequency Interference
The RFI sensitivity has been minimised by the consequent use of CMOS technology and one overall ground and
by having differential inputs with a relative low input impedance.
For further application information see application notes for the AS2520 series.
Rev. 5.1
La
Lb
510
1µ5
510
1µ5
TONE RINGER MELODIES
33 n
CONTROL INPUTS
MPSA92
INPUT FOR DTMF
(FROM µC)
DD
2.2 mH
5V1
has reached its minimum operating voltage (>2.5V).
AND
V
5k6
DD
10 k
2N5551
33 n
Figure 9: Application Diagramme
10 V
470 µ
BC327
30
Page 13
BC327
10 µ
100 µ
27
28
18
16
15
17
24
11
12
14
25
26
1
4
9
5
SS
CM
V
V
CS
Vss
LS
RI
V
TI
HS
PD
MT
LE
A
LI
PP
SSP
DD
GND
DD
of AS252x. The digital inputs (HS, LE, PD, and
STB
RTH
VOL
LLC
RO
LSI
M2
M3
M4
LO
M1
CI
19
22
10
21
20
13
7
23
2
6
3
8
1 µ
10 µ
1k8
7k5
AS2521
AS2520
High
Low
Off
300
100 n
AS2520/21/20B/21B
10 n
2k2
Side tone
balance
network
A
220 µ
100 n
100 n
15 n
15 n
GND
100 µ
100 n
100 k
V
DD
1k8
1k8
10 k
VOL+
VOL-
May 1999
1k2
1k2
32