U4084B Datasheet, PDF (18/26 Pages) TEMIC Semiconductors – Low-Voltage, Voice-Switched Circuit for Hands-Free Operation

U4084B
60
MICO,
C_VB = 1000 mF
40
= 220 mF
20
0
0
94 7870 e
1
10
f ( kHz )
Figure 19. Power supply rejection of the microphone amplifier
6
5
MICO
4
3
TO
2
TO,RO
1
RO
0
3
4
5
6
94 7872 e
V_S ( V )
Figure 20. Typical output swing versus V_S
MIC amp.
MICO
I₁
R₁
TI
TO
T attenuator
ext. Transmit. amp.
12677
R₂
I₂
–
+
Acoustic
coupling
+
–
RLI2
Comparator
Comparator
C1
Attenuator
control
C2
I₃
R₃
SAO
Speaker amp.
R attenuator
RECO
RI
Figure 21. Basic block diagram for design purposes
TLI1
–
+
Tip
G_ST
Hybrid
+
Ring
–
RLI1
R₄
I₄
ext. Receive amp.
18 (26)
TELEFUNKEN Semiconductors
Preliminary Information
Rev. A1, 31-Jan-97