AN618 Panasonic Semiconductor, AN618 Datasheet - Page 11
AN618
Manufacturer Part Number
AN618
Description
Recording and playing amplifier IC for answering telephones
Manufacturer
Panasonic Semiconductor
Datasheet
1.AN618.pdf
(21 pages)
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
AN6180K
Manufacturer:
OKI
Quantity:
6 242
ICs for Telephone
The external components, R12, R13, C6, and C45, determine the MIC preamplifier gain/frequency characteristics in the HS mode
as shown in Fig. 2—2. R12 and C6 form a low-pass filter, and R13 and C45 form a high-pass filter.
Referring to the above calculations :
The HS mode transmitter frequency characteristics are calculated as follows :
MIC Preamplifier Gain/Frequency Characteristics Adjustment
V
CC
MAI
1
R14
• High-band cutoff frequency, f
• Low-band cutoff frequency, f
• For the high-pass filter, the larger the C45 capacitance, the lower the cutoff frequency, or the smaller the capacitance, the
• For the low-pass filter, the larger the C6 capacitance, the lower the cutoff frequency, or the smaller the capacitance, the
higher the frequency.
higher the frequency. See Fig.2—3.
ECM
Fig.2—2 MIC Preamplifier
3
Vr
R13
C45
+
–
R12
C6
AN6175K
4
Fig.2—3 HS Mode Transmitter Frequency Characteristics
To APC
MAO
LC
HC
Larger C45
=1/(2 C45 · R13)
=1/(2 C6 · R12)
Standard C45
300
Smaller C45 Larger C6
Input Frequency (Hz)
Referring to Fig.2—2, the MIC preamplifier gain, G
culated as follows :
G
In the standard condition, R12=R13=10 k , C6=102 pF, and C45
= 0.1 F.
(HSMIC)
1k
= 20log
4k
Standard C6
{1/ (2 f C45)} + R13 (dB)
{1/ (2 f C6)}// R12
Smaller C6
(HSMIC)
AN6175K
, is cal-
11