CXA2647N
Description of Functions
• RFAC
The RF signal input by connecting capacitance to EQ_IN (Pin 3) is equalized, arithmetically amplified and then
output from RFAC (Pin 15).
VCC
6
7
8
9
A
B
C
D
AC
SUM
Amp
100k
BST VFC
24 25 26 RFC
AC_SUM
4
Amp
3
VCA
15
EQ
RFAC
EQ_IN
RFG
RFAC OFF when BST = VCC
23
ROM/RW
Control Bias
VC – 1V to VC + 1V
Low frequency gain (100kHz)
AC_SUM (ABCD to AC_SUM) 13dB
RFAC (EQ_IN to RFAC) ROM: 1.5dB
RW: 13.5dB
When BST (Pin 24) is connected to VCC, the RFAC function is turned off and the low consumption mode is
entered.
If RF (summing signal) is present at the pickup output pin, input the addition output signal to EQ_IN (Pin 3)
coupled by capacitance.
When using a pickup without a summing output function, perform addition with the AC_SUM and then input the
signal to EQ_IN (Pin 3) coupled by capacitance.
ROM/RW switching is done by the VCA block, so either input method can be used without problem.
The RW gain is 12dB higher than the ROM gain.
Gain [dB]
VCA variable range
The VCA low frequency gain can be adjusted by the RFG
8
(Pin 23) voltage control.
The control voltage vs. low frequency gain characteristics
0
are shown in the graph to the right.
–8
Vcnt
[V]
VC – 1
VC
VC + 1
The RFAC pin (Pin 15) is an NPN transistor emitter follower output.
The maximum drive current is approximately 1.4mA.
If the load capacitance distorts the output waveform, connect resistance between the RFAC pin and GND to
increase the drive current.
– 9 –
SONY [ SONY CORPORATION ]
