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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).

AC

SUM

Amp

EQ

VCA

ROM/RW

Control Bias

VC – 1V to VC + 1V

6

7

8

9

A

B

C

D

RFG

EQ_IN

AC_SUM

26

25

24

VFC

RFC

100k

BST

4

3

23

15 RFAC

Amp

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.

Low frequency gain (100kHz)

AC_SUM (ABCD to AC_SUM) 13dB

RFAC (EQ_IN to RFAC) ROM: 1.5dB

RW: 13.5dB

VC – 1

VC

VC + 1

Vcnt

[V]

8

0

–8

Gain [dB]

VCA variable range

The VCA low frequency gain can be adjusted by the RFG

(Pin 23) voltage control.

The control voltage vs. low frequency gain characteristics

are shown in the graph to the right.

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.