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CXA2581N

Description of Functions

• RFAC

The RF signal input by connecting capacitance to the EQ_IN pin is equalized, arithmetically amplified and then

output from the RFAC pin.

AC

SUM

EQ

RW/ROM

6

7

8

9

A

B

C

D

RFG

EQ_IN

AC_SUM

RF

26

25

24

VFC

RFC

5.1k

BST

4

3

23

Amp

0.1

µ

In this case only the EQ block enters sleep mode and low power consumption mode (slim mode) is activated.

The low frequency gain is the same value as for EQ ON mode.

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 block and then

input the signal to EQ_IN (Pin 3) coupled by capacitance.

RW/ROM 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

AC_SUM:

13dB (both ROM/RW)

VCA to RFAC ROM: 0dB

RW: 12dB

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.

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 2mA.

If the load capacitance distorts the output waveform, connect resistance between Pin 15 and GND to increase

the drive current.