SM6801A

SEIKO NPC CORPORATION —10

Input Equalizer (IN, EQP, EQN)

An input equalizer network can be connected to pins IN, EQP and EQN, as shown in the input equivalent cir-

cuit and equalizer circuit below.

The frequency response of the equalizer circuit is given by the following equation, where

ƒ is the frequency.

Dynamic Range Compression Mode (DRCN)

The dynamic range compression mode is set when DRCN is LOW. When a compression mode is used, the gain

for small input signals is increased while large input signals are converted using a curve that performs soft-clip-

ping. This increases the average sound pressure level emitted from the speaker during playback.

EQN

VREF1

EQP 5

6

R04

R03 C03

C04

R01

60k

R02 C02

60k

IN

4

C01

IN'

+

−

Response =

20 × log

10

[dB]

11

60000

1

R04

++

+ 2πƒC04

1

2

πƒC03

R03

+

+

1

2

πƒC01

1

1

60000

1

R01

+

1

+

1

2

πƒC02

R02

+

1

-20

-15

-10

-5

0

5

10

-40

-35

-30

-25 -20

-15

-10

-5

0

5

10

-40

-35

-30

-25

Input [dBV]

normal mode

DRC mode