NCP2990

http://onsemi.com

10

In order to optimize device and system performance, the

NCP2990 should be used in low gain configurations.

The low gain configuration minimizes THD + noise

values and maximizes the signal to noise ratio, and the

amplifier can still be used without running into the

bandwidth limitations.

A closed loop gain in the range from 2 to 5 is

recommended to optimize overall system performance.

W is realistic in most

of applications, and doesn’t require the use of a too large

The input coupling capacitor blocks the DC voltage at

the amplifier input terminal. This capacitor creates a

fc

+

1

2*

P *Rin *Cin

.

The size of the capacitor must be large enough to couple

in low frequencies without severe attenuation.

An input capacitor value between 33 nF and 220 nF

W).

Bypass Capacitor Selection (Cby)

The bypass capacitor Cby provides half−supply filtering

and determines how fast the NCP2990 turns on. With a

single−ended audio input, the amplifier will be a zero pop

noise device no matter the bypass capacitor.

Figure 25. Schematic of the NCP2990 Demonstration Board

+

−

+

−

INM

8

W

OUTA

OUTB

20 k

W

20 k

W

INP

BYPASS

20 k

W

1

mF

100 nF

VM

VM_P

SHUTDOWN

CONTROL

C3

1

mFC4

SHUTDOWN

R1

C1

AUDIO

INPUT

R2

20 k

W

R3

150 k

W

C2*

*C2, TP1, TP2, and TP3: Not Mounted

J11

J5

J7

J12

J6

J8

J3*

TP1*

TP2*

OUTA

TP3*

OUTB