NCP4894 ON Semiconductor, NCP4894 Datasheet - Page 12

• Manufacturer Part Number: NCP4894
• Description: Differential Audio Power Amplifier
• Manufacturer: ON Semiconductor

Gain−Setting Resistor Selection (R
NCP4894 should be used in low gain configurations.
values and maximizes the signal to noise ratio, and the
amplifier can still be used without running into the
bandwidth limitations.
recommended to optimize overall system performance.
applications, and doesn’t require the use of a very large
capacitor C
Input Capacitor Selection (C
the amplifier input terminal. This capacitor creates a
high−pass filter with Rin, the cut−off frequency is given by
fc
J2
R
In order to optimize device and system performance, the
The low gain configuration minimizes THD + noise
A closed loop gain in the range from 2 to 5 is
An input resistor (R
The input coupling capacitor blocks the DC voltage at
+
in
2 * P * R in * C in
and R
in
f
1
100 kW
set the closed−loop gain of both amplifiers.
.
1 mF
C2
1 mF
C1
R3
in
.
J1
) value of 22 kW is realistic in most
J10
J5
20 kW
in
20 kW
R1
GND
VP
VP
)
R2
J4
C3
in
Figure 30. Demonstration Board Schematic
and R
1 mF
f
)
BYPASS
SD SELECT
SD MODE
INP
INM
http://onsemi.com
NCP4894
BYPASS
BYPASS
12
VP
in low frequencies without severe attenuation. However a
large input coupling capacitor requires more time to reach
its quiescent DC voltage (VP/2) and can increase the
turn−on pops.
performs well in many applications (With R
Bypass Capacitor Selection (Cby)
and determines how fast the NCP4894 turns on.
turn−on pop. A 1.0 mF bypass capacitor value
(C
shutdown transitions. The amplifier is still functional with
a 0.1 mF capacitor value but is more susceptible to “pop and
click” noises.
VMC
BRIDGE
20 kW
20 kW
VP
The size of the capacitor must be large enough to couple
An input capacitor value between 0.1 m and 0.39 mF
The bypass capacitor Cby provides half−supply filtering
This capacitor is a critical component to minimize the
Thus, a 1.0 mF bypassing capacitor is recommended.
VP
in
R5
R4
VM
= < 0.39 mF) should produce clickless and popless
C4
1 mF
SHUTDOWN
+
−
−
+
CONTROL
OUTA
OUTB
J3
in
= 22 kW).
RL
8W