ncp4896 ON Semiconductor, ncp4896 Datasheet - Page 12

• Manufacturer Part Number: ncp4896
• Description: 1w Audio Amplifier With Earpiece Driving Capability
• Manufacturer: ON Semiconductor

− The possible output power is four times larger (the
− Output pins (OUTA and OUTB) are biased at the same
Thermal Overload Protection
temperature exceeds 160 C, and will be switched on again
only when the temperature decreases below 140 C.
external components besides gain−setting resistors, an
input coupling capacitor and a proper bypassing capacitor
in the typical application.
and R
advantages:
given by
the voltage seen by the load and V
the input differential signal.
output voltage).
output power, check that the amplifier is not current limited
or clipped.
is 500 mA
P orms
Internal
The NCP4896 is unity−gain stable and requires no
Both internal amplifiers are externally configurable (RF
The differential−ended amplifier presents two major
The differential closed loop−gain of the amplifier is
Output power delivered to the load is given by
When choosing gain configuration to obtain the desired
The maximum current which can be delivered to the load
output swing is doubled) as compared to a single−ended
amplifier under the same conditions.
potential VP/2, this eliminates the need for an output
coupling capacitor required with a single−ended
amplifier configuration.
in
+
) with gain configuration.
A vd
(Vopeak) 2
I opeak
amplifiers are switched off when the
2 * R L
+
*
R in
R f
+
V opeak
+
(Vopeak is the peak differential
R L
V inrms
V orms
.
.
V
inrms
orms
is the rms value of
is the rms value of
http://onsemi.com
NCP4896
12
Gain−Setting Resistor Selection (R
NCP4896 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.
of applications, and doesn’t require the use of a too 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
good coupling at low frequencies without 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 NCP4896 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.
fc
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
The value of the capacitor must be high enough to ensure
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.
+
in
in
= < 0.39 mF) should produce clickless and popless
2 * P * R in * C in
and RF set the closed−loop gain of both amplifier.
in
1
.
.
in
) value of 22 kW is realistic in most
in
)
in
and RF)
in
= 22 kW).