LM4862MX National Semiconductor, LM4862MX Datasheet - Page 9

• Manufacturer Part Number: LM4862MX
• Description: IC AMP AUDIO PWR .825W AB 8SOIC
• Manufacturer: National Semiconductor
• Series: Boomer®r
• Type: Class ABr

Specifications of LM4862MX

• Output Type: 1-Channel (Mono)
• Max Output Power X Channels @ Load: 825mW x 1 @ 8 Ohm
• Voltage - Supply: 2.7 V ~ 5.5 V
• Features: Shutdown, Thermal Protection
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Operational Class: Class-AB
• Audio Amplifier Output Configuration: 1-Channel Mono
• Output Power (typ): 0.825x1@8OhmW
• Audio Amplifier Function: Speaker
• Total Harmonic Distortion: 0.55@8Ohm@500mW%
• Single Supply Voltage (typ): 3/5V
• Dual Supply Voltage (typ): Not RequiredV
• Power Supply Requirement: Single
• Rail/rail I/o Type: No
• Power Supply Rejection Ratio: 50dB
• Single Supply Voltage (min): 2.7V
• Single Supply Voltage (max): 5.5V
• Dual Supply Voltage (min): Not RequiredV
• Dual Supply Voltage (max): Not RequiredV
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: SOIC N
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *LM4862MX

Application Information
Once the power dissipation equations have been addressed,
the required differential gain can be determined from Equa-
tion 4.
From Equation 4, the minimum A
Since the desired input impedance was 20 kΩ, and with a
A
= R
bandwidth requirements which must be stated as a pair of −3
dB frequency points. Five times away from a –3 dB point is
VD
f
of 2, a ratio of 1:1 of R
= 20 kΩ. The final design step is to address the
R
f
/R
f
i
to R
= A
i
VD
results in an allocation of R
VD
/2
is 2; use A
(Continued)
VD
= 2.
(4)
(5)
i
9
0.17 dB down from passband response which is better than
the required
and high frequency pole of 20 Hz and 100 kHz respectively.
As stated in the External Components section, R
junction with C
The high frequency pole is determined by the product of the
desired high frequency pole, f
A
= 100 kHz which is much smaller than the LM4862 GBWP of
12.5 MHz. This figure displays that if a designer has a need
to design an amplifier with a higher differential gain, the
LM4862 can still be used without running into bandwidth
problems.
VD
. With an A
C
i
≥ 1/(2π*20 kΩ*20 Hz) = 0.397 µF; use 0.39 µF.
±
VD
0.25 dB specified. This fact results in a low
i
create a highpass filter.
= 2 and f
H
= 100 kHz, the resulting GBWP
H
, and the differential gain,
www.national.com
i
in con-