675 mW Audio Power Amplifier with Shutdown Mode
The LM4862 is a bridge-connected audio power amplifier ca-
pable of delivering typically 675 mW of continuous average
power to an 8Ω load with 1% (THD) from a 5V power supply.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. Since the LM4862 does not require
output coupling capacitors, bootstrap capacitors, or snubber
networks, it is optimally suited for low-power portable sys-
The LM4862 features an externally controlled, low-power
consumption shutdown mode, as well as an internal thermal
shutdown protection mechanism.
The unity-gain stable LM4862 can be configured by external
n THD at 500 mW continuous average
output power at 1 kHz into 8Ω
n Output power at 10% THD+N at
1 kHz into 8Ω
n Shutdown Current
825 mW (typ)
0.7 µA (typ)
n No output coupling capacitors, bootstrap capacitors or
snubber circuits are necessary
n Small Outline or DIP packaging
n Unity-gain stable
n External gain configuration capability
n Pin compatible with LM4861
n Portable Computers
n Cellular Phones
n Toys and Games
Small Outline and DIP Package
Order Number LM4862M, LM4862N
See NS Package Number M08A or N08E
*Refer to the Application Information section for information
concerning proper selection of the input coupling capacitor.
FIGURE 1. Typical Audio Amplifier Application Circuit
Boomer® is a registered trademark of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation DS012342
Absolute Maximum Ratings (Note 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Power Dissipation (Note 3)
ESD Susceptibility (Note 4)
ESD Susceptibility (Note 5)
Small Outline Package
Vapor Phase (60 sec.)
−65˚C to +150˚C
−0.3V to VDD + 0.3V
Infrared (15 sec.)
See AN-450 “Surface Mounting and their Effects on
Product Reliability” for other methods of soldering surface
θJC (typ) — M08A
θJA (typ) — M08A
θJC (typ) — N08E
θJA (typ) — N08E
TMIN ≤ TA ≤ TMAX
−40˚C ≤ TA ≤ 85˚C
2.7V ≤ VDD ≤ 5.5V
Electrical Characteristics(Note 1) (Note 2)
The following specifications apply for VDD = 5V unless otherwise specified. Limits apply for TA = 25˚C.
(Note 6) (Note 7)
VDD Supply Voltage
2.7 V (min)
5.5 V (max)
THD + N
Quiescent Power Supply Current
Output Offset Voltage
Total Harmonic Distortion +
Power Supply Rejection Ratio
VIN = 0V, IO = 0A (Note 8)
VPIN1 = VDD
VIN = 0V
THD = 1% (max); f = 1 kHz; RL = 8Ω
THD + N = 10%; f = 1 kHz; RL = 8Ω
PO = 500 mWrms; RL = 8Ω
AVD = 2; 20 Hz ≤ f ≤ 20 kHz
VDD = 4.9V to 5.1V
3.6 6.0 mA (max)
0.7 5 µA (max)
5 50 mV (max)
675 500 mW (min)
Note 1: All voltages are measured with respect to the ground pin, unless otherwise specified.
Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is func-
tional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guar-
antee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is
given, however, the typical value is a good indication of device performance.
Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX, θJA, and the ambient temperature TA. The maximum
allowable power dissipation is PDMAX = (TMAX − TA)/θJA. For the LM4862, TJMAX = 150˚C. The typical junction-to-ambient thermal resistance, when board mounted,
is 170˚C/W for package number M08A and is 107˚C/W for package number N08E.
Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 5: Machine Model, 200 pF–240 pF discharged through all pins.
Note 6: Typicals are measured at 25˚C and represent the parametric norm.
Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 8: The quiescent power supply current depends on the offset voltage when a practical load is connected to the amplifier.
Automatic Switching Circuit
FIGURE 2. Automatic Switching Circuit
External Components Description (Figure 1)
Inverting input resistance which sets the closed-loop gain in conjunction with Rf. This resistor also forms a
high pass filter with Ci at fc = 1/(2πRiCI).
Input coupling capacitor which blocks the DC voltage at the amplifier’s input terminals. Also creates a
highpass filter with Ri at fc = 1/(2πRiCi). Refer to the section, Proper Selection of External Components,
for an explanation of how to determine the value of Ci.
Feedback resistance which sets the closed-loop gain in conjunction with Ri.
Supply bypass capacitor which provides power supply filtering. Refer to the Power Supply Bypassing
section for proper placement and selection of the supply bypass capacitor.
Bypass pin capacitor which provides half-supply filtering. Refer to the Proper Selection of External
Components section for proper placement and selection of the half-supply bypass capacitor.
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