LM4950TS National Semiconductor, LM4950TS Datasheet - Page 19

• Manufacturer Part Number: LM4950TS
• Description: Audio Power Amplifier IC
• Manufacturer: National Semiconductor

Specifications of LM4950TS

• Amplifier Case Style: TO-220
• No. Of Pins: 9
• Peak Reflow Compatible (260 C): No
• Termination Type: Through Hole
• Leaded Process Compatible: No
• Package / Case: 9-TO-220
• Operational Class: Class-AB
• Audio Amplifier Function: Speaker
• Input Offset Voltage: 30@12VmV
• Total Harmonic Distortion: 0.05@4Ohm@2.5W%
• Single Supply Voltage (typ): 12/15V
• Dual Supply Voltage (typ): Not RequiredV
• Power Supply Requirement: Single
• Rail/rail I/o Type: No
• Power Supply Rejection Ratio: 70dB
• Single Supply Voltage (min): 9.6V
• Single Supply Voltage (max): 16V
• 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: 9 +Tab
• Package Type: TO-263
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Application Information
and an
As mentioned in the SELECTING EXTERNAL COMPO-
NENTS section, R
sets the amplifier’s lower bandpass frequency limit. Find the
coupling capacitor’s value using Equation (14).
The result is
Use a 0.82µF capacitor, the closest standard value.
The product of the desired high frequency cutoff (100kHz in
this example) and the differential gain A
Demonstration Board Layout
1 / (2πx20kΩx10Hz) = 0.795µF
f
L
INA
= 20kHz x 5 = 100kHz
C
and C
i
= 1 / 2πR
INA
create a highpass filter that
IN
f
L
FIGURE 5. Recommended TS SE PCB Layout:
VD
(Continued)
, determines the
Top Silkscreen
(13)
(14)
19
upper passband response limit. With A
100kHz, the closed-loop gain bandwidth product (GBWP) is
700kHz. This is less than the LM4950’s 3.5MHz GBWP. With
this margin, the amplifier can be used in designs that require
more differential gain while avoiding performance restricting
bandwidth limitations.
RECOMMENDED PRINTED CIRCUIT BOARD LAYOUT
Figure 5 through Figure 7 show the recommended two-layer
PC board layout that is optimized for the TO263-packaged,
SE-configured LM4950 and associated external compo-
nents. Figure 8 through Figure 10 show the recommended
two-layer PC board layout that is optimized for the TO263-
packaged, BTL-configured LM4950 and associated external
components. These circuits are designed for use with an
external 12V supply and 4Ω(min)(SE) or 8Ω(min)(BTL)
speakers.
These circuit boards are easy to use. Apply 12V and ground
to the board’s V
speaker between the board’s OUT
DD
and GND pads, respectively. Connect a
20047063
A
and OUT
VD
= 7 and f
B
outputs.
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H
=