LM4752T/NOPB National Semiconductor, LM4752T/NOPB Datasheet - Page 15

• Manufacturer Part Number: LM4752T/NOPB
• Description: IC AMP AUDIO PWR 11W AB TO220-7
• Manufacturer: National Semiconductor
• Type: Class ABr

Specifications of LM4752T/NOPB

• Output Type: 2-Channel (Stereo)
• Max Output Power X Channels @ Load: 11W x 2 @ 4 Ohm
• Voltage - Supply: 9 V ~ 32 V
• Features: Thermal Shutdown Protection
• Mounting Type: Through Hole
• Package / Case: TO-220-7 (Bent and Staggered Leads)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LM4752T; *LM4752T/NOPB; LM4752T

PREVENTING OSCILLATIONS
With the integration of the feedback and bias resistors on-
chip, the LM4752 fits into a very compact package. However,
due to the close proximity of the non-inverting input pins to
the corresponding output pins, the inputs should be AC ter-
minated at all times. If the inputs are left floating, the amplifier
will have a positive feedback path through high impedance
coupling, resulting in a high frequency oscillation. In most ap-
plications, this termination is typically provided by the previ-
ous stage's source impedance. If the application will require
an external signal, the inputs should be terminated to ground
with a resistance of 50 kΩ or less on the AC side of the input
coupling capacitors.
FIGURE 6. THD+N vs. P
FIGURE 5. Bridge-Mode Application
10003931
OUT
15
for Bridge-Mode Application
UNDERVOLTAGE SHUTDOWN
If the power supply voltage drops below the minimum oper-
ating supply voltage, the internal under-voltage detection cir-
cuitry pulls down the half-supply bias line, shutting down the
preamp section of the LM4752. Due to the wide operating
supply range of the LM4752, the threshold is set to just under
9V. There may be certain applications where a higher thresh-
old voltage is desired. One example is a design requiring a
high operating supply voltage, with large supply and bias ca-
pacitors, and there is little or no other circuitry connected to
the main power supply rail. In this circuit, when the power is
disconnected, the supply and bias capacitors will discharge
at a slower rate, possibly resulting in audible output distortion
as the decaying voltage begins to clip the output signal. An
10003930
10003937
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