LM4732TA/NOPB National Semiconductor, LM4732TA/NOPB Datasheet

LM4732TA/NOPB

Manufacturer Part Number
LM4732TA/NOPB
Description
Manufacturer
National Semiconductor
Datasheet

Specifications of LM4732TA/NOPB

Operational Class
Class-AB
Audio Amplifier Output Configuration
2-Channel Stereo
Output Power (typ)
50x2@8OhmW
Audio Amplifier Function
Speaker
Input Offset Voltage
10@±29VmV
Input Bias Current
200nA
Total Harmonic Distortion
0.02@4Ohm@1W%
Single Supply Voltage (typ)
18V
Dual Supply Voltage (typ)
±9V
Power Supply Requirement
Single/Dual
Power Dissipation
125W
Rail/rail I/o Type
No
Power Supply Rejection Ratio
89dB
Single Supply Voltage (min)
20V
Single Supply Voltage (max)
80V
Dual Supply Voltage (min)
±10V
Dual Supply Voltage (max)
±40V
Operating Temp Range
-20C to 85C
Operating Temperature Classification
Commercial
Mounting
Through Hole
Pin Count
27 +Tab
Package Type
TO-220
Lead Free Status / Rohs Status
Compliant
© 2003 National Semiconductor Corporation
LM4732
Stereo 50W Audio Power Amplifier with Mute
General Description
The LM4732 is a stereo audio amplifier capable of typically
delivering 50W per channel of continuous average output
power into a 4Ω or 8Ω load with less than 10% THD+N from
20Hz - 20kHz.
The LM4732 has short circuit protection and a thermal shut
down feature that is activated when the die temperature
exceeds 150˚C. The LM4732 also has an under voltage lock
out feature for click and pop free power on and off.
Each amplifier of the LM4732 has an independent smooth
transition fade-in/out mute.
The LM4732 has a wide operating supply range from +/-10V
- +/-40V allowing for lower cost unregulated power supplies
to be used.
The LM4732 amplifiers can easily be configured for bridge or
parallel operation for 100W mono solutions.
Typical Application
FIGURE 1. Typical Audio Amplifier Application Circuit
DS200724
Key Specifications
Features
n Low external component count
n Quiet fade-in/out mute mode
n Wide supply range: 20V - 80V
Applications
n Audio amplifier for component stereo
n Audio amplifier for compact stereo
n Audio amplifier for self-powered speakers
n Audio amplifier for high-end and HD TVs
j
j
j
j
j
Output Power/Channel at 10% THD+N,
THD+N at 2 x 1W into 8Ω, 1kHz
Mute Attenuation
PSRR
Slew Rate
1kHz into 4Ω or 8Ω
20072422
www.national.com
19V/µs (typ)
110dB (typ)
0.01% (typ)
89dB (typ)
50W (typ)
July 2003

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LM4732TA/NOPB Summary of contents

Page 1

... The LM4732 amplifiers can easily be configured for bridge or parallel operation for 100W mono solutions. Typical Application FIGURE 1. Typical Audio Amplifier Application Circuit © 2003 National Semiconductor Corporation Key Specifications j Output Power/Channel at 10% THD+N, 1kHz into 4Ω or 8Ω j THD into 8Ω ...

Page 2

Connection Diagrams www.national.com Plastic Package (Note 13) 200724D7 Top View Order Number LM4732TA See NS Package Number TA27A TO-220 Top Marking 200724D6 Top View U - Wafer Fab Code Z - Assemble Plant Code XY - Date Code TT - ...

Page 3

... Absolute Maximum Ratings 2) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications Supply Voltage | Common Mode Input Voltage Differential Input Voltage (Note 12) Output Current Power Dissipation (Note 3) ESD Susceptability (Note 4) ESD Susceptability (Note 5) ...

Page 4

Electrical Characteristics Note 3: The maximum power dissipation must be de-rated at elevated temperatures and is dictated by T allowable power dissipation DMAX JMAX and the typical θ is 0.8˚C/W. Refer to the Thermal Considerations section ...

Page 5

Bridged Amplifier Application Circuit FIGURE 2. Bridged Amplifier Application Circuit 5 20072414 www.national.com ...

Page 6

Parallel Amplifier Application Circuit www.national.com FIGURE 3. Parallel Amplifier Application Circuit 6 20072413 ...

Page 7

Single Supply Application Circuit FIGURE 4. Single Supply Amplifier Application Circuit Note: * Optional components dependent upon specific design requirements. Auxiliary Amplifier Application Circuit FIGURE 5. Special Audio Amplifier Application Circuit 20072406 200724D5 7 www.national.com ...

Page 8

External Components Description (Figures 1-5) Components 1 R Prevents current from entering the amplifier’s non-inverting input. This current may pass through to the load B during system power down, because of the amplifier’s low input impedance when the undervoltage circuitry ...

Page 9

Optional External Component Interaction The optional external components have specific desired functions. Their values are chosen to reduce the bandwidth and eliminate unwanted high frequency oscillation. They may, however, cause certain undesirable effects when they interact. Interaction may occur when ...

Page 10

Typical Performance Characteristics THD+N vs Output Power/Channel ± 22V 4Ω, 80kHz BW L Output Power/Channel vs Supply Voltage f = 1kHz 4Ω, 80kHz BW L Total Power Dissipation vs Output Power/Channel 1% THD (max ...

Page 11

Typical Performance Characteristics Crosstalk vs Frequency ± 22V 10W OUT R = 4Ω, 80kHz BW L Mute Attenuation vs Mute Pin Current P = 10W/Channel OUT THD+N vs Frequency ± 22V & 50W OUT Bridge ...

Page 12

Typical Performance Characteristics THD+N vs Output Power ± 22V, Bridge Mode (Note 16 8Ω, 80kHz BW L Output Power vs Supply Voltage, Bridge Mode (Note 16 1kHz 8Ω, 80kHz BW L Note 16: Bridge ...

Page 13

Application Information MUTE MODE The muting function allows the user to mute the amplifier. This can be accomplished as shown in the Typical Applica- tion Circuit. The resistor R is chosen with reference to the M negative supply voltage and ...

Page 14

Application Information resistance is analogous to electrical resistance, and tem- perature drops are analogous to voltage drops, the power dissipation out of the LM4732 is equal to the following −T DMAX JMAX AMB where T = 150˚C, ...

Page 15

Application Information with proper circuit biasing, a few other considerations must be accounted for to take advantage of all of the LM4732 functions, like the mute function. CLICKS AND POPS In the typical application of the LM4732 as a split-supply ...

Page 16

Application Information In comparing audio amplifiers it is necessary to measure the magnitude of noise in the audible bandwidth by using a “weighting” filter (Note 14). A “weighting” filter alters the frequency response in order to compensate for the average ...

Page 17

Application Information The load current I will be much larger than input bias current thus V will follow the output voltage directly, i.e. in phase Therefore the voltage appearing at the non-inverting input is effectively ...

Page 18

Application Information www.national.com (Continued) FIGURE 6. Inverting Amplifier Application Circuit 18 20072421 ...

Page 19

Application Information (Continued) FIGURE 7. Reference PCB Schematic 19 200724F9 www.national.com ...

Page 20

Application Information LM4732 REFERENCE BOARD ARTWORK Composite Layer Top Layer www.national.com (Continued) 200724F6 200724F5 20 200724F7 Silk Layer 200724F8 Bottom Layer ...

Page 21

Application Information Symbol Value 15kΩ IN1 IN2 1kΩ 20kΩ 1kΩ 2.7Ω SN1 SN2 R 2.7Ω 10kΩ ...

Page 22

... NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant ...

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