LM4734TA/NOPB National Semiconductor, LM4734TA/NOPB Datasheet

LM4734TA/NOPB

Manufacturer Part Number
LM4734TA/NOPB
Description
Manufacturer
National Semiconductor
Datasheet

Specifications of LM4734TA/NOPB

Operational Class
Class-AB
Audio Amplifier Output Configuration
3-Channel Stereo
Output Power (typ)
20x3@8OhmW
Audio Amplifier Function
Speaker
Input Offset Voltage
15@±21VmV
Input Bias Current
200nA
Total Harmonic Distortion
0.05@4Ohm@1W%
Single Supply Voltage (typ)
18V
Dual Supply Voltage (typ)
±12/±15/±18/±24V
Power Supply Requirement
Single/Dual
Power Dissipation
125W
Rail/rail I/o Type
No
Power Supply Rejection Ratio
75dB
Single Supply Voltage (min)
20V
Single Supply Voltage (max)
60V
Dual Supply Voltage (min)
±10V
Dual Supply Voltage (max)
±30V
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
© 2006 National Semiconductor Corporation
LM4734
3 Channel 20W Audio Power Amplifier with Mute and
Standby
General Description
The LM4734 is a three channel audio amplifier capable of
typically delivering 20W per channel of continuous average
output power into a 4Ω or 8Ω load with less than 10%
THD+N from 20Hz - 20kHz.
The LM4734 has short circuit protection and a thermal shut
down feature that is activated when the die temperature
exceeds 150˚C. The LM4734 also has an under voltage lock
out feature for click and pop free power on and off.
Each amplifier of the LM4734 has an independent smooth
transition fade-in/out mute and a power conserving standby
mode. The mute and standby modes can be controlled by
external logic.
The LM4734 has a wide supply operating supply range from
±
supplies to be used.
The LM4734 can easily be configured for bridge or parallel
operation for higher power and bi-amp solutions.
Typical Application
SPiKe
10V -
Protection and Overture
±
30V allowing for lower cost unregulated power
are trademarks of National Semiconductor Corporation.
FIGURE 1. Typical Audio Amplifier Application Circuit
DS200898
Key Specifications
Features
n Low external component count
n Quiet fade-in/out mute mode
n Low power standby mode
n Wide supply range: 20V - 60V
Applications
n Audio amplifier for component stereo
n Audio amplifier for compact stereo
n Audio amplifier for home theater in a box (HTB)
n Audio amplifier for high-end and HD TVs
j
j
j
j
j
1kHz into 4Ω or 8Ω
Output Power/Channel with 10% THD+N,
THD+N at 3x1W into 8Ω, 1kHz
Mute Attenuation
PSRR
Slew Rate
200898D2
www.national.com
18V/µs (typ)
110dB (typ)
0.03% (typ)
March 2006
64dB (typ)
20W (typ)

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LM4734TA/NOPB Summary of contents

Page 1

... Typical Application FIGURE 1. Typical Audio Amplifier Application Circuit SPiKe ™ Protection and Overture ™ are trademarks of National Semiconductor Corporation. © 2006 National Semiconductor Corporation Key Specifications j Output Power/Channel with 10% THD+N, 1kHz into 4Ω or 8Ω j THD+N at 3x1W into 8Ω ...

Page 2

Connection Diagrams www.national.com Plastic Package (Note 13) 200898I4 Top View Order Number LM4734TA See NS Package Number TA27A TO-220 Top Marking Top View U - Wafer Fab Code Z - Assembly Plant Code XY - Date Code TT - Die ...

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 The following specifications apply for V 25˚C. Symbol Parameter Standby V Standby Low Input Voltage IL V Standby High Input Voltage IH Mute V Mute Low Input Voltage IL V Mute High Input Voltage IH Note 1: All ...

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Bridged Amplifier Application Circuit FIGURE 2. Bridged Amplifier Application Circuit 5 200898D3 www.national.com ...

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Parallel Amplifier Application Circuit www.national.com FIGURE 3. Parallel Amplifier Application Circuit 6 200898D4 ...

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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 200898D5 200898D6 7 www.national.com ...

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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 Although the optional external components have specific desired functions that are designed to reduce the bandwidth and eliminate unwanted high frequency oscillations they may cause certain undesirable effects when they interact. Inter- action may occur for ...

Page 10

Typical Performance Characteristics THD+N vs Output Power/Channel ± 17V 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 ...

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Typical Performance Characteristics Crosstalk vs Frequency ± 17V 10W, Channel 1 OUT R = 4Ω, 80kHz BW L Crosstalk vs Frequency ± 17V 10W, Channel 3 OUT R = 4Ω, 80kHz BW L Crosstalk vs Frequency ...

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Typical Performance Characteristics Crosstalk vs Frequency ± 21V 10W, Channel 3 OUT R = 8Ω, 80kHz BW L Mute Attenuation vs Mute Pin Voltage P = 10W/Channel OUT Common-Mode Rejection Ratio www.national.com (Continued) Two Channels On Crosstalk vs ...

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Typical Performance Characteristics THD+N vs Frequency ± 21V & 15W, Chs 1 & OUT Parallel Mode (Note 16 4Ω, 80kHz BW L THD+N vs Output Power ± 17V, Chs 1 & ...

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Typical Performance Characteristics Output Power vs Supply Voltage Chs 1 & Parallel Mode (Note 16 1kHz 4Ω, 80kHz BW L Note 15: Bridge mode graphs were taken using the demo board and inverting the ...

Page 15

Application Information 2π DMAX CC Thus by knowing the total supply voltage and rated output load, the maximum power dissipation point can be calcu- lated. The package dissipation is three times the number ...

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Application Information PARALLEL AMPLIFIER APPLICATION Parallel configuration is normally used when higher output current is needed for driving lower impedance loads (i.e. 4Ω or lower) to obtain higher output power levels. As shown in Figure 3 , the parallel amplifier ...

Page 17

Application Information CLICKS AND POPS In the typical application of the LM4734 as a split-supply audio power amplifier, the IC exhibits excellent “click” and “pop” performance when utilizing the mute and standby modes. In addition, the device employs Under-Voltage Pro- ...

Page 18

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 17). A “weighting” filter alters the frequency response in order to compensate for the average ...

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Application Information LAYOUT, GROUND LOOPS AND STABILITY The LM4734 is designed to be stable when operated at a closed-loop gain greater, but as with any other high-current amplifier, the LM4734 can be made to oscillate under certain ...

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Application Information If the DC blocking input capacitor (C IN lower -3dB point is found using Equation (8) as discussed in the Proper Selection of External Components section. www.national.com (Continued used as shown, the FIGURE 7. Inverting Amplifier ...

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Application Information (Continued) FIGURE 8. Reference PCB Schematic 21 200898D8 www.national.com ...

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Application Information LM4734 REFERENCE BOARD ARTWORK Composite Layer Top Layer www.national.com (Continued) 200898I7 200898I9 22 200898I8 Silk Layer 200898I6 Bottom Layer ...

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Application Information Bill Of Materials For Reference PCB Symbol Value 33kΩ IN1 IN2 IN3 1kΩ 20kΩ ...

Page 24

... BANNED SUBSTANCE COMPLIANCE National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2. ...

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