Document
LM1896 LM2896 Dual Audio Power Amplifier
February 1995
LM1896 LM2896 Dual Audio Power Amplifier
General Description
The LM1896 is a high performance 6V stereo power amplifier designed to deliver 1 watt channel into 4X or 2 watts bridged monaural into 8X Utilizing a unique patented compensation scheme the LM1896 is ideal for sensitive AM radio applications This new circuit technique exhibits lower wideband noise lower distortion and less AM radiation than conventional designs The amplifier’s wide supply range (3V – 9V) is ideal for battery operation For higher supplies (VS l 9V) the LM2896 is available in an 11-lead single-inline package The LM2896 package has been redesigned resulting in the slightly degraded thermal characteristics shown in the figure Device Dissipation vs Ambient Temperature
Features
Y Y Y Y Y Y Y Y Y
Low AM radiation Low noise 3V 4X stereo Po e 250 mW Wide supply operation 3V – 15V (LM2896) Low distortion No turn on ‘‘pop’’ Adjustable voltage gain and bandwidth Smooth waveform clipping Po e 9W bridged LM2896
Applications
Y Y Y
Compact AM-FM radios Stereo tape recorders and players High power portable stereos
Typical Applications
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FIGURE 1 LM2896 in Bridge Configuration (AV e 400 BW e 20 kHz) Order Number LM1896N Order Number LM2896P See NS Package Number N14A See NS Package Number P11A
C1995 National Semiconductor Corporation
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RRD-B30M115 Printed in U S A
Absolute Maximum Ratings
If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Supply Voltage LM1896 LM2896 Operating Temperature (Note 1) Storage Temperature VS e 12V VS e 18V 0 C to a 70 C b 65 C to a 150 C Junction Temperature Lead Temperature (Soldering 10 sec ) Thermal Resistance iJC (DIP) iJA (DIP) iJC (SIP) iJA (SIP) 150 C 260 C 30 137 10 55 C C C C W W W W
Electrical Characteristics
Unless otherwise specified TA e 25 C AV e 200 (46 dB) For the LM1896 VS e 6V and RL e 4X For LM2896 TTAB e 25 C VS e 12V and RL e 8X Test circuit shown in Figure 2 Parameter Supply Current Operating Supply Voltage Output Power LM1896N-1 LM1896N-2 LM2896P-1 LM2896P-2 THD e 10% f e 1 kHz VS e 6V RL e 4X Dual Mode VS e 6V RL e 8X Bridge Mode VS e 9V RL e 8X Dual Mode VS e 12V RL e 8X Dual Mode VS e 12V RL e 8X Bridge Mode VS e 9V RL e 4X Bridge Mode VS e 9V RL e 4X Dual Mode f e 1 kHz Po e 50 mW Po e 0 5W Po e 1W CBY e 100 mF f e 1 kHz CIN e 0 1 mF Output Referred VRIPPLE e 250 mV CBY e 100 mF f e 1 kHz CIN e 0 1 mF Output Referred Equivalent Input Noise RS e 0 CIN e 0 1 mF BW e 20 b 20 kHz CCIR ARM Wideband 28 50
b 40 b 50
Conditions Min Po e 0W Dual Mode 3
LM1896 Typ 15 Max 25 10 11 18 13 3 Min
LM2896 Typ 25 Max 40 15
Units mA V W ch W W ch W ch W W W ch % % % dB dB
(
*
09 TA e 25 C
21 20 72 25 90 78 25 0 09 0 11 0 14
b 40 b 50 b 54 b 64
TTAB e 25 C
Distortion
0 09 0 11
Power Supply Rejection Ratio (PSRR) Channel Separation Noise
b 54 b 64
14 14 20 3 100 5 32 350 56 50
14 14 20 6 100 5 20 10 120 20 64 350
mV mV mV V kX mV mV nA
DC Output Level Input Impedance Input Offset Voltage Voltage Difference between Outputs Input Bias Current LM1896N-2 LM2896P-2
10 120
Note 1 For operation at ambient temperature greater than 25 C the LM1896 LM2896 must be derated based on a maximum 150 C junction temperature using a thermal resistance which depends upon mounting techniques
2
Typical Performance Curves
LM2896 Device Dissipation vs Ambient Temperature LM1896 Maximum Device Dissipation vs Ambient Temperature
b 3 dB Bandwidth vs Voltage Gain for Stable Operation
THD and Gain vs Frequency AV e 54 dB BW e 30 kHz
THD and Gain vs Frequency AV e 54 dB BW e 5 kHz
THD and Gain vs Frequency AV e 46 dB BW e 50 kHz
THD and Gain vs Frequency AV e 40 dB BW e 20 kHz
THD and Gain vs Frequency AV e 34 dB BW e 50 kHz
AM Recovered Audio and Noise vs Field Strength for Different Speaker Lead Placement
Power Supply Rejection Ratio (Referred to the Output) vs Frequency
Channel Separation (Referred to the Output) vs Frequency
Power Output vs Supply Voltage
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3
Typical Performance Curves (Continued)
Total Harmonic Distortion vs Power Output Power Dissipation vs Power Output RL e 4X Power Dissipation vs Power Output RL e 8X
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Equivalent Schematic
6 9 No connection on LM1896 ( ) indicates pin number for LM2896
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Connection Diagrams
Single-In-Line Package Dual-In-Line Package
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Top View
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Top View 4
Typical Applications (Continued)
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6 9 No connection on LM1896 ( ) Indicates pin number for LM2896
FIGURE 2 Stereo Amplifier with AV e 200 BW e 30 kHz
External Components (Figure 2)
Components 1 R2 R5 R10 R13 2 R3 R12 3 Ro 4 C1 C14 Comments Sets voltage gain AV e 1 a R5 R2 for one channel and AV e 1 a R10 R13 for the other channel Bootstrap resistor sets drive current for output stage and allows pins 3 and 12 to go above VS Works .