LM381/LM381A Low Noise Dual Preamplifier General Description Features The LM381/LM381A is a dual preamplifier for the amplification of low level signals in applications requiring optimum noise performance. Each of the two amplifiers is completely independent, with individual internal power supply decoupler-regulator, providing 120 dB supply rejection and 60 dB channel separation. Other outstanding features include high gain (112 dB), large output voltage swing (VCC b 2V) p-p, and wide power bandwidth (75 kHz, 20 Vp-p). The LM381/ LM381A operates from a single supply across the wide range of 9V to 40V. Either differential input or single ended input configurations may be selected. The amplifier is internally compensated with the provision for additional external compensation for narrow band applications. For additional information see AN-64, AN-104. Y Y Y Y Y Y Y Y Y Y Low noise Ð 0.5 mV total input noise High gain Ð 112 dB open loop Single supply operation Wide supply range 9V – 40V Power supply rejection Ð 120 dB Large output voltage swing (VCC b 2V)p-p Wide bandwidth 15 MHz unity gain Power bandwidth 75 kHz, 20 Vp-p Internally compensated Short circuit protected Schematic Diagram TL/H/7841 – 1 C1995 National Semiconductor Corporation TL/H/7841 RRD-B30M115/Printed in U. S. A. LM381/LM381A Low Noise Dual Preamplifier July 1987 Absolute Maximum Ratings Operating Temperature Range If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/Distributors for availability and specifications. Supply Voltage Storage Temperature Range 260§ C Lead Temperature (Soldering, 10 sec.) a 40V Power Dissipation (Note 1) 0§ C to a 70§ C b 65§ C to a 150§ C 1.56 W Electrical Characteristics TA e 25§ C, VCC e 14V, unless otherwise stated. Parameter Voltage Gain Supply Current Conditions Min Max Units 160,000 V/V Open Loop (Single Ended), f e 100 Hz 320,000 V/V 10 mA VCC 9V to 40V, RL e % Input Resistance (Positive Input) (Negative Input) Input Current (Negative Input) Output Resistance Open Loop Output Current Source Sink Output Voltage Swing Typ Open Loop (Differential Input), f e 100 Hz Peak-to-Peak Unity Gain Bandwidth 100 kX 200 kX 0.5 mA 150 X 8 mA 2 mA VCC b 2 V 15 MHz 75 kHz Power Bandwidth 20 VPP (VCC e 24V) Maximum Input Voltage Linear Operation Supply Rejection Ratio f e 1 kHz 120 dB Channel Separation f e 1 kHz 60 dB Total Harmonic Distortion 60 dB Gain, f e 1 kHz 0.1 % Total Equivalent Input Noise LM381A LM381 RS e 60X, 10–10,000 Hz (Single Ended Input, Flat Gain Circuit, AV e 1000) 300 0.5 0.5 0.7 1.0 mVrms mVrms mVrms Note 1: For operation in ambient temperatures above 25§ C, the device must be derated based on a 150§ C maximum junction temperature and a thermal resistance of 80§ C/W junction to ambient. Connection Diagram Dual-In-Line Package TL/H/7841 – 2 Top View Order Number LM381N or LM381AN See NS Package Number N14A 2 Typical Applications Typical Tape Playback Amplifier Typical Magnetic Phono Preamp TL/H/7841 – 3 Two-Pole Fast Turn-On NAB Tape Preamp TL/H/7841 – 4 Audio Mixer TL/H/7841 – 5 TL/H/7841 – 6 Ultra-Low Distortion Amplifier (AV e 10, THD k 0.05%, VOUT e 3 VRMS) TL/H/7841 – 7 3 Typical Performance Characteristics Large Signal Frequency Response VCC vs ICC P-P Output Voltage VCC Swing vs % Distortion Channel Separation PSRR vs Frequency Gain and Phase Response Noise Voltage vs Frequency Noise Current vs Frequency Pulse Response TL/H/7841 – 8 4 5 LM381/LM381A Low Noise Dual Preamplifier Physical Dimensions inches (millimeters) Molded Dual-In-Line Package (N) Order Number LM381N or LM381AN NS Package Number N14A LIFE SUPPORT POLICY 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 OF NATIONAL SEMICONDUCTOR CORPORATION. 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