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LM386

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The LM386N-1

The LM386 is an integrated circuit containing a low voltage audio power amplifier.[1] It is suitable for battery-powered devices such as radios, guitar amplifiers, and hobby electronics projects. The IC consists of an 8 pin dual in-line package (DIP-8) and can output 0.25 to 1 watts of power depending on the model using a 9-volt power supply.

Models

There are three different models of the LM386 that have slightly different specifications, outlined below.

Chip Name Min Voltage Max Voltage Minimum Output Power Typical Output Power Load Impedance
LM386N-1 4 volts 12 volts 250 mW 325 mW 8 ohms
LM386N-3 4 volts 12 volts 500 mW 700 mW 8 ohms
LM386N-4 5 volts 18 volts 700 mW 1000 mW 32 ohms

The LM386 was invented by Ernie Leroy Long at Motorola in 1969. It was originally for part of a fuel injection system for a Ford Car.[citation needed]

Almost identical versions of the device are available from Unisonic (Unisonic Technologies Co. or UTC) as the LM386 [2] and the New Japan Radio Co. Ltd. (JRC) [3] as the NJM386 [4] and NJM386B.[5]

The JRC devices are also available in a single-in-line package.[6]

JRC devices, marked as 386 JRC, are sometimes misleadingly referred to as the JRC386.

SPICE simulation models

Although National Semiconductor and Texas Instruments (who bought Nat Semi in 2011[7]) do not provide an official SPICE model for the LM386, there are two independently developed models freely available:

  • The original "No-Frills LM386 Model" by Dave Dilatush.[8]
  • An improved model, "The EasyEDA LM386EE spice model" developed for the simulations of the "Tesseract Guitar Practice Amplifier" project.[9]

Usage in guitar amplifiers

  • The LM386 is one of the most common amps used in DIY guitar preamplifiers and sustainers due to its ability to run on a single 9V battery.
  • The EasyEDA "Tesseract" Guitar Practice Amplifier is a versatile design based on the LM386 and features distortion and full-wave rectification effects.[10]
  • The well-known "Smokey Amp" created by Bruce Zinky uses an LM386 and is notable for being able to fit in a cigarette package.
  • The "Little Gem" and "Little Gem MkII" are modified/cloned versions of the "Smokey Amp".[11]
  • The "Ruby" amp[12] is a modified version of a Little Gem amplifier.
  • The Marshall MS-2 and MS-4 miniature practice amplifiers use a single-in-line packaged NJM386 manufactured by JRC.

Usage in amateur radio

The LM386 is very commonly used in the audio amplifier of low power QRP amateur radio rigs, like the Pixie.

See also

References

  1. ^ "Data Sheet (National Semiconductor)" (PDF). Texas Instruments. 2000. Retrieved 4 Nov 2013.
  2. ^ "Data Sheet (Unisonic Technologies Co.)" (PDF). Unisonic Technologies Co. 2014. Retrieved 2 Sep 2015.
  3. ^ "Data Sheet (New Japan Radio Co. Ltd.)" (PDF). New Japan Radio Co. Ltd. Retrieved 29 Aug 2015.
  4. ^ "Data Sheet (New Japan Radio Co. Ltd.)" (PDF). New Japan Radio Co. Ltd. Retrieved 29 Aug 2015.
  5. ^ "Data Sheet (New Japan Radio Co. Ltd.)" (PDF). New Japan Radio Co. Ltd. Retrieved 2 Sep 2015.
  6. ^ "Single-in-line package outline drawing (New Japan Radio Co. Ltd.)" (PDF). New Japan Radio Co. Ltd. Retrieved 2 Sep 2015.
  7. ^ "Texas Instruments completes acquisition of National Semiconductor".
  8. ^ "LM386 audio amp Spice model?".
  9. ^ "The EasyEDA Tesseract Guitar Practice Amp simulation files".
  10. ^ "Tesseract Guitar Practice Amp".
  11. ^ "Little Gem amps at runoffgroove".
  12. ^ "Ruby amp at runoffgroove".
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