LM7909 Pinout, Equivalent, Features, Applications, and More

LM7909 is a negative voltage regulator IC that provides accurate and stable -09V at the output, in this article we are going to discuss about LM7909 pinout, equivalent, features, applications, and other details about this IC.


LM7909 Pinout, Equivalent, Features, Applications



LM7909 IC Features / Technical Specifications

  • TO-220 Package
  • Up to 1.5A output current (Some manufacturers also make in 1A output current)
  • Short circuit protection circuitry
  • Overheat shutdown circuitry
  • Low price
  • Reliable for commercial use
  • Stable -09V output
  • Maximum input voltage is 35V DC
  • Low quiescent current


LM7909 Description

LM7909 is negative voltage regulator IC of LM79XX series provides accurate and stable -09V output, there are also other negative voltage regulators in this series which are LM7905, LM7906, LM7908, LM7909, LM7910, LM7912, LM7915, LM7918 and LM7924. All the ICs in this series are available in TO-220 package and have 3 output pins which are Input, Output and Ground. The IC also have many features like thermal overload protection, safe area protection, short circuit protection etc. all these features makes this IC robust and reliable for commercial equipment and also for experimental projects of students and tinkerers.

Moreover, the IC requires only one component at the output which is a capacitor that stabilizes the output voltage. The input capacitor is only necessary if the IC is more than 3 inches far from the input supply filter capacitor. If the input and output capacitors values are more than 100uf then two protection diodes should be used to protect the IC from capacitors output spikes to protect the IC’s internal circuitry from damaging.



Where & How to Use

LM7909 can be used in variety of power supplies, Charger circuits, voltage converter circuits. To get stable -09V at the output the input must be -2V to -3V higher than the output. A suitable heatsink will be required with the IC. Using the IC is pretty straight forward; it will be connected to the negative supply of the load.



Dual power supply circuits

Voltage step down circuits

Battery charger circuits

Solar power supply circuits 

Motor drivers circuits


Replacement and Equivalent / Other Part Numbers

UA7909, GL7909, KIA7909P if LM7909 is not available then you can also use LM337 adjustable negative voltage regulator IC and set it to -09V fixed output.


How to Safely Long Run in a Circuit

To get long term performance from this IC do not apply more than 35V voltage at the input, do not drive load of more than 1.5A, use a suitable heatsink with this IC and always store and operate this IC in temperature from -65 degree centigrade to +150 degree centigrade.



To download the datasheet just copy and paste the below link in your browser.


You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *