Solid State Guitar Amp Forum | DIY Guitar Amplifiers
Solid State Amplifiers => The Newcomer's Forum => Topic started by: Zappacat on August 27, 2009, 12:39:09 PM
The following is an excerpt of the LM317 datasheet:
Output Current 500, 1500, 1000 mA
Input Min Voltage 4.2 Volt
Input Max Voltage 40, 37 Volt
Adjustable Output Yes
On/Off Pin No
Error Flag No
Temperature Min -40, 0 deg C
Temperature Max 125 deg C
RegType Linear Regulator
What do the 40, 37 volt input max voltage figures mean? Why are there 2 figures? Thanks in advance.
According to datasheet, 40V is the recommended maximum voltage potential that can exist between input and output pins of the regulator.
Since there's some voltage drop over the regulator ("dropout V") too the maximum output voltage is naturally limited by this voltage drop. Furthermore, there's always a certain voltage potential that must exist between output and reference pins. I think these two summed together make up about 3V.