ESP8266 voltage spikes on power rail

I used esp8266 for broadcasting message to my website. But to operate this chip smoothly one needs to redesign its power supply.

There are voltage spikes of around 320 mV

esp8266 voltage spikes on power rail
esp8266 voltage spikes on power rail

at normal operation the chip uses around 70 mA or current. and when broadcasting something over WiFi current  can rise to about 170mA( according to its datasheet).

This all is not the problem. Because everything works.

Problem is the voltage drop accross the lm317t.

Input voltage = 12v

output voltage = 3.3v

voltage difference = 12v – 3.3v = 8.7v

load current = 105 ma

power dissipating = 8.7V x 0.105A = 0.9135W

That’s a lot of power which is being thermal dissipated.

I used a very tiny heat sink. Also the heat sink is attached by a drop of fevicol instead of thermal paste (cheap solution)

My Suggestion:
use a 5V input at lm317t

volatge difference = 5v – 3.3v = 1.7v

power dissipation = 1.7 x 0.105 = 0.178 W

 

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