Heat sink for this - Page 1
Forum section: electronics / beginners

author: Atom_slayer
author_rank: Newbie
timestamp: January 12, 2025, 06:18:47 am
content: HiLetgo AMS1117-3.3 DC-DC Step-Down Power Module AMS1117-3.3V Buck Module LDO 800MA I am going to use this with an esp-8266 module and I. Any need a heat sink. What kind of heat sink should I use? Thanks

author: ataradov
author_rank: Super Contributor
timestamp: January 12, 2025, 08:12:15 am
content: Why would you need a heat sink? Have you done any calculations or just assume? Generally this package is not designed for use with heat sinks and if you need one, you may want to consider using a different voltage regulator, may be even a switching one.

author: Nominal Animal
author_rank: Super Contributor
timestamp: January 12, 2025, 02:27:19 pm
content: HiLetgo AMS1117-3.3is just a linear regulator (AMS1117-3.3, from unknown manufacturer; there are many for this), some bypass capacitors, and a 1kΩ resistor to provide a minimum 3.3mA load for stability. The excess voltage (at load current) will be turned into waste heat, with the device junction heating by about 100°C per watt of waste heat. ESP8266 modules draw a maximum of 170mA of current, so if you do not power anything else from this, you can safely use the HiLetgo AMS1117-3.3 if the input voltage is between 4.5V and 6.0V or so.In comparison, if you used a MicrochipMIC29150-3.3WTin TO-220 (with standard IN, GND, OUT pinout with tab GND), with 0.1µF to 1µF X7R ceramic capacitor between IN and GND, a 22µF tantalum capacitor between OUT and GND, and a 470Ω or 680Ω resistor (will dissipate less than 25mW of heat) between OUT and GND to ensure load is always at least 5mA for stability (you could use that with a power indicator LED, although at 5mA it will be quite bright), you can draw the 200mA or so current from as low a supply voltage as 3.5V, up to at least 9V, safely, without any kind of heatsink. (Maximum input voltage is 24V or so, but at that you'll be generating over 4W of heat, so you'll need a TO-220 heatsink (cheap, easily available) if the input is higher than 9V or so. Plus, MIC29150 is fully protected against inverted input, overcurrent, overheating, and even transient voltage spikes (up to 60V or so). It is a bit more expensive, 4.54€ at Digikey, 3.74€ at Mouser in singles, 2.57€ at LCSC, currently, but overall a much better solution.)If you have a widely varying input voltage, a buck regulator (to say 4V) followed by a linear regulator (like MIC29150-3.3, although many cheaper ones can perform the same or even better), will produce less heat with about the same supply noise.

author: Atom_slayer
author_rank: Newbie
timestamp: January 12, 2025, 09:32:45 pm
content: Thank you for such a great explanation. One of the examples that i looked at said i would probably need a heat sink since i would be continuously using the Wi-Fi. My project is a temperature and humidity sensor hooked to the esp8266 and blynk for a cigar humidor. Is it critical? Not in the slightest, but I enjoy doing this. Thanks again.

author: ataradov
author_rank: Super Contributor
timestamp: January 12, 2025, 09:59:20 pm
content: Whether you need heat sink depends on how much power that regulator has too dissipate, which in turn depends on the input voltage, output voltage and the current. If you have very high input voltage, then you will be wasting a lot of energy into heat. In that case it is better to use switching supply.