How to manually solder the 28VQFN package?

zpccx

How to manually solder the 28VQFN package? [Copy link]

 

There is a large heat sink under a TI ADS8372 28-pin VQFN package chip The pad spacing on the PCB is very small I asked someone and they said to drip solder on the pad first and then blow it with a hot air gun. Will this not damage the chip due to excessive temperature? In addition, when dripping solder on the large heat sink at the bottom, do you drip it from the front or the back? When blowing with a hot air gun, do you blow from the front of the chip or the back?

yddq

First tin the pad, then place the chip, and then heat it with a hot air gun

yddq

First tin the pad, then place the chip, and then heat it with a hot air gun

bluefox0919

When I solder, I always tin the front side with a soldering iron, and then use a hot air gun to heat the tin until it melts before placing the IC. You can consider leaving the soldering pad longer to facilitate soldering with a soldering iron later.

ljj3166

When making a PCB, the heat sink uses a through-hole pad and is directly soldered on the back.

qwqwqw2088

Second floor correct answer

qwqwqw2088

When manually soldering such a chip, 1. Do not solder for too long! 2. Heat the hot air gun evenly

strong161

Leave vias on the PCB. When soldering, apply a layer of thin tin to the pad first, solder the feet first, and drag it around. It is very easy to solder, then solder the hot plate from the opposite side through the via.

ddllxxrr

First, use a soldering iron to apply a layer of tin on the pad, then apply flux, then place the chip, and then add some flux on the chip to prevent it from being damaged. Then, turn on the appropriate temperature and wind speed and blow on the chip. Blow for one or two minutes, touch it slightly with tweezers, and see if it can bounce back under the tension.

ienglgge

Wouldn't it damage the chip due to overheating? Don't blow the chip too hard. Adjust the temperature of the air gun to the right level. It's usually fine. When dripping solder on the large heat sink at the bottom, do you drip it from the front or the back? Apply the tin on the side that is in direct contact with the chip pad. When using the hot air gun, do you blow it from the front or the back of the chip? For the front, you can slightly tilt it. Let the wind enter the gap between the chip and the PCB from the side. Use tweezers to hold the chip well. Apply a little force. Hold the chip well. It won't take long. The tin will melt. Remove the air gun and carefully remove the tweezers. Check whether it is soldered. That's it. Just practice a few more times.

季yy

Hey hey simple

通宵敲代码

When making a PCB for this kind of chip, if it is not absolutely necessary, I usually don't leave the center pad, which can save a lot of unnecessary trouble. If it must be left, soldering is usually done in two steps: 1. Tin the center pad first, with an appropriate amount, then heat it evenly with an air gun to solder the chip, 2. Then manually solder the pins around it,

qwqwqw2088

The center pad should be checked in the chip datasheet. If it is drawn in the manual, it is better to follow the manual. It is very troublesome to manually solder the center pad when using a patch machine for batch processing.