Is your MAX232 or MAX3232 is getting heat or burned ? I have also faced similar issue and struggled a lot to find the problem when I was working in some projects involving RS232 communication. It is very easy to solve this problem, just follow the below guidelines.

Follow Manufacturer Specific Datasheet

As you know MAX232 / MAX3232 is manufactured by different companies. Each one is having it’s own specifications and properties. So first you need to refer the manufacturer specific datasheet. You can see the datasheets of popular manufactures below.

• MAX232 – Texas Instruments
• MAX232 – Maxim Integrated
• ST232 – STMicroelectronics
• IC232 – Renesas
• SP232A – Exar Corporation
• ADM232A – Analog Devices
• HIN232 – Renesas
• MAX3232 – Texas Instruments
• MAX3232 – Maxim Integrated
• ST3232 – STMicroelectronics

I have seen peoples making following two mistakes very commonly.

Connection of Charge Pump Capacitors

Just check the MAX232 datasheet of Texas Instruments and Maxim Integrated. You can find that for Texas Instruments ICs you can connect charge pump capacitor C3 to GND or VCC (check the footer note).

But for Maxim Integrated we need to connect it to VCC itself. So your IC will get damage if the capacitor C3 is connected to Ground in your circuit and you are using Maxim Integrated’s IC.

So it is better to connect Capacitor C3 to VCC (5V) such that it is compatible to both Texas Instruments and Maxim Integrated chips.

Value of Capacitors

Different capacitor (C1, C2, C3, C4) values are required for different ICs. Especially if you are using MAX3232 please refer the particular datasheet and select capacitor values. If you are using MAX232 chip, then you can use 1µF ceramic capacitors as it is compatible to both Texas Instruments and Maxim Integrated.

Ground Unused Inputs

This is also very important as all of these driver ICs have 2 input and 2 output channels. If you refer above datasheets you can see that some of the ICs have internal pull up or pull down resistors for all the inputs but usually it is not available for commonly available chips in the market. So if the input pin is left floated it may pickup noise and high voltages may get generated due to oscillations.

It doesn’t cost anything to ground unused inputs of these ICs.

Purchase from Good Suppliers

I have noticed that lots of fake low quality chips are available in the market. Usually same suppliers will have cheap and good quality products. So it is better to purchase chips from reputed suppliers and ask them for good quality chips.

Hope this helps you. Please do comment below if you found any other mistakes such that it will help others.