MAX3232: what is the function of C1, C2, C3 and C4

user021864

Intellectual 2145 points

Part Number: MAX3232
Other Parts Discussed in Thread: TRS3232E

Hi,

My customer is wondering what is the function of C1 to C4, and how to know if those pin are working fine?

Can you help to let us know the internal configuration of these circuit?

What should we see on the pin1 to pin 6?

Thanks for your help.

over 6 years ago

0 Miguel Robertson over 6 years ago

TI__Guru 62920 points

Hello,

These capacitors are used by the transceiver's charge pump circuitry to generate the higher voltage V+ and V- rails from the VCC supply. You can read about how the charge pump operates in this blog:

How the RS-232 transceiver’s regulated charge-pump circuitry works

Other Parts Discussed in Post: TRS3232E The RS-232 interface is popular in single-ended low-speed serial communications. The interface was originally designed to connect the serial port of a computer to…

By Hao L over 7 years ago in Technical articles > Analog

Please let us know if you have any additional questions.

Regards,

Max

0 Hermes Lin1 over 6 years ago

Intellectual 420 points

hi sir,

if customer in ICT test, Measure MAX3232CP Pin_1 to GND. the different IC have different Voltage. Is this correct?

0 Hao L over 6 years ago in reply to Hermes Lin1

TI__Mastermind 25705 points

Hermes,

Do you mean some devices show high impedance from C1+ to GND? What's the test condition, like supply, load? Is the result checked by a multimeter? For the problematic parts, what's the reading on V+/V- pins?

Regards,

Hao

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MAX3232: what is the function of C1, C2, C3 and C4