Hi, why the capacitor value need to change according to VCC?
If I choose C1=0.1uF when Vcc=5V, what will happen?
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Hi, why the capacitor value need to change according to VCC?
If I choose C1=0.1uF when Vcc=5V, what will happen?
I ask this because one of my customer is using 5V VCC and 0.1uF cap. And they will get below waveforms after operating correctly a period of time:
what may cause such malfunction? How should I check?
Besides, the customer says that they can not observe below waveforms of the charge pump clearly, I'm not sure if our device will behave as below, our datasheet does not provide waveforms that shows how V+, V- looks like.
Howard,
The capacitor values can be tweaked to control the ripple of the output voltage. You can take a look at this post for some details (https://e2e.ti.com/support/interface/rs232/f/392/t/463809).
Can you describe what happened during the malfunction? Did the output Dout become zero during communication? Can you check to see if the V+ voltage is normal (above 5V)?
MAX3232E has similar power up ramp behavior as what's shown in the figure.
Regards,
Hao
Howard,
Can you send FA request for the damaged devices? Can you also send me the schematic/layout and some description of the system by email? Thanks,
Hao