MAX3232: High Idle Current

Franz Schellhase

Part Number: MAX3232

Hi team,

One of my customers has the following issue:

"I'm using MAX3232 with 5V supply. It consumes a lot of power when idle (about 2mA). I can't find how to reduce the current in the data sheet."

Is there a common mistake that might be the cause for this?

Thank you,

Franz

over 6 years ago

0 Hao L over 6 years ago

TI__Mastermind 25705 points

Franz,

What's the load condition of the device? Is it possible to check the waveforms of V+, V-? (V+ should stay around 5.4V and V- around -5.4V.) Another experiment is trying to connect the device to an established supply, rather than ramp up the power with the device.

Regards,

Hao

0 Franz Schellhase over 6 years ago in reply to Hao L

TI__Expert 3605 points

Hi Hao,

They measured:
VDD= 4.8 V
V+=7,2V (Pin2 )
V-=-5.4V (Pin6)
They are investigating further and will follow up with more information.

Looks like V+ is too high. Any thoughts on that?

This is their schematic:

Thank you,

Franz

0 Hao L over 6 years ago in reply to Franz Schellhase

TI__Mastermind 25705 points

Franz,

This C1=C2=C3=C4=0.1uF setup is supposed to work with Vcc=3.3V. With 5V supply, it's recommended to use different values.

Also with your setup, the voltage ripple of V+ pin could be high. Can you check 7.2V is the peak or average value? You can refer to this app note for some detail.

e2e.ti.com/.../how-the-rs-232-transceiver-s-regulated-charge-pump-circuitry-works

Please let me know if you have more questions.

Regards,

Hao

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MAX3232: High Idle Current