LM2664: Are the electrolytic capacitors required for the voltage inverter application?

David__

Part Number: LM2664
Other Parts Discussed in Thread: INA828,

Hi, I'm using the MSP-EXP432P401R board with some Op Amps. Both +5V from the launchpad's USB and -5V will power the INA828 Instrumentation Amplifier.

May I ask

Q0. do both C1 and C2 have to be an electrolytic capacitor? Since the electrolytic capacitors are bigger than the ceramic capacitors, I wish to choose ceramic types to shrink the size.

Q1. The input is 5V from the USB and I want to generate -5V, max output current of 20mA.

For this case, how can I calculate the capacitance for both C1 and C2?

over 5 years ago

0 Youhao Xi over 5 years ago

TI__Guru* 78060 points

Hi David,

Thank you for your interests in the LM2664. To your questions,

A0. Yes, you can use ceramic capacitors. The datasheet actually mentioned both ceramic and electrolytic in Table 1.

A1. Datasheet Equations (1) and (2) determines the capacitor selection. Do a simple math process, you can get C1 and C2 value based on other parameters.

Happy Holidays!

Youhao Xi, Applications Engineering

0 David__ over 5 years ago in reply to Youhao Xi

Genius 3585 points

Thanks for your kind reply, Youhao. Before closing this,

Youhao Xi said:
The datasheet actually mentioned both ceramic and electrolytic in Table 1.

Thanks, I haven't noticed this part.

Youhao Xi said:
Datasheet Equations (1) and (2) determines the capacitor selection. Do a simple math process, you can get C1 and C2 value based on other parameters.

Do you mean these two equations?