TRS3223E: TRS3223 waveform problem

Mark Liao

Prodigy 40 points

Part Number: TRS3223E
Other Parts Discussed in Thread: TRS3223

Hi,

Voltage vibration at high/low voltage level,

Pls see attached file in details, Thank you.TRS3223.pptx

over 3 years ago

0 Tyler Townsend over 3 years ago

TI__Mastermind 47888 points

Hi Mark,

This ripple is caused by the charge pump circuitry which drives the RS232 signal high and low.

This charge pump blog post describes the affects of capacitors C1, C2, C3, and C4. Changing the ratios of these capacitors determines several effects such as ripple height and ripple frequency.

https://e2e.ti.com/blogs_/b/analogwire/posts/how-the-rs-232-transceiver-s-regulated-charge-pump-circuitry-works

Regards,

Tyler

0 Mark Liao over 3 years ago in reply to Tyler Townsend

Prodigy 40 points

Hi Tyler,

Even ripple on RS232 signal high and low, but i think our voltage level is ok for Vih/Vil, and no impact to the RS232 data transmission, is it correct?

Thank you.

0 Tyler Townsend over 3 years ago in reply to Mark Liao

TI__Mastermind 47888 points

Hi Mark,

Yes there will be ripple on RS232 signals HIGH and LOW. If you meet the recommended operating conditions for Vih/Vil, the voltage ripple will not impact RS232 data transmission. The voltage ripple is caused by the charge pump circuitry driving the signal high and low... this is normal operation of the device.

Regards,

Tyler

0 Mark Liao over 3 years ago in reply to Tyler Townsend

Prodigy 40 points

Hi Tyler,

Thanks for your reply.

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TRS3223E: TRS3223 waveform problem