MAX3243: charge pump function purpose

Fred Cheng

Expert 5970 points

Part Number: MAX3243

Hi team,

1.what does the charge pump's function for this IC?

2. what does MAX3243 use to compensate loss ? EQ?

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 321410 points

1. The charge pumps generate ±5.4 V out of the 3.3 V supply.

2. There is no compensation. (And 250 kbit/s isn't much; the edges just are slow.)

0 Fred Cheng over 3 years ago in reply to Clemens Ladisch

TI__Expert 5970 points

Hi Ladisch,

thanks

1. what's this 5.4V for?

2. so basically it's just a buffer right?

0 Parker Dodson over 3 years ago in reply to Fred Cheng

TI__Guru 54042 points

Hi Fred,

1. +/-5V is the minimum output voltage required for RS-232 - the typical value is a bit higher in magnitude to ensure compliance minimum of +/-5V.

2. It has a bit more functionality than a buffer - allowing for a negative output voltage to be generated by the charge pump from a single supply - so it also has a logic conversion component as well. But it also has a buffering component to the device.

Best,

Parker Dodson

0 Fred Cheng over 3 years ago in reply to Parker Dodson

TI__Expert 5970 points

Hi Parker,

I see Rs232 can support up to +/-15V , so MAX3243 can only support +/-5V is that right?

+1 Clemens Ladisch over 3 years ago in reply to Fred Cheng

Guru 321410 points

The RS-232 specification says that a driver must generate signals with a voltage anywhere between ±5 V and ±15 V. A receiver must accept between ±3 V and ± 25 V.

The MAX3243's drivers and receivers conform to these specifications.

0 Fred Cheng over 3 years ago in reply to Clemens Ladisch

TI__Expert 5970 points

Hi Ladisch,

got it , as long as it within the range 5~15V,

we don't care if it's 10V or 7V or 14V.

Interface

Interface forum

MAX3243: charge pump function purpose