TRS232: p2p replacement with ADUM202E

Hi Brian,

These looks pretty comparable to me when comparing slides 5 and 7 (since these are the ones that correspond to the same capacitance values for both ICs).  The differences are more minor than they initially appear as well since slide 5 plots the waveform with a 3 V/div scale rather the 2 V/div scale used elsewhere.  Despite this, though, I would expect slight differences between different part numbers and manufacturers due to different circuit implementations (regulation technique, target output voltage, quiescent current draw, etc.).  Some ripple can be expected from any charge pump (or switched-mode converter), and can generally be tolerated by RS-232 interfaces given that the receiver just needs to be able to decode whether the line is "high" (above a threshold) or "low" (below a threshold).  If there are other concerns outside signal integrity (such as noise coupling to other components), they could experiment with other capacitance values (this blog would be a useful reference) or filtering the switching noise on VCC (e.g., by using a ferrite bead).

Please let me know if you have any further questions or concerns.

Regards,
Max