This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
Part Number: SN65C3232
Built 10 prototypes, and 2 of 10 provide 'garbage' during RS-232 communication at 155200 bps. Charge pump capacitors are 220 nF 25V X5R at 3.3 V supply voltage. Can it be the problem? What are requirements and tolerance for those capacitors? What else may cause such failure? There are also 33 Ohms 250 mA thermistors in series with TX and RX pins 7 and 8 and TVS and 1 nF 50 V X7R capacitors and TVS 5V diodes from those pins to ground. Can 5V TVS cause such problems. It seems that it work fine with few characters, like OK, but does not provide correct characters with longer streams of data.
We are glad that we were able to resolve this issue, and will now proceed to close this thread.
If you have further questions related to this thread, you may click "Ask a related question" below. The newly created question will be automatically linked to this question.
In reply to Oleh Kernytskyy64:
In reply to Hao L:
Capacitors values are 220 nF. TVS diodes are bi-directional.
Measured Driver Output signal (DOUT2) on pin 7, and it has saw shape ripple (approximately 1 V peak to peak ripple).
When changed capacitors to recommended for 3.3 V supply voltage value 100 nF - signal on pin 7 became worst (deep voltage sags added after each second teeth ),
It's OK to see some ripples on the output signal due to the internal charge pump circuitry. You can refer to this post (e2e.ti.com/.../463809) for the waveforms. The DOUT signal should be aligned the voltage level of V+ (pin2) and V- (pin6).
Can you give more information how the device failed communication?
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.