Dear Analog Devices,
I use ADM3252E as a level shifter (converting TTL to RS232 and vice versa) in a project. Data is generated by a microprocessor at TTL the voltage level, and then pass through ADM3252E so that a communication is provided between the PC and microprocessor. When the RS232 connector is not connected to the PC, the data is clear and has a voltage rating of (-8V to -5V & 5V to 8V) and there is not problem. However, when the RS232 connector is connected to the COM port of the PC, the voltage level decreases dramatically. The voltage level is between -1V to 1V, so the voltage rating is not provided for RS232 standards. Therefore, the data is transmitted to the COM port of the PC. How can this problem be solved? Why does the voltage level decrease?
Note: The charge pump capacitors are selected to be 220nF, but 100nF and 2.2uF capacitors are also used and no change was observed.