RS 232 Interface with MAX 232

Several times we needs a simple RS232 interface, between TTL and RS-232 logical levels. For example, various equipments have TTL output (0 - 5 Volts), which it's not compatible with COM port on PCs, Laptops etc, that needs " + / - " Voltage Level.
MAX 232 is an excellent IC, that works very well, just by using five capacitors.

FIG.1 shows the electronic diagram. The IC including 4 inputs and 4 outputs.

max232diag.gif - 10270 Bytes


Figure below shows the PCB and Components Layout.

max232pcb.gif - 7979 Bytes


All capacitors are Tantalium-type. Table on Fig.1 describes the Capacitors values depending upon IC type, but I have used the MAX232 with 1uF cap's. You can easily find it.

max232.gif - 11154 Bytes max232_pcb-ps.gif - 4657 Bytes


Fig.3 shows the MAX232 construction on PCB (Left) with 7805 regulator in the same PCB. Picture on the Right shows my PCB.

Makis SV1BSX(Febr.' 03)