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Hi

I am building a project that uses an Intersil HIN232ACPZ, which is a TTL-RS-232 level shifter like the Maxim MAX232. In fact, the two have identical pinouts and so I was wondering if they are supposed to be exchangeable. I'm asking because I don't have the Intesil part, but I've got some spare MAX232s and I'm thinking of substituting.

Thanks
JonB

I haven't looked at the data sheet, but I suspect it's the same thing. I ordered MAX232's one time and got Sipex SP232's, probably from Jameco. (Mouser and Digi-Key wouldn't substitute like that.) I got them for boards laid out by someone else though, and ended up never using them. For my own stuff, I use the MC145406 which has three line drivers and three line receivers in a 16-pin DIP, so you can have TX, RX, RTS, CTS, DSR, and DTR, with no external components. It requires the higher + and - voltages, but I always have those for other things anyway.

The MAX232 requires larger capacitors (1µF) than the HIN232A (.1µF). Either use a MAX232A or replace the capacitors including the decoupling capacitor (5 caps total).

The HIN232ACPZ is an exact cross for a MAX232ACPE+. As Klaus notes, you can substitute the MAX232ACPE+ as long as you use 1µF charge pump capacitors. I use tantalums for that purpose, mainly due to their small size—MLCC ceramics will wok as well. The HIN232ACPZ can work with 0.1µF charge pump capacitors, but will not perform as well as it would with the 1µF caps. Also note that the HIN232ACPZ is several dollars (US) cheaper than the Maxim part.

Technical note: every so often, one will see a schematic in which the MAX232 is used with charge pump capacitors that are larger than 1µF. That is incorrect design and according to Maxim, may cause the MAX232 to eventually fail. What happens is the larger capacitors draw more current at initial power-on than the MAX232 is designed to handle. The charge pump circuitry in the MAX232 is overloaded and eventually goes south. There is absolutely nothing to be gained by oversizing these capacitors.