Timeline for How can I use MC1489?
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
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| Aug 10, 2020 at 7:09 | vote | accept | alfonso | ||
| Aug 6, 2020 at 20:39 | answer | added | jonk | timeline score: 1 | |
| Aug 5, 2020 at 7:11 | comment | added | jonk | Since you appear to want 8 inputs, I'd be looking for a transistor array. Something like the MMPQ2222A. The datasheet is here. Two of those ICs and you'd have all the BJTs you need. You'll also want some resistor arrays. Arrays of BJTs are available from a variety of suppliers, as are resistor arrays. So nothing boutique. Should be cheap to do and easy to find new suppliers, if needed. | |
| Aug 5, 2020 at 6:52 | comment | added | jonk | Look here for example. (You don't need the diode and capacitor that is connected to the RS-232 pin.) | |
| Aug 5, 2020 at 6:47 | comment | added | alfonso | I didn't know it. I will try something else then. Thanks a lot. | |
| Aug 5, 2020 at 6:44 | comment | added | jonk | All you need to do is design a simple BJT receiver with from 3k to 7k input impedance and tolerating about 25 V worst case at the input. It's dead trivial. The MC1489 runs "hot." Not as horribly hot as the MC1488 transmitter. But pretty hot, just the same. It's 1970's technology from Jim, and after my experience with them in the early 1980's, I'd be looking ANYWHERE else, right now. The MC1488 and MC1489 are on my "never use again" list. (They meet specs very well. But they burn power like it's free.) | |
| Aug 5, 2020 at 6:41 | comment | added | alfonso | @jonk I don't know how i can make 24V input compatible with 5V MCU. So, I try whatever i find. Do you have any recommendation instead? | |
| Aug 5, 2020 at 6:37 | comment | added | jonk | Are you seriously using Jim Thompson's MC1489 today???? Seriously? The control lines allow you to vary the input thresholds. Have you read the datasheet? | |
| Aug 5, 2020 at 6:32 | history | edited | JRE | CC BY-SA 4.0 |
added 90 characters in body
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| Aug 5, 2020 at 6:22 | history | asked | alfonso | CC BY-SA 4.0 |