#garfield Logs

May 28 2020

02:38 AM polprog: thanks everyone :)
09:17 AM rue_mohr: polprog, TD62381
09:18 AM polprog: npn drivers huh
09:22 AM rue_mohr: no should be N channel
09:22 AM polprog: ah
09:22 AM polprog: well thats what google said
09:22 AM polprog: The TD62381P and TD62381F are comprised of eight NPN low saturation drivers. These devices are specifically designed for multiplexed digit ...
09:22 AM rue_mohr: https://www.digchip.com/datasheets/parts/datasheet/487/TD62381F.php
09:23 AM rue_mohr: whaaat
09:23 AM rue_mohr: would something please decide?
09:23 AM rue_mohr: there must be variants of these chips
09:24 AM polprog: heh
09:24 AM polprog: you mean some mos variant?
09:24 AM polprog: ill search at home
09:25 AM rue_mohr: there is a 7407 made that is a 7 element fet driver
09:25 AM rue_mohr: I was looking for an 8 on d/k
09:25 AM rue_mohr: that chip comes up, BUT as a 1 ohm
09:26 AM rue_mohr: hmm frustrating
09:26 AM rue_mohr: it looks like a person is better off etching a pcb with discrete SOT23 fets
09:26 AM polprog: hmm
09:27 AM rue_mohr: could totally do a dip18
09:27 AM rue_mohr: 8 channels + flyback diodes
09:27 AM rue_mohr: cheaper than $1ea too
09:27 AM polprog: i wonder if its better to use a low side driver with pullups or a high side driver with pulldowns
09:27 AM polprog: speaking of driving VFDs i assume
09:28 AM rue_mohr: ah, I'm just thinking gernerally
09:28 AM polprog: ah
09:28 AM rue_mohr: but high side is better for vfd
09:28 AM polprog: oh yea these are handy
09:28 AM polprog: thats what i think too
09:29 AM rue_mohr: but if their not mosfet, might as well just use ULN2903
09:29 AM rue_mohr: laskdfjl;j
09:29 AM rue_mohr: 2803
09:29 AM rue_mohr: the 2983 is a high side version, but $$$
09:29 AM polprog: ugh
09:29 AM polprog: probably unobtanium as well
09:30 AM rue_mohr: no, but pricey
09:31 AM rue_mohr: I had like 7 in the whole shop
09:32 AM rue_mohr: hmm
09:32 AM rue_mohr: pc817
09:33 AM rue_mohr: 35V
09:33 AM rue_mohr: tight, but yea
09:35 AM rue_mohr: I think the switching speed would be ok
03:42 PM polprog: https://twitter.com/TheSignalPath/status/1266082607508402177/photo/1
04:47 PM polprog: im reading that that TPS2000 series is some heavy duty, battery powered scope for electroenergetics
04:47 PM polprog: with fully isolated channels.. amazing
07:32 PM rue_mohr: heh
09:41 PM rue_shop1: si2302
09:42 PM rue_shop1: ao3400
09:42 PM rue_shop1: cj2302
09:43 PM rue_shop1: use the AO3400
09:45 PM rue_mohr: 30V to
09:46 PM rue_mohr: 30V tho
09:46 PM rue_mohr: whats the uln2003
09:46 PM rue_mohr: 50V
09:47 PM rue_mohr: well the 2302 is 20V
09:48 PM rue_mohr: but all the same pinout
09:50 PM rue_mohr: anyone want to find a "ok" sot23 N channel fet that fits 50V, better than 500mA continious, at rdson better than 4 ohms?
09:51 PM * Tom_L pulls a fistfull outta his pocket
09:53 PM Tom_L: i dunno what those are on my led strips
09:57 PM Tom_L: http://tom-itx.no-ip.biz:81/~webpage/scope/led_front.jpg
09:57 PM Tom_L: Q5?
09:57 PM Tom_L: those are likely just regular transistors
10:02 PM rue_mohr: yea, that size
10:02 PM rue_mohr: if their hexfet, they can do it
10:02 PM rue_mohr: up to a few amps
10:02 PM rue_mohr: I have some 5A ones
10:41 PM rue_mohr: these diodes are an issue
11:33 PM rue_mohr: ok I give up
11:33 PM rue_mohr: after hours of looking for parts the only ones I can find are too big
11:34 PM rue_mohr: there are just no ways I can see to make a descent fet version of the uln2803