Questions About JRS

[eddie]

Hi, this is my first post.

I'm planning to mod a external DAC, the Citypulse 7.2. Looking inside, i'll change some capacitors, and put some SILMIC II and some Oscon caps. And sure try to use the JRS in replacement of 7805s, 7812 and 7912, Cause in rail +12 and -12 use a emiter follower regulator and in digital supply only the 7805. Till now it's ok.

Let's make you some questions, i was reading about super regulator and you told the JRS don't like capacitive loads, how much?
The voltages i'll need are +12V,-12V and +5V and 3.3V but the 3.3V i'll take with a regulator after the JRS. Cause The circuit has a lot of 100uF caps near the ICs with bypass caps with tantalum and i added some styroflex caps.

Assuming i'll use the JRS-03, i must take care about the inputs voltages about 5-6V more, i'm alright?
May i use the AD797 in lower voltages like 5v?
The inputs voltages are 25V to 12V, -25V to -12V and 14V to 5+.

Resuming, to work with JRS, i must take care amout the referece voltage and "look" the led?

cheers!

[peranders]

With capacitve load I mean very good caps directly at the regulator output, not so good. If you have 20-30 mm wire you'll add a bit inductance and you won't get any oscillations. 100 uF is max I'll recommend. Remember that the regulator fix the low impedance in an artificial way.

Avoid AD797, my advice. Many 10 V/us devices will work such as OPA134 and fast opamps AD825, AD817 are both good choices.

5 volts more in than out is the absolute minimum but you should have 6-8 V to be sure.

[eddie]

Tks for the fast reply.

I'll try AD825, AD843, and others i have here.
I forgot to ask you about the transistors, i have to choose between BC860 or BC560? Or use both? Same with BD139?

[peranders]

I have made room for TO92 devices (BC5560/550) and for SOT23 devices (BC850/860), one type at the time of course. The advantage of having room for SOT23 transistors is that you have many good types to choose from. The same goes for TO220 devices (D44H11) or TO126 types (BD139). TO220 and TO126 have different pinning.