Quick - and clean! - bias voltage

[Phorhas]

well, pardon my ignorance, but, what is the big advantage over the usual resistors and cap divider - if you you low value resistors the it shouldn't introduce an ippadence problem, right?

[spongebob]

what about power supplies of the 18v to 40v?

http://focus.ti.com/docs/prod/folders/print/tle2426.html
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1/2 VI Virtual Ground for Analog Systems
Self-Contained 3-terminal TO-226AA Package
Micropower Operation...170 uA Typ, VI = 5 V
Wide VI Range...4 V to 40 V
High Output-Current Capability
Source...20 mA Typ
Sink...20 mA Typ
Excellent Output Regulation
-45 uV Typ at IO = 0 to -10 mA
+15 uV Typ at IO = 0 to +10 mA
Low-Impedance Output...0.0075 Ω Typ
Noise Reduction Pin (D, JG, and P Packages Only)
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I have used the 3-legged version for my opamp builds, really easy to use, only drawback is that they are a little bit hard to find, but you could always get a few as samples! :wink:

[Gilles C]

That's what I began to use (R.G. told me about this TLE2426 a couple years ago) in a couple of projects, and I love it.

I only had a few samples I received free from the company so I couldn't use them erywhere, but I'd like to use them all the time.

I'll order some when I go back into full building mode...

[Paul Perry (Frostwave)]

http://focus.ti.com/docs/prod/folders/print/tle2426.html
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I have used the 3-legged version for my opamp builds, really easy to use, only drawback is that they are a little bit hard to find

Not that hard, about $1.30 Digikey & Mouser.

[Phorhas]

buy why use them?

is the 10k/10k & cap network that high impadence?
or does the chip trick (cute...) have a real advantage in another field?

[R.G.]

buy why use them?
is the 10k/10k & cap network that high impadence?

(1) read

http://geofex.com/circuits/Biasnet.htm

for some considerations.
(2) Some circuits - especially high gain things with high impedances and high currents flying around - are quite sensitive to noise and un-shunted signal on their references
(3) the 10k/10k/cap setup is a 5K ohm source at DC, and equal to the cap at higher frequencies. Electro caps are not all that good a low impedance source at higher frequencies. An amplifier after the reference makes for a really low impedance reference that prevents the problems in (2) and does not require a high reference current as noted in (1)
(4) The TLE device in particular and the LM386 device to a lesser extent provide superior performance in a smaller board space than the 10k/10k/cap.

[cpm]

uh, old topic here...

i tried this with a 13700, it actually made for more noise than a standard divider buffered with a TL074
does it need some more filtering on the 386, a cap somewhere?

[R.G.]

uh, old topic here...

Wow. Nearly seven years!

i tried this with a 13700, it actually made for more noise than a standard divider buffered with a TL074
does it need some more filtering on the 386, a cap somewhere?

Details matter. Could have been a noisy 386; did you have the 386 jumpered for lowest gain? That would make it more noisy. TL074 probably IS quieter than an LM386 overall, but can source/sink less current. I'm guessing (because I haven't looked at one of these in a long time) that you could use a single resistor and a cap after the 386 to make it quieter. But check out the other stuff first.

[Gurner]

Well since it's been resurrected - If you're gonna go with an 8 DIL format just to get half supply (a bit chunky for the intended purpose), I'd be inclined to spend the extra 60p for one of these...

http://focus.ti.com/lit/ds/symlink/tle2426.pdf

upto 40v

less quiescent current

less noise

and also availabe as a 3 pin TO-226 package (or DIL-08)

0.0075 Ω output impedance (!!!)


Not a particular high current output drive ability, but for most stompboxes it ought to be fine.

[R.G.]

My only complaint about the TI rail splitter is that they're harder to find. If you can find them, they're great. I always liked the the TO92 version myself.

The LM386 is useful as a target of opportunity.

[Gurner]

My only complaint about the TI rail splitter is that they're harder to find. If you can find them, they're great. I always liked the the TO92 version myself.

The LM386 is useful as a target of opportunity.

Agreed....incidentally, most small audio amp ICs, sit at 1/2 VCC & therefore can be brought into play like this , eg TD7052A etc - so if you want  to go this way, have a look in you parts box for any audio amp IC you might have lying spare.