Article View: sci.electronics
Article #19192Op amp for audio applications -- roll your own!
From: Richard S D'Ippolito
Date: Fri, 27 May 1988 17:44
Date: Fri, 27 May 1988 17:44
70 lines
2608 bytes
2608 bytes
In article <1196@neoucom.UUCP> Bill Mayhew writes:
An integrated operational amplifier that would probaly perform
quite well for audio (hifi?) applications might be the Analog
devices AD318K. This chip can be characterised as a wideband, low
drift, FET input opamp.
Here is a synopsis of its characteristics:
open loop gain: 100,000
output: +/-12v (+/-10 min) at Rl=1K
20 mA short circuit output current limit
dynamic:
unity gian, ss 5 MHz
full power bw 500 KHz
slew rate 30v/uS
.1% settle 700 nS
.01% 1.2 uS
input bias current: 10pA avg, 50 pA max
imput impedances:
differential 1E12 ohms in parallel with 7 pF
common mode 1E12 ohms in parallel with 7 pF
input volrate range:
differential +/- 20 v (maximum safe limit)
common mode +/- 12 v (+/-10 min)
CMR 80 dB minimum
noise figures:
0.1 - 10KHz 2 uV peak-peak
10 Hz 70 nV/Hz^.5
100 Hz 45 nV/Hz^.5
1 KHz 30 nV/Hz^.5
10 KHz 25 nV/Hz^.5
case style: TO-99
Why not make your own? After all, a hundred bucks is a small price to pay
for perfection! (Seriously, these make good QUIET mike preamps.)
The JE-990 discrete op amp(*)
Open loop gain 125 dB
Gain error @ 100-dB gain 0.4 dB
Noise voltage spectral dens. 1.13nV/root Hz
Equiv input noise voltage,
20Khz bandwidth, shorted input 160nV
Noise index, 1000 ohm source 0.6dB
THD @ 20KHz, at 12.3V output
(+24dB)
Load = 75 ohms, gain = 40dB 0.06%
Load = 75 ohms, gain = 20dB 0.005%
Load = 600 ohms, gain = 40dB 0.015%
Unity gain small sig bandwidth 10MHz
Large signal bandwidth
Load = 150 ohms 145Khz
Supply voltage +/- 24V
(*) Parts list and full description is in the Journal of the Audio
Engineering Society, Vol 28, No. 1/2, Jan/Feb 1980. The article is entitled
"JE-990 Discrete Operational Amplifier" by Deane Jensen of Jensen
Transformers. You can buy them already assembled.
Rich
Technical Details
Message-ID:
<5605@aw.sei.cmu.edu>Path:
arc1-ca.pugleaf.net!utzoo!attcan!uunet!lll-winken!lll-tis!ames!ll-xn!husc6!bbn!rochester!pt.cs.cmu.edu!sei!sei.cmu.edu!rsdReferences:
<3601@pasteur.Berkeley.Edu> <1196@neoucom.UUCP>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!lll-winken!lll-tis!ames!ll-xn!husc6!bbn!rochester!pt.cs.cmu.edu!sei!sei.cmu.edu!rsd From: rsd@sei.cmu.edu (Richard S D'Ippolito) Newsgroups: sci.electronics Subject: Op amp for audio applications -- roll your own! Message-ID: <5605@aw.sei.cmu.edu> Date: 27 May 88 17:44:23 GMT References: <3601@pasteur.Berkeley.Edu> <1196@neoucom.UUCP> Sender: netnews@sei.cmu.edu Reply-To: rsd@ae.sei.cmu.edu.UUCP (Rich D'Ippolito) Organization: Carnegie-Mellon University, SEI, Pgh, Pa Lines: 69