INTRODUCTION.
The OPA604 (Burr-Brown) is a single FET-input opamp which claims to be specially designed to give low distortion. The simplified internal circuit diagram in the data sheet includes an intriguing box labelled "Distortion Rejection Circuitry".
However, distortion is not very low even with no load, and is inferior to the 5532.
The OPA2604 is the dual version.
SPECS.
Here are the vital statistics:
All typical values, for +/-15V supply rails.
| Supply voltage | +/-25V abs max
|
| Output range | +/-12V typ (600R load)
|
| CM range | +/-12V
|
| en | 11 nV/rtHz typ 1 kHz
|
| in | 4 fA/rtHz typ
|
| Ibias | +/-50 pA typ
|
| Slew rate: | 25 V/us
|
| Supply current | 5.3 mA
|
| Unity gain stable | YES
|
| Cost | 107p RS Jan 2001
|
DECOUPLING AND STABILITY.
No particular difficulties were encountered.
| OP2604 driving various loads at 7.75 Vrms.
Series feedback, gain= 3.2x
|
