OPA2277: searching solution for wider range

Hello Kay,

The OPA2277 is what we consider a precision high-voltage op amp, having an absolute maximum supply voltage of 36 V (+/-18 V), and a somewhat lower than usual minimum supply voltage of 4 V (+/-2 V). Nearly all of TI's newer Precision op amps have a minimum supply rating of 4.5 V (+/-2.25 V), but an absolute maximum that is extended to 40 V (+/-20 V). The 4 V minimum would be an issue for them.

The other consideration, the 50 mA output current, exceeds the high end capability for most of our precision amplifiers. One reason for that is thermal limitations of the very small packages that the op amps commonly come in. If an op amp can provide that level of output current that must be fully considered before applying the device in a high-voltage, high-current application.

If the application can accommodate a minimum supply voltage of 4.5 V, the OPA189 that is available now might be an option. Its supply range is from 4.5 V to 40 V, and its typical short-circuit short-circuit current ISC is rated at ±65 mA. The Output Voltage Swing vs. Output Current graphs shown in datasheet Figures 12 and 13 indicate that the typical output current is above 50 mA over temperature. A thermal analysis would need to be undertaken to make sure the OPA189 maximum junction temperature (Tj, 150°C)) isn't exceeded under the expected operating conditions. The dual op amp version OPA2189, will be available in 2019.

You can see the OPA189 datasheet here:

Another precision op amp that is well suited for this kind of high-voltage, high-current application is the OPA454. Its package is designed for use in higher power designs. Its high-voltage capability is 100 V (+/-50 V) maximum and its output current capability is >50 mA, but its minimum voltage rating is 10 V (+/-5 V). If the application could accommodate the higher low voltage requirement, this op amp would likely be ideal.

Regards, Thomas

Precision Amplifiers Applications Engineering