OPA847 / the detect voltage of DIS_B pin

Hello, You can use OPA847 on +/-4V supplies. In this case the device will be Enabled when the voltage on the DIS pin > 2.75V and will be disabled when the voltage on the pin is < 0.7V

Hi Samir -san,

Thank you for the reply. I have some questions.

Q1

I understood OPA847 could be used on ±4V supplies. However, the datasheet don't be described minimum recommended supply voltage.what is the spec ?

Q2

In the OPA847 on ±4V supplies case, could the datasheet specification be guaranteed ?

Q3

How to calculate the detection voltage of DIS pin ?

Q4

We would like to use OPA847 on ＋3.3V/－5V. In this case, how is Q2 and Q3 ?

Regards,

Kato

Hello Kato,
Q1. The minimum supply on this is around 7V. (+/-3.5V)

Q2. The specifications are guaranteed for only +/-5V. There will be little degradation in the dc specs at +/-4V, however it will not be significant. Distortion which is a typical spec will suffer slightly by a few dB due to the lower supplies.

Q3. To find the Dis voltage I would put an input voltage in a non-inverting configuration and a slow ramping triangular wave on the DIS pin. I would then look at the output of the device and the triangular wave on the scope to find the DIS voltage.

Q4. With 3.3/-5V, you should have no problems with performance except for what I mentioned in Q2. Please note that with lower supplies you should pay attention to the input common-mode range and output swing limitations of the amplifier. They will hold to within 1.7V (input) and 1.5(output) of the rail.

-Samir

Hi Samir -san,

Thank you for the reply. if we use the supply with 3.3/-5V, what is the VIH_min /VIL_max voltage for DIS pin ?

Regards,

Kato

Hello Kato-san,
VIH_Min is now 2.05Vand VIL_max will be 0V.
-Samir