Hello all!

There's no information about the maximum power dissipation of the REF195ESZ in the datasheet. I have an application with the following conditions:

REF195ESZ input voltage 13V

Output load 11 mA

The power dissipation is (13V-5V)*0,011A = 0,088W. Is this too much?

Br,

Antti Ryhänen

Hi Antti,

Max power dissipation is not specified in the data sheet. But, one way we can look at it is to calculate max junction temperature you would be expecting in your application and checking whether it will violate the abs max rating.

What is the package you are using, and what is the ambient temperature?

Let’s assume you are using TSSOP package with theta_ja = 240 (table 24) and ambient temp is 50C.

Total power dissipation will be the sum of the quiescent power dissipation (Isy x Vsy – I am going to ignore it to simplify calculation since Isy is low) and the power dissipation of the output stage transistor (what you calculated).

Assuming identical test conditions as the thermal test standard, die junction temperature can be estimated using the following:

junction temperature = 50C + (88mW x 240C/W) = 50 + 21.12 = 71.12C.

You will be fine in this case.