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Hello guys,
One of my customers is considering using INA333 for their new products.
They have a question about the output current as the below. Could you please give me your reply for them?
Q. What is the minimum output current of INA333?
The device datasheet shows that typical output currents are +5mA and -40mA.
They want to know whether INA333 output can sink 5mA or not when the device is operating under all temperature and Vs=1.8V~5.5V.
If the answer is NO, could you please tell me what the minimum output current is?
Best regards,
Kazuya.
Those values are short-circuit current, i.e., the current that you get when you force the output to ground.
Figure 29 shows what output voltages you can achieve, depending on the output current and the supply voltage.
There is no minimum output current. Lower output currents allow more output swing.
Hi Kazuya,
unfortunately, it's a well established tradition to confuse signs in datasheets 
Because of that, figure 29 is so important.
Kai
Actually, the INA333 Iout signs are correct because, unlike in case of logic devices, in linear circuits (like op amps or INA's) positive and negative current polarity mean different thing depending whether one refers to the input bias current (IB) or the output current drive (Iout). Thus, when it comes to the input bias current, IB, positive polarity means that the current goes into the input terminal (like in case of NPN input transistor) while negative polarity means that current comes out of the input terminal (like in case of PNP input transistor). However, in case of output current, Iout, the definition of polarity is reversed - positive current means the current comes out of Vout (output is sourcing current) while negative means the current goes into Vout (output is sinking current).
Therefore, the INA333 datasheet table and Vout vs Iout graph are correct in showing sourcing Iout as positive and sinking Iout as a negative number - see below.
Having said that, INA333 can easily sink anywhere between 25mA to 40mA output current on 5.5V supply over entire -40C to 125C temperature range BUT may not be able to sink 5mA on 1.8V supply - especially at high temperature. HOWEVER, please show us the detail customer schematic so we may confirm if in fact their application require 5mA sinking capability because on a single supply, with load resistor connected to ground, NO SINKING current is possible - see below.
