Tool/software:
The datasheet shows the input impedance of Vbus is 830K. in current detection mode from the shunt resistor, will the input current of Vbus be I=V/830K or what's the input current of Vbus in current detection mode?
when in power-down mode as mentioned in the following datasheet, what is the input current of VBUS, is it still I=V/830K or what's the input current of Vbus in power-down mode
Hello Zhongfei,
This will be slightly different depending on the die revision you have. (Currently, there are two die revisions for the INA226 (Rev 0 and Rev 1), see this thread for more details: https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1441248/ina226-input-bias-current)
In general, the input current on the VBUS pin will be I=V/830K (as you stated), but only when the 830K VBUS input impedance not disabled. Both versions of the INA226 disable the 830K input impedance when in shutdown mode. The leakage current into the pin at this state is not specified in the datasheet, but it will be very low/negligible.
The Rev 0 version of the INA226 has the 830K VBUS input impedance when the device is in active mode (ie, when converting VBUS or Current), while the Rev 1 version of the INA226 only has the 830K VBUS input impedance while in VBUS Measurement Mode (and is high impedance when in Current measurement mode and shutdown mode).
Regards,
Mitch
Got it, thanks for your reply.
Could you please help confirm when the A version of the device will be consumed? This is because the large input bias current of the A version affect the current accuracy of the uA.
Hello Zhongfei,
Unfortunately there is no way for me to be able to know that, but my guess is that it would be in several months.
Regards,
Mitch
One more thing please help me confirm. In INA226, what's the relationship between Input Bias Current and Differential Input Voltage. in INA228, The relationship between input bias current and differential voltage appears to be I = V/92K, Is the relationship the same for INA226?
Hello Zhongfei,
Unfortunately, we do not spec this for the INA226.
Regards,
Mitch