Part Number:DRV8305
Dear all,
I investigated the gain settings of shunt amplifier in DRV8305NPHPR in following way.
As a result, the gain is half as value as the setting value.
Do you have any idea to understand the result?
[measurement method]
Constant current is applied between SP1 and SN1.
Measure the voltage between SP1 and SN1. And measure the voltage of SO1.
3.3V which is generated by LDO is applied to Vreg
EN_GATE is high
[result]
Gain setting: 10V/V
SP1-SN1 voltage, SO1 voltage
0.0mV , 1.652V
1.0mV , 1.647V
2.0mV , 1.642V
3.0mV , 1.637V
4.0mV , 1.632V
--> gain looks like 5V/V
Gain setting: 20V/V
SP1-SN1 voltage, SO1 voltage
0.0mV , 1.652V
1.0mV , 1.644V
2.0mV , 1.633V
3.0mV , 1.623V
4.0mV , 1.612V
--> gain looks like 10V/V
Gain setting: 40V/V
SP1-SN1 voltage, SO1 voltage
0.0mV , 1.655V
1.0mV , 1.636V
2.0mV , 1.615V
3.0mV , 1.594V
4.0mV , 1.572V
--> gain looks like 20V/V
Thank you in advance,
Shirai