步进电机驱动芯片，3DescriptionTheULN2803Adeviceisa50V,500mADarlingtontransistorarray.ThedeviceconsistsofeightNPNDarlingtonpairsthatfeaturehigh-voltageoutputswithcommon-cathodeclampdiodesforswitchinginductiveloads.Thecollector-currentratingofeachDarlingtonpairis500mA