MAX4173 Low-Cost, SOT23, Voltage-Output, High-Side Current-Sense AmplifierTable 1. Recommended Component ValuesFULL-SCALE OUTPUT VOLTAGEFULL-SCALE LOAD CURRENTCURRENT-SENSE RESISTORGAIN(FULL-SCALE VILOAD (A)RSENSE = 100mV)SENSE (m Ω )VOUT (V) 20 2.0 0.1 1000 50 5.0 100 10.0 20 2.0 1 100 50 5.0 100 10.0 20 2.0 5 20 50 5.0 100 10.0 20 2.0 10 10 50 5.0 100 10.0 INPUT LOAD/BATTERY RSENSE ILOAD V 0.3 in. COPPER 0.1 in. COPPER 0.3 in. COPPER VIN LOW-COST 0 TO +28V SENSE + _ SWITCHING V REGULATOR SENSE RSENSE +3V TO +28V RS+ RS- RS+ RS- +3V TO +28V VCC VCC 0.1µF 0.1µF MAX4173 MAX4173T OUT LOAD/ OUT BATTERY GND GND Figure 2. MAX4173 Connections Showing Use of PC Board Figure 3. Current Source amp’s supply voltage range should be at least as high Current Source Circuit as any voltage the system may encounter. Figure 3 shows a block diagram using the MAX4173 The percent error introduced by output loading is with a switching regulator to make a current source. determined with the following formula: ⎛ R ⎞ % = 100 LOAD ⎜ − 1 ERROR ⎟ ⎝12k Ω + RLOAD ⎠ where RLOAD is the external load applied to OUT. 8 Maxim Integrated
