Click here to ask about the production status of specific part numbers. Evaluates: MAX49921 MAX49921 Evaluation Kit General Description Quick Start The MAX49921 evaluation kit (EV kit) provides a proven Required Equipment design to evaluate the MAX49921 high precision, high The following items are required for operation: voltage, unidirectional current-sense amplifier. This EV MAX49921 EV kit kit demonstrates the MAX49921 in a small, 2mm x 3mm 8-pin TDFN package. DC PS1 (power supply 1 for the IC, 2.7V to 5.5V, 100mA) The EV kit PCB comes with a MAX49921FATA/VY+ installed, which is the 50V/V gain version. The other gain DC PS2 (power supply 2 for the common-mode option available is the pin-compatible MAX49921TATA/ input, up to 70V, 3A) VY+ (G = 20V/V). Contact the factory for MAX49921TATA/ Electronic load (capable of sinking up to 3A and VY+ availability. up to 70V) Note that if the electronic load is not available, EV Kit Contents remove the R1 sense resistor, and directly apply a MAX49921 EV kit board sense voltage across the RS+ and RS- test points. Two digital multimeters (DMMs) Features Precision Real-Time Current Monitoring MAX49921 EV Kit Photo 0V to +70V Input Common-Mode Range Proven PCB Layout Fully Assembled and Tested Ordering Information appears at end of data sheet. 319-100591 Rev 2 1/21Evaluates: MAX49921 MAX49921 Evaluation Kit Procedure Detailed Description of Hardware The MAX49921 EV kit provides a proven design to evalu- MAX49921 Evaluation ate the MAX49921 high-side, unidirectional current-sense The MAX49921 EV kit is fully assembled and tested. Use amplifier, which offers precision accuracy specifications of the following steps to verify board operation. input offset voltage (V ) of 0.5V (typ) and a gain error OS Caution: Do not turn on power supply or the elec- of 0.05% (typ). tronic load until all connections are made. Applying the VRS+ Supply and the Load 1) Set the PS1 to 5V and turn it off. Connect the posi - The EV kit is installed with a MAX49921FATA/VY+, tive terminal of the PS1 to the VDD test point and the which has a 50V/V gain. The current-sense resistor R1 negative terminal of the supply to the nearest GND test point. (R ) value is 0.05 with 0.5% tolerance. The SENSE V can be estimate by: OUT 2) Set the PS2 to 12V (common-mode voltage) and turn it off. Connect the positive terminal of the PS2 to V = I x R x A OUT LOAD SENSE V the VSENSE+ test point and the negative terminal of the PS2 to the nearest GND test point. where A is the gain and I is the current load applied V LOAD 3) Set the electronic load to sink 1A. to the device. Normal operating V and V range is RS+ RS- Note that the voltage at PS2 together with this 1A 0V to 70V. load develops approximately 50mV input voltage Measuring the Load Current across the sense resistor (R1). The load current is measured as a voltage drop (V ) SENSE 4) Connect the positive terminal of the electronic load across an external sense resistor (R1). This voltage is to the VSENSE- test point and the negative terminal then amplified by the current-sense amplifier and pre- of the supply to the nearest GND test point. sented at its V pin. Like all differential amplifiers, the OUT 5) Connect the first voltmeter between test points RS+ output voltage has two components of error (an offset and RS- to measure VSENSE. error and a gain error). The offset error affects accuracy 6) Connect the second voltmeter between VOUT and at low currents and a gain error affects accuracy at large the nearest GND test points. currents. Both errors affect accuracy of measurement at intermediate currents. By minimizing both offset and gain 7) Enable the PS1 and then PS2 power supplies. errors, accuracy can be optimized over a wide dynamic 8) Enable the electronic load. range. Note that if the electronic load is not available, remove the R1 sense resistor, and directly apply a 50mV sense voltage across the RS+ and RS- test points. Ordering Information 9) Verify that the first voltmeter displays 50mV and the PART U1 (INSTALLED) TYPE second voltmeter displays 2.5V. MAX49921EVKIT MAX49921FATA/VY+ EV Kit 10) Disable the electronic load first, then turn off the PS2 Denotes RoHS compliance. and then PS1 last. Maxim Integrated 2 www.maximintegrated.com