Evaluates: MAX9938 19-4262 Rev 0 8/08 MAX9938 Evaluation Kit General Description Features The MAX9938 evaluation kit (EV kit) provides a proven Precision Real-Time Current Monitoring design to evaluate the MAX9938 high-side current- 1.6V to 28V Input Common-Mode Range sense amplifier, which offers precision accuracy speci- fications of V less than 500V (max) and gain error OS Lead-Free and RoHS Compliant less than 0.5% (max). This EV kit demonstrates the Proven PCB Layout MAX9938 in a tiny 1mm x 1mm x 0.6mm, 4-bump UCSP package. The MAX9938 is also available in a Fully Assembled and Tested 5-pin SOT23, but that package is not compatible with this EV kit. Ordering Information The MAX9938 EV kit PCB comes with a MAX9938FEBS+ installed, which is the 50V/V gain version. Contact the PART TYPE factory for free samples of the pin-compatible MAX9938EVKIT+ EV Kit MAX9938TEBS+ and MAX9938HEBS+, which are 25V/V +Denotes lead-free and RoHS compliant. and 100V/V gain versions, respectively. Component List DESIGNATION QTY DESCRIPTION DESIGNATION QTY DESCRIPTION 1F 10%, 50V X7R ceramic TP1, TP2 2 Test points C1 1 capacitor (1206) Precision current-sense amplifier Murata GRM31MR71H105KA (4 UCSP) U1 1 M axim M AX99 38FE BS+ ( Gai n: 50V/V ) Not installed, ceramic capacitor C2 0 (0603) 1 PCB: MAX9938 Evaluation Kit+ 0.05 0.5%, 0.5W 4-terminal R1 1 current-sense resistor (1206) Ohmite LVK12R050DER Component Suppliers SUPPLIER PHONE WEBSITE Murata Electronics North America, Inc. 770-436-1300 www.murata-northamerica.com Ohmite Mfg. Co. 866-964-6483 www.ohmite.com Note: Indicate that you are using the MAX9938 when contacting these component suppliers. UCSP is a trademark of Maxim Integrated Products, Inc. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.MAX9938 Evaluation Kit Quick Start Detailed Description of Hardware The MAX9938 evaluation kit (EV kit) provides a proven Recommended Equipment design to evaluate the MAX9938 high-side current- Before beginning, the following equipment is needed: sense amplifier, which offers precision accuracy speci- MAX9938 EV kit fications of V less than 500V (max) and gain error OS 3.6V, 1A DC power supply less than 0.5% (max). An electronic load capable of sinking 800mA (e.g., Applying the V Supply and the Load RS+ HP 6060B) The EV kit is installed with a MAX9938FEBS+, which Two digital voltmeters has a gain of 50V/V. The current-sense resistor (R ) value is 0.05 with 0.5% tolerance. The SENSE Procedure V is given by: OUT The MAX9938 EV kit is fully assembled and tested. V =I x R x A OUT LOAD SENSE V Follow the steps below to verify the board operation. where A is the gain and I is the current load Caution: Do not turn on power supply or the elec- V LOAD applied to the device. tronic load until all connections are made. 1) Connect the positive terminal of the 3.6V supply to Normal operating V and V range is 1.6V to 28V. RS+ RS- the VBATT pad and the negative terminal of the Measuring the Load Current supply to the GND pad closest to the VBATT pad. The load current is measured as a voltage drop 2) Set the electronic load to sink 800mA. (V ) across an external sense resistor. This volt- SENSE 3) Connect the electronic loads positive terminal to age is then amplified by the current-sense amplifier and the LOAD pad and the negative terminal to the presented at the VOUT pad. Like all differential ampli- GND pad closest to the bottom of the EV kit. fiers, the output voltage has two components of error (an offset error and a gain error). The offset error affects 4) Connect the first voltmeter across test points TP1 accuracy at low currents and the gain error affects and TP2 to measure V . SENSE accuracy at large currentsboth errors affect accuracy 5) Connect the second voltmeter across the VOUT at intermediate currents. By minimizing both offset and pad and the closest GND pad. gain errors, accuracy is optimized over a wide dynamic 6) Turn on the power supply. range. 7) Turn on the electronic load. Evaluating Other Gain Versions 8) Verify that the first voltmeter reading is approxi- The MAX9938 EV kit can also be used to evaluate other mately 40mV and the second voltmeter is approxi- gain versions of the MAX9938 (25V/V or 100V/V, T or H mately 2V. suffix, respectively). Replace U1 of the MAX9938 EV kit with a different version of the MAX9938. 9) Adjust the current load from 800mA to 0A and verify that the reading of the second voltmeter is approxi- mately 50 times the reading of the first voltmeter. 2 Evaluates: MAX9938