DEMO MANUAL DC2746A LT6372-1/LT6372-0.2 Precision, Low Drift, Low Noise Instrumentation Amplifiers DESCRIPTION Demonstration circuit 2746A is a blank/un-stuffed evalua- 3. Common mode or differential input. tion board to beused to facilitate prototyping of LT 6372-1 4. Input CM and differential filtering caps if needed. and LT6372-0.2 instrumentation amplifiers in the MSOP- 5. Upper and lower clamp pins driven externally 16 package. The board is designed to be as flexible as ordisabled. possible by providing many stuffing options and jumpers to configure. This board can be used with either LT6372-1 6. Output drive filtering and isolation resistor and cap. (for gains 1V/V amplification) or LT6372-0.2 (for gains 7. Prototyping area provided for SO-8 device to be used as low as 0.2V/V attenuation). if needed. This prototype footprint can be run using Below are some of the capabilities of the board using the LT6372 power supplies or could be powered by board jumper selection or stuffing option. different supply rails applied to the board. 1. Single or dual supply operation. Design files for this circuit board are available. 2. Flexible connections of REF1 and REF2 instrumentation All registered trademarks and trademarks are the property of their respective owners. amplifier reference voltage inputs. Options are: Both references to be tied together or separately driven, orgrounded. BOARD PHOTO Figure1. DC2746A Top and Bottom Board Views Rev. 0 1DEMO MANUAL DC2746A QUICK START PROCEDURE Here are some of the highlights of operating the DC2746A REF2 pin can be driven externally (V test point) REF2 to evaluate the LT6372. with JP5 set to V or unstuffed. To run REF2 with REF2 the same voltage as REF1, move JP5 to V position. REF 1. Gain: Set by setting the value of R3. 5. Output: Available at OUT test point. R5, and R4 can be 2. LT6372 Operating Supplies: For dual supply operat- used to set any output isolation or load if needed. C14 + ing, apply complimentary power supplies to V and V can be used to do some low pass filtering with R5, if test points. Do not exceed 18V. needed. When used to drive an ADC at OUT test point, For single positive supply operation, V can be tied C14 can be used for charge storage to improve the + to GND and V should be driven by external positive ADC analog input settling time due to ADC input charge power supply. kickback. 3. Inputs: To be brought in at +IN and IN test points. 6. Clamps: For positive/high side clamping, apply the CM filtering can be implemented by using C8, and appropriate clamp voltage to CLHI test point and move C11. Differential mode filtering is with C10 if needed. JP7 to CLHI position. To disable positive clamping, + Use JP1 to switch between differential mode (normal move JP7 to the V position. In-Amp operation) or common mode (for testing the For negative/low side clamping, apply the appropriate LT6372 CM rejection) configuration. If the input is sin- clamp voltage to CLLO test point and move JP6 to gle ended, put JP1 in differential mode (or unstuffed) CLLO position. To disable negative clamping, move JP6 + and ground either IN (or IN ) and apply the input to to the V position. + the other IN (or IN ). 4. Reference Inputs: REF1 pin can be driven externally Example Configuration Setup (V test point) with JP4 set to V (or unstuffed). REF REF As an example, Figure2, is a typical application using To ground REF1, move JP4 to STAR-G position. DC2746A. Figure2 shows the LT6372-x configured to drive an ADC with clamps set to limit the output swing. C13 + V 0.1F ADC VREF C9 R1 OPT 0 C15 IN IN 0.1F + V R G,F EXP. R5 R G,S PAD CLHI 15 OUTPUT C10 R2 CLLO LT6372-X OPT 2.67k REF2 +R C14 G,S R4 REF1 R2 0.01F C16 OPT +R G,F 0 V 0.1F +IN +IN C11 OPT C12 ADC VREF 0.1F V V+ V V+ DC2746A F02 C2 C1 C5 C6 10F 10F OPT OPT V Figure2. Typical LT6372-X Example Configuration to Drive an ADC Rev. 0 2