J11 J10 J9 J8 J13 J7 USERS MANUAL ISL281X7MSOPEVAL1Z AN1565 Rev 0.00 Evaluation Board May 25, 2010 terminal. For split supplies, +V and -V terminals Introduction connect to their respective power supply terminals. De- The ISL281X7MSOPEVAL1Z evaluation board is a coupling capacitors C2 and C4 connect close to their design platform containing all the circuitry needed to respective supplies, while two additional capacitors, C1 characterize critical performance parameters of the and C5, are connected close to the part to filter out ISL281X7 operational amplifiers in MSOP-8 package, high frequency noise. Anti-reverse diodes D1 and D2 using a variety of user defined test circuits. protect the circuit in the case of accidental polarity reversal. The ISL281X7 operational amplifiers feature low bias current, low noise, and low offset and temperature drift. V- V+ VREF Reference Documents ISL28107 Data Sheet, FN6631 C2 C4 ISL28117 Data Sheet, FN6632 4. 7 F 4. 7 F ISL28127 Data Sheet, FN6633 D1 D2 S1 A B S1AB Evaluation Board Key Features FIGURE 1. POWER SUPPLY CIRCUIT The ISL281X7MSOPEVAL1Z is designed to enable the IC to operate from a single supply, +4.5VDC to Amplifier Configuration (Figure +40VDC or from split supplies, 2.25VDC to 20V. The board is configured for a single op amp connected 2) for differential input with a closed loop gain of 10. A The schematic of 1/2 of the op amp with the components single external reference voltage (VREF) pin and supplied is shown in Figure 2. The circuit implements a provisions for a user-selectable voltage divider-filter differential input amp with a closed loop gain of 10. The are included. circuit can operate from a single supply or from dual supplies. The VREF pin must be connected to ground to Power Supplies (Figure 1) establish a ground referenced input for dual supply External power connections are made through the +V, operation, or can be externally set to any reference level -V, VREF and Ground connections on the evaluation for single supply operation. VREF should not be left board. For single supply operation, the -V and Ground floating. pins are tied together to the power supply negative RF ISL281X7 100k IN - VP RIN- IN- - IN- 0 V+ 10k VOUT V- RIN+ IN+ + IN+ 10k VM IN + RL VCM RREF+ VREF DNP 100k GND VREF FIGURE 2. BASIC AMPLIFIER CONFIGURATION AN1565 Rev 0.00 Page 1 of 5 May 25, 2010 R4 DNP R16 DNPISL281X7MSOPEVAL1Z The outputs (Figure 4) have additional resistor and User-selectable Options capacitor placements for filtering and loading. (Figures 3 and 4) NOTE: Operational amplifiers are sensitive to output Component pads are included to enable a variety of user- capacitance and may oscillate. In the event of oscillation, selectable circuits to be added to the amplifier VREF, reduce output capacitance by using shorter cables, or inputs, outputs, and the amplifier feedback loops. The add a resistor in series with the output. Inputs (Figure 3) have additional resistor and capacitor, and jumper placements for loading and/or measurement of frequency sensitive parameters. IN- IN+ NODE OUT R8 R10 DNP DNP J1 R5 R9 R11 R1 0 10k 100k C3 R18 DNP To Output J12 OPEN To IN- 0 J2 R14 R12 To IN+ R2 10k VREF DNP R15 R13 DNP 100k FIGURE 3. INPUT STAGE FIGURE 4. OUTPUT STAGE TABLE 1. ISL281X7MSOPEVAL1Z COMPONENTS PARTS LIST DEVICE DESCRIPTION COMMENTS C2, C4 CAP, SMD, 0805, 4.7F, 50V, 10%, X7R, ROHS Power Supply Decoupling C1, C5 CAP, SMD, 0603, 0.01F, 50V, 10%, X7R, ROHS Power Supply Decoupling C3, C6 CAP, SMD, 0603, DNP-PLACE HOLDER, ROHS User selectable capacitors - not populated D1, D2 DIODE-RECTIFIER, 40V, 0.5A, ROHS Reverse Power Protection U1 (ISL28107FUZ) OP AMP, MSOP, ROHS U1 (ISL28117FUZ) OP AMP, MSOP, ROHS U1 (ISL28127FUZ) OP AMP, MSOP, ROHS R1-R4, R6-R8, R10, R13, RESISTOR, SMD, 0603, 0.1%, MF, DNP-PLACE HOLDER User selectable resistors - not populated R14, R16, R17, R19, R20 R5, R18 RES, SMD, 0603, 0 , 1/10W, TF, ROHS Zero ohm user selectable resistors R9, R12 RES, SMD, 0603, 10k, 1/10W, 1%, TF, ROHS Gain resistors R11, R15 RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS Gain resistors AN1565 Rev 0.00 Page 2 of 5 May 25, 2010 R3 DNP R7 R6 DNP DNP R14 DNP C6 OPEN R17 DNP