1 application note 1509 ISL282X7SOICEVAL2Z evaluation board user?s guide introduction the ISL282X7SOICEVAL2Z evaluation board is a design platform containing all the circuitry needed to characterize critical performance parameters of the isl282x7 operational amplif iers in soic-8 package, using a variety of user defined test circuits. the isl282x7 operational am plifiers feature low bias current, low noise, and low offset and temperature drift. reference documents ? isl28207 data sheet, fn6631 ? isl28217 data sheet, fn6632 ? isl28227 data sheet, fn6633 evaluation board key features the ISL282X7SOICEVAL2Z is designed to enable the ic to operate from a single su pply, +4.5vdc to +40vdc or from split supplies, 2.25vdc to 20v. the board is configured for a dual op amp connected for differential input with a closed loop gain of 10. a single external reference voltage (vref) pin and provisions for a user-selectable voltage divider - filter are included. power supplies (figure 1) external power connections are made through the +v, -v, vref and ground connections on the evalua tion board. for single supply operation, the -v and ground pins are tied together to the power supply negative terminal. for split supplies, +v and -v terminals connect to their respective power supply terminals. de-coupling capacitors c2 and c4 connect to their respective supplies through r16 and r31 zero-ohm resistors. these resistors are 0 but can be changed by the us er to provide additional power supply filtering, or to reduce the voltage rate-of-rise to less than 1v/s. two addi tional capacitors, c3 and c5 are connected close to the part to filter out high frequency noise. anti-reverse diode d1 protects the circuit in the case of accidental polarity reversal. amplifier configuration (figure 2) the schematic of 1/2 of the op-amp with the components supplied is shown in figure 2. the circuit implements a differential input amp with a closed loop gain of 10. the circuit can operate from a single supply or from dual supplies. the vref pin must be connected to ground to establish a ground referenced input for dual supply operation, or can be externally set to any reference level for single supply operation. vref should not be left floating. 0.01f 0.01f r31 r16 d1 c2 c4 c3 c5 j11 j14 j12 j13 j6 j8 0 0 1f 1f vref v+ v- figure 1. power supply circuit in- in+ rf vref in - in + gnd 100k rref+ vout isl282x7 (1/2) vp v- 0 vm vcm in- in+ vref v+ rin- 10k rin+ 10k - + 100k rl dnp figure 2. basic amplifier configuration caution: these devices are sensitive to electrostatic discharge; follow proper ic handling procedures. 1-888-intersil or 1-888-352-6832 | intersil (and design) is a registered trademark of intersil americas inc. copyright intersil americas inc. 2009. all rights reserved all other trademarks mentioned are the property of their respective owners. november 6, 2009 an1509.0
2 an1509.0 november 6, 2009 user-selectable options (figures 3 and 4) component pads are included to enable a variety of user-selectable circuits to be added to the amplifier vref, inputs, outputs, and the amplifier feedback loops. the inputs (figure 3) have additional resistor and capacitor, and jumper placements for loading and/or measurement of frequency sensitive parameters. the outputs (figure 4) have additional resistor and capacitor placements for loading. note: operational amplifiers are sensitive to output capacitance and may oscillate. in the event of oscillation, reduce output capacitance by using shorter cables, or add a resistor in series with the output. figure 3. input stage (1/2) figure 4. output stage (1/2) in- out node in+ c1 r5 r4 j2 j1 r1 r6 r17 r2 r14 r3 r18 r15 r12 r10 r13 r11 dnp dnp dnp dnp dnp dnp dnp open dnp dnp 10k 100k 100k 10k 0 vref to output to in+ to in- r26 c6 c8 r28 dnp open open 0 from output table 1. ISL282X7SOICEVAL2Z components parts list device # description comments c2, c4 cap, smd, 0805, 1f, 50v, 10%, x7r, rohs power supply decoupling c3, c5 cap, smd, 0603, 0.01f, 50v, 10%, x7r, rohs power supply decoupling c1, c6-c10 cap, smd, 0603, dnp-place holder, rohs user selectable capacitors - not populated d1 diode-rectifier, smd, sod-123, 2p, 40v, 0.5a, rohs reverse power protection u1 (isl28207fbz) op amp, soic, rohs u1 (isl28217fbz) op amp, soic, rohs u1 (isl28227fbz) op amp, soic, rohs r1-r3, r5-r8, r10, r12, r15, r17, r20,r22, r28-r30, r32, r34-r36 resistor, smd, 0603, 0.1%, mf, dnp-place hold er user selectable resistors - not populated r5, r18 res, smd, 0603, 0 , 1/10w,tf, rohs zero ohm us er selectable resistors r11, r14, r21, r24 res, smd, 0603, 10k, 1/10w, 1%, tf, rohs gain resistors r13, r18, r19, r23 res, smd, 0603, 100k, 1/10w, 1%, tf, rohs gain resistors application note 1509
3 intersil corporation reserves the right to make changes in circui t design, software and/or specifications at any time without n otice. accordingly, the reader is cautioned to verify that the application note or technical brief is current before proceeding. for information regarding intersil corporation and its products, see www.intersil.com an1509.0 november 6, 2009 figure 5. ISL282X7SOICEVAL2Z top view application note 1509
4 an1509.0 november 6, 2009 out in+ in- in+ node out in- node close to dut r29 r26 open 0.01f 0.01f r30 j21 r31 r16 j23 j18 j24 j22 j20 j19 j17 r36 r32 r34 r35 d1 c1 r22 r19 r21 r20 c10 r8 r7 r5 r4 r24 c2 c4 c3 c5 j15 j16 j2 j1 j3 j4 j11 j14 j12 j13 j6 j8 r27 c7 c6 c8 c9 r1 r25 r23 r6 r17 r2 r28 r14 r3 r18 r15 r12 r10 r13 r11 u1 10k 100k 0 0 soic8 dnp 0 dnp open dnp open open 0 dnp dnp dnp dnp open dnp dnp dnp dnp dnp dnp dnp dnp dnp dnp open dnp dnp 10k 100k 100k 10k 10k 0 0 dnp 100k 1f 1f vref vref v+ v- 5 6 7 8 3 4 1 2 generic pack. figure 6. ISL282X7SOICEVAL2Z schematic diagram application note 1509
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