ISL282X8MSOPEVAL1Z ISL282X8SOICEVAL1Z Evaluation Board User’s Guide ® Application Note August 28, 2008 AN1419.0 Introduction J6 J11 V- V+ The ISL28238 and ISL28248 high-speed operational amplifiers feature low power consumption, while ISL28258 and ISL28268 operational amplifiers feature ultra-low power consumption. All op amps have rail-to-rail output drive capability and are designed to operate with a single lithium cell or two Ni_Cd batteries. R31 C2 C4 4.7µF C3 4.7µF C5 0.01µF • ISL28248 Data Sheet, FN6337 • ISL28258 Data Sheet, FN6377 • ISL28268 Data Sheet, FN6378 Evaluation Board Key Features The ISL282xEVAL1Z is designed to enable the IC to operate from a single supply, +2.4VDC to +5.5VDC or from split supplies, ±1.2VDC to ±2.75V. 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. 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 External power connections are made through the +V, -V, VREF and Ground connections on the evaluation board. RF ISL282X8 (1/2) 100kΩ IN RIN- VP IN- IN- V+ 10kΩ RIN+ IN+ VREF 0.01µF D1 Amplifier Configuration Power Supplies VREF J14 User-selectable SMA edge connectors are also provided for +V and -V. 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 0Ω resistors. These resistors are 0Ω but can be changed by the user to provide additional power supply filtering, or to reduce the voltage rate-of-rise to less than ±1V/µS. Two additional 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 (see Figure 1). • ISL28238 Data Sheet, FN6336 VCM J13 FIGURE 1. POWER SUPPYLY CIRCUIT Reference Documents IN + VREF J12 0 R16 J8 0 The ISL282X8MSOPEVAL1Z and ISL282X8SOICEVAL1Z evaluation board are design platforms containing all the circuitry needed to characterize critical performance parameters of the ISL282X8 operational amplifiers in both MSOP-8 and SOIC-8 packages, using a variety of user defined test circuits. IN+ 0Ω VOUT V- + VM 10kΩ REF+ RL 100kΩ 10kΩ GND FIGURE 2. BASIC AMPLIFIER CONFIGURATION 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2008. All Rights Reserved All other trademarks mentioned are the property of their respective owners. Application Note 1419 jumper placements for loading and/or measurement of frequency sensitive parameters. 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. The outputs (see Figure 4) have a 10kΩ load resistor to ground and have additional resistor and capacitor placements for loading. User-selectable Options 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 (see Figure 3) have additional resistor and capacitor, and DNP R15 R18 DNP 100k OPEN R26 0 10k C6 FROM OUTPUT OPEN R28 VREF 10k TO OUTPUT TO INTO IN+ C8 DNP R2 OPEN R14 DNP J20 R13 100k C1 R17 J19 DNP R11 10k DNP R3 R12 DNP 0 R6 J2 R10 R4 R1 DNP OUT DNP R5 J1 NODE J18 IN+ J17 IN- 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 4. OUTPUT STAGE FIGURE 3. INPUT STAGE TABLE 1. ISL282X8EVAL1Z COMPONENTS PARTS LIST DEVICE # COMMENTS DESCRIPTION C2, C4 CAP-TANTALUM, SMD, D, 4.7µF, 50V, 10% LOW ESR, ROHS Power Supply Decoupling C3, C5 CAP, SMD, 0603,1µF, 25V,10%, X7R, ROHS Power Supply Decoupling C1, C6 to C10 CAP, SMD, 0603, DNP-Place Holder, ROHS User-Selectable Capacitors - Not Populated D1 Diode-Schottky Barrier, SMD, SOT-23, 3P, 40V, ROHS Reverse Power Protection U1 (ISL28238FUZ) IC-5 MHz RRIO OP AMP, 8P, MSOP, ROHS U1 (ISL28238FBZ) IC-5 MHz RRIO OP AMP, 8P, SOIC, ROHS U1 (ISL28248FUZ) IC-5 MHz RRIO OP AMP, 8P, MSOP, ROHS U1 (ISL28248FBZ) IC-5 MHz RRIO OP AMP, 8P, SOIC, ROHS U1 (ISL28258FUZ) IC-39µA RRIO OP AMP, 8P, MSOP, ROHS U1 (ISL28258FBZ) IC-39µA RRIO OP AMP, 8P, SOIC, ROHS U1 (ISL28268FUZ) IC-39µA RRIO OP AMP, 8P, MSOP, ROHS U1 (ISL28268FBZ) IC-39µA RRIO OP AMP, 8P, SOIC, ROHS R30, R32, R34 to R36 RES, SMD, 0603, 0.1%, MF, DNP-PLACE HOLDER User-Selectable Resistors - Not Populated R4, R16, R25 to R27, R31 RES, SMD, 0603, 0Ω, 1/10W, TF, ROHS 0Ω User-Selectable Resistors R11, R14, R21, R24, R28, R29 RES, SMD, 0603, 10k, 1/10W, 1%, TF, ROHS Gain and Other User-Selectable Resistors R13, R18, R19, R23 Gain Resistors RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS 2 AN1419.0 August 28, 2008 Application Note 1419 ISL282X8EVAL1Z Top View (SOIC Shown) 3 AN1419.0 August 28, 2008 Application Note 1419 J16 OPEN OPEN 0 C7 R29 DNP C9 OPEN R27 0 R28 DNP C8 OPEN R26 C6 J15 ISL282X8EVAL1Z Schematic Diagram R36 0 DNP 100k 100k DNP VREF 8 1 8 U1 7 2 7 SOIC 8 6 6 3 MSOP 8 5 5 4 R13 100k DNP J19 J17 R11 10k J18 DNP DNP R6 R5 R4 0 IN- R17 1 OPEN 2 3 10k 4 D1 DNP J20 10k R24 DNP OPEN J21 10k DNP R34 DNP J22 R23 100k C10 0.01µF DNP R25 DNP 0 R35 J23 2 1 NODE OUT R16 J24 R30 IN+ J6 C2 V- J8 4.7µF C3 3 0.01µF C4 J11 4.7µF C5 V+ R31 0 J12 DNP R20 R32 DNP J13 OUT NODE IN+ IN- VREF J14 R3 R8 DNP J4 R7 DNP J3 DNP DNP R2 J2 J1 R1 DNP Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. 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 4 AN1419.0 August 28, 2008