ISL2828xEVAL1Z Evaluation Board User’s Guide Application Note August 2, 2007 Introduction AN1344.0 R49 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, C10 and C18, are connected close to the part to filter out high frequency noise. Anti-reverse diodes D1, D2 and zener diode D3 protect the circuit in the case of accidental polarity reversal. 1 Reference Documents R40 C10 C10 • ISL28286 Data Sheet, FN6312 J2 C12 C12 R46 R46 + 4.7UF 4.7μF D2 D2 00 1 1 A A 2 NC NC RF + IN(A, B)IN- IN- 0 C18 C18 0.1UF 0.1μF C16 C16 + DNP VP 1/2 ISL2828x VP 0Ω V+ IN+ VOUT(x) V- + VM 10kΩ 10kΩ RREF(A,B)+ 0Ω R49 CC 3 3 100kΩ 10kΩ VREF D3 The schematic of each of the 2 op amps 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 2.4VDC to +5VDC supply, or from dual supplies from ±1.2VDC to ±2.5VDC. The VREF pin can be connected to ground to establish a ground referenced input for split supply operation, or can be externally set to any reference level for single supply operation. External power connections are made through the V+, Vand Ground connections on the evaluation 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 C12, C17, connect to ground through R1, R46, 0Ω resistors. Resistors R40 and VCM 1 Amplifier Configuration (Figure 2) Power Supplies (Figure 1) IN(A, B)+ + FIGURE 1. POWER SUPPLY CIRCUIT The ISL2828xEVAL1Z is designed to enable the IC to operate from a single supply (+2.4VDC to +5VDC), or from split supplies (±1.2VDC to ±2.5V). The board is configured for 2 independent op amps 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 is included). IN+ C17 C17 V+ V+ 4.7UF D1 4.7μF D1 MMBZ52xxB Evaluation Board Key Features RIN+ 2 D3 0 VM RIN- R1 R1 00 0.1μF • ISL28288 Data Sheet, FN6339 J1 1 J3 V- R49 The ISL2828x amplifiers feature low noise, low distortion, and rail-to-rail output drive capability. They are designed to operate with single and dual supplies from +5VDC (±2.5VDC) down to +2.4VDC (±1.2VDC). 1 The ISL2828xEVAL1Z evaluation board is a design platform containing all the circuitry needed to characterize critical performance parameters of the ISL28286 and ISL28288 dual operational amplifiers, using a variety of user defined test circuits. R40 ® 100kΩ 0Ω TO OTHER CHANNEL VREF GND 10kΩ 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. 2007. All Rights Reserved All other trademarks mentioned are the property of their respective owners. Application Note 1344 User-Selectable Options (Figures 3 to 5) Component pads are included to enable a variety of user-selectable circuits to be added to the amplifier inputs, the VREF input, outputs and the amplifier feedback loops. The outputs (Figure 3) have additional resistor and capacitor placements for loading. A voltage divider and filter option (Figure 4) can be added to establish a power supply-tracking common mode reference at the VREF input. The inverting and non-inverting inputs have additional resistor placements for adding input attenuation, or to establish input DC offsets through the VREF pin. ROUT A R55 R55 0 DNP R44 R39 IN+ A DNP ENA 6 3 R57 V- 7 ENB 11 IN+ B R37 DNP RFA1, R45, 100k R36 DNP INA+ 5 J15 OUT A 12 5 2 34 DNP R57 10K IN- A 2 OUT 10K R53 OPEN 1 R51 DNP R51 DNP 1 R53 C19 OPEN 2 In the standard configuration (Figure 5), R41 and R45 are RF feedback resistors for the two independent amplifiers, set for AV = 10. Resistors R47 and R48 connect the DUT output to the output circuit (Figure 3). The additional unpopulated components, R34 to R39, R42 to R44, C10, C11, C13 to C15 and C18 allow the user to configure the board for a variety of other applications such as cascaded gain stages, active feedback loops, etc. C13 CFA DNP - 4 INA+ 3 OUTA R42 15 V+ RGDIFF DNP +14 OUTB INB+ 12 R38 DNP 13 INB- R47 RSA OUT A C14 DNP CLA C15 CLB DNP OUT B RSB R48, 0 R43, DNP IN- B FIGURE 3. 1/2 OUTPUT STAGE RFB1, R41,100k C11 CFB DNP 1 OPEN 2 100k RREF 1 RREFAR31 R31 C9 C9 1 2 + 4.7µF DNP 3 R2 R2 RINA2RINA2- DNP R8 R8 DNP DNP 1 R17 R17 J6 4 INA2- RINAR21 R21 10k C6 C6 2 1 0 00 R32 R32 2 OPEN OPEN R33 R33 1 FIGURE 5. OPTIONAL COMPONENTS VREF 10k C2 C2 2 DNP DNP 3 1 5 R25 R25 J5 4 INA1- J4 J4 REF1 REF1 RINA1R13 R13 + C3 C3 2 1 OPEN OPEN R9 R9 1 OPEN DNP DNP RINA2+ RINA2+ R18 DNP 100k 1 ININ+ R26 100k RGA+ 1 R3 R3 2 R18 2 RINA+ R22 R22 10k C7 210K C7 00 DNP 3 1 4 INA2+ J8 2 RREFA+ R30 R30 R26 3 1 4 INA1+ RINA1+ R14 R14 1 2 DNP J7 J7 FIGURE 4. 1/2 INPUT STAGE ISL2828xEVAL1Z Components Parts List DEVICE NUMBER DESCRIPTION C9, C12, C17 CAP-TANTALUM, SMD, D, 4.7µF, 50V, 10%, LOW ESR, ROHS COMMENTS Power supply decoupling C10,C18 CAP, SMD, 0603, 0.1µF, 25V, 10%, X7R, ROHS Power supply decoupling C6-C25 CAP, SMD, 0603, DNP-PLACE HOLDER, ROHS User selectable capacitors not populated DIODE-RECTIFIER, SMD, SOD-123, 2P, 40V, 0.5A, ROHS Reverse power protection DIODE-ZENER, SMD, SOD-123, 2P, 5.1V, 350mV, ROHS Reverse power protection D1,D2 D3 U1 (ISL28286EVAL1Z) ISL28286FAZ, IC-RAIL-TO-RAIL PRECISION OP AMP, 16P, QSOP, ROHS U1 (ISL28288EVAL1Z) ISL28288FAZ, IC-RAIL-TO-RAIL PRECISION OP AMP, 16P, QSOP, ROHS RESISTOR,SMD, 0603, 0.1%, MF, DNP-PLACE HOLDER User selectable resistors - not populated RES, SMD, 0603, 0W, 1/10W, TF, ROHS 0Ω user selectable resistors R6, R7, R20-R23, R33, R53, R54 RES, SMD, 0603, 10k, 1/10W, 1%, TF, ROHS RG gain resistors R28, R30, R41, R45 RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS RF gain resistors R2-R5, R8-R10, R12, R16-R19, R24-R27, R29, R31, R34-R39, R42-R44, R50-R52, R57, R58 R1, R11, R13-R15, R24, R25, R32, R40, R46-R49, R55, R56 2 AN1344.0 August 2, 2007 Application Note 1344 ISL2828xEVAL1Z Top View 3 AN1344.0 August 2, 2007 4 INB2- INB1- INB2+ INB1+ ENB ENA INA2+ INA1+ INA2- INA1- (C6) DNP DNP (R5) DNP (R12) RINB2- DNP (C1) (C8) DNP (C5) (10 k) (R20) RINB- (R24) DNP RGB- RREFB-(R29) DNP RGB+ (R27) DNP RINB+ (R23) (10 k) (R16) DNP RINB1- (R11) (0) (R4) DNP (R10) RINB2+ DNP V+ RGA+ (R26) DNP RREFB+ (R28) (100 k) (R19) DNP RINB1+ (R15) (0) (C4) DNP (C7) (R18) DNP (R7) (10 k) (R6) (10 k) (R3) DNP DNP RINA+ (R22) (10 k) RINA2+ DNP (R9) RREFA+(R30) (100 k) (C3) DNP RGA(R25) DNP RREFA- (R31) DNP RINA- (R21) (10 k) (R17) DNP RINA1+ (R14) (0) (R2) DNP (R8) RINA2- DNP (C2) DNP RINA1- (R13) (0) (C10) V- (R32) RREF (R37) DNP 4 3 2 (0) 4.7uF (C9) (10 k) (R33) (R38) DNP INB+ 5 ENB V- ENA INA+ 1 (R36) DNP VREF (R35) DNP (R34) DNP (R39) DNP - - (0) 4.7uF (R43) DNP (C18) V- (0) (R40) (D2) GND 5.1V (C16) (D3) DNP + CFB DNP (C11) V+ 4.7uF (C17) (C15) CLB DNP DNP (C14) CLA V+ (0) (R49) (D1) (R42) RGDIFF DNP RFB1 (R41) (100 k) V- OUTB V+ 6 INB- 7 8 9 OUTA 10 INA- (R46) (C12) + + CFA DNP (C13) RFA1 (R45) (100 k) (R44) DNP DNP (0) (R1) RSB (R48) (0) ROUTAB (R47) (0) RSA (C20) DNP (R52) DNP (R50) DNP (C19) DNP (R51) DNP (R54) (10 k) (R56) (0) ROUTB (R53) (10 k) (R55) (0) ROUTA (R58) DNP (R57) DNP OUTB OUTA Application Note 1344 ISL2828xEVAL1Z Schematic Diagram 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 AN1344.0 August 2, 2007