USERS MANUAL HIP2103 4DEMO2Z AN1575 Rev 0.00 Evaluation Boards October 1, 2010 Application Note 1575 Introduction Power Supplies (Figure 1) The ISL28433SOICEVAL1Z and ISL28433TSSOPEVAL1Z External power connections are made through the V+, Evaluation Board is designed to evaluate the performance V-, VREF, and GND connections on the evaluation of the ISL28433 Chopper Stabilized op amp. The board. The circuit can operate from a single supply or evaluation board contains the circuitry needed to from dual supplies. For single supply operation, the V- evaluate the high performance of the ISL28433 amplifier. and GND pins are tied together to the negative or The ISL28433 chopper stabilized rail-to-rail quad op amp ground reference of the power supply. For split features a low 8V maximum V over-temperature and supplies, V+ and V- terminals connect to their OS a 0.1Hz 1/f noise corner frequency enabling very high respective supply terminals. De-coupling capacitors C1 gain single-stage DC amplifiers that can operate from and C2 provide low-frequency power-supply filtering, single cell batteries while consuming only 20A of while additional capacitors, C3 and C4, which are current. The ISL28433SOICEVAL1Z and connected close to the part, filter out high frequency ISL28433TSSOPEVAL1Z evaluation board can be noise. Anti-reverse diodes D1 and D2 (optional) configured as a precision high-gain (G = 10,000V/V) protects the circuit in the momentary case of differential amplifier and demonstrates the level of accidentally reversing the power supplies to the performance possible with this type of amplifier while evaluation board. The VREF pin can be connected to operating from battery voltages as low as 1.65V. ground to establish a ground referenced input for split supply operation, or can be externally set to any Reference Documents reference level for single supply operation. ISL28233, ISL28433 Data Sheet FN7692 V- V+ J3 J1 VREF J4 Evaluation Board Key Features Single Supply Operation: +1.65V to +5.5V C2 R44 R1 C1 GND Dual Supply Operation: 0.825V to 2.75V 4.7F 0 0 4.7F J2 Singled-Ended or Differential Input Operation with D2 D1 High Gain (G= 10,000V/V) External VREF input V- V+ Banana Jack Connectors for Power Supply and V- AND V+ VREF Inputs IC SUPPLY PINS BNC Connectors for Op Amp Input and Output Terminals FIGURE 1. POWER SUPPLY CIRCUIT Convenient PCB Pads for Op Amp Input/Output Impedance Loading R39, R47, R49, R50 IN-A 2 1M IN-B 6 R14, R16, V+ IN-C 9 R18, R40 4 IN-D 13 - IN- 100 0 IN+A 3 ISL28433 OUT IN+B 5 R15, R17, IN+C 10 R51-R54 OUT A 1 R19, R41 IN+D 12 + IN+ OUT B 7 11 OUT C 8 100 IN + V- OUT D 14 VCM R24, R27, R29, R45 R67-R70 OPEN OPEN VREF OPEN VREF GND FIGURE 2. BASIC DIFFERENTIAL AMPLIFIER CONFIGURATION AN1575 Rev 0.00 Page 1 of 5 October 1, 2010 C4 R37 0.1F 0 C3 R48 0.1F 0HIP2103 4DEMO2Z additional resistor and capacitor placements for adding Amplifier Configuration (Figure 3) input attenuation or feedback capacitors (Figure 3). The schematic of the op amp input stage with the components supplied is shown in Figure 3, with a closed The output (Figure 4) also has additional resistor and loop gain of 10,000V/V. The circuit implements a Hi-Z capacitor placements for filtering and loading. differential input with unbalanced common mode NOTE: Operational amplifiers are sensitive to output impedance. The differential amplifier gain is expressed in capacitance and may oscillate. In the event of oscillation, Equation 1: reduce output capacitance by using shorter cables, or (EQ. 1) V = V V R R + V OUT IN+ IN- F IN REF add a resistor in series with the output. C6 C23 For single-ended input with an inverting gain OPEN OPEN G = -10,000V/V, the IN+ input is grounded and the R6 R14 R39 FROM OUT A IN-A signal is supplied to the IN- input. VREF must be 0 100 1M connected to a reference voltage between the V+ and V- supply rails. For non-inverting operation with TO IN-A G = 10,001V/V, the IN- input is grounded and the signal is supplied to the IN+ input. The non-inverting R5 R15 TO IN+A IN+A gain is strongly dependent on any resistance from IN- 100 0 to GND. For good gain accuracy, a 0 resistor should C7 be installed on the empty R11 pad. OPEN User-selectable Options FIGURE 3. INPUT STAGE (Figures 3 and 4) Component pads are included to enable a variety of R51 R63 OUT A J13 OUT A user-selectable circuits to be added to the amplifier 0 0 inputs, the VREF input, outputs and the amplifier feedback loops. A voltage divider can be added to establish a power supply-tracking common mode reference using the VREF input (see ISL28433SOICEVAL1Z Schematic Diagram on page 4). The inverting and non-inverting inputs have FIGURE 4. OUTPUT STAGE TABLE 1. ISL28433TSSOPEVAL1Z and ISL28433MSOPEVAL1Z COMPONENTS PARTS LIST DEVICE DESCRIPTION COMMENTS C1, C2 CAP, SMD, 1210, 4.7F, 50V, 10%, X7R, ROHS Power Supply Decoupling C3, C4 CAP, SMD, 0805, 0.1F, 50V, 10%, X7R, ROHS Power Supply Decoupling D1, D2 40V SCHOTTKY BARRIER DIODE Reverse Power Protection R32, R33 RESISTOR, SMD, 0603, DNP, 1%, ROHS VREF Resistor Divider C5 CAP, SMD, 1210, 4.7F, 50V, 10%, X7R, ROHS VREF Supply Decoupling R5, R7, R9, R14, R16, RESISTOR, SMD, 0603, 100, 1%, 1/16W, ROHS Gain Setting Resistor R18, R35, R40 R39, R47, R49, R50 RESISTOR, SMD, 0603, 10M, 1%, 1/16W, ROHS Gain Setting Feedback Resistor R2-R4, R11-R13, RESISTOR, SMD, 0603, DNP-PLACE HOLDER, ROHS User selectable resistors - not populated R20-R23, R25,R26,R34, R38, R42, R43, R55-R58, R67-70, R24, R27-R31, R33, R45, R46, R59-R62 U1 (ISL28433) ISL28433FBZ (SOIC), ISL28433FVZ (TSSOP), IC-RAIL-TO-RAIL OP AMP, ROHS AN1575 Rev 0.00 Page 2 of 5 October 1, 2010 R2 C14 DNP OPEN R11 C15 R55 DNP DNP OPEN R21 R59 R20 DNP DNP DNP R67 DNP