MAX9911EVKIT+

19-5734; Rev 0; 1/11 MAX9911 Evaluation Kit The MAX9911 evaluation kit (EV kit) provides a proven design to evaluate the MAX9911 low-power, MOS-input operational amplifier (op amp) in a 6-pin wafer-level package (WLP). The EV kit circuit is preconfigured as a noninverting amplifier, but can easily be adapted to other topologies by changing a few components. Low power, low-input VOS, and rail-to-rail input/output stages make this device ideal for a variety of measurement applications. The component pads accommodate 0805 packages, making them easy to solder and replace. The EV kit comes with a MAX9911EWT+ installed. Features S 1.8V to 5.5V Supply Voltage Range S Accommodates Multiple Op-Amp Configurations S Component Pads Allow for Sallen-Key Filter S Rail-to-Rail Inputs/Outputs S Accommodates Easy-to-Use 0805 Components S Proven PCB Layout S Fully Assembled and Tested Ordering Information PART TYPE MAX9911EVKIT+ EV Kit +Denotes lead(Pb)-free and RoHS compliant. Component List DESIGNATION QTY DESCRIPTION 1 0.1FF Q10%, 16V X7R ceramic capacitor (0603) Murata GRM188R71C104K C2 1 4.7FF Q10%, 6.3V X5R ceramic capacitor (0603) Murata GRM188R60J475K C3, C4, C8, C9 0 Not installed, ceramic capacitors (0805) JU1 1 2-pin header JU2 1 3-pin header C1 DESIGNATION QTY R1, R2 2 1kI Q1% resistors (0805) DESCRIPTION R5 1 10kI Q1% resistor (0805) R6, R8 2 0I Q5% resistors (0805) U1 1 Single low-power, rail-to-rail I/O op amp (6 WLP) Maxim MAX9911EWT+ — 2 Shunts — 1 PCB: MAX9911 EVALUATION KIT+ Component Supplier SUPPLIER Murata Electronics North America, Inc. PHONE 770-436-1300 WEBSITE www.murata-northamerica.com Note: Indicate that you are using the MAX9911 when contacting this component supplier. ________________________________________________________________ Maxim Integrated Products   1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. Evaluates: MAX9911 General Description Evaluates: MAX9911 MAX9911 Evaluation Kit Quick Start Detailed Description of Hardware Required Equipment The MAX9911 EV kit provides a proven layout for the MAX9911 low-power, MOS-input op amp. The device is a single-supply op amp that is ideal for buffering sensor signals. The Sallen-Key topology is easily accomplished by changing and removing some components. The Sallen-Key topology is ideal for buffering and filtering sensor signals. • MAX9911 EV kit • +5V, 10mA DC power supply (PS1) • Precision voltage source • Digital multimeter (DMM) Procedure The EV kit is fully assembled and tested. Follow the steps below to verify board operation: 1) Verify that jumpers are in their default positions, as shown in Table 1. 2) Connect the positive terminal of the +5V supply to the VDD PCB pad and the negative terminal to the GND PCB pad closest to VDD. 3) Connect the positive terminal of the precision voltage source to the IN+ PCB pad. Connect the negative terminal of the precision voltage source to GND (GND or IN- PCB pads). 4) Connect the DMM to monitor the voltage on the OUT PCB pad. With the 10kI feedback resistor (R5) and 1kI series resistor (R1), the gain is +11 (noninverting configuration). Op-Amp Configurations The device is a single-supply op amp that is ideal for differential sensing, noninverting amplification, buffering, and filtering. A few common configurations are detailed in the next few sections. Noninverting Configuration The EV kit comes preconfigured as a noninverting amplifier. The gain is set by the ratio of R5/R1. The EV kit comes preconfigured for a gain of +11. For a voltage applied to the IN+ PCB pad, the output voltage for the noninverting configuration is given by the equation below: VOUT = (1 + R5 )(VIN+ VOS ) R1 5) Turn on the +5V power supply. where VOS = input-referred offset voltage. 6) Apply 100mV from the precision voltage source. Observe the output at OUT on the DMM. OUT should read approximately +1.1V. Differential Amplifier To configure the EV kit as a differential amplifier, replace R1, R2, RC3, and R5 with appropriate resistors. When R1 = R2 and RC3 = R5, the CMRR of the differential amplifier is determined by the matching of the resistor ratios R1/ R2 and RC3/R5: 7) Apply 400mV from the precision voltage source. OUT should read approximately +4.4V. Table 1. Jumper Descriptions (JU1, JU2) JUMPER SHUNT POSITION DESCRIPTION Installed* Connects the IN- PCB pad to GND. Open Isolates the IN- PCB pad from GND. JU1 1-2* Connects SHDN to VDD (normal operation). 2-3 Connects SHDN to GND (shutdown). JU2 VOUT = Gain(VIN+ − VIN− ) + (1 + where: Gain = R5 R C3 = R1 R2 *Default position. 2   _______________________________________________________________________________________ R5 )VOS R1 MAX9911 Evaluation Kit Lowpass Sallen-Key Filter To configure the Sallen-Key as a lowpass filter, populate the R2 and R8 pads with resistors and the C3 and C4 pads with capacitors. The corner frequency and Q are then given by: fC = 1 Highpass Sallen-Key Filter To configure the Sallen-Key as a highpass filter, populate the C3 and C4 pads with resistors and the R2 and R8 pads with capacitors. The corner frequency and Q are then given by: fC = 1 2π C R8 × R C4 × C R2 × R C3 Q= C R8 × R C4 × C R2 × R C3 R R3 (C R2 + C R8 ) Capacitive Loads Some applications require driving large capacitive loads. To improve the stability of the amplifier in such cases, replace R6 with a suitable resistor value to improve amplifier phase margin in the presence of the capacitive load (C9), or apply a resistive load in parallel with C9. 2π R2 × C3 × R8 × C4 Q= R2 × C3 × R8 × C4 C4(R2 + R8) _______________________________________________________________________________________   3 Evaluates: MAX9911 Sallen-Key Configuration The Sallen-Key topology is ideal for filtering sensor signals with a 2nd-order filter and acting as a buffer. Schematic complexity is reduced by combining the filter and buffer operations. The EV kit can be configured in a Sallen-Key topology by replacing and populating a few components. The Sallen-Key topology is typically configured as a unity-gain buffer, which can be done by replacing R1 and R5 with 0I resistors. The signal is noninverting and applied to IN+. The filter component pads are R2, R3, R4, and R8, where some have to be populated with resistors and others with capacitors. Evaluates: MAX9911 MAX9911 Evaluation Kit Figure 1. MAX9911 EV Kit Schematic 4   _______________________________________________________________________________________ MAX9911 Evaluation Kit Figure 2. MAX9911 EV Kit Component Placement Guide— Component Side 1.0” Figure 3. MAX9911 EV Kit PCB Layout—Component Side 1.0” Figure 4. MAX9911 EV Kit PCB Layout—Solder Side _______________________________________________________________________________________   5 Evaluates: MAX9911 1.0” Evaluates: MAX9911 MAX9911 Evaluation Kit Revision History REVISION NUMBER REVISION DATE 0 1/11 DESCRIPTION Initial release PAGES CHANGED — Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 6 Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ©  2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.