Evaluates: MAX40006 MAX40006 Evaluation Kit General Description Quick Start The MAX40006 evaluation kit (EV kit) provides a proven Required Equipment design to evaluate the MAX40006 low-power, MOS-input MAX40006 EV kit operational amplifier (op amp) in a 6-bump wafer-level +5V, 10mA DC power supply (PS1) package (WLP). The EV kit circuit is preconfigured as a noninverting amplifier, but can easily be adapted to other Precision voltage source topologies by changing a few components. Low-power, Digital multimeter (DMM) low-input V , and rail-to-rail input/output stages make OS this device ideal for a variety of measurement applications. Procedure The component pads accommodate packages, making The EV kit is fully assembled and tested. Follow the steps them easy to solder and replace. The EV kit comes with a below to verify board operation: MAX40006ANT+ installed. 1) Verify that the jumpers are in their default positions, as shown in Table 1. Features 2) Connect the positive terminal of the +5V supply to the +1.7V to +5.5V Supply Voltage Range V PCB pad and the negative terminal to the GND DD Accommodates Multiple Op-Amp Configurations PCB pad closest to V . DD Component Pads Allow for Sallen-Key Filter 3) Connect the positive terminal of the precision voltage Rail-to-Rail Inputs/Outputs source to the IN+ PCB pad. Connect the negative terminal of the precision voltage source to GND (GND Proven PCB Layout or IN- PCB pads). Fully Assembled and Tested 4) Connect the DMM to monitor the voltage on the OUT PCB pad. With the 10k feedback resistor (R5) and 1k series resistor (R1), the gain is +11 (noninverting configuration). 5) Turn on the +5V power supply. Ordering Information appears at end of data sheet. 6) Apply 100mV from the precision voltage source. Observe the output at OUT on the DMM. OUT should read approximately +1.1V. 7) Apply 400mV from the precision voltage source. OUT should read approximately +4.4V. 19-8683 Rev 0 10/16Evaluates: MAX40006 MAX40006 Evaluation Kit Sallen-Key Configuration Detailed Description of Hardware The Sallen-Key topology is ideal for filtering sensor signals The MAX40006 EV kit provides a proven layout for the with a 2nd-order filter and acting as a buffer. Schematic MAX40006 low-power, MOS-input op amp. The device is complexity is reduced by combining the filter and buffer a single-supply op amp that is ideal for buffering sensor operations. The EV kit can be configured in a Sallen-Key signals. The Sallen-Key topology is easily accomplished topology by replacing and populating a few components. by changing and removing some components. The The Sallen-Key topology is typically configured as a unity- Sallen-Key topology is ideal for buffering and filtering gain buffer, which can be done by replacing R1 and R5 sensor signals. with 0 resistors. The signal is noninverting and applied Op-Amp Configurations to IN+. The filter component pads are R2, R3, R4, and The device is a single-supply op amp that is ideal for R8, where some have to be populated with resistors and differential sensing, noninverting amplification, buffering, others with capacitors. and filtering. A few common configurations are detailed in Lowpass Sallen-Key Filter the next few sections. To configure the Sallen-Key as a lowpass filter, populate Noninverting Configuration the R2 and R8 pads with resistors and the C3 and C4 The EV kit comes preconfigured as a noninverting amplifier. pads with capacitors. The corner frequency and Q are The gain is set by the ratio of R5/R1. The EV kit comes then given by: preconfigured for a gain of +11. For a voltage applied to 1 the IN+ PCB pad, the output voltage for the noninverting f = C 2 R2C3R8C4 configuration is given by the equation below: R2C3R8C4 R5 Q = V=1++(V V ) OUT IN+ OS C4(R2 +R8) R1 Highpass Sallen-Key Filter where V = Input-referred offset voltage. OS To configure the Sallen-Key as a highpass filter, populate Differential Amplifier the C3 and C4 pads with resistors and the R2 and R8 pads with capacitors. The corner frequency and Q are To configure the EV kit as a differential amplifier, replace then given by: R1, R2, R , and R5 with appropriate resistors. When C3 R1 = R2 and R = R5, the CMRR of the differential C3 1 f = amplifier is determined by the matching of resistor ratios C 2 C R C R R8 C4 R2 C3 R1/R2 and R /R5: C3 C R C R R8 C4 R2 C3 R5 Q = V Gain(V V )++1 V R (C +C ) OUT IN+IN OS R3 R2 R8 R1 Capacitive Loads where: Some applications require driving large capacitive loads. To improve the stability of the amplifier in such cases, R5 R C3 Gain replace R6 with a suitable resistor value to improve amplifier R1 R2 phase margin in the presence of the capacitive load (C9), or apply a resistive load in parallel with C9. Maxim Integrated 2 www.maximintegrated.com = = =