Evaluates: MAX9636 19-5287 Rev 0 5/10 MAX9636 Evaluation Kit General Description Features The MAX9636 evaluation kit (EV kit) is an assembled S Accommodates Multiple Op-Amp Configurations and tested PCB used to evaluate the MAX9636 low- S On-Board LED Driver power, low-noise, CMOS input op amp, which is suitable S Accommodates Multiple Wavelength LEDs for photodiode transimpedance front-ends in portable S Proven PCB Layout medical instruments. The EV kit is preconfigured for a transimpedance amplifier (TIA). Additionally, an on- S Fully Assembled and Tested board LED driver circuit provides a controlled light source to help evaluate the performance of the MAX9636 TIA circuit. The EV kit can easily be adapted to act as Ordering Information noninverting, inverting, or differential amplifier by chang- ing a few components. Another EV kit is offered for the PART TYPE MAX9638 dual version of this op amp to enable evalua- MAX9636EVKIT+ EV Kit tion in an active filter circuit configuration. +Denotes lead(Pb)-free and RoHS compliant. The EV kit comes with a MAX9636AXT+ installed. Component List DESIGNATION QTY DESCRIPTION DESIGNATION QTY DESCRIPTION Photodiode 18pF Q5%, 50V C0G ceramic D2 1 Vishay BPW46 C1 1 capacitor (0603) TDK C1608C0G1H180J JU1, JU2 2 3-pin headers n-channel MOSFET (6 SC70) 0.1FF Q10%, 16V X7R ceramic M1 1 Fairchild FDG410NZ C2, C7, C8, C9 4 capacitors (0603) Murata GRM188R71C104K R1, R6, R7 3 0I Q5% resistors (0603) R2 1 10kI Q1% resistor (0603) Not installed, ceramic capacitors C3, C6 0 (0603) R3, R9, R12 0 Not installed, resistors (0603) R4 1 100kI Q1% resistor (0603) Not installed, ceramic capacitor C4 0 (0805) R5 1 249I Q1% resistor (0603) R8, R10, R11 3 976I Q1% resistors (0603) 4.7FF Q10%, 25V X5R ceramic TP1 1 Red test point C5 1 capacitor (0805) Murata GRM21BR61E475K Low-power op amps (6 SC70) U1, U2 2 Maxim MAX9636AXT+ Red side LED 2 Shunts D1 1 (4mm x 3.6mm x 4mm) OSRAM LS A676-R1S1 PCB: MAX9636 EVALUATION 1 KIT+ Component Suppliers SUPPLIER PHONE WEBSITE Fairchild Semiconductor 888-522-5372 www.fairchildsemi.com Murata Electronics North America, Inc. 770-436-1300 www.murata-northamerica.com TDK Corp. 847-803-6100 www.component.tdk.com Vishay 402-563-6866 www.vishay.com Note: Indicate that you are using the MAX9636 when contacting these component suppliers. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.MAX9636 Evaluation Kit 10) Verify that the red LED (D1) turns on. At 1kHz, the Quick Start LED pulsing cannot be seen due to persistence of Required Equipment vision. Verify that the oscilloscope screen shows MAX9636 EV kit a square waveform with an approximate 1kHz frequency. 2.1V to 5.5V DC power supply (e.g., Agilent E3620A) Function generator (e.g., Agilent 33220A) Detailed Description of Hardware Digital oscilloscope (e.g., Tektronix TDS3014) The MAX9636 EV kit is an assembled and tested PCB used to evaluate the MAX9636 low-power op amp, which Procedure is suitable for photodiode transimpedance front-ends in The EV kit is fully assembled and tested. Follow the portable medical instruments. The EV kit is preconfig- steps below to verify board operation. Caution: Do ured for a TIA, but can easily be adapted to other topolo- not turn on power supply until all connections are gies by changing a few components. completed. Transimpedance Amplifier (TIA) 1) Since the photodiode on the EV kit is sensitive to By default, the EV kit is set up for a TIA. The output volt- ambient and infrared light, it is recommended that age of the TIA is the photodiode current multiplied by the the EV kit be placed in a suitable dark environment feedback resistor: to minimize the idling current. 2) Verify that a shunt is installed in the 1-2 position V = (I x R4) + V OUT PD OS of both jumpers JU1 and JU2. See Table 1 for a description of the jumper settings. where R4 comes installed as a 100kI resistor, I is PD defined as photodiode current, and V is the input off- OS 3) Set the DC power supply to 5V and connect the set voltage of the op amp. Use capacitor C1 to stabilize positive terminal to the VDD and INP pads on the EV the op amp by rolling off high-frequency gain due to the kit. Connect the negative terminal to the GND pad. photodiode capacitance. 4) Set the function generator for a square-wave For ease of evaluation of the TIA circuit, LED D1 is frequency of 1kHz, and amplitude to 2V with a P-P provided on-board to emit light from the side. A second DC offset of 1V. op amp (U2), MOSFET M1, and resistors R8, R10, and 5) Disable the function generator. R11 form a controlled current-sink circuit to regulate 6) Connect the function generator across the the LED current. Due to the negative feedback action, VCONTROL and GND pads on the EV kit. the voltage at test point TP1 is the same as the control voltage (VCONTROL). The LED current is given by the 7) Connect an oscilloscope channel across the VOUT following equation: and GND pads on the EV kit. 8) Turn on the DC power supply. VCONTROL I = LED 9) Enable the function generator. (R8 R10 R12) Table 1. Jumper Descriptions (JU1, JU2) JUMPER SHUNT POSITION DESCRIPTION 1-2* Connects the SHDN pin of the MAX9636 (U1) to VDD for normal operation. JU1 2-3 Connects the SHDN pin of the MAX9636 (U1) to GND to put the part in shutdown mode. 1-2* Powers LED D1 using the supply applied at the VDD pad of the EV kit. JU2 Powers LED D1 and its LED driver circuit using a separate power supply applied at the 2-3 VLED pad on the EV kit. *Default position. 2 Evaluates: MAX9636