19-2264; Rev 0; 12/01 MAX3277 Evaluation Kit Features ♦ Fully Assembled and Tested ♦ Includes Photodiode Emulation Circuit ♦ Includes Calibration Circuit for Accurate Bandwidth and Jitter Measurements Component List DESIGNATION QTY Ordering Information DESCRIPTION PART TEMP RANGE IC PACKAGE MAX3277EVKIT 0°C to +85°C MAX3277UID Chip On-Board C1 1 0.01µF ±10% ceramic capacitor (0402) C2 1 10µF ±10% tantalum capacitor C5–C9 5 0.1µF ±10% ceramic capacitors (0402) C11, C12 2 1000pF ±10% ceramic capacitors (0402) FAX 5 SMA connectors, edge mount (round contact) PHONE J1–J5 AVX 843-444-2863 843-626-3123 J8 1 1 × 2-pin header (0.1in center) Coilcraft 408-224-8566 408-224-6304 Murata 415-964-6321 415-964-8165 Ventel 800-950-8365 512-794-0087 L1 1 56nH inductor Coilcraft 0805CS-560XKBC R1, R6 2 49.9Ω ±1% resistors (0402) R2, R5 2 1kΩ ±1% resistors (0402) R3, R4, R7, R8 4 499Ω ±1% resistors (0402) TP1, TP2, J6, J7 4 Test points MAX3277U/D die U1 1 None 1 MAX3277 EV kit circuit board None 1 MAX3275/MAX3277 data sheet Component Suppliers SUPPLIER Note: Please indicate that you are using the MAX3277 when contacting these component suppliers. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 Evaluates: MAX3277 General Description The MAX3277 evaluation kit (EV kit) allows complete evaluation of the MAX3277 transimpedance amplifier. The EV kit includes a circuit that emulates the highspeed, zero-to-peak current input signal that would be produced by a photodiode. The kit also includes a calibration circuit that allows accurate bandwidth and jitter measurements. The MAX3277 EV kit is fully assembled and tested. Evaluates: MAX3277 MAX3277 Evaluation Kit Quick Start 1) Connect a signal source to IN (J3). Set the signal amplitude to 50mVP-P (corresponding to 50µAP-P current into the TIA). This may require attenuation between the source and the MAX3277 EV kit. The signal should have a data rate of up to 2.125Gbps. 2) Apply 30µA to TP1 using a constant current source to emulate the DC component of the input signal. 3) Connect OUT+ (J1) and OUT- (J2) to the 50Ω inputs of a high-speed oscilloscope. 4) Remove the shunt from jumper J8 to enable DC cancellation loop. 5) Connect a 3.3V supply to the VCC terminal (J6) and ground to the GND terminal (J7). 6) The differential signal at the oscilloscope should be approximately 165mVP-P. Detailed Description The MAX3277 EV kit allows characterization of the MAX3277 TIA without a photodiode. The MAX3277 is designed to accept a DC-coupled input from a highspeed photodiode. Diode currents can have 10µAP-P to 2mAP-P AC current with a DC component from 5µA to 1mA. The high-speed current source of the photodiode is emulated on the EV kit using separate AC and DC paths. The AC signal is supplied from a standard 50Ω lab source that delivers power to an on-board termination resistor. A current is then generated from the voltage signal by a resistor with low stray capacitance. The effect of the DC photodiode current can be emulated by a current source at TP1. An isolation resistor prevents the DC source from loading the AC path. The values of the series-resistive elements, R4 and R7, have been selected carefully so that the bandwidth of the transimpedance amplifier is not altered. Surface- 2 mount resistors have parasitic capacitance that reduces their impedance at frequencies above 1GHz. Changes to R4 and R7 must be evaluated using the calibration network. Photodiode Emulation Use the following procedure to emulate the high-speed current signal generated by a photodiode: 1) Select the desired optical power (PAVE in dBm) and extinction ratio (re). 2) Calculate the average current (IAVE in Amps). Set the DC current at TP1 to IAVE: 10(PAVE / 10) IAVE = ρ 1000 (ρ = photodiode responsivity in A / W) 3) Calculate the AC signal current (lAC) and adjust the signal generator to obtain it: r − 1 IAC = 2IAVE e re + 1 For example: To emulate a photodiode with an average power of -16dBm and an extinction ratio of 10: 1) -16dBm optical power will produce 25µA of average input current (assume photodiode responsivity of 1A/W). Set the DC current input to 25µA at TP1. 2) The AC signal current is 2 IAVE (re - 1)/(re + 1) = 41µA. To generate this current through the 1000Ω input resistors, set the signal source to produce an output level of 41µA (1000Ω) = 41mVP-P. _______________________________________________________________________________________ MAX3277 Evaluation Kit J6 VCC L1 56nH J7 GND C7 0.1µF VCC C12 1000pF J4 CALIN C2 10µF R2 1kΩ R8 499Ω R1 49.9Ω C1 0.01µF VCC 1 TP1 2 J3 IN C11 1000pF 5 R5 1kΩ R7 499Ω J5 CALOUT VCC C9 0.1µF C8 0.1µF R3 499Ω R4 499Ω 8 VCC VCCZ GND U1 FILTER GNDZ MAX3277 OUT+ IN OUT- 9 7 J8 J1 OUT+ 4 3 C5 0.1µF J2 OUTC6 0.1µF R6 49.9Ω PC BOARD FEATURES EMULATING CAPACITORS Figure 1. MAX3277 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX3277 TP2 Evaluates: MAX3277 MAX3277 Evaluation Kit Figure 2. MAX3277 EV Kit Component Placement Guide— Component Side 4 _______________________________________________________________________________________ MAX3277 Evaluation Kit Evaluates: MAX3277 Figure 3. MAX3277 EV Kit PC Board Layout—Component Side _______________________________________________________________________________________ 5 Evaluates: MAX3277 MAX3277 Evaluation Kit Figure 4. MAX3277 EV Kit PC Board Layout—Solder Side 6 _______________________________________________________________________________________ MAX3277 Evaluation Kit Evaluates: MAX3277 Figure 5. MAX3277 EV Kit PC Board Layout—Ground Plane _______________________________________________________________________________________ 7 Evaluates: MAX3277 MAX3277 Evaluation Kit Figure 6. MAX3277 EV Kit PC Board Layout—Power Plane 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. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.