19-2059; Rev 1; 4/02 MAX3970 Evaluation Kit Features ♦ Easy +3.3V Electrical Evaluation of the MAX3970 ♦ Fully Assembled and Tested ♦ EV Kit Designed for 50Ω Interfaces Ordering Information PART TEMP RANGE MAX3970EVKIT 0°C to +85°C Component Suppliers SUPPLIER PHONE FAX AVX 843-444-2863 803-626-3123 Murata 814-237-1431 814-238-0490 Note: Please indicate that you are using the MAX3970 when ordering from these suppliers. IC PACKAGE Dice Component List DESIGNATION QTY DESCRIPTION C2, C4, C13 3 1000pF ±10% ceramic capacitors (0402) C11, C12, C15, C16 4 0.01µF ±10% ceramic capacitors (0402) C14 1 33µF ±10% tantalum capacitor J1–J5 5 SMA connectors edge mount JU1 1 2-pin header, 0.1in centers 1 Ferrite bead (0603) Murata BLM11HA601SG (0603) L1 R1, R2, R4, R5 4 243Ω 1% resistors (0402) R3, R6 2 49.9Ω 1% resistors (0402) R7 1 10kΩ 1% resistor (0402) TP1, TP2, VCC, GND 4 Test points U1 1 MAX3970U/D None 1 Shunt ________________________________________________________________ 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: MAX3970 General Description The MAX3970 evaluation kit (EV kit) is a fully assembled chip-on-board electrical demonstration kit that provides easy evaluation of the MAX3970 10.3Gbps, +3.3V transimpedance amplifier. Note that the MAX3970 EV kit provides an electrical interface to the IC, which is similar to, but not exactly the same as, a photodiode. The circuit used tends to increase bandwidth and jitter beyond what is expected for typical photodiode inputs. Evaluates: MAX3970 MAX3970 Evaluation Kit Quick Start 1) Connect a signal source with 500mVP-P amplitude to the INPUT. Set the data rate for the signal source to 10.3Gbps. 2) Connect OUT+ (J2) and OUT- (J3) to the 50Ω inputs of a high-speed oscilloscope. 3) Remove the shunt from JU1. 4) Connect a +3.3V supply to the proper terminals and power up the EV kit. 5) The differential signal at the oscilloscope should be approximately 450mVP-P. Detailed Description The MAX3970 accepts a DC-coupled input from a highspeed photodiode, at optical modulation amplitudes ranging from 40µAP-P to 2.0mAP-P. To facilitate characterization without a photodiode, the MAX3970 EV kit provides a simple circuit that emulates the photodiode using the signal voltage from a 50Ω source. The connector at IN (J1) is terminated with 50Ω to ground. Signal voltage applied to the EV kit's input is AC-coupled to a resistance in series with the MAX3970's input, creating an input signal current. Photodiode DC current can be emulated by injecting DC current into the TEST pin (TP1). The TEST pin is connected to IN through an on-chip 1kΩ resistor. 3) Calculate the AC signal current (IINPUT in amps) as follows, and adjust the signal generator to obtain it: (r − 1) I INPUT = 2IAVE e (re + 1) For example, to emulate a signal with an average power of -10dBm and an extinction ratio of 8: 1) -10dBm optical power will produce 85µA of average input current (assume a photodiode responsivity of 0.85A/W). Install a current meter between the TEST pin and a DC source. Adjust the source to provide 85µA. 2) The signal amplitude is 2IAVE(re -1)/(re +1) = 132µA. To generate this current through the two 243Ω series input resistors, set the signal source to produce an output level of 64mVP-P. Noise Measurements Remove R1 before attempting noise measurements. With R1 removed, the total capacitance at the IN pin is approximately 0.2pF. Photodiode Emulation The following procedure can be used 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) as follows: IAVG = 10(PAVE / 10) ρ 1000 where ρ is photodiode responsivity in A/W 2 _______________________________________________________________________________________ MAX3970 Evaluation Kit Evaluates: MAX3970 J8 GND 3.3V C15 0.01µF C14 33µF J7 VCC L1 BP17 TP2 R7 10kΩ 3.3V 3.3V 3.3V 3.3V BP18 BP1 17 BP16 16 18 VCC1 RSSI 1 VCC2 15 VCC1 BP2 2 U1 VCC1 VCC2 BP3 JU1 J1 IN R2 243Ω MAX3970 FILTER GND C13 1000pF BP14 14 13 BP13 BP4 C16 TP1 0.01µF C2 1000pF 3 BP15 VCC2 4 R1 243Ω TEST OUT+ 12 BP5 C11 0.01µF BP12 C12 0.01µF BP11 5 IN OUT- GND GND BP6 11 J3 OUT - BP10 R3 49.9Ω 6 BP7 C4 1000pF J5 CALIN R6 49.9Ω GND GND 7 8 BP8 R5 243Ω J2 OUT + 10 GND 9 BP9 R4 243Ω J4 CALOUT Figure 1. MAX3970 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX3970 MAX3970 Evaluation Kit 1.0" Figure 2. MAX3970 EV Kit Component Placement Guide— Component Side 1.0" Figure 4. MAX3970 EV Kit PC Board Layout—Solder Side 4 1.0" Figure 3. MAX3970 EV Kit PC Board Layout—Component Side 1.0" Figure 5. MAX3970 EV Kit PC Board Layout—Ground Plane _______________________________________________________________________________________ MAX3970 Evaluation Kit Figure 6. MAX3970 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 5 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. Evaluates: MAX3970 1.0"