19-2898; Rev 1, 9/03 MAX3657 Evaluation Kit ________________ General Description The MAX3657 evaluation kit is a fully assembled chip-onboard electrical demonstration kit that provides easy evaluation of the MAX3657 155Mbps +3.3V transimpedance amplifier. Note that the MAX3657 Evaluation Kit provides an electrical interface to the IC that is similar, but not exactly the same as a photodiode. ______________ Ordering Information PART TEMP. RANGE IC PACKAGE MAX3657EVKIT -40°C to +85°C Dice ______________Component Suppliers PHONE FAX AVX SUPPLIER 843-444-2863 843-626-3123 ____________________________ Features Coilcraft 847-639-6400 847-639-1469 Digi-Key 218-681-6674 218-681-3380 ♦ Easy +3.3V Electrical Evaluation of the MAX3657 EF Johnson 402-474-4800 402-474-4858 ♦ Fully Assembled and Tested Murata 415-964-6321 415-964-8165 ♦ EV Kit Designed for 50Ω Ω Interfaces Note: Please indicate that you are using the MAX3657 when ordering from these suppliers. ____________________ Component List DESIGNATION QTY C2 C23 2 DESCRIPTION 0.01µF ± 5% Ceramic Capacitor (0201) - Do not Install 1 10µF ±10% tantalum capacitor Do Not Install C4 1 0.9pF ± .075pF Capacitor (0402) Ceramic C5 C100 2 0.01µF ± 10% Capacitor (0402) Ceramic C3 C6, C7, C24, 4 C27 1µF ± 5% Ceramic Capacitor (0402) Do Not Install C8, C9, C13, C14, C96, C98, 8 C118, C119 1µF ± 5% Ceramic Capacitor (0402) C17, C99 2 10µF ±10% tantalum capacitor 1 0.4pF ± 0.05pF Capacitor (0402) J3 J4 J5, J22 6 J26 J27 SMA connectors (edge-mount, round) J19, J23, J24, 4 J25 SMA connectors (edge-mount, round) Do not Install JU3, JU4, JU5, 4 JU6 2-pin headers (0.1in centers) L1 1 56nH inductors (0805) Coilcraft CS-560XKBC Do Not Install L2 L30 2 56nH inductors (0805) Coilcraft CS-560XKBC C97 Ceramic DESIGNATION QTY DESCRIPTION R2, R98 2 49.9Ω ±1% resistor (0402) R3, R4 R120, 4 R121 100Ω ±1% resistor (0402) R5 R100 2 10kΩ ±1% resistor (0402) R6 1 1kΩ ±1% resistor (0402) R7, R38 2 499Ω ±1% resistor (0402) 4 100Ω ±1% resistor (0402) Do Not Install 1 1kΩ ±1% resistor (0402) Do Not Install R28-R29 R34 R31 R33- R99 R102 R103 3 4.99kΩ ±1% resistor (0402) TP2, TP4, TP5, TP6 TP8, TP9, 10 TP10 TP13TP14, TP19 TESTPOINT DIGI-KEY 5000KND TP1, TP18, 4 TP11, TP12 TESTPOINT DIGI-KEY 5000KND Do Not Install U1 1 MAX3657 ETC 12 QFN U2 1 MAX3657 DIE U3 1 User Supplied 4 PIN TO CAN U4 1 User Supplied 5 PIN TO CAN _________________________________________________________________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 MAX3657 Evaluation Kit _________________________ Quick Start Evaluate: MAX3657 Test Equipment Required • • +3.3V power supply with 100mA current capability • Oscilloscope with at least 100MHz performance Signal-source, 155Mbps minimum capability Procedure This procedure will set up the 12 Pin QFN section of the evaluation board for 155Mbps operation. 1) Connect a signal source to J26 (IN). Set the signal amplitude to 250mVP-P (Corresponding to 250µAP-P current into the TIA). Set the data rate to 155Mbps. 2) Apply 150µA to the DC_IN test point (TP10) using a constant current source to emulate the DC component of the input signal. A voltage source connected from TP10 to GND may be used if a constant current source is not available. 3) 4) 5) 6) 7) Connect OUT+ (J22) and OUT- (J27) to the 50Ω inputs of a high-speed oscilloscope. Remove the shunt from JU6 to enable the DC cancellation loop. Install the shunt on JU5.to enable the average current monitor. Connect a 3.3V supply to the supply terminal (TP 13) and to the GND terminal. The differential signal at the oscilloscope should be approximately 150mVP-P. _______________ Detailed Description The MAX3657 accepts a DC-coupled input from a highspeed photodiode, for optical modulation amplitudes ranging from -38dBm to 0dBm. The MAX3657 evaluation board facilitates characterization of the MAX3657 TIA with or without a photodiode. The MAX3657 comes from the factory with the die attached and 12 pin QFN sections completely assembled. The user must assemble the TO header sections, if used. Die Attached Section The die-attached section provides a simple circuit for emulating a photodiode current input. The connector at IN (J1) is terminated with 50Ω to ground. Signal voltage applied to the evaluation kit's input is AC coupled to a resistance in series with the MAX3657's input, creating an input signal current. Photodiode DC current can be emulated by injecting DC current into the DC_IN_ pin. 12 Pin QFN Section The 12 pin QFN section provides photodiode emulation using similar circuitry as the die-bonded section. An optional TO assembled photodiode interface is also provided. To use a TO mounted photo diode, remove R38, R7, and C4. Figure 2 shows a typical mounting scheme for a photo diode in a TO header. 4 and 5 Pin TO Header Layout The TO header assembly layout provides a userassembled interface for evaluation of 4 and 5 pin TO headers. (See the MAX3657 datasheet for a suggested TO header layout.) Test Equipment Interface The MAX3657 outputs are back terminated with 100 ohms. To facilitate interface with 50Ω equipment, the MAX3657 EV Kit places external 100Ω termination resistors in parallel with each output so that the EV Kit will match a 50Ω environment. Note that the output load has a direct effect on the overall gain and output signal swing. Because of the external 100Ω resistors, the overall gain is reduced by 50%. If matching a 50Ω environment is not critical, higher gain can be achieved by increasing the load resistance. Photodiode Emulation Use the following procedure to emulate the high-speed current signal generated by a photodiode: Select the desired optical power (PAVE in dBm) and extinction ratio (re). Calculate the average current (IAVE in Amps) as follows: IAVG = 10 ( PAVE / 10) ρ 1000 where ρ is photodiode responsivity in A/W Calculate the AC signal current (IINPUT in AmpsP-P) as follows, and adjust the signal generator to obtain it: IINPUT = 2IAVE (re − 1) (re + 1) For example, to emulate a signal with an average power of -25dBm and an extinction ratio of 8. -25dBm optical power will produce 2.7µA of average input current (assume a photodiode responsivity of 0.85A/W). Install a current meter between an external DC source and the DC_IN test point. Adjust the source to provide 2.7µA. The signal amplitude is 2IAVE(re-1)/(re+1) = 4.2µA. To generate this current through the two 4.99kΩ series input resistors and the 800Ω internal resistance, set the signal source to produce an output level of 45mVP-P. Noise measurements Remove the input resistors and shunt capacitor before attempting noise measurements. Be very careful when working around the exposed bond wires of the die bonded section. With the input resistors and shunt capacitor removed, the total capacitance at the IN pin is approximately 0.25pF for the die-attached section and about 0.5pF for the QFN section. 2 ________________________________________________________________________________________ MAX3657 Evaluation Kit J10 3.3V TP13 TP14 L2 56nH GND TP19 JU5 TP10 DC_IN1 TP9 MON1 C8 1µF C9 1µF J26 IN1 Evaluate: MAX3657 R6 1kΩ VCC1 C17 10µF R5 10kΩ R7 499Ω 1 NC 2 GND 4 MON R38 499Ω C4 0.9pF R2 49.9Ω 3 GNDZ 5 IN Detail A C13 1µF 12 OUT- MAX3657EGG J27 OUT1R3 100Ω 11 NC J22 OUT1+ U1 6 FILT 10 OUT+ 7 VCCZ JU6 8 VCC C14 1µF 9 NC R4 100Ω VCC1 C5 .01µF Detail A: Optional Interface For Photodiode TO Header TP4 L30 56nH 3.3V TP6 VCC2 R102 4.99kΩ C99 10µF GND TP2 TP5 DC_IN2 JU3 C98 1µF J5 IN2 R100 10kΩ C96 1µF R98 49.9Ω R103 4.99kΩ 3 GNDZ TP8 MON2 2 GND 4 MON R99 4.99kΩ 5 IN C97 0.4pF JU4 C118 1µF J4 OUT2R120 100Ω MAX3657E/D J3 OUT2+ U2 6 FILT 7 NC 1 OUT- 8 VCCZ 9 VCC 10 OUT+ C119 1µF R121 100Ω VCC2 C100 .01µF Figure 1. MAX3657 EV Kit Schematic Diagram - QFN and Die-Attach Sections _________________________________________________________________________________________ 3 MAX3657 Evaluation Kit 4 MON Detail A 5 IN PD MAX3657EGG (U1) Evaluate: MAX3657 T0-46 CAN PHOTODIODE 6 FILT Figure 2. Photodiode Interface (QFN Section). C6 1µF J19 OUT3R34 100Ω TP11 3.3V TP18 L1 56nH OUT- GND U3 VCC3 VCC3 C3 10µF VCC J25 OUT3+ OUT+ C2 .01µF GND TP1 C15 1µF TP12 MON MON J23 OUT4R29 100Ω OUT- U4 VCC C23 .01µF R33 100Ω C27 1µF J16 R31 1kΩ VCC3 C7 1µF J24 OUT4+ OUT+ GND C24 1µF R28 100Ω Alternate Ground Point Figure 3. MAX3657 EV Kit Schematic Diagram - Optional TO-Header Interface (Assembly Required). 4 ________________________________________________________________________________________ MAX3657 Evaluation Kit Evaluate: MAX3657 Figure 4. MAX3657 EV Kit Component Placement Guide - Component Side Figure 5. MAX3657EV Kit PC Board Layout Solder Side _________________________________________________________________________________________ 5 Figure 6. MAX3657EV Kit PC Board Layout Ground Plane Figure 7. MAX3657EV 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. 6 ___________________ Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.