19-1763; Rev 1; 10/01 MAX3781 Evaluation Kit Features ♦ Fully Assembled and Tested ♦ +3.3V Operation ♦ On-Board Output Termination ♦ Easy Selection of Operating Modes Ordering Information Component List DESIGNATION QTY PART TEMP RANGE IC PACKAGE MAX3781EVKIT 0°C to +85°C 48 TQFP-EP* DESCRIPTION C1−C24, C27−C30 28 0.1µF ±10%, 25V min ceramic capacitors (0603) C25 1 33µF tantalum capacitor (C) C26 1 2.2µF ±10%, 25V min tantalum capacitor (B) R1, R2, R3 3 1kΩ ±1% resistors (0603) R4−R9 6 100Ω ±1% resistors (0603) L1 1 4.7nH inductor TOKOLL1608-FH4N7K SUPPLIER AVX PHONE 803-946-0690 FAX 803-626-3123 U1 1 MAX3781UCM 48-pin TQFP-EP TOKO 800-745-8656 847-699-7864 J1–J24 24 SMA connectors (PC mount) EFJohnson 142-0701-301 JU1, JU2, JU3 3 2-pin headers (0.1in centers) Digi-Key S1012-36-ND JU1, JU2, JU3 3 Shunts Digi-Key S9000-ND VCC, GND 2 Test points Digi-Key 5000-ND 1) Apply +3.3V to the VCC pin. Connect power-supply ground to the GND pin. None 1 MAX3781 EV kit circuit board, rev A None 1 MAX3781 data sheet 2) Shunt jumpers JU1 (SELA), JU2 (PD), and JU3 (SELB). Refer to Table 1 in the MAX3781 data sheet for other configurations. *Exposed pad Component Suppliers Note: Please indicate that you are using the MAX3781 when contacting these component suppliers. Quick Start 3) Apply up to 2.75Gbps differential data to LI2A± (J17 and J18). 4) Remove R9 (differential termination resistor) from the evaluation board. 5) Connect SOA± (J23 and J24) to a high-speed 50Ω oscilloscope. ________________________________________________________________ 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: MAX3781 General Description The MAX3781 evaluation kit (EV kit) is an assembled demonstration board that provides easy evaluation of the MAX3781 multiplexer/buffer. The MAX3781 EV kit provides 100Ω differential output terminations onboard, simplifying termination of unused outputs. Evaluates: MAX3781 MAX3781 Evaluation Kit Detailed Description Connecting CML Outputs to 50Ω Oscilloscopes CML outputs have a common-mode voltage near VCC. To avoid changing this optimum common-mode voltage, all CML outputs are AC-coupled on-board with 0.1µF capacitors. The CML outputs should not be connected directly through 50Ω to ground. Terminating Unused Outputs The MAX3781 EV kit has 100Ω differential resistors placed across all outputs. These resistors must be removed before connecting the outputs to a 50Ω oscilloscope. For best performance, keep all outputs terminated, either to a 50Ω measurement device or to the 100Ω differential resistor. 2 Control Lines Jumpers JU1, JU2, and JU3 are provided to set the operating mode of the MAX3781. Shorting these jumpers pulls the corresponding TTL control line to a logical zero. All TTL control lines are internally pulled high through 15kΩ resistors. See Table 1 for more information regarding setting operating modes. Exposed-Pad Package The exposed paddle (EP) 48-pin TQFP has features that provide a very low thermal resistance path for heat removal from the IC. The paddle is electrical ground on the MAX3781 and should be soldered to the circuit board for proper thermal and electrical performance. Table 1. Operating Modes SEL_ PD LO1_ LO2_ SO_ 0 0 SI_ SI_ LI2_ 0 1 − SI_ LI2_ 1 0 SI_ SI_ LI1_ 1 1 SI_ − LI1_ _______________________________________________________________________________________ MAX3781 Evaluation Kit J23 C23 0.1µF J30 VCC VCC J4 C4 0.1µF SELB GND SIB+ SIBVCC GND 9 10 11 12 VCC GND LO2A- VCC LO2A+ LO1A- VCC LO1A+ VCC VCC SIA+ SELA PD MAX3781 LI1BLI1B+ VCC LI2B+ LI2B- 36 35 34 33 32 31 30 29 28 27 26 25 GND J3 SIA- VCC C3 0.1µF LI2ALI2A+ VCC LI1A+ LI1AGND GND LO2B- JU2 JU3 J28 J26 VCC LO2B+ C2 0.1µF GND VCC VCC J2 1 2 3 4 5 6 7 8 LO1B- R3 1kΩ VCC J25 CALIBRATION STRIP R7 100Ω VCC VCC LO1B+ R2 1kΩ VCC VCC J1 JU1 J27 48 47 46 45 44 43 42 41 40 39 38 37 C1 0.1µF R1 1kΩ C19 0.1µF R8 100Ω R9 100Ω C30 0.1µF C20 0.1µF VCC C29 0.1µF SOA- C28 0.1µF VCC C27 0.1µF J19 J20 C22 0.1µF SOB- C26 2.2µF SOA+ C25 33µF SOB+ J29 J21 C21 0.1µF C24 0.1µF VCC L1 4.7nH J22 Evaluates: MAX3781 J24 13 14 15 16 17 18 19 20 21 22 23 24 VCC VCC C18 0.1µF J18 J17 VCC C17 0.1µF C16 0.1µF J16 J15 C15 0.1µF C14 0.1µF J14 VCC C13 0.1µF J13 C12 0.1µF J12 J11 C11 0.1µF VCC VCC R4 100Ω R5 100Ω C6 0.1µF C5 0.1µF J5 C8 0.1µF R6 100Ω C9 0.1µF C7 0.1µF J6 J7 C10 0.1µF J8 J9 J10 Figure 1. MAX3781 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX3781 MAX3781 Evaluation Kit 1.0" Figure 2. MAX3781 EV Kit Component Placement Guide—Component Side 4 _______________________________________________________________________________________ MAX3781 Evaluation Kit Evaluates: MAX3781 1.0" 1.0" Figure 3. MAX3781 EV Kit PC Board Layout—Component Side 1.0" Figure 4. MAX3781 EV Kit PC Board Layout—Solder Side 1.0" Figure 5. MAX3781 EV Kit PC Board Layout—Power Plane Figure 6. MAX3781 EV Kit PC Board Layout—Ground 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. 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