19-1911; Rev 0; 9/00 MAX1425 Evaluation Kit Features ♦ 20Msps Conversion Rate ♦ Clock Shaping Circuit ♦ On-Board TTL Buffers ♦ Wideband Transformer Accepts Single-Ended Input ♦ Fully Assembled and Tested Ordering Information PART MAX1425EVKIT TEMP. RANGE IC PACKAGE -40°C to +85°C 28 SSOP Component List DESIGNATION QTY DESCRIPTION C1, C4–C8, C15, C16, C20, C22, C25, C27, C30, C34, C35, C37 16 C2, C10 2 100pF ceramic capacitors (0805) C3, C9 2 22pF ceramic capacitors (0805) C11, C17, C18, C21, C26, C28, C29, C31, C32, C33 10 2.2µF, 10V capacitors Sprague 595D “A” case size C12, C13, C14, C23 4 100µF, 25V capacitors Sprague 595D “R” case size J1 1 2x10-pin header DESIGNATION QTY DESCRIPTION R4, R5 2 25Ω ±5% resistors (1206) R6, R7, R8 3 51Ω ±5% resistors (1206) R9 1 2.5kΩ ±5% resistor (1206) R10 1 2.5kΩ ±5% resistor (0805) R11 1 1kΩ ±5% resistor (0805) R12 1 4kΩ ±5% resistor (0805) R13–R33 21 200Ω ±5% resistors (0805) R34 1 2kΩ potentiometer R36 1 3kΩ ±5% resistor (0805) R37 1 100Ω ±5% resistor (1206) T1 1 Transformer Minicircuits T1-1T-KK81 U1 1 Maxim MAX1425EAI U2, U3 2 74ALS541A 0.1µF ceramic capacitors (0805) REF IN, IN1, CLK IN 3 SMA connectors JU1 1 2-pin header JU2 1 3-pin header R1 1 2kΩ ±5% resistor (0805) U4 1 Maxim MAX473ACSA R2, R3, R35, R38 4 100Ω ±5% resistors (0805) U5 1 Maxim MAX961CSA ________________________________________________________________ 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: MAX1425/MAX1426 General Description The MAX1425 evaluation kit (EV kit) is an assembled and tested board for prototyping designs using the MAX1425 or MAX1426 analog-to-digital converters (ADCs). The board interfaces to a user-provided logic analyzer or data-acquisition system. An external clock generator and +5V power supply are required. Evaluates: MAX1425/MAX1426 MAX1425 Evaluation Kit _________________________Quick Start You’ll need the following required equipment: • DC power supplies: 2 each (use for digital +5V and analog +5V) • Function generator for clock input, 2Vp-p • Function generator for signal input, 2Vp-p • Logic analyzer or data-acquisition system • Voltage reference (optional) Note: To ensure maximum performance, use a clock generator with low phase noise, such as the HP 8662A filtered with an appropriate bandpass filter. The MAX1425 EV kit is fully assembled and tested. Follow these steps to verify board operation. Do not turn on the power supply until all connections are complete. 1) Connect one +5V DC power supply to +5VA and +5VADUT. Connect the negative terminal of this supply to AGND. Connect the second +5V supply to +5VDDUT and +5VD. Connect the negative terminal of the second supply to DGND. See Table 1. 2) If using an external reference, connect a 2.500V ±1mV voltage reference to the REF IN connector. If using the internal reference, do not connect anything to the REF IN connector. 3) Connect a 20MHz, 1Vp-p clock function generator to the CLK IN connector. 4) Connect the signal function generator to the IN1 connector. used with a user-supplied data-acquisition system. Jumper JU2 selects the polarity of the J1 strobe signal. The analog input signal from the IN1 connector is terminated by R2/R3 and coupled through transformer T1. The transformer converts the single-ended input into a differential signal between VINP and VINN, with commonmode voltage set by the CML pin and buffered by U4. The device under test, U1, samples analog input VINPVINN. Its digital outputs are buffered by U2 and U3 (74ALS541). The twenty 200Ω series resistors help isolate the A/D converter from switching transients. The buffered digital outputs appear on connector J1. Performance Considerations Careful attention to setup and testing is necessary to achieve optimum results with this high-performance converter. Precise and accurate phase-locked signal sources should be employed in all cases. Low jitter sources, such as the HP 8664B for the input phaselocked with a second low-jitter clock generator, will give the best results. In addition, lowpass or bandpass filters should be used on the input signal to ensure that the MAX1425’s low-distortion characteristics are maintained. Table 1. Power Connections TERMINAL FUNCTION +5VA Analog Supply to the Signal Conditioning Op Amps +5VADUT Analog Supply to the Device Under Test 5) Connect a logic analyzer (e.g. HP16500C) or dataacquisition system to header J1. Configure jumpers JU1 and JU2 as shown in Table 2. 6) Turn on the power supplies and reference supply (if used). +5VDDUT Digital Supply to the Device Under Test 7) Enable the function generators. Adjust potentiometer R34 so that the strobe signal has 50% duty cycle. +5VD Digital Supply to the Digital Buffers AGND Analog Ground Return DGND Digital Ground Return 8) Begin acquiring digital data. Detailed Description of the Hardware The MAX1425 EV kit is a proven PC board layout pattern that gives good analog performance. Refer to the MAX1425 data sheet for more information. The clock signal from the CLK IN connector is terminated by R35/R38 and AC-coupled by C16 into U5, the MAX961 comparator. Potentiometer R34 sets the clock threshold. Comparator U5 produces a square-wave output, driving the MAX1425 and providing a clock output (J1-20) to be 2 Table 2. Jumper Settings JUMPER JU1 SETTING FUNCTION Open Output Enable = low (enabled) Closed Output Enable = high (disabled) 1-2 (bottom position) STROBEIN polarity is the same as CLK 2-3 (top position) STROBEIN polarity is the opposite of CLK JU2 _______________________________________________________________________________________ IN1 J2 C7 0.1µF C5 0.1µF C6 0.1µF C8 0.1µF CLK J4 J12 +5VDDUT D5 10 VINN CLK STROBE IN CLK IN SEE CLOCK INTERFACE PAGE +5VADUT R8 51Ω R7 51Ω R1 2k D9 14 OE/PD C24 50pF C19 50pF JU1 D8 D6 DGND 9 VINP 11 CMLP DGND DVDD DVDD D4 D3 D2 D7 C17 2.2µF 10V MAX1425 7 AGND 1 AGND 2 AV DD 8 AV DD 5 REFN 6 CML D1 3 REFP U1 D0 AGND J7 4 REFIN +5VD J9 13 CLK C14 100µF 25V +5VA J6 INN C4 0.1µF C11 2.2µF 10V C28 2.2µF 10V C18 2.2µF 10V +5VD C23 100µF 25V 12 CMLN C37 0.1µF C27 0.1µF +5VA INP CML C10 100pF C2 100pF REF IN C13 100µF +5VDDUT J5 25V IN1 SEE ANALOG INTERFACE PAGE +5VADUT AGND +5VDDUT J11 C12 +5VADUT 100µF 25V 15 16 17 18 19 23 21 22 20 24 25 26 27 28 R31 200Ω R24 200Ω R25 200Ω R26 200Ω R28 200Ω C21 2.2µF 10V 200Ω R30 R27 200Ω C20 0.1µF 200Ω R29 200Ω R32 R33 200Ω DGND J10 C1 0.1µF DGND 2 3 4 5 6 7 8 9 1 19 2 3 4 5 6 7 8 9 +5VDDUT C29 2.2µF 10V 1 19 U3 Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7 18 17 16 15 14 13 12 11 20 VCC 10 GND 0.1µF +5VD U2 Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7 18 17 16 15 14 13 12 11 20 VCC 10 GND 0.1µF 74ALS541A A0 A1 A2 A3 A4 A5 A6 A7 OE1 OE2 C35 +5VD 74ALS541A C26 2.2µF 10V A0 A1 A2 A3 A4 A5 A6 A7 OE1 OE2 C34 C31 2.2µF 10V R13 200Ω R14 200Ω R15 200Ω R16 200Ω R17 200Ω R18 200Ω R19 200Ω R20 200Ω R21 200Ω R22 200Ω R23 200Ω J1-20 J1-19 J1-17 J1-15 J1-13 J1-11 J1-9 J1-7 J1-5 J1-3 J1-1 J1-18 J1-16 J1-14 J1-12 J1-10 J1-8 J1-6 J1-4 J1-2 Evaluates: MAX1425/MAX1426 +5VADUT MAX1425 Evaluation Kit Figure 1. MAX1425 EV Kit Schematic _______________________________________________________________________________________ 3 Evaluates: MAX1425/MAX1426 MAX1425 Evaluation Kit +5VA C30 0.1µF R10 2.5k U4 3 7 MAX473A 6 2 4 AGND R6 51Ω C15 0.1µF R9 2.5k R4 25Ω C3 22pF IN1 R2 100Ω N.C. R3 100Ω 1 6 2 5 3 4 INP MINICIRCUITS T1-1T-KK81 C9 22pF R5 25Ω +5VA +5VA C32 2.2µF 10V R37 100Ω R34 2k C25 0.1µF C33 2.2µF 10V C22 0.1µF 1 R36 3k +5VA R38 100Ω C16 0.1µF 8 U5 VCC GND JU2 3 2 7 6 3 5 R12 4k AGND Figure 1. MAX1425 EV Kit Schematic (continued) 4 STROBEIN 1 Q Q SHDN 2 CLK IN 4 LE MAX961 R11 1k R35 100Ω INN _______________________________________________________________________________________ CLK MAX1425 Evaluation Kit Evaluates: MAX1425/MAX1426 Figure 2. MAX1425 EV Kit Component Placement Guide—Component Side Figure 3. MAX1425 EV Kit Component Placement Guide—Reverse Side _______________________________________________________________________________________ 5 Evaluates: MAX1425/MAX1426 MAX1425 Evaluation Kit Figure 4. MAX1425 EV Kit PC Board Layout—Layer 1 Figure 5. MAX1425 EV Kit PC Board Layout—Layer 2 6 _______________________________________________________________________________________ MAX1425 Evaluation Kit Evaluates: MAX1425/MAX1426 Figure 6. MAX1425 EV Kit PC Board Layout—Layer 3 Figure 7. MAX1425 EV Kit PC Board Layout—Layer 4 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. 7 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.