DESCRIPTION Demonstration circuit 7A features the LTC 9 Dual Differential Amplifier/ADC Driver. It incorporates a variety of passive components to support configurations for varied applications. These fully-differential amplifiers accept single-ended or differential input with almost no difference in distortion performance. The LTC9 is a high speed dual differential amplifier with superior distortion and low noise, suitable for demanding communications transceivers, cellular base-stations and other high speed signal chain applications. ADDITIONAL INFORMATION The DC7A demo board is ready for use as-is and is designed for ease of use and with minimum modification. The demo board has features that can be accessed by adding, removing or changing components on the board to configure for single-ended and/or differential inputs and outputs. By default, the board is configured to have dual single-ended inputs with transformers, J (IN ) and J (IN ) and dual single-ended outputs with transformers, J (OUT ) and J7 (OUT ). Each of these ports is matched to 5Ω impedance to facilitate direct connections to test equipment. Driving the Inputs DC-Coupled It is possible to configure the DC7A inputs differentially with DC coupling. Transformers and components at locations T, T, C, C, C and C7 connections should be replaced with Ω resistors. The inputs are now DC-coupled and can be driven single-ended or differentially (resistor values may be changed to balance the source impedances). Changing the Output Common-Voltage The turrets marked VOCM and VOCM (E and E) control the output (and input, if AC-coupled) common mode voltage of the DC7A. This function can be used to level-shift the DC output voltage for optimum system performance. If used for this purpose, output capacitors DEMO MANUAL DC7A LTC9 Dual Differential Amplifier/ADC Driver C, C7, C and C8 can be replaced by Ω resistors to allow the DC bias to reach the outputs. By default, VOCMA and VOCMB are self-biased and float to a typical.5v on each of the common-mode pins (with V + = 5V). The VOCMA and VOCMB voltage of the two amplifiers can be set independently with external DC supply voltage source, or on board voltage dividers R8/ R9 and R7/R8. Enable (Shutdown) Jumpers JP and JP control the enable functions of amplifiers A and B. When set to the EN position, the part will be on and draw normal operating current. In the DIS position, the part will be in shutdown and draw a very small amount of leakage current. Ground and V CC Connections DC7A GND turret is not only connected to V of the LTC9, it also serves as the demo board s ground. For best result, a low impedance return path to the power supply from GND is recommended. Short, low impedance wires to the V + and GND connectors of DC7A will yield the best performance from the LTC9. Schematic Notes For a 5Ω external load, transformer T or T and the series Ω resistors (R7, R9 or R, R8) present each amplifier with a Ω load impedance. These resistors produce a db voltage drop when driving loads. Because the unmodified amplifier has db voltage gain, and each transformer adds approximately db insertion loss, the total unmodified demo board will measure approximately 8dB insertion loss from the input port (J or J) to the output port (J or J7). Design files for this circuit board are available at http://www.linear.com/demo/dc7a L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. dc7af
DEMO MANUAL DC7A QUICK START PROCEDURE Table shows the function of each SMA connector on the board. Refer to Figure for the connection diagram and follow the procedure below:. Connect the power supply as shown. The power labels of V + and GND directly correspond to the power supply. Typical current consumption of LTC9 is about ma for both amplifiers. Jumpers JP and JP enable or shut down the amplifier A and amplifier B, respectively.. Apply input signal or network analyzer to J (IN ) or J (IN ). DC7A s input is impedance matched to 5Ω.. Observe the output via J (OUT ) or J7 (OUT ). The output is impedance matched to 5Ω, suitable for the input of a network or spectrum analyzer. Table shows the function of each input and output on the board. Table. DC7A Board I/O Descriptions CONNECTOR J (IN + )/J (IN ) J (IN )/J8 (IN + ) J (OUT )/J (OUT + ) J5 (OUT + )/J7(OUT ) E (VCM), E (VCM) E (VOCM), E (VOCM) E5 (V + ) E8 (GND) FUNCTION Can be configured to either single-ended or differential input. Can be configured to either single-ended or differential output. With proper impedance matching, the device can be used to drive a network analyzer, spectrum analyzer or an ADC. The input common mode voltage. Leave open if unused. Output common mode adjust. By default, these pins are self-biasing within UA and UB. Leave open if unused. Positive Supply voltage source Supply Ground dc7af
DEMO MANUAL DC7A QUICK START PROCEDURE NETWORK ANALYZER POWER SUPPLY V + GND NETWORK ANALYZER V + =.7V TO 5.5V dc7a F Figure. Proper Equipment Setup for Frequency Response Measurement dc7af
DEMO MANUAL DC7A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER C, C8, C, C9 CAP., CG,.pF, 5V, ±.pf, MURATA, GJM5CERBB 9 C, C, C, C5, C, C7, C9, C, C, CAP., X7R,.µF, V, %, AVX, YCKA C, C, C5, C, C7, C8, C, C, C, C C CAP., CG, pf, 5V, 5%, MURATA, GRM555CEJA C CAP., X7R, pf, 5V, %, MURATA,GRM5AR7HKA8 5 C5 CAP., X7R,.µF, 5V, %, MURATA, GRM55R7EKA C7 CAP., X5R,.7µF, 5V, %, MURATA, GRM55RE7KE 7 C9 CAP., X5R, µf, 5V, %, 85 MURATA, KRMEREKFA 8 E, E, E, E, E5, E8 TESTPOINT, TURRET,. MILL-MAX, 8---8---7-9 JP, JP CONN., HEADER,, mm SULLINS, NRPNPAEN-RC XJP, XJP SHUNT, mm SAMTEC, SN-BK-G 8 J-J8 CONN., SMA, 5Ω, EDGE-LANCH E. F. JOHNSON, -7-85 8 R, R, R8, R, R, R5, R7, R RES., CHIP, 5Ω /W,.%, YAGEO, RTBRE75RL R, R, R5, R, R, R5, R, R, RES.,, R, R, R, R5 R, R, R, R9 RES., Ω, VISHAY, CRCWZED 5 R7, R9, R, R8 RES., Ω, /W, %, VISHAY, CRCWRFKEA R, R, R, R RES., Ω, /W, %, VISHAY, CRCWRFKEA 7 R7, R RES., Ω, /W, %, VISHAY, CRCWRFKEA 8 R8, R9, R7, R8 RES.,, 9 T, T, T, T RF TRANS., 5Ω, MHz 9MHz, TCM-9 MINI CIRCUITS, TCM-9+ U IC., DUAL ADC DRIVER, -PIN LGA, LINEAR TECH., LTC9IV#PDF dc7af
5 5 DEMO MANUAL DC7A SCHEMATIC DIAGRAM IN- R 5.% C.pF R5 R UA R OUT- R LTC9 J D D : Xfmr by Mini-Circuits : Xfmr by Mini-Circuits C R7 R 5.% C IN+ Pd S C 8 +INA -OUTA 7 C5 Sd P J P CT VCMA CT Pd OUT+ Sd -INA +OUTA S R8 5.% R9 C7 T TCM-9 C T TCM-9 R J R R R R5 IN- J R C9 C.pF C8 R7 VCM E C R8 C JP C VCM E R9 R 5.% SHDN DIS EN R 5.% OUT- J R : Xfmr by Mini-Circuits S Pd CT P Sd T TCM-9 R : Xfmr by Mini-Circuits R R R IN+ C9.pF J8 R9 C C B B R 5.% UB LTC9 9 7 -INB VCMB +INB +OUTB -OUTB R J7 8 -FBB SHDNB V- +FBB 5 B V- +FBA SHDNA V- -FBA 9 A 5 R C5 C C7 R R5 R7 5.% 5.% C.pF R R R8 C C C8 Sd CT S T TCM-9 P Pd R5 J5 OUT+ VCM VCM E E R8 SHDN C DIS EN R7 JP.7V-5.5V E5 McCarthy Blvd. C9 C C C5 C C7 CUSTOMER NOTICE A uf pf pf.uf.7uf APPROVALS Milpitas, CA 955 A 85 LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A Phone: (8)-9 www.linear.com CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; TECHNOLOGY Fax: (8)-57 HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO PCB DES. VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL AK LTC Confidential-For Customer Use Only GND E8 APPLICATION. COMPONENT SUBSTITUTION AND PRINTED APP ENG. TITLE: CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT JOHN C. SCHEMATIC PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. DUAL DIFFERENTIAL AMPLIFIERS/ADC DRIVERS NOTES: UNLESS OTHERWISE SPECIFIED, SIZE IC NO. LTC9 REV.. ALL CAPACITORS AND RESISTORS ARE N/A THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND DEMO CIRCUIT 7A SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. SCALE = NONE DATE: Thursday, December 5, SHEET OF Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. dc7af 5
DEMO MANUAL DC7A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user s responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology McCarthy Blvd. Milpitas, CA 955 Copyright, Linear Technology Corporation LT 7 PRINTED IN USA Linear Technology Corporation McCarthy Blvd., Milpitas, CA 955-77 (8) -9 FAX: (8) -57 www.linear.com LINEAR TECHNOLOGY CORPORATION 7 dc7af