DC1716A LTC2473: Selectable 240sps/1ksps 16-Bit, Differential, ADC with I2C Interface DESCRIPTION Demonstration circuit 1716A features the LTC2473, a 16-bit high performance ΔΣ analog-to-digital converter (ADC) with an I2C interface. The input is differential with a range of ±VREF. The modulator’s proprietary sampling technique reduces the average input current to less than 50nA–orders of magnitude lower than typical delta sigma ADCs. DC1716A is a member of Linear Technology’s QuikEval™ family of demonstration boards. It is designed to allow easy evaluation of the LTC2473 and may be connected directly to the target application’s analog signals while using the DC590 USB serial controller board and supplied software to measure performance. The exposed ground planes allow proper grounding to prototype circuitry. After evaluating with Linear Technology’s software, the digital signals can be connected to the end application’s processor/controller for development of the serial interface. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and QuikEval is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. RIBBON CABLE TO DC590 INPUTS DC1716A F01 Figure 1. Proper Measurement Equipment Set-Up dc1716af 1 DC1716A QUICK START PROCEDURE Connect DC1716A to a DC590 USB serial controller using the supplied 14 conductor ribbon cable. Connect DC590 to host PC with a standard USB A/B cable. Run the QuikEval evaluation software supplied with DC590 or downloaded from http://www.linear.com/software. The correct program will be loaded automatically. Click the COLLECT button to start reading the input voltage. Details on software features are documented in the control panel’s help menu. Tools are available for logging data, changing reference voltage, changing the number of points in the strip chart and histogram, and changing the number of points averaged for the DVM display. Figure 2. Software Screenshot dc1716af 2 DC1716A HARDWARE SET-UP CONNECTION TO DC590 SERIAL CONTROLLER J1 is the power and digital interface connector. Connect to DC590 serial controller with supplied 14 conductor ribbon cable. ANALOG CONNECTIONS Analog signal connections are made via the row of turret posts along the edge of the board. Also, when connecting the board to an existing circuit the exposed ground planes along the edges of the board may be used to form a solid connection between grounds. GND: This turret is connected directly to the internal ground planes. VCC: This is the supply and reference voltage for the ADC. Do not draw any power from this point. IN+: This is the positive input to the ADC. The maximum differential voltage between IN+ and IN– is ±1.25V. IN–: This is the negative input to the ADC REFOUT: This turret is connected to the LTC2473 REFOUT pin. This pin may be used to provide a reference voltage to an external circuit and can source up to 100µA. Do NOT drive this pin. This pin is normally at 1.25V. dc1716af 3 DC1716A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER 1 2 7 C1 to C5, C7, C8 CAP, 0402 0.1µF 20% 16V X7R MURATA, GRM155R71C104KA88D 1 C6 CAP, 0603 10µF 20% 6.3V X5R MURATA, GRM188R60J106ME47D 3 5 E1, E2, E3, E4, E5 TURRET MILL MAX, 2308-2-00-80-00-00-07-0 4 1 JP1 HEADER, 3-PIN, 2mm SAMTEC, TMM-103-02-L-S 5 1 J1 HEADER, 2×7 2mm MOLEX, 87831-1420 6 2 R1, R5 RES, 0402 1k 5% 1/16W YAGEO, RC0402JR-071KL 7 3 R2, R3, R4 RES, 0402 4.99k 1% 1/16W YAGEO, RC0402FR-074K99L 8 1 U1 IC, 16-BIT ADC W/ INTEGRATED PRECISION REFERENCE LINEAR TECHNOLOGY, LTC2473CDD#PBF 9 1 U2 IC, IC SERIAL EEPROM 2k MICROCHIP TECH., 24LC025-I/ST dc1716af 4 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. A B C GND VCC IN- IN+ REFOUT E4 E3 E5 E1 E2 5 VCC 1K R5 1K R1 C3 0.1uF 0.1uF 0.1uF C8 C7 C2 0.1uF 10 9 SDA SCL 3 2 1 JP1 0 A0 1 VCC 6 1% 1% 4 3 R3 4.99K R2 4.99K 10uF 0.1uF 5 C6 C4 IN- IN+ VCC U1 LTC2473CDD 0.1uF C1 12 D 1 REFOUT 2 COMP GND GND GND 13 11 7 4 VCC REF8 A0 3 3 1 2 3 7 6 A0 A1 A2 WP SCL 1 REV 8 5 1% R4 4.99K TECHNOLOGY 0.1uF C5 VCC FIRST PROTOTYPE DESCRIPTION LEO C. NC EEGND EESDA EEVCC EESCL MISO MOSI/SDA SCK/SCL CS 5V VUNREG J1 DATE 06/02/10 APPROVED 1 LTC2473CDD 2 1 1 DEMO CIRCUIT 1716A Wednesday, June 02, 2010 N/A 1 1 16-BIT DIFFERENTIAL DELTA SIGMA I2C ADC 14 12 9 10 11 5 7 4 6 2 1 REVISION HISTORY U2 24LC025-I/ST SDA ECO 2 GND 3 4 GND 8 VCC GND 4 GND 13 5 A B C D DC1716A SCHEMATIC DIAGRAM dc1716af 5 DC1716A 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 30 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 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright © 2004, Linear Technology Corporation dc1716af 6 Linear Technology Corporation LT 0311 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2011