DEMO MANUAL DC1011A LTC2498, LTC2496, LTC2494 24-bit/16-bit, 8-/16-Channel, Easy Drive S ADC with SPI Interface Description Demonstration Circuit 1011A-A features the LTC(R)2498 8-/16-channel, 24-bit Delta Sigma ADC with Easy DriveTM inputs. Key DC specifications include 2ppm INL, 1ppm offset, 25ppm full-scale error and 10nV/C offset drift. In the 6.9Hz/280nVRMS mode, input normal mode rejection of 50Hz and 60Hz noise is better than 87dB. DC1011A-B features the LTC2496 16-bit ADC that is pinout and software compatible with the LTC2498. DC1011A-C features the LTC2494 16-bit ADC with internal PGA and temperature sensor. DC1011A is a member of Linear Technology's QuikEvalTM family of demonstration boards. It is designed to allow easy evaluation of the LTC2498, LTC2496 or LTC2494 and may be connected directly to the target application's analog signals while using the DC590 USB Serial Controller board and QuikEval software to measure performance. The exposed ground planes allow proper grounding to prototype circuitry. After evaluating with LTC's software, the digital signals can be connected to the 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 Easy Drive and QuikEval are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Figure 1. Proper Measurement Equipment Setup dc1011af 1 DEMO MANUAL DC1011A Quick Start Procedure Connect the DC1011A 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 evaluation software supplied with DC590 or downloaded from www.linear.com/software. The correct program will be loaded automatically. Click the COLLECT button to start reading the input voltage. Click the slider at the bottom of the strip-chart display to change the oversample ratio (OSR) which will in turn change the data output rate. 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. Hardware Setup Jumpers Connection to DC590 Serial Controller JP1, JP3: Select the source for REF+ and REF-, respectively. REF+ can be 5V from the on-board LT1236 reference (default) or supplied externally. REF- can be Ground (0V, default) or supplied externally. J2 is the power and digital interface connector. Connect to a DC590 serial controller with the supplied 14-conductor ribbon cable. Digital signals are also connected to throughhole test points on the circuit board. JP2: Select source for analog COM input, either tied to ground or supplied externally to the COM turret post. dc1011af 2 DEMO MANUAL DC1011A Hardware Setup Analog Connections Analog signal connections are made via the row of turret posts along the edge of the board. Also, if you are 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: Ground turrets are connected directly to the internal analog ground plane. PWR GND: Power ground, connected to the power return trace. VCC: This is the supply for the ADC. Do not draw any power from this point. External power may be applied to this point after disabling the VCC supply on DC590. See the DC590 quick start guide for details. REF+, REF-: These turrets are connected to the LTC2496/2498/2494 REF+ and REF- pins. If the onboard reference is being used, the reference voltage may be monitored from this point. An external reference may be connected to these terminals if JP1 and JP3 are configured for external reference. Note: The REF+ and REF- terminals are decoupled to ground with 0.1F and 10F capacitors in parallel. Thus any source connected to these terminals must be able to drive a capacitive load and have very low impedance at DC. Examples are series references that require an output capacitor and C-load stable op amps such as the LT1219 and LT1368. CH0 to CH15: These are the differential inputs to the LTC2496/2498/2494. They may be configured either as single-ended inputs with respect to the COM pin, or adjacent pairs may be configured as differential inputs (CH0-1, CH2-3, etc.) Experiments Input Noise Input Normal Mode Rejection Solder a short wire between the CH0 and CH1 turrets. Connect the inputs to ground through a short wire and start taking data. LTC2498 Noise should be approximately 0.12ppm of 5V (600nVRMS). The electrical noise of the LTC2496 is also 600nVRMS, however this is masked by the 76.3V quantization level. If the input is midway between code transitions, the noise level will read zero. If the input is exactly on a code transition such that the two adjacent output codes have equal probability, the noise level will be approximately 7.9ppm. The LTC2498's SINC4 digital filter can be software selected to reject 50Hz, 60Hz by 120dB, or both 50Hz and 60Hz by 87dB. The LTC2496's SINC4 filter is fixed at 50/60Hz. To measure input normal mode rejection, connect COM to a 2.5V source such as an LT1790-2.5 reference or a power supply. Connect any other input (CH0 to CH15) to the same supply through a 10k resistor. Apply a 10Hz, 2V peak-to-peak sine wave to the input through a 1F capacitor. Common Mode Rejection Tie the two inputs (still connected together from previous experiment) to ground through a short wire and note the indicated voltage. Tie the inputs to REF+; the difference should be less than 5V due to the 120dB+ CMRR of the LTC2498. The LTC2496 will produce less than 1LSB difference. Set the rejection frequency to 55Hz (LTC2498 only) and start taking data. The input noise will be quite large, and the graph of output vs time should show large variations. Next, slowly increase the frequency to 55Hz. The noise should be almost undetectable in the graph. Note that the indicated noise in ppm may still be above that of the data sheet specification because the inputs are not connected to a DC accurate source. dc1011af 3 DEMO MANUAL DC1011A Parts List ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER CAP., CHIP X7R 0.01F 16V AVX, 0603YC103KAT1A 0603 Required Circuit Components 1 4 C3, C7, C10, C13 2 2 C11, C15 CAP., CHIP X7R 0.1F 16V 10% AVX, 0603YC104MAT1A 0603 3 1 C29 CAP., CHIP X5R 1F 10V TAIYO YUDEN, LMK107BJ105KA 0603 4 3 C2, C9, C12 CAP., CHIP X5R 4.7F 6.3V TAIYO YUDEN, JMK212BJ475MG 0805 CAP., CHIP X5R 10F 6.3V 5 1 C8 6 25 TP1-TP6, TP8, TP10-TP12, TP14-TP27, TP31 TURRET, TESTPOINT 0.064" 7 0 TP7, TP9, TP13, TP28-TP30, TP32-TP35 TDK, C2012X5R0J106M 0805 MILL-MAX, 2308-2 OPT. (SURFACE MOUNT PAD ONLY) 8 3 JP1-JP3 HEADER, 3-PIN 1 ROW 0.079CC SAMTEC, TMM-103-01-LD 9 3 FOR ( JP1-JP3) SHUNT, 0.079" CENTER SAMTEC, 2SN-BK-G 10 1 J2 HEADER, VERTICAL DUAL 2X7 0.079CC MOLEX, 87831-1420 11 2 R1, R2 RES., CHIP 0 VISHAY, CRCW06030000Z0EA 12 1 R6 RES., CHIP 100 5% AAC, CR16-101JM 0603 13 3 R8, R9, R10 RES., CHIP 4.99k 1% AAC, CR16-4991FM 0603 14 1 R12 RES., CHIP 10k 5% AAC, CR16-103JM 0603 15 1 U4 I.C., PRECISION REFERENCE SO8 LINEAR TECH., LT1236ACS8-5#PBF 16 1 U3 I.C., SERIAL EEPROM, TSSOP-8 MICROCHIP, 24LC025-I/ST (PbF) U1 I.C., 24-BIT 8-/16-CHANNEL DELTA SIGMA ADCs LINEAR TECH., LTC2498CUHF 38QFN U1 I.C., 16-BIT 8-/16-CHANNEL DELTA SIGMA ADCs LINEAR TECH., LTC2496CUHF 38QFN U1 I.C., 16/PGA 8-/16-CHANNEL DELTA SIGMA ADCs LINEAR TECH., LTC2494CUHF 38QFN DC1011A-A 1 1 DC1011A-B 1 1 DC1011A-C 1 1 dc1011af 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. D C B 1 NOTES: C15 0.1uF V+ REF- REF+ COM CH15 CH14 CH13 CH12 CH11 CH10 CH9 CH8 CH7 CH6 CH5 CH4 CH3 CH2 2 VIN VOUT U4 LT1236ACS8-5 TP24 TP22 TP21 TP19 TP18 TP17 TP16 TP15 TP14 TP12 TP11 TP10 TP8 TP6 TP5 TP4 TP3 61 5V TP2 2 2 3 JP1 REF+ Ext. 1 3 JP2 COM C29 1uF LTC2496CUHF LTC2494CUHF DC1011A-B DC1011A-C 3 U1 LTC2498CUHF Table REF- REF+ COM CH15 CH14 CH12 CH11 CH10 CH9 CH13 CH8 CH7 CH6 CH5 CH4 CH3 CH2 CH1 CH0 4 16/PGA 16 24 Bits 30 29 C13 0.01uF DC1011A-A 3 JP3 REF- C12 4.7uF 6.3V C10 0.01uF ASSEMBLY 1 C9 4.7uF 6.3V 7 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 U1 (See Table) C2 4.7uF 6.3V GND 3 TP1 VCC GND SCK SDO CS FO SDI NC MUXOUTP ADCINP ADCINN MUXOUTN C3 0.01uF 39 38 37 36 35 34 2 24 25 26 27 5 5 R6 100 R2 0 R1 0 FO MUXOUTP ADCINP ADCINN MUXOUTN CS SCK TP32 6 Linear Technology Has Made A Best Effort To Design A Circuit That Meets Customer-Supplied Specifications; However, It Remains The Customer's Responsibility To Verify Proper And Reliable Operation In The Actual Application. Component Substitution And Printed Circuit Board Layout May Significantly Affect Circuit Performance Or Reliability. Contact Linear Technology Applications Engineering For Assistance. This Circuit Is Proprietary To Linear Technology And Supplied For Use With Linear Technology Parts. Customer Notice SDI TP34 7 TP28 SDA SCL WP VCC 4 3 2 1 SMT Pad TP29 VSS A2 A1 A0 C11 0.1uF V+ C7 0.01uF 14 12 11 9 10 5 7 4 6 2 1 TP25 TP20 NC EEGND EESCL EESDA EEVCC MISO SDA/MOSI SCK CS 5V V+ J2 HD2X7 C8 10uF 6.3V 8 TP27 TP26 TP23 FAX (408) 434-0507 Document Number 7 Sheet 1 8 of 1 Demo Circuit 1011A-A / B / C Rev 24-/16-Bit Easy Drive 8-/16-Channel Delta Sigma ADC Date:Friday, June 20, 2008 Size Title 1630 McCARTHY BLVD. MILPITAS, CA. 95035-7487 VOICE (408) 432-1900 GND GND GND Pwr GND VCC LINEAR TECHNOLOGY CORPORATION SMT Pad 5 6 7 8 VCC U3 24LC025 TP35 SDO R8-R10 = 4.99K 1% TP33 LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY R12 10K TP31 TP30 TP13 TP9 TP7 6 R8 4 R9 CH1 Ext. 3 R10 A 2 GND 2 Ext. GND 4 GND GND 13 CH0 GND 4 2 GND exposed pad, solder side 1 GND 8 28 VCC GND 5 GND 6 GND 31 GND 32 GND 33 GND 3 1 D C B A DEMO MANUAL DC1011A Schematic Diagram dc1011af 5 DEMO MANUAL DC1011A 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 (c) 2004, Linear Technology Corporation dc1011af 6 Linear Technology Corporation LT 0613 * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com LINEAR TECHNOLOGY CORPORATION 2013