DC1009A-C

DEMO MANUAL DC1009A LTC2492/LTC2488/LTC2486 2-/4-Channel 24-/16-Bit ΔΣ ADC with Easy Drive Input Current Cancellation DESCRIPTION Demonstration circuit 1009A-A features the LTC®2492 2-/4-channel, 24-bit ΔΣADC with Easy Drive™ inputs. Key DC specifications include 2ppm INL, 1ppm offset, 25ppm full-scale error and 10nV/°C offset drift. In the 6.8Hz/600nVRMS mode, input normal mode rejection of 50Hz and 60Hz noise is better than 87dB. The LTC2492 also includes an internal temperature sensor that is accurate to 2°C over the operating temperature range. Demonstration circuit 1009A-B features the LTC2488 2-/4-channel, 16-Bit ADC that is pinout and software compatible with the LTC2492. Demonstration circuit 1009A-C features the LTC2486 2-/4-channel 16-Bit ADC that also includes a PGA with a gain range from 1 to 256 and the same temperature sensor as the LTC2492. DC1009 is a member of Linear Technology‘s QuikEval™ family of demonstration boards. It is designed to allow easy evaluation of the LTC2492, LTC2488 or LTC2486. DC1009 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. 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, μModule, 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. BOARD PHOTO COM BIAS OR TIE TO GROUND RIBBON CABLE TO DC590 SINGLE-ENDED SIGNALS DIFFERENTIAL SIGNALS (OBSERVE COMMON MODE LIMITATIONS) REFERENCE MONITOR (OR EXTERNAL SOURCE: SEE HARDWARE SET-UP) + – dc1009af 1 DEMO MANUAL DC1009A QUICK START PROCEDURE Connect the DC1009 to a DC590 USB serial controller using the supplied 14 conductor ribbon cable. Connect DC590 to the 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. The software allows for selecting the input channel, single-ended or differential mode and 50Hz/60Hz rejection settings. Selecting 2x speed located at the bottom of the strip chart display will double the data output rate at the expense of offset accuracy (LTC2492 and LTC2486 only). 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 1. dc1009af 2 DEMO MANUAL DC1009A HARDWARE SETUP Jumpers JP1, JP2: Select the source for REF+ and REF–, respectively. REF+ can be 5.00V from the onboard LT1236 reference (default) or supplied externally. REF – can be ground (0V, default) or supplied externally. Connection To DC590 Serial Controller 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. Analog Connections Analog signal connections are made via the row of turret posts along the edge of the board. 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 LTC2486/ LTC2488/LTC2492 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 JP2 are configured for external reference. CH0-CH3: These are the differential inputs to the LTC2492/ LTC2488/LTC2486. They may be configured as single– ended inputs with respect to the COM pin, or as differential inputs (CH0-CH1, CH2-CH3) with the polarity software selected. GND: Ground turrets are connected directly to the internal analog ground plane. EXPERIMENTS Input Noise Solder a short wire between the CH0 and CH1 turrets. Connect the inputs to ground through a short wire and start taking data. LTC2492 Noise should be approximately 0.12ppm of 5V (600nVRMS.) The electrical noise of the LTC2488 is also 600nVRMS, however this is masked by the 76.3μV quantization level. If the input is well between code transitions, the noise level will read zero. If the input is exactly between two codes such that the two adjacent output codes have equal probability, the noise level will be approximately 7.9ppm. The input noise of the LTC2486 is apparent at very high gain settings (128 or 256.) Note that with a 5V reference and gain set to 256, 1LSB is equal to 298nV which is lower than the 600nVRMS electrical noise of the input stage. 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 0.5μV due to the 140dB+ CMRR of the LTC2492. The LTC2488 will produce less than 1LSB difference. Input Normal Mode Rejection The LTC2492 and LTC2486 SINC4 digital filter can be software selected to reject 50Hz, 60Hz by 110dB, or both 50Hz and 60Hz by 87dB. The LTC2488’s SINC4 filter is fixed at 50Hz/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-CH3) to the same supply through a 10k resistor. Apply a 10Hz, 2V peak-to-peak sine wave to the input through a 1μF capacitor. Set the rejection frequency to 55Hz (LTC2492 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. dc1009af 3 DEMO MANUAL DC1009A PARTS LIST ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 3 C1, C2, C6 CAP., X7R 0.1μF 16V, 0603 AVX, 0603YC104MAT1A 2 1 C3 CAP., X5R 4.7μF 6.3V, 20%, 0805 TAIYO YUDEN, JMK212BJ475MGT 3 1 C4 CAP., X5R, 10μF 6.3V, 20%, 0805 TDK, C2012X5R0J106M 4 1 C5 CAP., X7R 0.01μF 16V, 10%, 0603 AVX, 0603YC103KAT1A 5 12 E1-E12 TESTPOINT, TURRET, .064” MILL-MAX, 2308-2 6 2 JP1, JP2 JMP, 3-PIN 1 ROW .079CC SAMTEC, TMM-103-02-L-S 7 2 JP1-JP2 (Pin 1 & 2) SHUNT, .079” CENTER SAMTEC, 2SN-BK-G 8 1 J2 HEADER, 2 × 7-PIN, 0.079CC MOLEX, 87831-1420 9 3 R1, R4, R5 RES., CHIP 4.99k 1/16W 1%, 0603 AAC, CR16-4991FM 10 1 R2 RES., CHIP 10k 1/16W 5%, 0603 AAC, CR16-103JM 11 1 R3 RES., CHIP 100Ω 1/16W 5%, 0603 AAC, CR16-101JM 12 1 U2 I.C., LT1236ACS8-5#PBF, SO8 LINEAR TECH., LT1236ACS8-5#PBF 13 1 U3 I.C., 24LC025, TSSOP8 MICROCHIP, 24LC025-I/ST 1 U1 I.C., LTC2492CDE#PBF, DFN14DE LINEAR TECH., LTC2492CDE#PBF 1 U1 I.C., LTC2488CDE#PBF, DFN14DE LINEAR TECH., LTC2488CDE#PBF 1 U1 I.C., LTC2486CDE#PBF, DFN14DE LINEAR TECH., LTC2486CDE#PBF DC1009A-A 14 DC1009A-B 14 DC1009A-C 14 dc1009af 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 E12 E11 E10 E7 E6 E5 E2 -A -B -C BITS 24 16 16/PGA CH3 EXT CH1 CH0 REF- REF+ CH2 JP2 REF- LTC2492CDE LTC2488CDE LTC2486CDE 5 4 1. ALL RESISTORS ARE IN OHMS, 0603. ALL CAPACITORS ARE IN MICROFARADS, 0603. 2. INSTALL SHUNT ON JP1-JP2 PIN 1 AND 2. C3 4.7UF,6.3V 0805 C4 C5 10UF,6.3V 0.01UF 0805 GND FOR ASSEMBLY ONLY * VERSIONS U1 COM VCC VOUT C2 0.1UF NOTES: UNLESS OTHERWISE SPECIFIED COM CH3 CH2 GND CH1 CH0 E3 REF+ E4 REF- VCC GND E1 EXT 5V * 3 100 3 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. KIM T. DESIGNER: ENGINEER: MARK T. APPROVED: CHECKED: DRAWN: APPROVALS R3 C6 0.1UF SDI DATE: A SIZE 2 SCHEMATIC 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 Fax: (408)434-0507 LTC Confidential-For Customer Use Only R5 4.99K 1% 12 EEGND 14 NC 9 EESDA 10 EEVCC 11 EESCL SDI CS 6 CS 7 SDA/MOSI 1 V+ 2 5V 4 SCK 5 MISO R1 4.99K 1% R4 4.99K 1% FO GND J2 HD2X7-079-MOLEX R2 10K FO E9 E8 MISO SCK TECHNOLOGY SDA 5 6 7 8 VIN VCC 1 Friday, January 05, 2007 1 SHEET DC1009A-1 * LTC2400 FAMILY DWG NO. 1 OF 1 A-1 REV 2/4 CHANNEL 24,16,16/PGA-BIT ADC WITH SPI TITLE: 4 VSS U3 24LC025 1 A0 VCC 2 A1 WP 3 A2 SCL SCK SDO CS CONTRACT NO. C1 0.1UF CUSTOMER NOTICE SDI 2 FO 1 SCK SDO 5 NCS 4 COM 7 GND 6 VIN 2 NC 1 GND 4 NC 3 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 CIRUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. 12 VCC 13 REF+ 14 REF- 10 CH2 11 CH3 8 CH0 9 CH1 U1 8 NC 5 TRIM 6 VOUT 7 NC U2 LT1236ACS8-5 GND 15 2 GND 3 3 GND 8 JP1 REF+ 4 GND 13 D 5 A B C D DEMO MANUAL DC1009A SCHEMATIC DIAGRAM dc1009af 5 DEMO MANUAL DC1009A 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 dc1009af 6 Linear Technology Corporation LT 0612 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2012