LINEAR TECHNOLOGY DC1011A Evaluation Board Instruction Manual

June 3, 2024
LINEAR TECHNOLOGY

LINEAR TECHNOLOGY logo DEMO MANUAL DC1011A
LTC2498, LTC2496, LTC2494
24-bit/16-bit, 8-/16-Channel, Easy Drive
ΔS ADC with SPI Interface

Description

Demonstration Circuit 1011A-A features the LT C ® 2498 8-/16-channel, 24-bit Delta Sigma ADC with Easy Drive™ 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 Δ∑ ADC that is pinout and software compatible with the LTC2498. DC1011A-C features the LTC2494 16-bit Δ∑ ADC with internal PGA and temperature sensor. DC1011A is a member of Linear Technology’s QuikEval™ 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 Control- ler board and QuikEval software to measure performance. The exposed ground planes allow proper grounding to prototype circuitry. After evaluating with LT C ’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

, 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. LINEAR TECHNOLOGY DC1011A Evaluation Board

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.LINEAR TECHNOLOGY DC1011A
Evaluation Board - fig

HarDware setup

JuMPErS
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. JP2: Select source for analog COM input, either tied to ground or supplied externally to the COM turret post.

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 through hole 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. 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 0.1μF and 10μF 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 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 76.3µV 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.

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 5μV due to the 120dB+ CMRR of the LTC2498. The LTC2496 will produce less than 1LSB difference.

INPUT NORMAL MODE REJECTION
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 1µF capacitor. 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.

Parts List

ITEM| QTY| REFERENCE| PART DESCRIPTION| MANUFACTURER/PART NUMBER
---|---|---|---|---
lequired Circuit Components
1| 4| C3, C7, C10, C13| CAP., CHIP X7R 0.01pF 16V| AVX, 0603YC103KAT1A 0603
2| 2| C11, C15| CAP., CHIP X7R 0.1pF 16V 10%| AVX, 0603YC104MAT1A 0603
3| 1| C29| CAP., CHIP X5R 1 pF 101/| TAIYO YUDEN, LMK107BJ105KA 0603
4| 3| C2, C9, C12| CAP., CHIP X5R 4.7pF 6.3V| TAIYO YUDEN, JMK212BJ475MG 0805
5| 1| C8| CAP., CHIP X5R 10pF 6.3V| TDK, C2012X5R0J106M 0805
6| 25| TP1-TP6, TP8, TP1O-TP12, TP14-TP27, TP31| TURRET, TESTPOINT 0.064″| MILL-MAX, 2308-2
7| 0| TP7, TP9, TP13, TP28-TP30, TP32-TP35| 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 OQ| VISHAY, CRCW06030000Z0EA
12| 1| R6| RES., CHIP 10012 5%| MC, CR16-101JM 0603
13| 3| R8, R9, R10| RES., CHIP 4.99k 1%| MC, CR16-4991FM 0603
14| 1| R12| RES., CHIP 10k 5%| MC, CR16-103JM 0603
15| 1| U4| I.C., PRECISION REFERENCE S08| LINEAR TECH., LT1236ACS8-5#PBF
16| 1| U3| I.C., SERIAL EEPROM, TSSOP-8| MICROCHIP, 24LCO25-I/ST (PbF)
3C1011A-A
1| 1| 1 U1| I.C., 24-BIT 8416-CHANNEL DELTA SIGMA ADCs| LINEAR TECH., LTC2498CUHF 380FN
3C1011A-B
1| 1| 1 U1| I.C., 16-BIT 8-/16-CHANNEL DELTA SIGMA ADCs| LINEAR TECH., LTC2496CUHF 380FN
3C1011A-C
1| 1| U1| I.C., 16/PGA 8-116-CHANNEL DELTA SIGMA ADCs| LINEAR TECH., LTC2494CUHF 38QFN

Schematic Diagram

LINEAR TECHNOLOGY DC1011A Evaluation Board - fig 1

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.

DEMONSTRATION BOARD IMPORTANT NOTICE

Linear Technology Corporation (LT C ) 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 LT C 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 LT C 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. lt C assumes no liability for applications assistance, customer product design, software  performance, or infringement of patents or any other intellectual property rights of any kind.
LT C 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 applica- tion engineer.

Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
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Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
408-432-1900
● FAX: 408-434-0507
www.linear.com
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LT 0613 • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 2013

References

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