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dc1011af
DEMO MANUAL DC1011A
Description
LTC2498, LTC2496, LTC2494
24-bit/16-bit, 8-/16-Channel, Easy Drive
ΔS ADC with SPI Interface
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
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.
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
Figure 1. Proper Measurement Equipment Setup
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dc1011af
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 aver-
aged for the DVM display.
HarDware setup
JUMPERS
JP1, JP3: Select the source for REF+ and REF–, respec-
tively. 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.
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dc1011af
DEMO MANUAL DC1011A
HarDware setup
experiments
ANALOG CONNECTIONS
Analog signal connections are made via the row of turret
posts along the edge of the board. Also, if you are connect-
ing 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.
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.
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.)
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.
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dc1011af
DEMO MANUAL DC1011A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 4 C3, C7, C10, C13 CAP., CHIP X7R 0.01µF 16V AVX, 0603YC103KAT1A 0603
2 2 C11, C15 CAP., CHIP X7R 0.1µF 16V 10% AVX, 0603YC104MAT1A 0603
3 1 C29 CAP., CHIP X5R 1µF 10V TAIYO YUDEN, LMK107BJ105KA 0603
4 3 C2, C9, C12 CAP., CHIP X5R 4.7µF 6.3V TAIYO YUDEN, JMK212BJ475MG 0805
5 1 C8 CAP., CHIP X5R 10µF 6.3V TDK, C2012X5R0J106M 0805
6 25 TP1-TP6, TP8, TP10-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 0Ω VISHAY, CRCW06030000Z0EA
12 1 R6 RES., CHIP 100Ω 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)
DC1011A-A
1 1 U1 I.C., 24-BIT 8-/16-CHANNEL DELTA SIGMA ADCs LINEAR TECH., LTC2498CUHF 38QFN
DC1011A-B
1 1 U1 I.C., 16-BIT 8-/16-CHANNEL DELTA SIGMA ADCs LINEAR TECH., LTC2496CUHF 38QFN
DC1011A-C
1 1 U1 I.C., 16/PGA 8-/16-CHANNEL DELTA SIGMA ADCs LINEAR TECH., LTC2494CUHF 38QFN
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dc1011af
DEMO MANUAL DC1011A
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
scHematic Diagram
1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
A A
B B
C C
D D
NOTES:
5V
LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY
However, It Remains The Customer's Responsibility To
Application. Component Substitution And Printed
Applications Engineering For Assistance.
Circuit That Meets Customer-Supplied Specifications;
Circuit Board Layout May Significantly Affect Circuit
This Circuit Is Proprietary To Linear Technology And
Supplied For Use With Linear Technology Parts.
Customer Notice
Linear Technology Has Made A Best Effort To Design A
Verify Proper And Reliable Operation In The Actual
Performance Or Reliability. Contact Linear Technology
GND
Ext.
Ext.
Ext.
GND
U1
Table
ASSEMBLY
DC1011A-A LTC2498CUHF
DC1011A-B
Bits
24
16LTC2496CUHF
DC1011A-C 16/PGALTC2494CUHF
Demo Circuit 1011A-A / B / C
24-/16-Bit Easy Drive 8-/16-Channel Delta Sigma ADC
LINEAR TECHNOLOGY CORPORATION
1630 McCARTHY BLVD.
MILPITAS, CA. 95035-7487
VOICE (408) 432-1900 FAX (408) 434-0507
1 1Friday, June 20, 2008
Title
Size Document Number Rev
Date: Sheet of
VCC
V+
VCC
V+
TP31 FO
R9
TP17
CH13
TP22
REF+
C2
4.7uF
6.3V
R8
TP18
CH14
TP19
CH15
TP20 VCC
exposed pad, solder side
U1
(See Table)
13
12
1
5
6
7
8
9
10
15
16
4
3
2
11
14
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
CH5
CH4
GND
GND
GND
COM
CH0
CH1
CH2
CH7
CH8
GND
GND
NC
CH3
CH6
CH9
CH10
CH11
CH12
CH13
CH14
CH15
MUXOUTP
ADCINP
ADCINN
MUXOUTN
VCC
REF+
REF-
GND
GND
GND
SDI
FO
CS
SDO
SCK
GND
R1
0
C8
10uF
6.3V
TP13 ADCINP
R10
R8-R10 = 4.99K 1%
C9
4.7uF
6.3V
C10
0.01uF
TP33
SCK
C7
0.01uF
U3
24LC025
1
6 3
45
27
8A0
SCL A2
VSSSDA
A1WP
VCC
TP30 MUXOUTP
R2
0
TP28
SMT Pad
TP29
SMT Pad
R12
10K
TP26 GND
TP34
SDI
C15
0.1uF
TP27 GND
C13
0.01uF
C11
0.1uF
R6
100
TP7 MUXOUTN
C12
4.7uF
6.3V
TP2
CH1
JP2
COM
1
2
3C29
1uF
TP23 GND
TP3
CH2
JP1
REF+
1
2
3
TP24
REF-
TP4
CH3
TP5
CH4
TP32
CS
TP6
CH5
J2
HD2X7
1
6
3
4
5
2
7
8
9
10
11
12
13
14
V+
CS
GND
SCK
MISO
5V
SDA/MOSI
GND
EESDA
EEVCC
EESCL
EEGND
GND
NC
TP8
CH6 TP25 Pwr GND
TP21
COM
TP10
CH7
TP1
CH0
TP11
CH8
TP12
CH9
TP14
CH10
JP3
REF-
1
2
3
TP9 ADCINN
U4
LT1236ACS8-5
2
4
6
VIN
GND
VOUT
TP15
CH11
TP35
SDO
C3
0.01uF
TP16
CH12
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dc1011af
DEMO MANUAL DC1011A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2013
LT 0613 • PRINTED IN USA
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 LT C applica-
tion engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
