Linear Technology LTC2418, DC571A Demo Manual

DEMO MANUAL DC571A

LTC2418

8-/16-Channel Differential

DESCRIPTION

The LTC®2418 is a high resolution, 24-bit ΔΣ ADC with
5ppm INL and 5μV offset. Channel selection is programmed
through a simple serial interface. Since there is no latency,
each conversion is valid, even after a change in input
channel.

DC571A is a member of Linear Technology‘s QuikEval™
family of demonstration boards.

It is designed to allow easy evaluation of the LTC2418 and
may be connected directly to the target application’s analog

QUICK START PROCEDURE

Connect DC571 to 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.

24-Bit

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

www.linear.com/demo

http://

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.

∆Σ ADC

Click the COLLECT button to start reading the input voltage.
Click the slider at the bottom of the strip-chart display to
change the input channel being displayed. For differential
measurements, Even channel pos and odd channel pos
correspond to even channels being positive inputs or
odd channels being positive inputs, respectively. See the
LTC2418 data sheet for details of channel selection.

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. DC590 Program

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1

DEMO MANUAL DC571A

HARDWARE SETUP

JUMPERS

JP1: Select the connection for the common pin, either

ground or external connection. Single-ended measure­ments are taken with respect to this pin.

JP2 and JP3: Select the source for differential reference.
Selecting 5V and GND will use the onboard 5V reference.
Select EXT to use an external reference.

JP5: Select notch frequency, 60Hz or 50Hz. Alternatively,
this jumper may be removed and an external conversion
clock applied to the center pin of JP5.

EXPERIMENTS

Figure 2 shows a number of applications for the LTC2418.

CH0, CH1, CH2

Channels 0 and 1 measure the differential output of an
Intersema MS5401 absolute pressure sensor. The 6.8k
resistor performs a first order temperature compensation
of the bridge output. CH2 measures the bridge voltage,
which provides a convenient temperature measurement.
This can also be used to perform further temperature
compensation in software.

CH3

Channel 3 measures the output of a thermistor in a half
bridge circuit. Many thermistors will work, the constraints
are that the bridge output must have an impedance of
less than 20k and the voltage must not go above V

CH4

Channel 4 measures the output of a type J thermocouple.
The circuit shown for channel 3 can be used for cold junc­tion compensation. The cold junction sensor should be
close to the connections of the thermocouple to the board.

CH5

REF

/2.

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 turret posts
along the edge of the board (CH0 to CH15.) Also, if you are
connecting the board to an existing circuit, make full use
of the four ground connections at the corners of the board.

CH7

Channel 7 measures the output of a resistive attenuator.

CH8, CH9

Channels 8 and 9 measure the drop across a Deltec SWE­3000-50 current shunt. Up to 3000A can be measured,
with a resolution of 60mA. With careful grounding, both
positive and negative currents can be measured. Care
must be taken to ensure that both inputs stay more posi­tive than GND–0.3V.

CH10

Channel 10 is buffered with an LT1793 FET input amplifier
suitable for very high source impedance measurements.

CH11

Channel 11 measures the output of a precision rectifier.

CH12, CH13

Channels 12 and 13 measure a 3-wire RTD. The differential
voltage is the output, and CH12 single-ended reading is
the ground lead compensation.

Channel 5 measures the output of an Omega OS36-01
infrared thermocouple. This can be used for remote tem­perature measurement.

CH6

Channel 6 measures the photocurrent of a Hamamatsu
S1336-5BK photodiode.

2

CH14, CH15

Channels 14 and 15 measure the output of a 350Ω bridge.
This is standard for a wide variety of sensors. Typically
the full-scale output voltage is only 10mV. However, the
LTC2418 still gives 13 effective bits of resolution with no
amplification.

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EXPERIMENTS

DEMO MANUAL DC571A

Figure 2. LTC2418 Applications

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3

DEMO MANUAL DC571A

PARTS LIST

ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER

1 1 C1 CAP, X5R, 10μF 6.3V, 20%, 0805 TDK, C2012X5R0J106M

2 1 C2 CAP, X7R 0.01μF 16V 10%, 0603 AVX, 0603YC103KAT1A

3 1 C3 CAP, X5R 4.7μF 6.3V, 20%, 0805 TAIYO YUDEN, JMK212BJ475MGT

4 5 C4, C5 ,C6, C7, C8 CAP, X7R 0.1μF 16V, 0603 AVX, 0603YC104MAT1A

5 26 E1 TO E26 TESTPOINT, TURRET, 0.064" MILL-MAX, 2308-2

6 5 JP1, JP2, JP3, JP4, JP5 JMP, 3PIN 1 ROW 0.079CC COMM-CON, 2802S-03-G1

7 5 SHUNTS FOR JP1 TO JP5 SHUNT, 0.079" CENTER COMM-CON CCIJ2MM-138G

8 1 J1 HEADER, 2 x 7PIN, 0.079CC MOLEX, 87331-1420

9 0 R1 RES, 0606 OPT

10 1 R2 RES, CHIP 100 1/16W 5%, 0603 AAC, CR16-101JM

11 2 R4, R3 RES, CHIP 4.99k 1/16W 1%, 0603 AAC, CR16-4991FM

12 1 R5 RES, CHIP 10k 1/16W 5%, 0603 AAC, CR16-103JM

13 1 U1 IC, LTC2418CGN, SSOP16GN LINEAR TECHNOLOGY, LTC2418CGN

14 1 U2 IC, NC7SZ157P6X, SC70-6P FAIRCHILD SEMI, NC7SZ157P6X

15 1 U3 IC, 24LC025, TSSOP-8 MICROCHIP, 24LC025-I /ST

16 1 U4 IC, NL17SZ74US, US8 ON SEMI, NL17SZ74US

17 1 U5 IC, LT1236ACS8-5, SO8 LINEAR TECHNOLOGY, LT1236ACS8-5

4

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SCHEMATIC DIAGRAM

J1

VCC

1

2

E15

CH3

E17

CH4

E16

CH2

CH1

E18

CH0

E26

E13

CH5

E11

CH7

E10

GND

E12

CH6

3

E14

DEMO MANUAL DC571A

A

8

5

6

OPT

5

MISO

7

8

9

6

7

MOSI

CS

C5

0.1UF

R2

100

C8

VCC

6

U2

1

342

1

342

1

SCK

VIN

FO

R1

9

U3

S

I1

0.1UF

10

10

81

VCCA0

5

VCC

GND

2

12

11

12

11

R4

4.99K

1%

R3

4.99K

1%

7

6

WP

SCL

A1A2VSS

234

4

Z

I0

NC7SZ157P6X

3

13

13

5

SDA

14

14

24LC025

VCC

HD2X7-079-MOLEX

13

NORMALTRIGGERED

2

TRIG MODE

3

5

Q

VCCGND

84

D

1

2

JP4

Q

CP

U4

CLR PR

NL17SZ74US
6 7

Fax: [phone]

Milpitas, CA 95035

Phone: [phone]

1630 McCarthy Blvd.

LTC Confidential-For Customer Use Only

TECHNOLOGY

KIM T.

APPROVALS

CONTRACT NO.

DRAWN:

SCHEMATIC

TITLE:

CHECKED:

APPROVED:

11

SHEET OF

1

DC571A-1 * LTC2418CGN

Thursday, January 09, 2003

DWG NO. REV

8-CHANNEL DIFFERENTIAL 24-BIT ADC

A

2

SIZE

DATE:

MARK T.

ENGINEER:

DESIGNER:

3

C6

0.1UF

C7

45

GNDTRIM

U5

VOUT

5V

13

R5

10K

E24

GND

0.1UF

2

3

NC

VIN

VOUTNCNC

678

2

EXT

JP2

REF+

1

NC

LT1236ACS8-5

4

ALL CAPACITORS ARE IN MICROFARADS, 0603.

2. INSTALL SHUNT ON JP1-JP5 PIN 1 AND 2.

1. ALL RESISTORS ARE IN OHMS, 0603.

NOTES: UNLESS OTHERWISE SPECIFIED

5

A A

2

60Hz

CH7

CH2

CH1

CH14

CH13

CH15

CH14

E7

CH13E9CH15

E8

CH14

VCC

2019181716

21

SDI

CH0

CH15

VCC

8

9

VCC

E19

VCC

2625242322

27

28

CH5

CH4

CH3

CH6

CH7

CH9

CH9

CH10

E4

D D

CH10

CH11

CH10

CH12

CH11

5

476

CH12

E5

CH11

E6

CH13

CH12

CH8

U1

4

5

123

CH9

CH8

E1

E3

GND

E2

CH8

FO

FO

COM

101112

COM

REF+

C2

0.01UF

C1

10UF,6.3V

SDO

SCK

REF+

REF-

0805

E20

CS/

15

CS

SDO

NC

REF-

13

14

GND

13

COM

COM

GND

NC

2

JP1

COM

MOSI

SCK

CH0

CH1

CH2

CH3

CH4

CH5

CH6

VCC

LTC2418CGN

EXT

REF+

E21

REF+

C C

50Hz

13

Fo

JP5

C4

0.1UF

C3

0805

4.7UF,6.3V

REF-

E22

2

GND

13

JP3

E25

GND

REF-

EXT

REF-

TRIG

E23

TRIG

B B

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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.

5

DEMO MANUAL DC571A

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

Linear Technology Corporation

6

1630 McCarthy Blvd., Milpitas, CA 95035-7417

[phone] ● FAX: [phone] ● www.linear.com

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LT 0612 • PRINTED IN USA

© LINEAR TECHNOLOGY CORPORATION 2012