TI ADS7861

User's Guide
SLAU094A – October 2002 – Revised May 2011
ADS7861/8361/7863EVM
ADS7861/8361/7863EVM
This user's guide describes the characteristics, operation, and use of the ADS7861/8361/7863EVM. This
evaluation model (EVM) is an evaluation board for the ADS7861, ADS7863, and ADS8361, a family of
12-/16-bit, dual, 500-kSPS, 2+2 channel, serial analog-to- digital converters (ADCs). The EVM allows
evaluation of all aspects of the ADS7861/7863/8361 devices. Complete circuit descriptions, a schematic
diagram, and a bill of materials are included in this document.
The following related documents are available for download through the Texas Instruments web site at
http://www.ti.com.
Related Documentation
1
2
3
4
5
6
Document
Literature Number
ADS7861 Product Data Sheet
SBAS110
ADS7863 Product Data Sheet
SBAS383E
ADS8361 Product Data Sheet
SBAS230
Op Amps for Everyone Design Guide
SLOD006B
Contents
EVM Overview ...............................................................................................................
Analog Interface .............................................................................................................
Digital Interface ..............................................................................................................
Power Supplies ..............................................................................................................
EVM Operation ..............................................................................................................
Schematic, Bill of Materials, and Layout .................................................................................
2
2
3
4
4
5
All trademarks are the property of their respective owners.
SLAU094A – October 2002 – Revised May 2011
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Copyright © 2002–2011, Texas Instruments Incorporated
ADS7861/8361/7863EVM
1
EVM Overview
www.ti.com
1
EVM Overview
1.1
Features
ADS7861/8361/7863EVM:
• Full-featured evaluation board for the ADS7861, ADS8361, and ADS7863, dual, 500-kSPS,
12-bit/16-bit, serial output, 2+2 analog input, simultaneous sampling analog-to-digital converters
• Analog inputs can be configured as single-ended or differential
• Built-in reference
• High-speed serial interface
This manual covers the operation of the ADS7861EVM, ADS8361EVM, and the ADS7863EVM,
collectively identified as ADS7861/8361/7863EVM. Throughout this document, the abbreviation EVM and
the term evaluation module are synonymous with the ADS7861/8361/7863EVM. Unless otherwise
indicated, all references to device operation apply to all three devices.
1.2
Introduction
The ADS7861 operates from 5 V for AVDD and DVDD while the ADS8361 operates from 2.7 V to 3.6 V for
AVDD and DVDD. The ADS7863 operates from 2.7 V to 5.5 V for AVDD and DVDD. Each device is a
high-speed, low-power, 12-bit or 16-bit A/D converter (ADC).
The four fully-differential analog inputs are divided into two pairs (A and B). Each ADC accepts an analog
input voltage in the range of –VREF to +VREF (5 VPP), centered on the internal 2.5-V reference. The
device also accepts bipolar input ranges when a level shift circuit is used in the analog frontend circuitry.
Refer to Section 12 of the Design Guide, Op Amps for Everyone (literature number SLOD006B) for
information on various circuit applications.
2
Analog Interface
For maximum flexibility, the ADS7861/8361/7863EVM is designed for easy interfacing to multiple analog
sources. Samtec part numbers SSW–110–22–F–D–VS–K and TSM–110–01–T–DV–P provide a
convenient, 10-pin, dual row header/socket combination at J1. This header/socket provides access to the
analog input pins of the ADC. Consult Samtec at http://www.samtec.com or call 1-800-SAMTEC-9 for a
variety of mating connector options. Table 1 summarizes the pinouts for analog interfaces J1.
Table 1. J1: Analog Interface Pinout
2
Pin Number
Signal
J1.2
B1+
Noninverting input, channel B1
J1.4
B1–
Inverting input, channel B1
J1.6
B0+
Noninverting input, channel B0
J1.8
B0–
Inverting input, channel B0
J1.10
A1+
Noninverting input, channel A1
J1.12
A1–
Inverting input, channel A1
J1.14
A0+
Noninverting input, channel A0
J1.16
A0–
Inverting input, channel A0
J1.18
Unused
Pins are unused and should be left open for
use with future amplifier and sensor input
modules.
J1.20
REFIN
External reference source input (2.5 V nom,
2.525 V max)
J1.1 to J1.19 (odd)
AGND
Analog ground connections
ADS7861/8361/7863EVM
Description
SLAU094A – October 2002 – Revised May 2011
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Digital Interface
www.ti.com
3
Digital Interface
The ADS7861/8361/7863EVM is designed for easy interfacing to multiple control platforms. Samtec part
numbers SSW–110–22–F–D–VS–K and TSM–110–01–T–DV–P provide a convenient, 10-pin dual row
header/socket combination at J2. This header/socket provides access to the digital control and serial data
pins of the ADS7861/8361. Consult Samtec at http://www.samtec.com or call 1-800-SAMTEC-9 for a
variety of mating connector options. Table 2 describes the J2 serial interface pins.
Table 2. J2: Serial Interface Pins
Pin Number
J2.1
3.1
Signal
Description
CS
Chip select; active low signal, enables data
transfer and device configuration
J2.3
SCLK
J2.5
SCLK(R)
Serial clock
Serial clock return for DSP host
J2.7
FS
J2.9
FS(R)
Frame sync
J2.11
SDI
Serial data input
J2.13
SDO
Serial data output
J2.15
INT
Interrupt output; provides an interrupt
source to the host processor
J2.17
CSTART
J2.19
SPARE
Frame sync return for DSP host
Conversion start; provides an alternate
method of conversion initialization
Additional Control Options
Table 3 shows the pinout of header J5. This dual-row, four-position header provides additional control
functionality to the ADS7861/8361/7863EVM. Signals A0, M0, and M1 are configured with pull-up resistors
by default. The jumper shunts supplied with the EVM can be used to set these signals to logic low. These
signals can also be connected to control signals in the user's system.
Table 3. J5: Header
Pin Number
Signal
J5.1
M0
Selects two-channel or four-channel mode
J5.3
M1
Selects between serial outputs A and B
J5.5
A0
Operates in conjunction with M0. See device
data sheet for details.
J5.7
OUT B
B channel secondary output
J5.2 to J5.8 (even)
DGND
Digital ground connections
SLAU094A – October 2002 – Revised May 2011
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Description
Copyright © 2002–2011, Texas Instruments Incorporated
ADS7861/8361/7863EVM
3
Power Supplies
4
www.ti.com
Power Supplies
The ADS7861 EVM board requires 5 VDC for both the analog and digital sections of the ADC. While filters
are provided for all power-supply inputs, optimal performance of the EVM requires a clean, well-regulated
power source. Positive 5-VDC power is applied to J3 and J4 (pin 1 referenced to pin 2). The ADS8361 and
ADS7863 each require 5 VDC for the analog supply located on J3, and 2.7 V to 5.5 VDC for the digital
supply located on J4.
An alternate power source can be applied via J6 located on the bottom side of the printed circuit board
(PCB). If a variable digital supply voltage is desired, completely remove the shunt jumper from W3. Apply
a 100-mA current limited dc voltage of not more than 5.5 V to J4.
NOTE: The shunt jumper at location W3 should be placed across pin 2 and pin 3 for proper
operation of the ADS7861. This configuration is the factory default condition for all device
versions of the ADS7861/8361/7863EVM.
4.1
Reference Voltage
The ADS7861/8361/7863 can be configured to use its internal reference or external reference source
through jumper W1 (see schematic appended to this document for details). If an external reference is
desired, the shunt jumper on W1 should cover pins 2 and 3. The external reference is supplied through
header/socket J1 pin 20 (J1.20).
5
EVM Operation
Apply a current limited (150 mA max) 5-VDC source to J3 and J4 before connecting the analog input
signals and digital control signals.
5.1
Analog Input
The analog input source can be applied directly to header/socket J1 (top or bottom side) or through
optional amplifier and signal conditioning modules. The analog input level should not exceed 5 VPP.The
analog input range is from –VREF to VREF (0 V to 5 VDC) centered at 2.5 V.
5.2
Digital Control
The digital control signals can be applied directly to header/socket J2 (top or bottom side). The
ADS7861/8361/7863EVM can also be connected directly to a DSP interface board. Consult the respective
device product folder for a complete list of DSP interface cards and optional analog interface modules.
5.3
Default Jumper and Header Settings
Jumper W2 is provided to allow separation of the convert start (CONVST) and read (RD) signals. The
factory default condition for the EVM is to place a shunt jumper between pin 1 and pin 2 of W2. This
configuration combines signals RD and CONVST, which are applied to the ADC via pin J2.7. When W2 is
moved to pin 2 and pin 3, the RD signal is applied via pin J2.7 while CONVST is applied to pin J2.17.
Header J5 provides a way to access the M0, M1, and A1 control lines as well as the OUTB serial data.
Shunt jumpers are placed on pins 1 and 2, 3 and 4, and 5 and 6 of J5, which defaults M0, M1, and A0 to
logic low levels. Removing the jumpers allows these lines to go to logic high levels through the associated
pull-up resistors R12, R13, and R14. In the factory default configuration, the ADC converts the A0 and B0
inputs, and places AOUT serial data on pin J2.13, and BOUT serial data on pin J5.7.
4
ADS7861/8361/7863EVM
SLAU094A – October 2002 – Revised May 2011
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Copyright © 2002–2011, Texas Instruments Incorporated
Schematic, Bill of Materials, and Layout
www.ti.com
6
Schematic, Bill of Materials, and Layout
A schematic for the ADS7861/8361/7863EVM is appended to this user's guide. The bill of materials is
provided in Table 4.
6.1
Bill of Materials
NOTE:
All components should be compliant with the European Union Restriction on Use of
Hazardous Substances (RoHS) Directive. Some part numbers may be either leaded or
RoHS. Verify that purchased components are RoHS-compliant. (For more information about
TI's position on RoHS compliance, see the Quality and Eco-Info information on the TI web
site.)
Table 4. Bill of Materials
Qty
Item No.
ADS7861
ADS8361
ADS7863
Ref Des
1
1
1
1
N/A
Description
Printed Wiring Board
Vendor
Part Number
–
–
2
8
8
8
C1 to C8
100pF, 0603, Ceramic, C0G, 50V,
5%
3
5
5
5
C9, C10, C11, C12,
C22
1000pF, 0603, Ceramic, C0G, 50V,
5%
Murata
GRM1885C1H102JA01D
4
5
5
5
C13, C14, C15, C16,
C23
0.1μF, 0603, Ceramic, X7R, 50V,
10%
Murata
GRM188R71H103KA01D
5
2
2
2
C17, C18
10μF, 0805, Ceramic, X5R, 10V,
10%
Murata
GRM219R61A106KE44D
6
2
2
2
C19, C20
1.0μF, 0603, Ceramic, X5R, 16V,
10%
Murata
GRM185R61C105KE44D
7
1
1
1
C21
0.47μF, 0603, Ceramic, X7R, 16V,
10%
Murata
GRM188R71C474KA88D
8
2
2
2
L1, L2
Ferrite Chip 600Ω 500MA 0805
9
2
2
2
J1, J2 (top side)
10-Pin, Dual Row, SMT Header (20
Pos.)
10
2
2
2
J1B, J2B (bottom
side)
10-Pin, Dual Row, SMT Socket (20
Pos.)
11
2
2
2
J3, J4
12
1
1
1
J5
GRM1885C1H101JA01D
TDK
MMZ2012R601A
Samtec
TSM-110-01-T-DV-P
Samtec
SSW-110-22-F-D-VS-K
OST
ED555/2DS
4-Pin, Dual Row, TH Header (8 Pos.)
Samtec
TSW-104-07-L-D
5-Pin, Dual Row, SMT Socket (10
Pos.)
Samtec
SSW-105-22-F-D-VS-K
13
1
1
1
14
0
0
0
W1
Not installed
15
2
2
2
W2, W3
3-Pin header
Samtec
TSW-103-07-L-S
16
2
2
2
W4, W5
3-Pin , 2mm header
Samtec
TMM-103-01-T-S
17
10
10
10
R1 to R8, R14, R15
49.9Ω, 0603, 1%, 1/10W
Yageo
RC0603FR-0749R9L
18
2
2
2
R9 R10
33Ω, 0603, 1%, 1/10W
Yageo
RC0603FR-0733RL
19
3
3
3
R11 R12 R13
10Ω, 0603, 1% 1/10W
Yageo
RC0603FR-0710KL
20
0
0
0
R16
Not installed
21
1
1
1
TP1
Red Test Point Loop
Keystone
5000
22
2
2
2
TP2 TP3
Black Test Point Loop
Keystone
5001
23
J6 (bottom side)
2 Terminal Screw Connector
Murata
TI
ADS7861E
IC, ADC Dual 16-Bit 500kSPS
24QSOP
TI
ADS8361IDBQ
TI
ADS7863IDBQ
Microchip
24AA256-I/ST
TI
OPA2365AID
0
0
0
1
0
0
0
1
IC, ADC 12-Bit SER 2M 24QSOP
24
1
1
1
U2
IC EEPROM 256kBIT 400KHz
8TSSOP
25
1
1
1
U3
IC OPAMP GP R-R 50MHz DUAL
8SOIC
SLAU094A – October 2002 – Revised May 2011
Submit Documentation Feedback
–
IC, ADC Dual 16-Bit 500kSPS
24QSOP
1
U1
–
Copyright © 2002–2011, Texas Instruments Incorporated
ADS7861/8361/7863EVM
5
Revision History
www.ti.com
Revision History
Changes from Original (October, 2002) to A Revision ................................................................................................... Page
•
•
•
Updated entire document to current standards ....................................................................................... 1
Added ADS7863EVM to document contents ......................................................................................... 1
Added figure of EVM ..................................................................................................................... 1
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
6
Revision History
SLAU094A – October 2002 – Revised May 2011
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Copyright © 2002–2011, Texas Instruments Incorporated
1
2
3
4
5
6
Revision History
REV
ECN Number
Approved
D
D
AVdd
U3A 8
C22
1000pF
3
1
2
U1
4
OPA2365
R15
49.9
R14
49.9
49.9
R16
J2
R1
NI
U3B
6
R2
7
5
2
C1
100pF
3
C9
4
5
49.9
R3
49.9
C
W5
J1
1
3
5
7
9
11
13
15
17
19
W4
R4
2
4
6
8
10
12
14
16
18
20
6
C3
100pF
7
C10
8
R6
9
R8
RD
W1
C11
TP1
10
Data A
A1A0+
A0REFout
M0
A0 (SDI)
REFin
Data B
C21
0.47uF
12
C12
33
18
23
21
C
17
W2
14
DVdd
15
16
R11
10K
22
R12
10K
R13
10K
AVdd
DVdd
AGND
DGND
24
1
3
5
7
1
DVdd
1000pF
C8
100pF
R9
20
2
4
6
8
10
12
14
16
18
20
J5
13
C7
100pF
1
3
5
7
9
11
13
15
17
19
A1+
NI
1000pF
C6
100pF
11
19
B0-
M1
C5
100pF
49.9
R7
49.9
B0+
CONVST
49.9
R5
49.9
B1-
BUSY
1000pF
C4
100pF
/CS
CLOCK
1000pF
C2
100pF
B1+
2
4
6
8
ADS7861/63E or ADS8361/63E
49.9
C20
1uF
AVdd
C15
0.1uF
C23
+3.3Vd
B
B
C19
1uF
U2
C14
0.1uF
1
2
3
4
AVdd
J3
+5Va
1
R10
33
L1
C17
0.1uF
TP2
TP3
+5Va
10uF
+Vd
1
2
A
VCC
SCL
SDA
WP
8
6
5
7
J6
1
3
5
7
9
DVdd
J4
A0
A1
A2
GND
24AA256-I/ST
C13
2
0.1uF
2
4
6
8
10
+Vd
+5Vd
+3.3Vd
ti
L2
W3
C18
C16
0.1uF
10uF
A
12500 TI Blvd. Dallas, Texas 75243
Title:
Engineer:
Tom Hendrick
Hendrick
6443171_C.DDB
Drawn By:Tom
FILE:
1
2
3
4
5
ADS78/8361/7863 EVM Schematic
SIZE:
B
DATE:
11-May-2011
REV:
SHEET:
6
C
1
OF:
1
Evaluation Board/Kit Important Notice
Texas Instruments (TI) provides the enclosed product(s) under the following conditions:
This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION
PURPOSES ONLY and is not considered by TI to be a finished end-product fit for general consumer use. Persons handling the
product(s) must have electronics training and observe good engineering practice standards. As such, the goods being provided are
not intended to be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations,
including product safety and environmental measures typically found in end products that incorporate such semiconductor
components or circuit boards. This evaluation board/kit does not fall within the scope of the European Union directives regarding
electromagnetic compatibility, restricted substances (RoHS), recycling (WEEE), FCC, CE or UL, and therefore may not meet the
technical requirements of these directives or other related directives.
Should this evaluation board/kit not meet the specifications indicated in the User’s Guide, the board/kit may be returned within 30
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Please read the User’s Guide and, specifically, the Warnings and Restrictions notice in the User’s Guide prior to handling the
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FCC Warning
This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION
PURPOSES ONLY and is not considered by TI to be a finished end-product fit for general consumer use. It generates, uses, and
can radiate radio frequency energy and has not been tested for compliance with the limits of computing devices pursuant to part 15
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equipment in other environments may cause interference with radio communications, in which case the user at his own expense
will be required to take whatever measures may be required to correct this interference.
EVM Warnings and Restrictions
It is important to operate this EVM within the input voltage range of 3.3 VDC to 5 VDC and the output voltage range of 0 VDC to 5
VDC.
Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM. If there are
questions concerning the input range, please contact a TI field representative prior to connecting the input power.
Applying loads outside of the specified output range may result in unintended operation and/or possible permanent damage to the
EVM. Please consult the EVM User's Guide prior to connecting any load to the EVM output. If there is uncertainty as to the load
specification, please contact a TI field representative.
During normal operation, some circuit components may have case temperatures greater than +30°C. The EVM is designed to
operate properly with certain components above +85°C as long as the input and output ranges are maintained. These components
include but are not limited to linear regulators, switching transistors, pass transistors, and current sense resistors. These types of
devices can be identified using the EVM schematic located in the EVM User's Guide. When placing measurement probes near
these devices during operation, please be aware that these devices may be very warm to the touch.
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