User's Guide
SLLU107 – August 2008
ISO1176EVM
This document describes the ISO1176 Evaluation Module (EVM). It will allow designers to develop and
analyze data transmission systems using the ISO1176 Isolated Profibus Transceiver from Texas
Instruments.
The EVM can be used to evaluate device parameters while acting as a guide for board layout. The board
allows the connection of a 50-Ω coaxial cable (via an SMA connector) to connect to instrumentation, or to
54-Ω controlled impedance cable of varying lengths (via a female header or Quietzone® connector). This
provides the designer with a tool for evaluation and successful design of an end product.
1
Overview
This EVM allows evaluation of the ISO1176 ProfiBus Transceiver. The EVM comes with a single
transceiver installed on the circuit board (U1), but because it has been designed into the industry standard
176 footprint for 16-pin devices, other 176- footprint devices may be evaluated as well. Take care with
regard to the isolated power and ground, as this is an isolating device. Power and ground for the
Data/Control side of the device (pins D, R, DE, RE) can be completely isolated from power and ground for
the Bus side of the device (pins A, B, ISODE). While initially intended for half-duplex or multipoint
applications, ProfiBus devices can also be used in point-to-point or multidrop configurations.
The ISO1176 meets or exceeds the requirements of EN50170 and TIA/EIA RS-485 while providing 4000
V of isolation between the Data/Control and Bus sides of the device. Additional features contribute to
making the ISO1176 an excellent choice for use in industrial and factory environments:
• Receiver hysteresis
• Low bus capacitance
• Failsafe receiver for bus open, short, or idle conditions while transmitting at rates up to 25 Mbps
CAUTION
Note that although the device provides galvanic isolation of up to 4000 V, this
EVM cannot be used for isolation voltage testing. It is designed for the
examination of device operating parameters only and will be damaged if high
voltage (>5.5 V) is applied anywhere in the circuit.
The data sheet for the ISO1176 is available at: SLLS897. A pin out of the device and functional block
diagram are shown below in Figure 1.
DW PACKAGE
(TOP VIEW)
VCC1
1
16
VCC2
GND 1
2
15
R
3
14
GND 2
NC
RE
4
13
B
DE
D
5
12
6
11
A
NC
PV
PV
7
10
ISODE
DE
GND 1
8
9
GND 2
R
RE
D
3
4
6
7
5
GALVANIC ISOLATION
ISO1176
function diagram
13
12
10
B
A
ISODE
Figure 1. ISO1176 Device Pin Out and Block Diagram
Quietzone is a registered trademark of W.L. Gore and Associates, Inc..
SLLU107 – August 2008
Submit Documentation Feedback
ISO1176EVM
© 2008, Texas Instruments Incorporated
1
Overview
1.1
www.ti.com
Profibus/RS-485
The TIA/EIA-485 (a.k.a. RS-485) standard was created in response to a demand from the data
communications community for a general-purpose high-speed balanced interface standard for multipoint
applications. The standard, Electrical Characteristics of Generators and Receivers for Use in Balanced
Digital Multipoint Systems. specifies differential signaling drivers and receivers for data interchange across
half-duplex or multipoint data bus structures. Although TIA/EIA-485 specifies requirements for drivers and
receivers operating at a signaling rate up to 10 Mbps, the standard also states that devices meeting the
electrical characteristics of the standard;
….“need not operate over the entire data signaling rate range specified nor be limited to 10 Mbps.
They may be specified to operate at data rates to satisfy specific applications. The upper bound is
application dependent and beyond the scope of this standard. Maximum signaling rate is typically
limited by the following: ratio of signal transition time to the unit interval, maximum allowable stub
length, and the bandwidth of the interconnecting media.”
Profibus (Process Field Bus), developed subsequently, made several improvements on the electrical
(physical) layer including an increase in the receiver noise margin, to allow the bus to be used in
extremely noisy EMI-rich environments. This was accomplished by increasing the minimum differential
voltage on the bus. The ISO1176 has been designed specifically for these types of environments.
1.2
ISO1176 EVM Kit Contents
•
•
•
•
ISO1176 EVM circuit board with ISO1176DW installed – (6493171)
Additional devices – (check website for availability of additional devices ‘176’ footprint)
ISO1176 EVM User’s Guide
ISO1176 Datasheet
The ISO1176 is shown in Figure 2.
Figure 2. The ISO1176EVM
2
ISO1176EVM
SLLU107 – August 2008
Submit Documentation Feedback
© 2008, Texas Instruments Incorporated
Overview
www.ti.com
1.3
Configurations
The ISO1176 EVM board allows the user to evaluate performance of the ISO1176 device, or to connect
easily to an existing Profibus or RS-485 bus to evaluate system performance in an existing system. Also,
multiple EVMs can be obtained to allow the user to construct various bus configurations. With just two
EVMs, the user may evaluate performance of a point-to-point simplex, parallel-terminated point-to-point
simplex, and two-node multipoint operation. When using multiple EVMs, all of these modes of operation
can be configured through on-board jumpers, external cabling and the R9 and R10 bus termination
resistors.
1.3.1
Point-to-Point
The point-to-point configuration is shown in Figure 3. This configuration requires two EVMs, and although
this is not the intended mode of operation for Profibus/RS-485 devices, it is used for high noise or longer
(higher loss) transmission lines. Due to the increased drive current, a single 100-Ω termination resistor on
the EVM will result in a differential bus voltage (VOD) twice as large as the normally-terminated line. This
practice is acceptable as long as the combination of input voltage and common-mode voltage does not
exceed absolute maximum ratings of the line circuits.
This configuration is shown in Figure 3. It consists of a single driver on the left, and a single receiver on
the right. Note that the termination resistors (R9 and R10) have been removed from the driver EVM.
This configuration shows the receiver disabled on the driver (JUMP2 connected to VCC) EVM and the
driver disabled on the receiver EVM (JMP4 tied to GND1). Note that with only a single termination, the
differential bus voltage will be higher than normal.
R9 and R10 Removed
EVM 1
EVM 2
T
Disabled
Disabled
Figure 3. Point-to-Point Simplex Circuit
This configuration can also have a termination at the source and load (parallel-terminated as shown in
Figure 4) thereby, keeping nominal Profibus/RS-485 signal levels.
EVM 1
EVM 2
T
T
Disabled
Disabled
Figure 4. Parallel Terminated Simplex Circuit
SLLU107 – August 2008
Submit Documentation Feedback
ISO1176EVM
© 2008, Texas Instruments Incorporated
3
Overview
1.3.2
www.ti.com
Multipoint
The multipoint configuration is the primary application of Profibus/RS-485, The RS-485 standard allows for
any combination of drivers, receivers, or transceivers up to a total of 32 Unit Loads on the line. The
ISO1176 device allow the total number of nodes to be increased because ISO1176 represents just 1/5 of
a “unit load”. This allows up to 160 nodes to be connected onto a single bus. Figure 4 shows a
representation of a five-node multipoint configuration using five ISO1176 transceivers. Increased drive
current in addition to the wide common-mode input allows the ISO1176 Profibus transceiver to drive
multiple receivers over longer line lengths. Notice that the termination resistors (R9 and R10) are only
installed on the EVMs at each end of the bus.
Figure 5. A Five-Node Multipoint Circuit
Notice that the bus configuration shown in Figure 4 can be redrawn as shown in Figure 6. Additional
EVMs can be obtained and connected to the bus, but the termination resistors on those EVMs must be
removed so that the bus is terminated only at each end.
T
T
U1
U2
Figure 6. Two-Node Multipoint Circuit
4
ISO1176EVM
SLLU107 – August 2008
Submit Documentation Feedback
© 2008, Texas Instruments Incorporated
Recommended Equipment
www.ti.com
1.4
Operation Over Extended Common Mode Voltage Range
One of the features of the ISO1176 device is its operation over an extremely wide common-mode voltage
range. This can be evaluated using two EVMs, each powered from a separate independent power supply.
This extended common mode range is important because communications between equipment located
hundreds of meters apart usually means there is a voltage offset between the grounds of each node. The
EVMs can be configured with three power supplies with isolated outputs in such a way as to input a fixed
offset between the grounds (see Figure 7). This will induce a ground-potential difference voltage (VGPD)
between EVM#1 and EVM#2. The following procedure demonstrates this capability:
1. Adjust PS1 and PS2 to the supply voltage (+5.0 V) and current-limit to 200 mA.
2. Set PS3 to 0 V.
3. Induce a ground offset by varying the output of PS3.
CAUTION
PS3 output must not exceed 12 V to –7 V to remain within the device ratings.
Input
Pattern to
Driver
P1
P3
P3
Vcc 1
Vcc 2
Vcc 2
P1
Vcc 1
Interconnecting media
J4
D
EVM #1
GND 1
A J8
J8 A
B J9
J9 B
GND 2
Power Supply
No. 1
EVM #2
GND 2
P3
Power Supply
No. 3
Output from
Receiver
R
GND 1
Power Supply
No. 2
Figure 7. EVM Configuration for Inducing a Ground Potential Difference Voltage Between Nodes
2
Recommended Equipment
•
•
•
•
Power supply, 5.0 Vdc at 0.5 A
Pattern generator capable of supplying single-ended signals at the desired signaling rate
Multiple-channel high-bandwidth oscilloscope, preferably above the 100 MHz range
Differential and single ended oscilloscope probes
When using two or more EVMs, a 100-Ω transmission medium between transceivers (twisted-pair cable
recommended, CAT5 cable for example) may be used using JMP8 and JMP9 between EVMs. Coaxial
cable may be used by connecting SMA J8 to SMA J8 and SMA J9 to SMA J9 together. This will result in
the topology shown in Figure 2.
2.1
EVM Configurations
The schematic for the ISO1176EVM is shown in Figure 8.
SLLU107 – August 2008
Submit Documentation Feedback
ISO1176EVM
© 2008, Texas Instruments Incorporated
5
Recommended Equipment
www.ti.com
Figure 8. ISO1176EVM Schematic
6
ISO1176EVM
SLLU107 – August 2008
Submit Documentation Feedback
© 2008, Texas Instruments Incorporated
Recommended Equipment
www.ti.com
Table 1 contains a list of the onboard jumpers and their function, as well as the input and output loading
installed on the board.
Table 1. EVM Configuration Options
JUMPER FUNCTION
CONFIGURATION
I/O LOAD
DATA/CONTROL SIDE JUMPERS
JMP1 – Receiver Output
JMP2 – Receiver Enable
JMP3 – Driver Enable
JMP4 – Driver Input
JMP5 – Power Valid
R1– Uninstalled
R2 – 50 Ω (1)
R3 – 50 Ω (1)
R4 – 50 Ω (1)
R5 – Uninstalled
BUS SIDE JUMPERS
JMP6 – ISODE
R6 – Uninstalled
JMP7 – N/C
C11– Uninstalled
R7,R8 – Uninstalled
JMP8 – A Output
C12 – Uninstalled
R7,R8 – Uninstalled
R9, R10 27 Ω
JMP9 – B Output
C13 – Uninstalled
R9, R10 – 27 Ω
R11, R12 Uninstalled
JMP10 – N/C
Reserved For Future Use
DEVICE OPERATION
Driver
JMP2 – Hi (Disable Receiver)
JMP4 – Hi (Enable Driver)
Receiver
JMP2 – Lo (Enable Receiver)
JMP4 – Lo (Disable Driver)
(1)
2.2
Reserved For Future Use
Reserved For Future Use
C14 – Uninstalled
R11, R12 – Uninstalled
These resistors are provided as impedance matching terminations to be used when driving these Signals with 50-Ω source
impedance test/measurement equipment. When not driving these signals with a 50Ω source, the components should be
removed
Bill of Materials
The items used in the ISO1176EVM are listed in Table 2.
Table 2. ISO1176EVM Bill of Material
2.3
Item
Qty
Ref Designator
MFR P/N
Footprint
Description
1
2
2
C1, C5
12061C104JAT2A
cc1206
X7RCap1206_0.1 mF
2
C2, C6
C1206C105Z3VACTU
cc1206
Y5VCap1206 1.0 mF
3
2
C3, C7
293D106X0035D2TE3
cc7343
Tantalum, 35V, 10 mF
4
2
C4, C8
TAJE686K025R
cc7343
Tantalum, 25V_68 mF
5
2
C9, C10
08051C103JAT2A
cc0805
X7R, 100V, 0.01 mF
6
4
C11 - C14
cc0603
cc0603 Uninstalled
7
7
J1 - J5, J7, J8, J9
141-0701-201
conn, jack, pcb, vert
sma_surface
8
10
JMP1–JMP10
4-103239-0x4
jmp4
4 pin berg_0
9
4
P1–P4
3267
Bjack
Banana-Jack
10
3
R2, R3, R4
CRCW120649R9FKEA
r1206
Res1206_49_9 Ω
11
2
R9, R10
RR1220Q-270-D
r0805
Res0805_27R0 Ω
12
1
U1
ISO1176DW
SOIC16-DW_TI
ISO100_0
PCB Layout and Construction
The ISO1176EVM Printed Circuit Board (PCB) is a four (4) layer board. The top and bottom layers (1 and
4) contain signal routing. The remaining layers (2 and 3) are power and ground planes. These are split
planes to keep the VCC1/GND1 separate from VCC2/GND2. The I/O traces are designed to have a
characteristic impedance of 50Ω.
SLLU107 – August 2008
Submit Documentation Feedback
ISO1176EVM
© 2008, Texas Instruments Incorporated
7
Recommended Equipment
www.ti.com
Figure 9. PWB Top Layer
Figure 10. PWB Bottom Layer
Figure 11. Signal Traces On Bottom Layer
Figure 12. EVM Mechanical Layout
EVM WARNINGS AND RESTRICTIONS
It is important to operate this EVM within the input voltage and the output voltage ranges as specified in the table below.
Input Range, VS
Input Range, VI
Output Range, VO
–0.5 V to 7 V
–0.5 V to 7 V NOT TO EXCEED VS+ or VS–9 V to 14 V NOT TO EXCEED VS+ or VS-
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.
8
ISO1176EVM
SLLU107 – August 2008
Submit Documentation Feedback
© 2008, Texas Instruments Incorporated
Recommended Equipment
www.ti.com
EVM WARNINGS AND RESTRICTIONS (continued)
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 170°C. The EVM is designed to
operate properly with certain components above 170°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.
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2009, Texas Instruments Incorporated
SLLU107 – August 2008
Submit Documentation Feedback
ISO1176EVM
© 2008, Texas Instruments Incorporated
9
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements,
and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should
obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are
sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard
warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where
mandated by government requirements, testing of all parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and
applications using TI components. To minimize the risks associated with customer products and applications, customers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right,
or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information
published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a
warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual
property of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied
by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive
business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional
restrictions.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all
express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not
responsible or liable for any such statements.
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably
be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing
such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products
and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be
provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in
such safety-critical applications.
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are
specifically designated by TI as military-grade or "enhanced plastic." Only products designated by TI as military-grade meet military
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at
the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use.
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are
designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated
products in automotive applications, TI will not be responsible for any failure to meet such requirements.
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:
Products
Applications
Audio
www.ti.com/audio
Communications and Telecom www.ti.com/communications
Amplifiers
amplifier.ti.com
Computers and Peripherals
www.ti.com/computers
Data Converters
dataconverter.ti.com
Consumer Electronics
www.ti.com/consumer-apps
DLP® Products
www.dlp.com
Energy and Lighting
www.ti.com/energy
DSP
dsp.ti.com
Industrial
www.ti.com/industrial
Clocks and Timers
www.ti.com/clocks
Medical
www.ti.com/medical
Interface
interface.ti.com
Security
www.ti.com/security
Logic
logic.ti.com
Space, Avionics and Defense
www.ti.com/space-avionics-defense
Power Mgmt
power.ti.com
Transportation and
Automotive
www.ti.com/automotive
Microcontrollers
microcontroller.ti.com
Video and Imaging
www.ti.com/video
RFID
www.ti-rfid.com
Wireless
www.ti.com/wireless-apps
RF/IF and ZigBee® Solutions
www.ti.com/lprf
TI E2E Community Home Page
e2e.ti.com
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2011, Texas Instruments Incorporated
