Process Control Solutions Guide

Process Control Solutions Guide
2nd Edition
PROCESS
CONTROL
Solutions Guide
www.maximintegrated.com
Process Control Solutions Guide
Table of Contents
3
Message from the Senior Vice President,
Industrial and Medical Solutions Group
4
Introduction
5
Industrial Power Supplies
5
Isolated Power Supplies
7
Isolated Power-Supply Reference Designs
8
High-Voltage Buck Regulators
9
Beyond-the-Rails Technology
9
Analog Switches
10
DeepCover Security
10
DeepCover Secure Authenticators
13
Accurate Measurement and Control
13
Analog Input Reference Designs
14
Industrial Op Amps
15
ADCs
16
DACs and Output Conditioners
17
Sensor Digitizers
18
Robust Communications
18
Digital Input Serializers
20 Overvoltage/Overcurrent Protectors
21
IO-Link Master and Device Transceivers
23
RS-485 Transceivers
2
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Process Control Solutions Guide
Maxim Integrated Means
Great Solutions and Support
A Message from the Senior Vice President,
Industrial and Medical Solutions Group
Thank you for considering Maxim Integrated as your analog IC supplier. Our goal is simple:
to be your supplier of choice. This handbook highlights our innovative solution and support
capabilities for the industrial market.
At Maxim, we pride ourselves in first understanding our customers’ needs, then developing
the appropriate solutions to meet them. As a result, we are able to provide application-specific
functionality, while still maintaining the flexibility needed for custom designs.
Leveraging our 30 years of experience, we offer exceptional products that deliver better
performance, use less power, and provide the accuracy and reliability necessary for your
industrial applications.
Our product portfolio addresses all aspects of sensor signal chains, control signal chains, and
communications interfaces from conditioning to capture, transmission to timing, and power
to precision.
In addition to our innovative solutions, we also provide great customer support, including
superior reference designs, and technical service.
Thank you again for considering Maxim. We look forward to working with you.
Sincerely,
Chris Neil
Senior Vice President, Industrial and Medical Solutions Group
3
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Process Control Solutions Guide
Introduction
Process control is primarily enabled by the PLC (programmable logic controller) or the PAC
(programmable automation controller). Today the controllers are quite similar, but both
began with slightly different roots. The modern PLC is the result of technology advancement
from the control realm, whereas the modern PAC is the result of technology advancement
from the data communications realm. Now PLCs have communications capability and PACs
have control capability, so the differences are blurred. We will use the term "PLC" to refer
to both controllers. The PLC's block diagram can be simplified to the one shown below. In
larger, modular PLCs, I/O modules exist as plug-in cards with their own microcontroller
per card and a backplane connection to a high-speed bus that runs between each I/O
module and a plug-in CPU module. Additionally, there is usually a power-supply module
and a communications module. For simplicity, we have not broken out this detail.
All the solutions presented in this guide are intended for use in industrial process control,
HVAC and building automation, motor control, and other industrial applications.
OV/OC
PROTECTORS
Integrated
FETs reduce size
IP protection, authentication,
secure key storage
SECURITY
Digital input serializer
reduces isolated channels
Saves 75% package area,
draws 20% less current
Single IC temperature
solution
SAR ADCs: Smallest bipolar
input + VREF in
3mm x 3mm package
ISOLATION
SENSOR DIGITIZERS
FC
AMP
RS-485 transceivers:
highest ESD at ±35kV
SENSOR
AMP
DAC
ADC
INTERFACE
SENSOR
IO-Link®:
Small complete solution
-15V to +35V signal range
on single 3.0V to 5.5V supply
Beyond-the-Rails signal
chains handle ±10V signals
on single 5V supply
DC-DC
POWER
91% peak efficiency,
small size, few parts
ISOLATED POWER
Transformer drivers
simplify isolated power
Generic PLC block diagram. Maxim offers solutions for most of the blocks in the PLC, indicated by the teal
color. Our microcontroller solutions are not typically suited for the high processing power required in the
PLC. More detailed block diagrams are available on our website at: www.maximintegrated.com/PLC.
4
ACTUATOR
Near zero DC
offset and drift
Beyond-the-Rails™
MUX
ISOLATION
DIGITAL SIGNAL
INPUT CONDITIONER
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Process Control Solutions Guide
Industrial Power Supplies
Isolated Power Supplies
Isolated power is a common system requirement in all types of PLC I/O modules. Depending
on how well the nonisolated input to the isolated converter is regulated, users can choose
different options. If the input to the isolation converter is fairly well regulated, a simplification
is possible using Maxim’s transformer drivers. They run open loop at a fixed 50% duty cycle to
drive the isolation transformer. With a regulated input, simple point of load LDOs are all that
are needed to provide a high-efficiency, tightly regulated final supply. This approach enables
simpler designs with many protections and performance enhancement features integrated.
Maxim’s family of transformer drivers accept wide DC input voltage ranges from 3V to 5V and
8V to 36V.
MAX13253 Transformer Driver
Key Features
Our latest transformer driver, MAX13253, is a 1A driver for push-pull
configurations and offers spread spectrum switching to reduce EMI/RFI.
Protection features include loss of clock watchdog, overcurrent protection,
thermal shutdown, and undervoltage lockout.
• Low RON 300mΩ (max) at 4.5V
• Up to 90% efficiency
• Internal or external clock source
• Optional spread-spectrum oscillation
• -40°C to +125°C operating temperature
range
5V
• Small 10-pin TDFN package (3mm x 3mm)
1FF
VDD
HICLK
T2
1CT:1.3CT
SPRD
FAULT
1FF ISOLATED
VOUT
MAX13253
10FF
EN
CLK
T1
GND
PGND
Selector Table: Transformer Drivers for Isolated Power Supplies
Part
Description
MAX256
Low-voltage transformer driver for
isolated power
MAX13253
MAX13256
Features
Benefits
3W output power, full bridge,
integrated protection
Simple open-loop circuit speeds isolated
power-supply design.
Low-voltage transformer driver with
spread spectrum
5W output power, 3V to 5V supply,
current limiting, 90% efficiency,
spread spectrum
Simple open-loop circuit for isolated
power eases EMI management with
spread-spectrum switching.
36V transformer driver
for isolated power
10W output, 8V to 36V supply, full
bridge, 90% efficiency, integrated
protection
Simple open-loop circuit speeds isolated
power-supply designs with higher voltage
and higher power requirements.
5
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Process Control Solutions Guide
Isolated Power Supplies (cont.)
MAX17599 Active-Clamp PWM Controller
Key Features
• 4.5V to 36V input
The MAX17599 supports active-clamp, peak-current mode, forward converter
topologies. Operating over 100kHz to 1MHz, this device provides frequency
dithering spread-spectrum to reduce EMI. Protection features include undervoltage lockout, overvoltage protection, short-circuit protection, and more.
• Spread spectrum and frequency
synchronization
• Adjustable soft-start and slope
compensation
VIN
• 3mm x 3mm, 16-pin TQFN package
D2
• -40°C to +125°C operating temperature
range
T1
C16
47nF
NB
VDC
L1
10μH
PGND
VOUT
VOUT
INPUT
17V TO
34V INPUT
C1
22μF
C2
0.1μF
R22
100kΩ
PGND
VIN
D3
VIN
SS
R11
OPEN
AUXDRV
SLOPE
R15
40kΩ
VFB
R19
49.9kΩ
COMP
GND0
C8
0.01μF
C18
2.2μF
R10
0R
P1
3
N1
R24
100kΩ
D1
PGND
5
R17
100mΩ
SGND
VDRV
FB
VDRV
VDC
VFB
EN /UVLO
EN/UVLO
R4
150kΩ
OVI
DT
R9
20kΩ
R21
47Ω
VOUT
R7
120Ω
U2
R13
22kΩ
2
R8
332kΩ
C10
10nF
4
SGND
SGND
R1
3.3MΩ
R25
150kΩ
C11
47pF
R14
470Ω
PGND
C7
2.2μF
2
1
C19
0.1μF
C12
4.7nF
MAX17599
1
GND0
VDRV
R16
100Ω
CS
C20
100pF
R20
33.2kΩ
3.3V, 3A
C5
OPEN OUTPUT
C15
100μF
GND0
R6
10kΩ
DITHER/
SYNC
C14
100μF
C4
100μF
N2
R12
0R
NDRV
SGND
SGND
PGND
C9
47nF
RT
R23
C17 OPEN
SHORT
R2
0R
N3
Z2
6.2V
C6
0.47μF
U1
NS
Q1
PGND
C13
47nF
NP
R3
0R
PGND
2
U3
3 1
R18
200kΩ
EP
GND0
OVI
SGND
R5
121kΩ
SGND
SGND
Selector Table: PWM Controllers for Isolated Power Supplies
6
Part
Description
Features
Benefits
MAX17497B
4.5V to 36V flyback converter with
integrated 12VIN/3.3VOUT buck regulator
10W+ output power, 4.5V to 36V supply,
250/500kHz, integrated protection,
60V FET
High frequency for tiny magnetics,
regulates both positive/negative outputs,
and has optional spread spectrum.
MAX17498B/C
4.5V to 36V flyback converters
10W+ output power, 4.5V to 36V supply,
250/500kHz, integrated protection,
60V FET
High frequency for tiny magnetics,
regulate both positive/negative outputs,
and have optional spread spectrum.
MAX17596
4.5V to 36V flyback converter
10W+ output, 4.5V to 36V supply,
100kHz to 1MHz, integrated protection
Spread spectrum mitigates EMI,
optimized magnetics/filters.
MAX17599
4.5V to 36V active clamp and forward
converter
100W+ output, 100kHz to 1MHz
operation, 92%+ efficiency, integrated
protection
Spread spectrum mitigates EMI,
optimized magnetics/filters.
www.maximintegrated.com
Process Control Solutions Guide
Isolated Power-Supply Reference Designs
Key Features
Proven isolated power-supply reference designs speed your design process. Maxim
is expanding our portfolio of bench-tested subsystem reference designs. The selector
table offers available designs for isolated industrial power-supply applications.
• Isolated power
• ±15V (±12V) outputs
The Oceanside design (MAXREFDES9#) uses a step-up controller (MAX668),
a 36V H-bridge transformer driver (MAX13256), and a pair of low dropout
(LDO) linear regulators (MAX1659 x2) to create a ±15V (±12V) output isolated
power supply from a wide range of input voltages. If the input to the isolated
converter is not regulated tightly, users would require a tightly regulated
PWM controller. Maxim provides PWM controllers for isolated applications
supporting 4.5V to 36V input in flyback and active-clamp topologies.
• Pmod™-compatible form factor
The Oceanside subsystem design board.
3.3V TO 15V VIN
BOOST
CONVERTER
MAX668
16V
TRANSFORMER
DRIVER
MAX13256
REGULATED
POWER
MAX1659 (x2)
VOUT
±12V
±15V
The Oceanside subsystem design block diagram.
Selector Table: Reference Designs for Isolated Industrial Power Supplies
Design
Input
Output
Description
Features
Benefits
Lakewood
(MAXREFDES7#)
3.3V
±12V (±15V)
Isolated power supply using
H-bridge transformer driver
and pair of LDOs
1500VRMS isolated power,
±12V at 90mA, ±15V at 40mA
output, Pmod-compatible
form factor
Simple isolated power,
reduced size, quick
prototyping.
Oceanside
(MAXREFDES9#)
3.3V to 15V
±15V (±12V)
Isolated power supply using
step-up controller, H-bridge
transformer driver, and pair
of LDOs
5000VRMS Isolated power,
±15V at 90mA, ±12V at
100mA output, Pmodcompatible form factor
Simple isolated power,
reduced size, quick
prototyping.
Riverside
(MAXREFDES8#)
3.3V
12V (15V)
Isolated power supply using
H-bridge transformer driver
and an LDO
1500VRMS isolated power,
12V at 165mA, 15V at 60mA
output, Pmod-compatible
form factor
Simple isolated power,
reduced size, quick
prototyping.
7
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Process Control Solutions Guide
High-Voltage Buck Regulators
MAX17503 Synchronous Step-Down Converter
Key Features
Maxim’s latest industrial synchronously rectified buck regulators offer wide
input voltage range and integrated FETs for a small size, low-component-count,
high-efficiency solution. Peak efficiency of > 90% can be achieved as a result
of synchronous rectification with internal high-side and low-side MOSFETs.
• Adjustable output voltage from 0.9V to
(0.92)VIN
The MAX17503 2.5A buck regulator is a good example of this family of parts.
We are expanding our portfolio of wide input voltage solutions to include lower
and higher output current capabilities from 10s of mA to 10s of Amperes.
• Operates from a 4.5V to 60V input supply
• 200kHz to 2.2MHz internally compensated
across output voltage and switching
frequency
• -40°C to +125°C operating temperature
range
• 4mm x 4mm TQFN package
C1
2.2FF
VIN
EN/UVLO
RT
VIN
SYNC
MODE
C2
2.2FF
VIN
BST
LX
MAX17503
VCC
C5
0.1FF
LX
L1
6.8FH
VIN
(4.5V TO 60V)
VOUT
3.3V, 2.5A
C4
47FF
LX
R3
127kI
FB
SGND
CF
R4
47.5kI
RESET
SS
PGND PGND PGND
C3
5600pF
fSW = 500kHz
Synchronously rectified 60VIN DC-DC step-down converter.
Selector Table: Industrial Regulators
8
Part
Description
Features
Benefits
MAX17503
60V, 2.5A high-efficiency
synchronous step-down DC-DC
converter
4.5V to 60V input range, synchronous
rectification with internal MOSFETs,
internal compensation
Address 24V nominal VIN with ample
tolerance, > 90% peak efficiency, as low as
five external components, small size.
MAX17502
60V, 1A, high-efficiency
synchronous step-down DC-DC
converter
4.5V to 60V input range, synchronous
rectification with internal MOSFETs,
internal compensation
Address 24V nominal VIN with ample
tolerance, > 90% peak efficiency, as low as
five external components, small size.
MAX17501
60V, 500mA, high-efficiency
synchronous step-down DC-DC
converter
4.5V to 60V input range, internal
synchronous MOSFETs, internal
compensation
Address 24V nominal VIN with ample
tolerance, > 90% peak efficiency, as low as
five external components, small size.
MAX15062A/B
60V, 300mA, high-efficiency
synchronous step-down DC-DC
converters
4.5V to 60V input range, internal
synchronous MOSFETs, internal
compensation PFM/PWM mode
Address 24V nominal VIN with ample
tolerance, > 90% peak efficiency, as low as
four external components, small size.
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Process Control Solutions Guide
Beyond-the-Rails Technology
Maxim's Beyond-the-Rails technology simplifies design challenges inherent in handling
industrial signaling levels, often ±10V or more. Beyond-the-Rails parts can handle signals that
go beyond their power-supply rails—both above and below. This can reduce the complexity
of designs by eliminating power supplies needed for just the front end, before attenuation is
possible. Additional benefits of Beyond-the-Rails include likely higher overall efficiency, fewer
parts, simpler layout with fewer power-supply rails to route, and smaller total solution size—
all leading to cost savings. Maxim's Beyond-the-Rails technology includes analog switches/
muxes, digipots, and ADCs.
Bipolar inputs need only a single supply!
+15V Supply
+5V Supply
SPI
ADC
AMP
±10V
INPUT
MULTIPLEXER
DIGIPOT
SPI
-15V Supply
Maxim's Beyond-the-Rails technology simplifies designs by eliminating power supplies
previously needed to handle high-voltage input signals.
Analog Switches
MAX14777 Quad Beyond-the-Rails Analog Switch
Key Features
The MAX14777 quad SPST switch supports analog signals above and
below the rails with a single 3.0V to 5.5V supply. The device features a
selectable -15V/+35V or -15V/+15V analog signal range for all switches.
• -15V/+35V signal range from a single 3.0V to
5.5V supply
SEL35
• High-performance 10Ω RON (max)
VCC
VL
BIAS
GENERATION
CONFIG
• 1.62V to 5.5V logic interface
VP
VN
• 150mΩ (max) RON flatness
• Small 20-pin TQFN package (4mm x 4mm)
• -40°C to +105°C operating temperature range
MAX14777
A1
B1
A2
B2
A3
B3
A4
B4
EN1 EN2 EN3 EN4
9
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Process Control Solutions Guide
DeepCover Security
Maxim’s DeepCover® Secure Authenticators provide a hardware-based solution to provide
cryptographic protection against intellectual property theft, counterfeiting, unauthorized
access, and other forms of cyber espionage that can compromise industrial systems. We build
in security at the hardware level, so designers can be assured that the underlying foundation
of algorithms and data remains secure and that higher level applications can run securely.
DeepCover solutions use the industry's strongest cryptographic algorithms and cloak sensitive
data under multiple layers of advanced physical security to provide the most secure key storage
possible. We also offer a low-cost secure service to factory-personalize authenticators to OEM
specification. This provides a means to preinstall authentication keys and application data
prior to device shipment to contract manufacturers, thereby eliminating concerns of exposing
sensitive data.
All the DeepCover solutions in this guide are intended for use in industrial applications that
require:
• Counterfeit prevention
• Identification and authentication of OEM modules and peripherals
• Reference design license management
• Sensor/accessory authentication and calibration
• System intellectual property protection
DeepCover Secure Authenticators
DS28E25 1-Wire SHA-256 and 4Kb EEPROM
Key Features
The DeepCover Secure Authenticator (DS28E25) combines bidirectional secure
challenge-and-response authentication with a FIPS 180-based Secure Hash
Algorithm (SHA-256) implementation. Highly secure memory stores a secretkey for SHA-256 operations. Additional user-programmable memory is used
to store application-specific data. The DS28E25 communicates over Maxim's
single-contact 1-Wire® interface.
• Symmetric-key secure authentication
with a bidirectional model
VCC
• Single-contact 1-Wire interface for host
communication
RPUP
DS28E25
GND
10
• 4Kb user EEPROM with programmable
protection options including SHA-256
authenticated, W/R protect, and OTP/
EPROM mode
• ±8kV HBM ESD protection (typ) for IO pin
IO
FC
• FIPS 180-based HW-accelerated
SHA-256 engine
• Operating range: 3.3V ±10%, 1.8V ±5%,
-40°C to +85°C
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Process Control Solutions Guide
DeepCover Secure Authenticators (cont.)
DS2465 SHA-256 Coprocessor and 1-Wire Master
Key Features
The DeepCover Secure Authenticator (DS2465) SHA-256 coprocessor
with 1-Wire master offloads SHA computations from a host processor
and provides a 1-Wire master interface to communicate with 1-Wire slave
devices such as the DS28E25. It securely stores a SHA-256 secret-key using
DeepCover die-level protection techniques. With an I2C control interface
and 1-Wire master port, the DS2465 also performs protocol conversion
between the I2C master and any of the attached 1-Wire SHA-256 slaves.
• FIPS 180-based SHA-256 engine to operate
symmetric-key-based secure authentication
• 256 bits user EEPROM with multiple
programmable protection options
• I2C interface for communication and control
• 1-Wire master port
• Operating range: 3.3V ±10%, -40°C to +85°C
3.3V
(I2C PORT)
SDA
SCL
VCC
DS2465
FC
SLPZ
IO
1-Wire LINE
DS28E25
#1
DS28E25
#2
DS28E25
#n
DS28C22 I2C SHA-256 and 3Kb EEPROM
With a FIPS 180-based SHA-256 hardware engine, the DeepCover Secure
Authenticator (DS28C22) provides bidirectional, secure challenge-andresponse authentication and offers optional small message encryption
functionality when performing R/W operations on stored data. A 3Kb userprogrammable EEPROM array provides nonvolatile storage for application
data. Additional protected memory holds a read-protected secret for
SHA-256 operations. Each device has its own guaranteed unique and
unalterable 64-bit ROM identification number (ROM ID) that is factory
programmed into the chip. This unique ROM ID is used as a fundamental
input parameter for cryptographic operations and also serves as an
electronic serial number within the application. A bidirectional security
model enables two-way authentication and encryption between a host
system and slave-embedded DS28C22. Slave-to-host authentication is
used by a host system to securely validate that an attached or embedded
DS28C22 is authentic. Host-to-slave authentication is used to protect
DS28C22 user memory from being modified by a nonauthentic host.
Optional encrypted small message read and write between host and
slave is implemented using a SHA-256 generated one-time pad.
Key Features
• Bidirectional symmetric-key
secure authentication
• FIPS 180-based HW-accelerated
SHA-256 engine
• 3Kb user EEPROM with programmable
protection
• Optional EEPROM data encrypted R/W with
one-time pad
• I2C interface supporting 100kHz and 400kHz
• Operating range: 3.3V ±10%,-40°C to +85°C
3.3V
(I2C PORT)
SDA
SCL
VCC
DS28C22
FC
SLPZ
11
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Process Control Solutions Guide
DeepCover Secure Authenticators (cont.)
DS28E35 1-Wire ECDSA and 1Kb EEPROM
Key Features
• FIPS 186-based ECDSA engine to operate
a public-key authentication model
The DeepCover Secure Authenticator (DS28E35) provides a highly
secure public-key based solution for a host controller to authenticate
peripherals and modules. System solution cost and key management
benefit from the FIPS 186 Elliptic Curve Digital Signature Algorithm
(ECDSA)-based implementation. This public-key (asymmetric)
solution eliminates the need for a host processor to securely protect
its authentication key since exposure of the public key is not a security
risk. Additionally, native support for public-key certificates provide a
flexible and secure solution for OEMs to manage authorized subsystem
suppliers. The DS28E35 also features a one-time settable and
nonvolatile, 17-bit, decrement-on-command counter that is designed
for secure use control of the object to which the DS28E35 is attached.
• Hardware random number generator for
key pair creation and ECDSA computation
• 17-bit one-time settable, nonvolatile
decrement-on-command counter
• 1Kb user EEPROM with programmable
protection options including, write and
read protect, and OTP/EPROM mode
• Single-contact 1-Wire interface
for host communication
• ±8kV HBM ESD protection (typ) for IO pin
HOST SYSTEM
• Operating range: 3.3V ±10%,
-40°C to +85°C
SENSOR
3.3V
VCC
PIOX
10kI
RPUP
BSS84
FP
PIOY
GND
1-Wire
DS28E35
IO
GND
STRONG PULLUP
BYPASS
Selector Table: DeepCover Secure Authenticators
Part
Description
DS2465
SHA-256 coprocessor with
1-Wire master
DS28E25
1-Wire SHA-256 authenticator
DS28C22
I2C SHA-256 authenticator
DS28E35
12
1-Wire ECDSA authenticator
Features
FIPS 180-based authentication; tamper
protection for authentication key,
I2C to 1-Wire conversion
Benefits
Offloads SHA-256 processing, protects
system authentication key, and simplifies
host-side 1-Wire I/O.
FIPS 180-based bidirectional
authentication, 4Kb user EEPROM
FIPS 180-based bidirectional
authentication, 3Kb user EEPROM with
optional encrypted R/W of data
FIPS 186-based public-key
authentication, 1Kb user EEPROM,
public-key certificate memory,
decrement-only usage counter
Authenticate peripherals, protect
intellectual property, securely store
end-product feature settings, manage
approved suppliers, and protect NV
memory for application data.
www.maximintegrated.com
Process Control Solutions Guide
Accurate Measurement and Control
Analog Input Reference Designs
When it comes to measuring analog signals from your industrial process, proven reference designs speed the process of selecting
the components that work best together. Here are several 16-bit analog input reference designs for industrial applications.
Schematics, layout files, BOM, test data, and firmware for the Pmod™-compatible reference designs are available
for quick prototyping and immediate evaluation on the Xilinx® ZedBoard™ and Nexys™3 systems.
Cupertino (MAXREFDES5#) 16-Bit, High-Accuracy,
Multi-Input Isolated AFE Reference Design
Key Features
• High accuracy
• ±10V, 0 to 10V, and 4–20mA inputs
The Cupertino (MAXREFDES5#) subsystem reference design
is a 16-bit, high-accuracy, industrial analog front-end (AFE) that
accepts -10V to +10V, 0 to 10V, and 4–20mA current-loop signals
with isolated power and data integrated into a small form factor.
• Isolated power and data
• Device drivers
• Example C source code
• Pmod-compatible form factor
VOLTAGE
REFERENCE
MAX6126
+10V
AMP
AIN0
-10V
+10V
MAX9632
DATA
ISOLATION
MAX14850
ADC
MAX1301
AIN1
-10V
AIN2 4-20mA
FPGA
DEVELOPMENT
KIT OR FC
Pmod
AMP
REGULATED
POWER
MAX1659
+10V
POWER
ISOLATION
MAX256
MAX9632
AIN3
0
The Cupertino subsystem design block diagram.
Monterey (MAXREFDES15#) 4−20mA Loop-Powered
Sensor Reference Design
Key Features
• Ultra-low power
• -100°C to +100°C RTD temperature
The Monterey (MAXREFDES15#) subsystem reference design is a highaccuracy, industrial loop-powered sensor transmitter that connects
to any standard PT1000 resistance temperature sensor and converts
the linearized temperature to a 4−20mA current signal, which is
immune to noise and remains constant over long distances.
OA
OA
MAX15007
REF
LDO
DAC
OA
• Simple power supply and wide input range
• System current consumption less than
2.1mA
• Resolution 10,000 counts or 0.01%
0–4mA
4–20mA
MAXQ615
ADC
RTD
MAX6133
• High accuracy and precision
MAX11200
FC
MAX5216
MAX9620
TR
0–4mA
0–20mA
R
4–20mA
MAX44248
4–20mA Tx
The Monterey subsystem design block diagram.
13
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Process Control Solutions Guide
Analog Input Reference Designs (cont.)
Loop-Powered Temperature Transmitter/Receiver Solution
By combining our Monterey and Cupertino subsystem reference designs, we realize
a high-precision, ultra-low-power, 4−20mA, loop-powered temperature transmitter
and receiver solution. This combination of designs targets the most demanding
applications, yielding a very high-accuracy, high-precision, low-power solution.
The Monterey design achieves 0.01% accuracy while drawing only 2.1mA.
MONTEREY
OA
OA
MAX15007
REF
LDO
DAC
OA
LOOP POWER
0−4mA
4−20mA
12V
24V
MAXQ615
ADC
RTD
MAX6133
FC
MAX5216
MAX11200
TR
MAX9620
0−4mA
0−20mA
R
CUPERTINO
4−20mA
ADC
R
MAX44248
4−20mA Tx
4−20mA Rx
The Monterey and Cupertino reference designs create a 4−20mA,
loop-powered temperature transmitter and receiver solution.
Industrial Op Amps
To handle large industrial signal ranges, the front-end op amp needs large signal handling
capability, while maintaining high DC precision, low power, and low noise. For the ultimate
in low-noise performance, Maxim has achieved single-digit nV/√Hz performance.
For the ultimate in DC precision, Maxim’s auto-zero amplifiers keep the long-term drift so
low that we achieve single-digit μV of input offset voltage over time and temperature.
Selector Table: Industrial Op Amps
14
Part
Description
MAX44241/246/243
36V, low-noise, precision,
single/dual/quad op amps
MAX44248/245
36V, precision, low-power, 90µA,
dual/quad op amps
MAX44250/251/252
20V, ultra-precision, low-noise
single/dual/quad op amps
MAX9632/33
36V, precision, low-noise,
wide-band single/dual amplifiers
Features
Benefits
2.7V to 36V power-supply range,
ultra-low input VOS: 5µV (max),
low 9nV/√Hz noise at 1kHz
Deliver low noise and precision in highvoltage applications.
Very low input voltage offset 7.5µV (max),
low 30nV/°C offset drift (max),
low 90µA quiescent current per amplifier
Deliver low noise and precision in lowpower applications.
2.7V to 20V power-supply range,
6µV input offset voltage (max) at room
temp, low 5.9nV/√Hz noise
Wide operating voltage range, shutdown
saves power, industry’s lowest noise and
auto-zero precision in a SOT-23 package.
0.94nV/√Hz ultra-low input voltage noise,
very fast 600ns settling time to 16-bit
accuracy, gain-bandwidth product 55MHz
Small TDFN package saves space; fast
settling ideal for an ADC buffer.
www.maximintegrated.com
Process Control Solutions Guide
ADCs
Key Features
To enable smaller high-performance, low-power industrial AFEs, with
the ability to handle bipolar inputs that go beyond the rails, Maxim
developed the MAX11156. This 18-bit, 500ksps, SAR ADC enables the
smallest possible solution (3mm x 3mm), without the need for an external
reference. And, as a Beyond-the-Rails device, only a single power supply
is needed. Performance is also enhanced since bipolar signals do not
need to be converted to single-ended signals for input to the ADC.
• 18-bit resolution with no missing codes
• SNR: 94.6dB, THD: -105dB at 10kHz
• Internal reference and reference buffer
• Tiny 12-pin, 3mm x 3mm TDFN package
• Bipolar ±5V analog input range
• 26.5mW at 500ksps
VDD
(5V)
1FF
SCLK
50I
±5V
MAX9632
OVDD
(2.3V TO 5V)
1FF
AIN+
AIN-
500pF
INTERFACE
AND CONTROL
18-BIT
ADC
DIN
DOUT
CNVST
MAX11156
REF
HOST
CONTROLLER
CONFIGURATION REGISTER
INTERNAL REFERENCE
10FF
REF
BUF
REFIO
GND
AGNDS
0.1FF
Selector Table: ADCs
Part
Description
MAX11156
18-bit, 500ksps, ±5V SAR
ADC with internal reference
in TDFN
MAX11154
18-bit, 500ksps, 0 to 5V SAR No missing codes, SNR: 93.5dB,
ADC with internal reference THD: -105dB at 10kHz,
in TDFN
3mm x 3mm, 12-pin TDFN package
MAX11100/01
MAX11200/10
MAX11213
16-/14-bit, +5V, 200ksps
SAR ADC with 10µA
shutdown
Features
No missing codes, SNR: 94.6dB,
THD: -105dB at 10kHz,
3mm x 3mm, 12-pin TDFN package
No missing codes, small 10-pin µMAX®
and WLP packages, low power: 140µA at
10ksps
Benefits
Integrated reference and reference
buffer saves space and cost; true bipolar
measurements above and below ground
improve system accuracy.
Internal or external reference modes add
flexibility; integrated reference buffer saves
the space and cost of an external amplifier.
Single-supply operation saves cost; logic level
(2.7V to 5.25V) saves level shifter; serial
interface simplifies isolation.
Ultra-low power dissipation; operating24-bit, single-channel,
mode < 300µA (max); programmable
ultra-low power, delta-sigma gain (1, 2, 4, 8, or 16) (MAX11210); four
ADCs with GPIO
SPI-controlled GPIOs for external
mux control
Low 230µA supply current meets 4−20mA
loop current budget; high resolution improves
accuracy; GPIOs reduce isolators for mux
control.
16-bit, single-channel, ultralow power, delta-sigma ADC
with programmable gain and
GPIO
Software-adjustable output rates allow speed
vs. ultra-low noise tradeoffs.
16-bit noise-free resolution, ultralow power dissipation, operating
mode current drain < 300µA (max);
programmable gain (1 to 128)
15
www.maximintegrated.com
Process Control Solutions Guide
DACs and Output Conditioners
Maxim’s precision digital-to-analog converter (precision DAC) product line is the
industry’s largest portfolio of products. Our comprehensive offering features small
WLP packaging, high-accuracy multichannel devices (up to 32 channels), the industry's
first true 16-bit DAC with ±1 LSB INL, and also the industry’s first 1.8V supply DAC. For
accurate control and safety, our industrial analog current/voltage output conditioners
include the industry’s first programmable output current up to ±24mA or voltage up
to ±12V. See the below selector table for a small sampling of available solutions.
DVDD
SCLK
DIN
DOUT
CS1
CS2
AVDD
AVDDO
MAX15500
MAX15501
SPI
INTERFACE
READY
SENSERP
COMP
ERROR
HANDLING
AIN
ERROR
MON
REFIN
ERROR
HANDLING
FSMODE FSSEL
SENSERN
BIDIRECTIONAL
CURRENT
DRIVER
OVERCURRENT
PROTECTION
BIDIRECTIONAL
VOLTAGE
DRIVER
AVSS
OUT
SENSEVP
SENSEVN
AVSSO
AGND
DGND
OUTDIS
Selector Table: DACs and Output Conditioners
16
Part
Description
Features
Benefits
MAX5705/02/15/25
Ultra-small, single-,
dual-, quad-, octal-channel,
12-bit buffered output
voltage DACs with internal
reference and SPI interface
Programmable interface watchdog
timer (MAX5725 only), three precision
selectable internal references, wide 2.7V
to 5.5V supply range
Watchdog version flags communication
breakdown; feature-rich 1-/2-/4-/8-channel
DAC family in a WLP footprint saves board
space and cost; independent 1.8V to 5.5V
digital I/O power-supply input adds flexibility.
MAX5214/16
14-/16-bit, low-power,
buffered output, rail-to-rail
DACs with SPI interface
Low power consumption (80µA max),
guaranteed monotonic over all operating
ranges, wide 2.7V to 5.25V supply range
Minimize power consumption; improve
system performance with high resolution,
high accuracy, and high precision; integrated
buffer reduces the board space needed.
MAX5316/18
16-/18-bit, high-accuracy
voltage output DAC with
digital gain, offset control,
and SPI interface
INL accuracy guaranteed with ±2 LSB
(max) over temperature, buffered voltage
output directly drives 2kΩ load rail-torail, no external amplifiers required
Lowest noise, fast-settling precision 16-/
18-bit DACs improve system speed and
accuracy; integrated output and reference
buffers save development time, development
cost, and PCB area.
MAX15500/01
Industrial analog current/
voltage output conditioners
Programmable output (plus overrange);
±10V, 0 to 10V, 0 to 5V; ±20mA, 0 to
20mA, 4mA to 20mA; HART compliant;
SPI interface, with daisy-chain capability
Extensive error reporting through the SPI
interface enhances system safety; protected
against short-circuit/overcurrent output
conditions.
www.maximintegrated.com
Process Control Solutions Guide
Sensor Digitizers
Thermocouples and RTDs (resistance temperature detectors) are the most common
industrial sensors for temperature due to their ability to handle very wide temperature
ranges, but interfacing to them is not easy. They must be properly biased and their signals
properly linearized to realize their potential accuracy and precision. Any loss of signal
from these sensors can be a critical problem since they are usually an integral part of the
temperature control loop. To help our customers realize simple and reliable solutions to these
challenges, Maxim developed single IC sensor digitizer solutions for both thermocouples
and RTDs. The solutions bias these sensors, handle the cold junction compensation needed
for thermocouples, have many built-in fault detections, and provide digital outputs.
MAX31865 RTD-to-Digital Converter
The MAX31865 RTD-to-digital converter is
optimized for platinum RTDs. An external resistor
sets the sensitivity for the RTD being used and a
precision delta-sigma ADC converts the ratio of
the RTD resistance to the reference resistance
into digital form. The MAX31865’s inputs are
protected against overvoltage faults as large as
±50V. Programmable detection of RTD and cable
open and short conditions is included.
Key Features
VDD
VDD
0.1FF
0.1FF
DVDD
VDD
BIAS
REFIN+
DRDY
REFIN-
SDI
HOST
INTERFACE
• Simple conversion of platinum RTD (PT100 to
PT1000)
• Compatible with 2-, 3-, and 4-wire sensor
connections
SCLK
ISENSOR
MAX31865
FORCE+
CS
FORCE2
SDO
RTDIN+
N.C.
• 15-bit ADC resolution
• Total accuracy: 0.5°C (0.05% of full scale) max
• ±50V input protection
RREF
RCABLE
RCABLE
CI*
RTDINFORCEGND1 GND2 DGND
RTD
RCABLE
RCABLE
*CI = 10nF FOR 1kI RTD
100nF FOR 100I RTD
• Multiple sensor fault detections
MAX31865 4-wire sensor connection.
MAX31855 Thermocouple-to-Digital Converter
The MAX31855 thermocouple-to-digital converter is a single IC solution
that provides functionality similar to the MAX31865, but digitizes the
signal from K-, J-, N-, T-, S-, R-, and E-type thermocouples. It includes
the necessary cold junction compensation. It allows readings as high as
+1800°C and as low as -270°C.
Key Features
• Cold-junction compensation
• 14-bit, 0.25°C resolution
• K-, J-, N-, T-, S-, R-, and E-type thermocouples
• Detects thermocouple shorts to GND or VCC
• Detects open thermocouple
VCC
0.1FF
MICROCONTROLLER
GND
MAX31855
SO
MISO
T+
SCK
SCK
T-
CS
SS
17
www.maximintegrated.com
Process Control Solutions Guide
Robust Communications
Digital Input Serializers
Key Features
• Eight high-voltage input channels (36V max)
MAX31913 Industrial Interface Serializer
• Configurable for IEC 61131-2 input Types 1, 2, 3
The MAX31913 industrial interface serializer translates, conditions,
and serializes the 24V digital output of sensors and switches to 5V
CMOS-compatible signals. The device features current limiting, lowpass
filtering, and channel serialization, thereby significantly reducing
power consumption, circuit complexity, and allowing a dramatic
reduction in the number of optocouplers used for isolation. This
serializer can be daisy-chained, reducing the number of optocouplers
needed to only three, regardless of the number of input channels.
24V
• Configurable input current limiting from
0.5mA to 6mA
• On-chip 5V regulator
• On-chip 24V field supply voltage monitor
• Multibit CRC code generation and
transmission for error
JUMPERS TO
5VOUT
AND GND
R1
D0
• Field-side energyless LED drivers
5VOUT
VCC24V
C0
• Selectable input filtering and debouncing from
0 to 3ms
C1
DB0
DB1
C3
C4
MODESEL
VDD_LOGIC
MAX31913
fIN1–8
SIN
RINX
CLK
IN1–8
CLK
CS
CS
ISOLATION
RT1–8
RIREF
SOUT
SOUT
FAULT
GND
FAULT
RREF
D1
0V C0
CLK
VCC24V
CS
C1
SOUT
FAULT
SIN
fIN1–8
RINX
MAX31913
IN1–8
JUMPERS TO
5VOUT
AND GND
5VOUT
DB0
DB1
RT1–8
MODESEL
RIREF
GND
RREF
18
C3
C4
www.maximintegrated.com
Process Control Solutions Guide
Digital Input Serializers (cont.)
Digital Input Reference Design
Key Features
The Corona (MAXREFDES12#) reference design is an isolated octal
digital input solution made from just three ICs that, when compared to the
traditional approach, provides significantly reduced size, power dissipation,
component count, isolation channels, processor I/O port usage, and cost.
• Eight high-voltage input channels (36V max)
• On-chip 8-to-1 serialization with SPI interface
• On-chip 5V regulator
• Isolated power and data
• Example C source code
FPGA
DEVELOPMENT
KIT OR FC
MAX31911
OCTAL FIELD INPUTS
-3V TO +36V
DIGITAL INPUT
TRANSLATOR/
SERIALIZER
5V REGULATOR
FIELD SUPPLY
+7V TO +36V
• Pmod-compatible form factor
MAX14850
DATA
ISOLATION
Pmod
VCC24V
MAX13256
POWER
ISOLATION
CONTROLLER SUPPLY
+7.6V TO +36V
Selector Table: Digital Input Serializers
Part
Description
Features
Benefits
MAX31911
Octal, digital input
translator/serializer
Programmable on-chip current limiter,
on-chip serializer, 3-bit CRC
Lowest-in-class power dissipation; only three
optocouplers required; reliable data transfer.
MAX31913
Octal, digital input
translator/serializer
with LED drivers
Programmable on-chip current limiter,
5-bit CRC, field-side energyless
LED drivers
Lowest-in-class power dissipation; only three
optocouplers required; reliable data transfer.
19
www.maximintegrated.com
Process Control Solutions Guide
Overvoltage/Overcurrent Protectors
Key Features
The MAX14571/MAX14572/MAX14573 are industrial protection ICs
that combine high overvoltage up to 36V and overcurrent protection
accurate up to 4.2A in a small 14-pin TSSOP (5mm x 6.5mm) package
with integrated FETs that have low 100mΩ (typ) RON. The back-to-back
FETs provide positive and negative input overvoltage protection and
reverse current protection. Besides eliminating the need for discrete
components, these parts are up to one-third smaller than comparable IC
solutions with external FETs. The individual parts in this family offer the
choice of turning off after a 20.7ms (typ) blanking time, latchoff after the
blanking time, or continuous current limiting at the threshold. All these
devices operate over the extended -40°C to +85°C temperature range.
VPOWER
CIN
IN
OUT
IN
OUT
SYSTEM
INPUT
R1
R4
OVLO
FLAG
EN
SET1
RIEN
R2
GND
• 100mΩ (typ) on-resistance FET
• ±3% accurate preset voltage thresholds
• ±15% accuracy current limit
VPULLUP
MAX14571
MAX14572
MAX14573
UVLO
• Adjustable current limit up to 4.2A
COUT
OUT
IN
R3
• Wide 4.5V to 36V operating input range
SYSTEM
HVEN
NOTE: R1, R2, R3, AND R4 ARE ONLY REQUIRED FOR ADJUSTABLE
OVLO/UVLO; OTHERWISE, CONNECT UVLO/OVLO TO GND.
MAX14626 Current Loop Protector
Key Features
The MAX14626 current loop protector is the industry’s first 4mA to
20mA integrated current loop protector. It features a current-limit switch
set to 30mA to prevent damage to the analog input module from sensor
failure. The current-limit switch features low 25Ω (typ) on-resistance
to significantly lower power dissipation compared to discrete solutions
consisting of a PTC poly switch, zener diodes, and resistors.
• +2.3V to +40V wide supply voltage range
• Low on-resistance 25Ω (typ)
• Accurate ±10% current limit
• Reverse input protection
• Low operating current
4–20mA CURRENT
SENSOR
(4–20mA)
CURRENT
SENSOR READING DEVICE
MAX14626
IN
OUT
REF
SUPPLY
CONTROL AND
PROTECTION
CURRENT LIMIT
GATE CONTROL
GND
20
RLOAD
IA
ADC
www.maximintegrated.com
Process Control Solutions Guide
IO-Link Master and Device Transceivers
The MAX14820 and MAX14821 transceivers are suitable for IO-Link
devices and 24V binary sensors/actuators. All specified IO-Link data rates
are supported. Additional 24V digital inputs and outputs are provided. Two
internal linear regulators generate common sensor and actuator power
requirements: 5V and 3.3V.
On-board C/Q and DO drivers are independently configurable for push-pull,
high-side (pnp), or low-side (npn) operation. The device detects the IO-Link
C/Q wake-up condition and generates a wake-up signal on the active-low
WU output.
The MAX14820 is available in a 4mm x 4mm, 24-pin TQFN package, and the
MAX14821 is available in both a 4mm x 4mm, 24-pin TQFN package and a
2.5mm x 2.5mm, 25-pin WLP package. Both devices are specified over the
extended -40°C to +85°C temperature range.
WLP
Key Features
• IO-Link v1.0 and v1.1 physical layer compliant
• Supports COM1, COM2, and COM3
data rates
• IO-Link device wake-up detection
• Push-pull, high-side, or low-side outputs
• 300mA (MAX14820) and 100mA
(MAX14821) specified C/Q output drive
• Extensive fault monitoring and reporting
• TQFN (MAX14820/MAX14821) and WLP
(MAX14821 only) packages
TQFN
(2.5mm x 2.5mm) (4mm x 4mm)
The USB drive is only shown for size reference.
5V
3.3V
1FF
0.1FF
0.1FF
10kΩ
VCC
GPIO2
UV
VL
TXQ LDO33 V5
LDOIN VP
VCC
SPI
MICROCONTROLLER
IRQ
WU
RX
RX
TX
TXC
RTS
GND
GPIO1
1FF
L+
DO
MAX14820
1
2
C/Q
TXEN
LO
0.8Ω
DI
GND
4
3
L-
21
www.maximintegrated.com
Process Control Solutions Guide
IO-Link Master and Device Transceivers (cont.)
MAX14824 IO-Link Master Transceiver
Key Features
• IO-Link v.1.0 and v.1.1 physical layer compliant
The MAX14824 is an IO-Link master interface that integrates an
IO-Link physical layer transceiver with an auxiliary digital input and
two linear regulators. High-port-count IO-Link master applications
are supported through in-band SPI addressing, and the 12MHz SPI
interface minimizes host controller access times. In-band addressing
and selectable SPI addresses enable cascading up to 16 devices.
• Supports COM1, COM2, and COM3 data rates
• 300mA C/Q output drive
• Generates 500mA wake-up pulse
• -40°C to +105°C operating temperature range
• 4mm x 4mm TQFN package
24V
1μF
1μF
0.1μF
270pF
VCC
VL
SPI
TXQ LDO33
V5
LDOIN VCC
C/Q
IO-LINK
CONTROLLER
GPO
WUEN
RX
RX
TX
TXC
RTS
GND
MAX14824
C/Q
270pF
DI
TXEN
A0
A1
A2
A3 GND
Selector Table: IO-Link Transceivers
22
Part
Description
Features
Benefits
MAX14820
IO-Link device transceiver
IO-Link v1.0 and 1.1 compliant, 300mA output
drive, reverse polarity and short-circuit
protection
Reduced solution footprint; low power
consumption.
MAX14821
IO-Link device transceiver
Small 2.5mm x 2.5mm package, IO-Link v1.0
and v1.1 compliant, reverse polarity and shortcircuit protection
Smallest size enables more compact
sensor designs; low power consumption.
MAX14824
IO-Link master transceiver
500mA WU pulse generation, IO-Link v1.0
and 1.1 compliant, reverse polarity and shortcircuit protection
Easily scalable to 16 channels with
in-band SPI addressing.
MAX14830
Quad UART with
integrated FIFOs
128-word FIFOs, SPI or I2C interface,
synchronized transmit capability
Reduced processor overhead; UART
expansion optimal for IO-Link
applications.
www.maximintegrated.com
Process Control Solutions Guide
RS-485 Transceivers
To continue our leadership position in providing the most robust interface
technology in the industrial market, the MAX14783E is a 3.3V/5V
ESD-protected transceiver intended for half-duplex RS-485/RS-422
communication up to 42Mbps. The device is optimized for high speeds over
extended cable runs, while maximizing tolerance to noise.
The MAX14783E integrated protection features include short-circuitprotected outputs, hot-swap functionality, and a true fail-safe receiver that
guarantee a logic-high receiver output when inputs are shorted or open.
Hot-swap capability eliminates undesired transitions on the bus during
power-up or hot insertion.
Key Features
• Integrated protection increases robustness
• ±35kV HBM ESD
• Short-circuit protected outputs
• True fail-safe receiver
• Hot-swap capability
• -40°C to +125°C operating temperature
range
VCC
MAX14783E
RO
R
RE
B
SHUTDOWN
A
DE
DI
D
GND
The MAX14783E matches the industry standard
pinout while protected to ±35kV HBM ESD.
120Ω
120Ω
DI
DE
B
B
D
D
DI
DE
RO
A
B
A
B
A
A
R
R
RE
R
R
D
MAX14783E
DI
RO
RE
D
DE
RO RE
DI
DE
RO RE
Typical half-duplex RS-485 network using the MAX14783E.
23
Process Control Solutions Guide
Beyond-the-Rails is a trademark and DeepCover, 1-Wire, and μMAX are registered trademarks of Maxim Integrated Products, Inc.
IO-Link is a registered trademark of ifm electronic GmbH.
Nexys and Pmod are trademarks of Digilent Inc.
Xilinx is a registered trademark and registered service mark of Xilinx, Inc.
ZedBoard is a trademark of ZedBoard.org.
Contact Maxim Direct at 1.888.629.4642 or for more information, visit www.maximintegrated.com.
© 2014 Maxim Integrated. All rights reserved. The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc., in the United
States and other jurisdictions throughout the world. All other company names may be trade names or trademarks of their respective owners.
Rev. 1; January 2014
www.maximintegrated.com
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