Field Instrument/Smart Transmitter Design PDF

Analog Devices’ Products
and Signal Chain Solutions for
Field Instrument/Smart
Transmitter Design
ADI Field Instrument Segment Overview
Analog Devices is a leading supplier of industrial precision signal measurement solutions. These products are designed into field instruments in process
and manufacturing plants across a wide range of industries including chemical and pharmaceutical, hydrocarbon (oil and gas), environmental (waste
water and treatment), and food and beverage. The combination of ADI’s proven system expertise in industrial applications and a comprehensive portfolio
of products with leading performance vs. power makes ADI a strong partner for engineers designing field instruments.
Main Challenges and System
Considerations
• High reliability, longevity of
supply, and lower assembly
and manufacturing costs
• Operation in harsh environments
requiring support for a wide
temperature range
• Limited available power for looppowered instruments drives the
need for components with high
performance at very low power
• Increasing end market need for
higher levels of functional safety
Field Instrument Applications
Why Choose ADI?
• ADI is a technology leader in
precision converters and signal
processing with a long history of
serving the needs of industrial
customers
• ADI’s dedicated team of industrial
application engineers provides
system expertise to support
our customers through their
complete design cycle
• ADI is continually investing in
core technology and application
specific products to meet current
and future industrial needs
• Long product life cycles, superior
reliability, and on time delivery
• Best-in-class signal chain solutions for precision measurement
over a wide range of sensor
inputs with high accuracy and
very low power
www.analog.com
• Temperature transmitters
• Pressure transmitters
• Electromagnetic flow transmitters
• Ultrasonic flow transmitters
• Differential pressure flow
transmitters
Temperature Transmitter
LDO
DC-TO-DC STEP DOWN
HART MODEM
INTEGRATED SOLUTION
DAC
RTD
THERMOCOUPLE
MUX
AMP
ADC
ISOLATION
CURRENT SOURCES
REF
MICROCONTROLLER/
INTEGRATED SOLUTION
TEMPERATURE
SENSOR
4mA TO 20mA
OUTPUT
PROTECTION
AMP
REF
PROFIBUS
CAN
RS-485
RS-232
WIRELESS
Pressure Transmitter
LDO
DC-TO-DC STEP DOWN
HART MODEM
TEMPERATURE
SENSOR
INTEGRATED SOLUTION
DAC
OUT+
MUX
IN–
RESISTIVE
BRIDGE
AMP
ADC
REF
MICROCONTROLLER/
INTEGRATED SOLUTION
ISOLATION
IN+
OUT–
4mA TO 20mA
OUTPUT
PROTECTION
AMP
REF
PROFIBUS
CAN
RS-485
RS-232
WIRELESS
Pressure and Temperature Analog Front End
A wide portfolio of very low power precision converters and integrated solutions to meet the requirements of temperature and pressure transmitters.
Part Number
Description
Integrated Digital Temperature Sensor
ADT7320/ADT7420
±0.25°C accurate, 16-bit SPI/I2C
temperature sensor
ADC
AD7793/AD7794/
AD7799
16-/24-bit, 3-channel/6-channel, low noise,
low power, Σ-Δ ADC with on-chip in-amp
Key Features and Benefits
• ±0.25°C accuracy from –20°C to +105°C at
3.3 V
• Ultralow temperature drift: 0.0073°C
• Easy implementation
• Low power
•
•
•
•
•
16-bit/24-bit versions available
Low power: 400 μA
Internal programmable gain amplifier
4 ppm/°C on-chip reference (AD7793/AD7794)
Programmable current sources
(AD7793/AD7794)
• Low-side power switch (AD7794, AD7799)
•
•
•
•
•
•
• Analog performance
• Dual PGA and 24 bit, 4 kSPS ADCs
• 12 multiplexed analog inputs
• 12-bit DAC
• Power consumption only 1 mA with core
operating at 500 kHz (both ADCs on, input
buffers off, PGA gain of 4, one SPI port on, and
all timers on)
• Package and temperature
• 48-lead LFCSP (7 mm × 7 mm)
• –40°C to +125°C
Burnout currents
Internal clock and buffer
Simultaneous 50 Hz and 60 Hz rejection
4.17 SPS to 400 SPS output data rate
Supply: 2.7 V to 5.25 V
Temperature: –40°C to +105°C
Microcontroller
ADuCM360/
ADuCM361
Low power precision analog microcontroller,
ARM Cortex™-M3 with dual/single Σ-∆ ADCs
ADuC7060/
ADuC7061
Low power, precision analog microcontroller,
dual Σ-∆ ADCs, flash/EE, 16-/32-bit
ARM7TDMI®
| Field Instrument/Smart Transmitter Design
2
• Digital performance
• 32-bit ARM Cortex-M3 processor
• 128 kB flash, 8 kB SRAM
• Dual 24-bit 8 kSPS Σ-∆ ADCs
• Single 14-bit DAC
• ARM7TDMI 16-/32-bit RISC controller
• 32 kB flash and 4 kB SRAM
• UART, SPI, GPIO, PWM
• Nominal supply 2.5 V
• Temperature range: –40°C to +125°C
Electromagnetic Flow Transmitter
CURRENT
SOURCE
DC-TO-DC STEP-DOWN
HART
MODEM
LDO
REF
GATE DRIVER
4mA TO 20mA
DAC
REF
MUX
AMP
ADC
INTEGRATED SOLUTION
MCU
ISOLATION
IN-AMP
AMP
OUTPUT
PROTECTION
PROFIBUS
CAN
RS-485
RS-232
INTEGRATED SOLUTION
WIRELESS
TEMPERATURE
SENSOR
WATCHDOG
TIMER
Electromagnetic Flow Transmitter Analog Front End
Part Number
Description
Instrumentation Amplifier
AD8228
Low gain drift precision instrumentation amplifier
Key Features and Benefits
• Fixed G = 10, 100
• 650 kHz –3 dB bandwidth (G = 10)
• Wide power supply range: ±2.3 V to ±18 V
• 2 ppm/°C max gain drift
• 2 V/µs slew rate
• 8 nV/√Hz @ 1 kHz min
• 100 dB CMRR to 10 kHz (G = 10)
• 0.8 μV/°C max voltage offset drift
Multiplexer
ADG1611
1 Ω typical on resistance, ±5 V, +12 V, +5 V,
and +3.3 V quad SPST switches
• 1 Ω on resistance
• 0.2 Ω on resistance flatness
ADG1411
1.8 Ω max on resistance, ±15 V/12 V/±5 V,
iCMOS,® quad SPST switch
• 1.5 Ω on resistance
• 0.3 Ω on resistance flatness
• Low offset voltage: 25 µV max
• Low input bias current: <1.0 nA max
• Low noise: 7 nV/√Hz typical
Amplifier
ADA4077-2
4 MHz, 7 nV/√Hz, low offset and drift,
high precision amplifier
• Low offset voltage drift: 0.25 µV/°C max
• Low supply current: 400 µA per
amplifier typical
Voltage Reference
ADR3412/ADR3420
ADR3425/ADR3430 Low power, 10 ppm/°C CMOS voltage reference
ADR3433/ADR3440 (1.20 V/2.048 V/2.50 V/3.00 V/3.30 V/4.096 V/5.00 V)
ADR3450
• Low quiescent current: 100 µA max
• Initial accuracy: ±0.1%
• Low frequency noise: <10 µV p-p
(0.1 Hz to 10 Hz)
• Max temperature coefficient: 8 ppm/°C
• Wide temperature range: –40°C to
+125°C operation
• 4.7 Hz to 4.8 kHz output data rate
• Offset drift: 5 nV/°C
• PGA: gain from 1 to 128
• Gain drift: 1 ppm/°C
• Analog performance
• Dual PGA and 24-bit, 4 kSPS ADCs
• 12 multiplexed analog inputs
• 12 bit DAC
• Power consumption only 1 mA with core
operating at 500 kHz (both ADCs on, input
buffers off, PGA gain of 4, one SPI port on,
and all timers on)
• Package and temperature
• 48-lead LFCSP (7 mm × 7 mm)
• –40°C to +125°C
ADC
AD7192
4.8 kHz ultralow noise 24-bit Σ-∆ ADC with PGA
Microcontroller
ADuCM360/
ADuCM361
Low power precision analog microcontroller,
ARM Cortex-M3 with dual/single Σ-∆ ADCs
• Digital performance
• 32-bit ARM Cortex-M3 processor
• 128 kB flash, 8 kB SRAM
Digital Processor
ADSP-BF504/
ADSP-BF504F/
ADSP-BF506F
ADSP-BF50x fixed-point DSP
• 400 MHz Blackfin® core
• PPI for LCD display interface
• True 12-bit, dual SAR ADC
(ADSP-BF506F)
• 32 MB executable flash (ADSP-BF504F/
ADSP-BF506F)
• UART, SPI, SPORT, and CAN interfaces
for communications
www.analog.com | 3
Ultrasonic Flow Transmitter
DC-TO-DC STEP-DOWN
LDO
TRANSDUCER
DRIVER
HART
MODEM
DAC
REF
DAC
DAC
MUX
OUTPUT
AMP
4mA TO 20mA
PROTECTION
INTEGRATED SOLUTION
ADC
VGA
TEMPERATURE
SENSOR
CONTROLLER
REFERENCE
ISOLATION
WATCHDOG
TIMER
PROFIBUS
CAN
RS-485
RS-232
WIRELESS
Ultrasonic Flow Transmitter Analog Front End
Part Number
Multiplexer
ADG1611
Description
Key Features and Benefits
1 Ω typical on resistance, ±5 V, +12 V, +5 V,
and +3.3 V quad SPST switches
1.8 Ω max on resistance, ±15 V/12 V/±5 V, iCOMS,
quad SPST switch
Integrated Digital Temperature Sensor
ADG1411
ADT7320/ADT7420
±0.25°C accurate, 16-bit SPI/I2C
temperature sensor
• 1 Ω on resistance
• 0.2 Ω on resistance flatness
• 1.5 Ω on resistance
• 0.3 Ω on resistance flatness
• ±0.25°C accuracy from –20°C to +105°C
at 3.3 V
• Ultralow temperature drift: 0.0073°C
• Easy implementation
• Low power
ADC
AD9609/AD9629/
AD9649
10-/12-/14-bit, 20 MSPS/40 MSPS/65 MSPS/
80 MSPS, 1.8 V analog-to-digital converter
• 2 V p-p analog input
• 1.8 V to 3.3 V parallel and SPI interface
• 74.3 dBFS SNR at 9.7 MHz input
Variable Gain Amplifiers
• LNA:
•
AD8331/AD8332/
AD8334
Single/dual/quad VGA with ultralow noise preamplifier
and programmable RIN
•
Ultralow noise: 0.74 nV/√Hz;
2.5 pA/√Hz
Active termination match via external
resistor
• VGA:
•
•
•
•
48 dB gain range
Postamplifier with 12 dB gain
switch: output SNR optimized for
10-/12-bit ADCs
Fully differential
Selectable output clamping levels
DAC
AD5641
2.7 V to 5.5 V, 100 μA, 14-bit nano DAC,®
SPI interface in LFCSP and SC70
• Minimum board area
•
14-bit in SC70 or 2 mm × 3 mm
6-lead LFCSP
• Low power DAC
•
Max 100 μA supply current
High Speed DAC
• 175 MSPS DAC update rate
®
AD9705
10-bit, 175 MSPS TxDAC
digital-to-analog converter
• Low power dissipation
12 mW at 80 MSPS, 1.8 V
Power-down mode: <2 mW
• SFDR to Nyquist
•
• 84 dBc at 5 MHz output
• Wide supply range 1.7 V to 3.6 V
•
• On-chip 1 V reference
• 400 MHz Blackfin core
• PPI for LCD display interface
• True 12-bit, dual SAR ADC
(ADSP-BF506F)
• 32 MB executable flash (ADSP-BF504F/
ADSP-BF506F)
Digital Processor
ADSP-BF504/
ADSP-BF504F/
ADSP-BF506F
ADSP-BF50x fixed-point DSP
| Field Instrument/Smart Transmitter Design
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• UART, SPI, SPORT, and CAN interfaces for
communications
Differential Pressure Flow Transmitter
LDO
DC-TO-DC STEP DOWN
HART MODEM
IN+
REF
OUT+
OUT–
4mA TO 20mA
REF
IN–
IN+
MUX
OUT+
AMP
ADC
MCU
IN–
ISOLATION
DAC
AMP
OUTPUT
PROTECTION
INTEGRATED SOLUTION
PROFIBUS
CAN
INTEGRATED SOLUTION
RS-485
RS-232
WATCHDOG
TIMER
WIRELESS
TEMPERATURE
SENSOR
Differential Pressure Flow Transmitter Analog Front End
Part Number
Description
Integrated Digital Temperature Sensor
ADT7320/ADT7420
±0.25°C accurate, 16-bit SPI/I2C
temperature sensor
Key Features and Benefits
• ±0.25°C accuracy from –20°C to +105°C
at 3.3 V
• Ultralow temperature drift: 0.0073°C
• Easy implementation
• Low power
• Latch-up proof
• Low on resistance: 13.5 Ω
• 8 kV HBM ESD rating
• Latch-up proof
• Low on resistance: 160 Ω
Multiplexer
ADG5409
High voltage latch-up proof 4-channel/8-channel
multiplexers
ADG5209
High voltage latch-up proof 4-channel/8-channel
multiplexers
• 0.4 pC charge injection
Amplifier
AD8226
Wide supply range, rail-to-rail output
instrumentation amplifier
• Fully specified: –40°C to +125°C
• Input noise: 22 nV/√Hz
• Gain of 1 to 1000
• 350 μA typical supply current
• 2.2 V to 36 V supply range
ADC
AD7794/AD7799
16-/24-bit, 3-channel/6-channel, low noise, low
power, Σ-Δ ADC with on-chip in-amp
•
•
•
•
•
16-/24-bit versions available
Low power: 400 μA
Internal programmable gain amplifier
4 ppm/°C on-chip reference (AD7794)
Programmable current sources
(AD7794)
• Low-side power switch
•
•
•
•
•
•
• Analog performance
• Dual PGA and 24-bit, 4 kSPS ADCs
• 12 multiplexed analog inputs
• 12-bit DAC
• Power consumption only 1 mA with core
operating at 500 kHz (both ADCs on, input
buffers off, PGA gain of 4, one SPI port on,
and all timers on)
• Package and temperature
• 48-lead LFCSP (7 mm × 7 mm)
• –40°C to +125°C
Burnout currents
Internal clock and buffer
Simultaneous 50 Hz and 60 Hz rejection
4.17 SPS to 400 SPS output data rate
Supply: 2.7 V to 5.25 V
Temperature: –40°C to +105°C
Microcontroller
ADuCM360/
ADuCM361
Low power precision analog microcontroller,
ARM Cortex-M3 with dual/single Σ-∆ ADCs
ADuC7060/
ADuC7061
Low power, precision analog microcontroller,
dual Σ-∆ ADCs, flash/EE, 16-bit/32-bit ARM7TDMI
• Digital performance
• 32-bit ARM Cortex-M3 processor
• 128 kB flash, 8 kB SRAM
• Dual 24-bit 8 kSPS Σ-∆ ADCs
• UART, SPI, GPIO, PWM
• Single 14-bit DAC
• Nominal supply 2.5 V
• ARM7TDMI 16-bit/32-bit RISC controller
• Temperature range: –40°C to +125°C
• 32 kB flash and 4 kB SRAM
www.analog.com | 5
Isolation, Power, and Communication
A wide range of supporting products to meet the various isolation, power, and communications requirements for temperature, pressure, and flow
transmitters.
Part Number
Isolation
Description
ADuM3481
3.75 kV rms quad-channel digital isolator
ADuM4401
5 kV rms quad-channel digital isolator
ADuM1401
2.5 kV rms quad-channel isolator
Key Features and Benefits
• Small package: 20-lead SSOP
• Low dynamic power consumption
• Low voltage I/O: 1.8 V to 5.5 V
• 50 year lifetime at 565 V pk
•
•
•
•
• 16-lead SOIC wide package
• 50 year lifetime at 565 V pk
• 50-year lifetime at 565 V pk
Low power operation
Reinforced isolation rating
Low power consumption
16-lead SOIC wide package
Integrated DAC
• Very low power: quiescent current: 300 µA max
• HART compatible
AD5421
16-bit, serial input, loop-powered,
4 mA to 20 mA DAC
• 16-bit resolution and monotonicity, pin
selectable NAMUR-compliant ranges
• Internal regulator and reference
• Total unadjusted error (TUE): 0.05% max
• Output TC: 3 ppm/°C typ
AD5420
16-bit, serial input, single-channel, 4 mA
to 20 mA current source DAC
• Current output ranges: 4 mA to 20 mA, 0 mA to
20 mA, or 0 mA to 24 mA
• ±0.01% FSR typical total unadjusted TUE
• ±3 ppm/°C typical output drift
• On-chip reference and output fault detection
• HART compatible
• 12-bit accuracy guaranteed
• On-chip, 1.25 V/2.5 V, 5 ppm/°C reference
(AD5660)
• Power-on reset to 0 V or midscale
• 10 µs settling time
DAC
AD5660/AD5662
Single nano DAC, 16-bit monotonic DAC
• Tiny 8-lead SOT-23 and MSOP packages
Power Management/LDO
ADP160
Ultralow quiescent current 150 mA,
CMOS linear regulator
ADP1720
50 mA, high voltage, micropower
linear regulator
•
•
•
•
Input voltage range: 2.2 V to 5.5 V
IQ = 11 μA at 10 mA load
Wide input voltage range: 4 V to 28 V
IQ = 74 μA at 1 mA load
•
•
•
•
Max output current: 150 mA
Low dropout voltage: 195 mV @ 150 mA load
Max output current: 50 mA
Low dropout voltage: 275 mV @ 50 mA load
Power management/DC-DC step-down
ADP2441
36 V, 1 A, synchronous step-down
dc-to-dc regulator
ADP2370
High voltage, 1.2 MHz/600 kHz, 800 mA,
low quiescent current buck regulator
•
•
•
•
Wide input voltage range: 4.5 V to 36 V
High efficiency up to 94%
Adjustable output down to 0.6 V
Input voltage range: 3.2 V to 15 V, output
current: 800 mA
• Quiescent current <14 µA in power saving
mode (PSM)
• ±1% output voltage accuracy
• Adjustable frequency 300 kHz to 1 MHz
• >90% efficiency
• Force PWM pin (SYNC), 600 kHz/1.2 MHz
frequency pin (FSEL)
Amplifier
AD5749
Industrial current out driver, single-supply,
55 V compliant with programmable ranges
• IOUT range
• 4 mA to 20 mA, 0 mA to 24 mA
• 0.03% accuracy (TUE)
•
2 ppm/°C full scale output drift
•
•
•
•
11.8 V to 55 V supply range
Diagnostic/fault detection
Digital input cyclical redundancy check
External 4.096 V reference
Voltage Reference
ADR3525
Micropower, precision, 2.5 V
voltage reference
ADR4525
Ultralow noise, high accuracy 2.5 V
voltage reference
ADR291
Low noise micropower precision
voltage reference (2.5 V)
| Field Instrument/Smart Transmitter Design
6
• Max temperature coefficient (TC):
5 ppm/°C (B grade)
• 100 μA max quiescence current
• ±0.02% max initial error
• Output noise (0.1 Hz to 10 Hz): <1.25 µV p-p
@ 2.5 VOUT typical
• Supply range: 2.8 V to 15 V
• Supply current 12 µA max
• Output noise (0.1 Hz to 10 Hz): 18 μV p-p
at 2.5 V (typical)
• 8-lead MSOP
• Max temperature coefficient (TC) : 2 ppm/°C
• Input voltage range: 3 V to 15 V
• Low noise: 8 µV and 12 µV p-p (0.1 Hz to 10 Hz)
• 10 ppm/°C
• –40°C to +125°C operating temperature range
Part Number
HART Modem
Description
AD5700/AD5700-1
Low power HART modem
Key Features and Benefits
• HART-compliant fully integrated FSK modem
• 115 µA maximum supply current in receive mode
• On-chip oscillator (AD5700-1)
• 4 mm × 4 mm, 24-lead LFCSP
• Buffered HART output
• Suitable for intrinsically safe applications
• 30 Mbps data rate
• 2.1 V min differential output with 54 Ω
termination
• Fully isolated digital interface
• 50 nodes on bus
• 5 V or 3.3 V operation
• Low power 0.8 mA |CC
• Fully isolated digital interface
• isoPower® integrated isolated dc-to-dc
converter
• ±15 kV ESD protection on RS-485 I/O pins
• 5 V or 3.3 V operation
• Integrated oscillator driver for external
transformer
• ±15 kV ESD protection on RS-485 I/O pins
• Connect up to 256 nodes on one bus
• Open- and short-circuit, fail-safe receiver inputs
PROFIBUS
ADM1486
5 V, high speed, low power, half duplex
RS-485 PROFIBUS transceiver
ADM2485/
ADM2486
2.5 kV single isolated, high speed,
half duplex RS-485 transceiver
• 16 Mbps/20 Mbps data rate (ADM2485/ADM2486)
• Integrated oscillator driver for external
transformer (ADM2485)
RS-485
ADM2587E
2.5 kV signal and power isolated,
±15 kV ESD protected, full/half duplex
RS-485 transceiver 500 kbps
ADM2482E
2.5 kV signal isolated, ESD protected,
full/half duplex RS-485 transceiver with
transformer driver 16 Mbps
ADM2490E
5 kV signal isolated, high speed (16 Mbps), • ±8 kV ESD protection on RS-485 I/O pins
ESD protected, full duplex RS-485
• Suitable for 5 V or 3 V operation
•
•
•
•
5 V or 3.3 V operation
256 nodes on bus
Open- and short-circuit, fail-safe receiver inputs
Receiver open-circuit fail-safe design
CAN
ADM3051
High speed industrial CAN transceiver
with bus protection for 24 V systems
ADM3052
5 kV rms isolated CAN transceiver with
integrated high voltage, bus side linear
regulator
ADM3053
2.5 kV rms signal and power isolated
CAN transceiver with integrated isolated
dc-to-dc converter
ADM3054
5 kV rms signal isolated high speed CAN
transceiver with bus protection
•
•
•
•
•
•
•
•
•
•
•
Physical layer CAN transceiver
5 V operation
Fully isolated digital interface
Integrated V+ linear regulator
Bus side powered by V+ and V–
Fully isolated digital interface
Signal and power isolation
5 V or 3.3 V operation
Fully isolated digital interface
5 V or 3.3 V operation
High speed data rate of up to 1 Mbps
• High speed data rates up to 1 Mbps
• 11 V to 25 V operation on V+
• High speed data rate up to 1 Mbps
• High speed data rate up to 1 Mbps
• Slop control for reduced EMI
• Short-circuit protection on CANH and CANL
against shorts to power/ground in 24 V systems
RS-232
ADM3251E/
ADM3252E
ADM3101E
• Fully isolated digital interface
• 2.5 kV fully isolated (power and data) RS-232
Isolated single-/dual-channel RS-232 line
transceiver
driver/receiver
• isoPower integrated, isolated dc-to-dc
converter
• 460 kbps data rate
±15 kV ESD protected, 3.3 V
single-channel RS-232 line driver/receiver • 0.1 μF charge pump capacitors
• 460 kbps data rate
• 15 kV ESD protection on R/N and TOUT pins
Wireless
ADuCRF101
Precision analog microcontroller
ARM Cortex-M3 with RF transceiver
ADF7023-J
High performance, low power, ISM band
FSK/GFSD/MSK/GMSK transceiver IC
ADF7242
Low power IEEE 802.15.4/proprietary
GFSK/FSK zero-IF 2.4 GHz transceiver IC
• 6-channel 12-bit SAR ADC
• Low power consumption
• Integrated RF transceiver: 862 MHz to 928 MHz
and 431 MHz to 464 MHz
•
•
•
•
Ultralow power
Frequency bands: 902 MHz to 958 MHz
Data rate supported; 1 kbps to 300 kbps
Frequency range (global ISM band) 2400 MHz
to 2483.5 MHz
• Programmable data rates and modulation
•
•
•
•
•
32-bit ARM Cortex-M3 processor
128 kB flash, 16 kB SRAM
UART, I2C, and SPI serial I/O
64-lead LFCSP
Flexible firmware programmable system
controller and packet processor
• Low power consumption
• High sensitivity
www.analog.com | 7
Circuits from the Lab Reference Designs
Analog Devices Circuits from the Lab® Reference Designs are engineered and tested by our technology and applications experts to ensure both
performance and function. Low cost hardware is available to allow for evaluation and rapid prototyping with several development platforms.
Thorough documentation and design files are provided to ease application understanding and minimize system integration issues.
CN0267 Complete 4 mA to 20 mA Loop-Powered Field Instrument with HART Interface
AD5421
L*
1.6𝛀
10𝛍F
PRIMARY
SENSOR
REGOUT
10𝛀
10𝛍F
10𝛍F
10𝛍F
1k𝛀
CS0
SCLK0
MOSI0
MISO0
VREF–
GND_SW
AVDD
1k𝛀
AIN4
IEXC
0.1𝛍F
1k𝛀
PT100 1k𝛀
CORTEX
M3
+
SRAM
FLASH
AVDD_
+
REG
DMA
UART
SPI
DVDD_
I2C
REG
CLOCK
RESET
WATCHDOG
0.01𝛍F AIN3
0.1𝛍F
AIN2
ADC1
AGND
SOUT
SIN
P0.5
P0.4
EXPOSED
PAD
RREF
5.62k𝛀
10ppm
AGND
DGND
AIN7
0.1𝛍F
0.47𝛍F
VREF
NOTES
1. L* = FERRITE BEAD, 0.3𝛀 @ DC, 1k𝛀 @ 100MHz.
2. THE ADuCM360 EXPOSED PAD IS CONNECTED TO DGND.
Features and Benefits
• Low power, small footprint
• 4 mA to 20 mA loop-powered field instrument
• HART compliant interface
• Registered by HART Communication Foundation (HFC)
For more information on this reference circuit,
visit www.analog.com/cn0267.
| Field Instrument/Smart Transmitter Design
8
SYNC
SCLK WATCHDOG
TIMER
SDIN
SDO
LDAC
COM
50𝛀
LOOP–
CIN
DVDD
4.7V
LOW LEAKAGE
470𝛀
0.47𝛍F
AD5700
1𝛍F
VCC
3.8664MHz
0.01𝛍F
1k𝛀
SPI INTERFACE
UART INTERFACE
0.068𝛍F
HART_OUT
0.22𝛍F
XTAL1
REF
XTAL2
TXD
RXD
CD
ADC_IP
RTS REG_CAP
DGND
AGND
4700pF
TVS
40V
LOW
LEAKAGE
10𝛍F
DAC
ADC0
AIN1
1M𝛍
TEMPERATURE
SENSOR
REFOUT1
REFOUT2 VREF
0.1𝛍F
0.01𝛍F
SECONDARY
SENSOR
1k𝛀
ADC
10𝛍F
IOVDD
0.01𝛍F AIN0
0.1𝛍F
LOOP+
20M𝛀
VREF+
1k𝛀
L*
REGIN
VLOOP
DVDD
DVDD
ADuCM360
AVDD
VOLTAGE
REGULATOR
1𝛍F
1𝛍F
1.2M𝛀
300pF
1.2M𝛀
150k𝛀
150pF
L*
LOOP–
Reference Circuits for Field Instruments
Circuit Description
Functions
Key Features and Benefits
Loop-Powered
CN0267
Complete 4 mA to 20 mA Loop-Powered Field
Instrument with HART Interface
• Sensors signal conditioning
• Digital processing
• Analog communication
CN0300
Complete Closed-Loop Precision Analog
Microcontroller Thermocouple Measurement
System with 4 mA to 20 mA Output
• Sensors signal conditioning
• Digital processing
• Analog communication
CN0319
4 mA to 20 mA Loop-Powered Temperature
Monitor Using the Integrated PWM On the
ADuCM360 Precision Analog Microcontroller
• Sensors signal conditioning
• Digital processing
• Analog communication
CN0145
4 mA to 20 mA Loop-Powered Temperature
Monitor Using the ADuC7060/ADuC7061 Precision
Analog Microcontroller
• Sensors signal conditioning
• Digital processing
• Analog communication
CN0289
Flexible, 4 mA to 20 mA, Loop-Powered Pressure
Sensor Transmitter with Voltage or Current Drive
• Sensors signal conditioning
• Analog communication
CN0206
Complete Type T Thermocouple Measurement
System with Cold Junction Compensation
• Sensors signal conditioning
CN0009
4 mA to 20 mA Process Control Loop Using the
AD5662 DAC
• Analog communication
CN0314
Precision, Low Cost, Highly Programmable 4 mA to
20 mA Current Loop Using the AD8420 Low Power • Analog communication
Instrumentation Amplifier
CN0247
12-Bit ,1 MSPS SAR ADC and Driver with Total
Power Dissipation Less Than 5 Milliwatts
• Sensors signal conditioning
• Data acquisition
• Complete 4 mA to 20 mA loop-powered field
instrument
• HART compliant interface
• Registered by HART Communication Foundation
(HCF)
• Low power, small footprint
• Complete 4 mA to 20 mA loop-powered field
instrument
• Thermocouple and RTD measurement
• Single chip solution with Cortex processing
core
• Complete 4 mA to 20 mA loop-powered field
instrument
• Thermocouple and RTD measurement
• 24-bit input, 14-bit output resolution
• Complete 4 mA to 20 mA loop-powered
field instrument
• RTD measurement
• 24-bit precision conversion with integrated
processor
• Complete 4 mA to 20 mA loop-powered field
instrument
• Optimized for pressure sensors
• Analog only design
• Thermocouple and thermister measurement
• Low power, 500 μA max
• Low system noise of 0.2° for T-type
thermocouple
• Loop-powered 4 mA to 20 mA output
• 16-bit resolution
• Transmitter or receiver board for 4 mA to 20 mA
systems
• Gain and scaling jumpers for different input
types
• Connects directly to ADC driver boards for
modular evaluation experience
• 12-bit, 1 MSPS data acquisition
• Single supply
• 5 mW power
Nonloop-Powered
CN0303
MEMS-Based Vibration Analyzer with Frequency
Response Compensation
• Sensor signal conditioning
CN0270
Complete 4 mA to 20 mA HART Solution
• Analog communication
CN0064
16-Bit Fully Isolated 4 mA to 20 mA Output Module
Using the AD5662 DAC, ADuM1401 Digital Isolator, • Analog communication
and External Amplifiers
CN0179
Less Than 200 μA, Low Power, 4 mA to 20 mA,
Process Control Current Loop
• Analog communication
CN0313
EMC Compliant RS-485 Transceiver Protection
Circuits
• Digital communication
•
•
•
•
•
•
•
•
•
•
•
•
High-g MEMS-based vibration analyzer
Flat response to 22 kHz
70 g, 250 g, and 500 g range
4 mA to 20 mA output
HART compliant solution
Low power
4 mA to 20 mA output
Digitally isolated
16-bit resolution
Low power 4 mA to 20 mA output
12-bit, 14-bit, or 16-bit resolution
Robust EMC compliant RS-485 transceiver
interface
• Tested to specific ESD, EFT, and surge levels
www.analog.com | 9
Online Tools And Resources
To learn more about products, signal chain solutions, and technical expertise offered by Analog Devices to help engineers meet today’s
field instrument design challenges, visit processcontrol.analog.com/fieldinstruments.
Signal Chain Designer—
www.analog.com/signalchaindesigner
Signal Chain Designer™ is an advanced selection and design
environment that accesses verified product combinations and
tested applications circuits, which can be customized or newly
created according to your specifications.
Analog Filter Wizard™­— www.analog.com/filterwizard
This online tool simplifies the
filter design process with an
intuitive user interface and
easily accessible tutorials
and help.
ADIsimDAC—www.analog.com/adisimdac
The purpose of
the ADIsimDAC™ tool is to
assist the user with finding
Analog Devices DACs and DAC
application circuits. It takes
user inputs along with typical
parametric data to sort, select,
and suggest applicable DACs, system
components, and circuits solutions.
Multisim ADC Component Evaluator,
ADI Edition—www.analog.com/multisim
The free downloadable version of NI Multisim™ 12.0 is tailored for
circuit design with ADI components in a SPICE simulation environment.
ADIsimPower—www.analog.com/adisimpower
ADIsimPower™ is a collection
of downloadable Excel spreadsheets that produce complete
power designs optimized to your
design goals. Get a schematic,
bill of materials, and performance data
customized to your specific needs in minutes.
Circuits from the Lab Reference Designs
For a complete list of Analog Devices Circuits from the Lab Reference Designs
for field instrument designs, visit www.analog.com/circuits.
EngineerZone® Online Support Community
Find answers to your design questions. Join our engineer community
at ez.analog.com.
Quality, Reliability, and Product Life Cycle
ADI is committed to the establishment and continuous improvement of world class systems and processes aimed at satisfying our customers’
evolving needs.
For information about our quality and reliability program, visit www.analog.com/quality.
For information about product life cycle, visit www.analog.com/product_status_info.
10 | Field Instrument/Smart Transmitter Design
Notes
www.analog.com | 11
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