AD7715AR-3 Analog Devices Inc, AD7715AR-3 Datasheet - Page 38

• Manufacturer Part Number: AD7715AR-3
• Description: A/D Converter (A-D) IC
• Manufacturer: Analog Devices Inc

Specifications of AD7715AR-3

• No. Of Bits: 16 Bit
• Mounting Type: Surface Mount
• Features: 3V, 16?Bit Sigma?Delta ADC W/PGA
• No. Of Channels: 1
• Interface Type: Serial
• Package / Case: 16-SOIC
• Rohs Status: RoHS non-compliant
• Number Of Bits: 16
• Sampling Rate (per Second): 500
• Data Interface: DSP, MICROWIRE™, QSPI™, Serial, SPI™
• Number Of Converters: 1
• Power Dissipation (max): 9.5mW
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• For Use With: EVAL-AD7715-3EBZ - BOARD EVALUATION FOR AD7715

AD7715
SMART TRANSMITTERS
Another area where the low power, single supply, three-wire
interface capabilities is of benefit is in smart transmitters. Here,
the entire smart transmitter must operate from the 4 mA to
20 mA loop. Tolerances in the loop mean that the amount of
current available to power the transmitter is as low as 3.5 mA.
SENSORS
ohm
RTD
mV
TC
DV
DD
AD7715
AV
DGND
DD
ISOLATED SUPPLY
ISOLATED GROUND
AGND
REF IN
MCLK
OUT
MCLK
IN
REFERENCE
VOLTAGE
ISOLATION
BARRIER
Figure 17. Smart Transmitter Using the AD7715
MICROCONTROLLER UNIT
*PID
*RANGE SETTING
*CALIBRATION
*LINEARIZATION
*OUTPUT CONTROL
*SERIAL COMMUNICATION
*HART PROTOCOL
Rev. D | Page 38 of 40
V
COM
CC
The AD7715 consumes only 450 μA, leaving 3 mA available for
the rest of the transmitter. Figure 17 shows a block diagram of a
smart transmitter which includes the AD7715. Not shown in
Figure 17 is the isolated power source required to power the
front end.
MAIN TRANSMITTER ASSEMBLY
COM
3V
BELL 202
MODEM
HART
DAC
REFERENCE
VOLTAGE
WAVEFORM
SHAPER
3V
CONDITIONER
REGULATOR
SIGNAL
VOLTAGE
INPUT/OUTPUT
STAGE
BANDPASS
FILTER
LOOP
RTN
4mA
TO
20mA