AD7705BR Analog Devices Inc, AD7705BR Datasheet - Page 40

• Manufacturer Part Number: AD7705BR
• Description: A/D Converter (A-D) IC
• Manufacturer: Analog Devices Inc

Specifications of AD7705BR

• Mounting Type: Surface Mount
• No. Of Channels: 2
• Peak Reflow Compatible (260 C): No
• Supply Voltage: 3.3V
• No. Of Bits: 16 Bit
• Leaded Process Compatible: No
• Features: 3V/5V, 1mW, 2?Channel, 16?Bit
• 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): 1mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 16-SOIC (0.300", 7.50mm Width)
• Number Of Elements: 1
• Resolution: 16Bit
• Architecture: Delta-Sigma
• Sample Rate: 0.5KSPS
• Input Polarity: Unipolar/Bipolar
• Input Type: Voltage
• Differential Input: Yes
• Power Supply Requirement: Single
• Single Supply Voltage (typ): 3/5V
• Single Supply Voltage (min): 2.7V
• Single Supply Voltage (max): 5.25V
• Dual Supply Voltage (typ): Not RequiredV
• Dual Supply Voltage (min): Not RequiredV
• Dual Supply Voltage (max): Not RequiredV
• Power Dissipation: 1mW
• Integral Nonlinearity Error: ±0.003%FSR
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 16
• Package Type: SOIC W
• Input Signal Type: Differential
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With: EVAL-AD7705EBZ - BOARD EVALUATION FOR AD7705
• Lead Free Status / Rohs Status: Not Compliant

AD7705/AD7706
SMART TRANSMITTERS
Another application where the low power, single-supply, 3-wire
interface capabilities of the AD7705/AD7706 are beneficial is in
smart transmitters. Figure 28 shows a block diagram of a smart
transmitter using the AD7705. Because a smart transmitter
must operate from a 4 to 20 mA loop, tolerances in the loop
SENSORS
RTD
mV
TC
Ω
V
DD
AD7705
GND
ISOLATED GROUND
REF IN
ISOLATED SUPPLY
MCLK OUT
MCLK IN
4.7μF
100kΩ
ISOLATION
Figure 28. Smart Transmitter Using the AD7705
BARRIER
Rev. C | Page 40 of 44
MICROCONTROLLER UNIT
•PID
•RANGE SETTING
•CALIBRATION
•LINEARIZATION
•OUTPUT CONTROL
•SERIAL COMMUNICATION
•HART PROTOCOL
V
CC
COM
MAIN TRANSMITTER ASSEMBLY
mean that the current available to power the transmitter can be
as low as 3.5 mA. The AD7705 consumes only 320 μA, leaving
at least 3 mA available for the rest of the transmitter. The
AD7705, with its dual-input channel, is ideally suited for
systems requiring an auxiliary channel whose measured
variable is used to correct that of the primary channel.
4.7μF
0.01μF
V
REF OUT1
REF OUT2
REF IN
C1 C2 C3
CC
0.01μF
2.2μF
AD421
0.1μF
0.0033μF
BOOST
COMP
DRIVE
LOOP
COM
RTN
DN25D
1000pF
0.01μF
1kΩ
4mA
TO
20mA