AD7705BRZ Analog Devices Inc, AD7705BRZ Datasheet - Page 40

• Manufacturer Part Number: AD7705BRZ
• Description: IC ADC 16BIT 2CH 16-SOIC
• Manufacturer: Analog Devices Inc

Specifications of AD7705BRZ

• Data Interface: DSP, MICROWIRE™, QSPI™, Serial, SPI™
• Number Of Bits: 16
• Sampling Rate (per Second): 500
• Number Of Converters: 1
• Power Dissipation (max): 1mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.300", 7.50mm Width)
• Resolution (bits): 16bit
• Input Channel Type: Differential
• Supply Current: 1.3mA
• Digital Ic Case Style: SOIC
• No. Of Pins: 16
• Operating Temperature Range: -40°C To +85°C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: EVAL-AD7705EBZ - BOARD EVALUATION FOR AD7705
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS 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