AD7706 Analog Devices, AD7706 Datasheet - Page 27

• Manufacturer Part Number: AD7706
• Description: 3V/5V, 1mW, 3-Channel Pseudo Differential, 16-Bit Sigma-Delta ADC
• Manufacturer: Analog Devices

Specifications of AD7706

• Resolution (bits): 16bit
• # Chan: 3
• Sample Rate: n/a
• Interface: Ser,SPI
• Analog Input Type: Diff-Bip,Diff-Uni
• Ain Range: Bip (Vref)/(PGA Gain),Uni (Vref)/(PGA Gain)
• Adc Architecture: Sigma-Delta
• Pkg Type: DIP,SOIC,SOP

If the part is used in bipolar mode with a required span of
±0.4 × V
handle is –0.65 × V
the part is used in bipolar mode with a required span of
±V
handle is –0.05 × V
part is used in bipolar mode and required to remove an offset of
±0.2 × V
calibration can handle is ±0.85 × V
AD7705/AD7706
INPUT RANGE
(0.8 × V
2.1 × V
REF
/gain, the offset range that the system calibration can
REF
REF
REF
REF
/GAIN)
/GAIN TO
/gain, the offset range that the system calibration can
/gain, the maximum span range that the system
–1.05 × V
Figure 16. Span and Offset Limits
1.05 × V
REF
REF
/gain to +0.65 × V
/gain to +0.05 × V
–0V DIFFERENTIAL
REF
REF
/GAIN
/GAIN
OFFSET CALIBRATIONS MOVE
INPUT RANGE UP OR DOWN
UPPER LIMIT ON
AD7705 INPUT VOLTAGE
GAIN CALIBRATIONS EXPAND
OR CONTRACT THE
AD7705/AD7706 INPUT RANGE
LOWER LIMIT ON
AD7705/AD7706 INPUT VOLTAGE
REF
/gain.
REF
REF
/gain. If
/gain. Similarly, if the
NOMINAL ZERO
SCALE POINT
Rev. C | Page 27 of 44
Power-Up and Calibration
Upon power-up, the AD7705/AD7706 internally reset, setting
the contents of the internal registers to a known state. Default
values are loaded to all registers after a power-on or reset. The
default values contain nominal calibration coefficients for the
calibration registers. However, to ensure correct calibration for the
devices, a calibration routine should be performed after power-up.
The power dissipation and temperature drift of the AD7705/
AD7706 are low, and no warm-up time is required before the
initial calibration is performed. However, if an external reference
is used, it must be stabilized before calibration is initiated.
Similarly, if the clock source for the part is generated from a
crystal or resonator across the MCLK pins, the start-up time
for the oscillator circuit should elapse before a calibration is
initiated on the parts (see Figure 11).
AD7705/AD7706