AD7170 Datasheet, PDF (1/16 Pages) Analog Devices – 12-Bit Low Power Sigma-Delta ADC

FEATURES
Output data rate: 125 Hz
Pin-programmable power-down and reset
Status function
Internal clock oscillator
Current: 135 μA
Power supply: 2.7 V to 5.25 V
–40°C to +105°C temperature range
Package: 10-lead 3 mm x 3 mm LFCSP
INTERFACE
2-wire serial (read-only device)
SPI compatible
Schmitt trigger on SCLK
APPLICATIONS
Pressure measurement
Industrial process control
Portable instrumentation
12-Bit Low Power Sigma-Delta ADC
AD7170
FUNCTIONAL BLOCK DIAGRAM
GND V_DD
REFIN(+) REFIN(–)
AIN(+)
AIN(–)
12-BIT Σ-Δ
ADC
DOUT/RDY
SCLK
AD7170
INTERNAL
CLOCK
PDRST
Table 1.
VREF = VDD
5V
3V
RMS Noise
11.5 μV
6.9 μV
Figure 1.
P-P Noise
76 μV
45 μV
P-P
Resolution
12 bits
12 bits
ENOB
12 bits
12 bits
GENERAL DESCRIPTION
The AD7170 is a very low power 12-bit analog-to-digital converter
(ADC). It contains a precision 12-bit sigma-delta (Σ-Δ) ADC
and an on-chip oscillator. Consuming only 135 μA, the AD7170
is particularly suitable for portable or battery operated products
where very low power is a requirement. The AD7170 also has a
power-down mode in which the device consumes 5 μA, thus
increasing the battery life of the product.
For ease-of-use, all the features of the AD7170 are controlled by
dedicated pins. Each time a data read occurs, eight status bits
are appended to the 12-bit conversion. These status bits contain
a pattern sequence that can be used to confirm the validity of
the serial transfer.
The output data rate of the AD7170 is 125 Hz, whereas the
settling time is 24 ms. The AD7170 has one differential input
and a gain of 1. This is useful in applications where the user
needs to use an external amplifier to implement system-specific
filtering or gain requirements.
The AD7170 operates with a power supply from 2.7 V to 5.25 V.
It is available in a 10-lead LFCSP package.
The AD7171 is a 16-bit version of the AD7170. It has the same
feature set as the AD7170 and is pin-for-pin compatible.
Rev. 0
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