AD7291 Datasheet, PDF (1/21 Pages) Analog Devices – 8-Channel, I2C, 12-Bit SAR ADC with Temperature Sensor

Preliminary Technical Data
FEATURES
12 bit SAR ADC
8 single-ended inputs
Channel sequencer functionality
Analog Input Range 0 to 2.5V
12-bit temperature-to-digital converter
Temperature sensor accuracy of ±2°C typical
Temperature range: −40°C to +125°C
Specified for V_DD of 2.8 V to 3.6V
Logic Voltage V_DRIVE = 1.65V to 3.6V
Power-down current : <10 µA
Internal 2.5V Reference
I²C-compatible serial interface supports
standard & fast modes
20-lead LFCSP
8-Channel, I²C, 12-Bit SAR ADC
with Temperature Sensor
AD7291
Functional Block Diagram
GENERAL DESCRIPTION
The AD7291 is a 12-bit, high speed, low power, 8-channel,
successive approximation ADC with an internal temperature
sensor. The part operates from a single 3.3V power supply and
features an I²C®-compatible interface. The track-and-hold
amplifier which can handle input frequencies of up to 70MHz,
and a multiplexer allows samples from eight channels.
Each AD7291 provides a 2-wire serial interface compatible with
I²C interfaces. The AD7291 offers a programmable sequencer,
which enables the selection of a pre-programmable sequence of
channels for conversion. The device has an on-chip 2.5 V
reference that can be disabled to allow the use of an external
reference.
The AD7291 includes a high accuracy band-gap temperature
sensor, which is monitored and digitized by the12-bit ADC to
give a resolution of 0.25°C. The AD7291 uses advanced design
techniques to achieve very low power dissipation at high
throughput rates. The part also offers flexible
power/throughput rate management options and is offered in a
20 lead LFCSP package
Figure 1.
PRODUCT HIGHLIGHTS
1. Ideally suited to monitoring system variables in a variety of
systems including telecommunications, process and
industrial control
2. I²C-compatible serial interface. Standard and fast modes.
3. Eight Single-Ended Inputs with a Channel Sequencer.
A consecutive sequence of channels can be selected on
which the ADC cycles and converts.
4. Integrated temperature sensor with 0.25°C resolution.
Table 1. AD7298 and Related Products
Device Resolution Interface Features
AD7298 12-Bit
SPI
8 Channel ADC & Temp Sensor
AD7291 12-Bit
I²C
8 Channel ADC & Temp Sensor
Rev. PrC
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