8-Channel, I2C, 12-Bit SAR ADC
with Temperature Sensor
AD7291
Preliminary Technical Data
Functional Block Diagram
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 VDD of 2.8 V to 3.6V
Logic Voltage VDRIVE = 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
Figure 1.
GENERAL DESCRIPTION
PRODUCT HIGHLIGHTS
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.
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.
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.
4. Integrated temperature sensor with 0.25°C resolution.
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
Table 1. AD7298 and Related Products
Device
Resolution
Interface Features
AD7298 12-Bit
AD7291 12-Bit
SPI
I2C
8 Channel ADC & Temp Sensor
8 Channel ADC & Temp Sensor
power/throughput rate management options and is offered in a
20 lead LFCSP package
Rev. PrC
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