AD7991 Datasheet, PDF (1/25 Pages) Analog Devices – 4-Channel, 12-/10-/8-Bit ADC with I2CCompatible Interface in 8-Lead SOT23

Preliminary Technical Data
4-Channel, 12-/10-/8-Bit ADC with I²C-
Compatible Interface in 8-Lead SOT23
AD7991/AD7995/AD7999
FEATURES
12-/10-/8-bit ADC with fast conversion time: 2 µs typ
4 Channel / 3 Channel with Reference input
Specified for VDD of 2.7 V to 5.5 V
Sequencer operation
Temperature Range: -40 °C to 125 °C
I²C®-compatible serial interface supports standard, fast,
and High-speed modes
2 versions allow 2 I²C addresses
Low power consumption
Shutdown mode: 1 µA max
8-lead SOT23 package
APPLICATIONS
System Monitoring
Battery Powered Systems
Data Acquisition
Medical Instruments
FUNCTIONAL BLOCK DIAGRAM
VDD
VIN0
VIN1
VIN2
VIN3/Vref
I/P _T/H
MUX
12-/10-/8-BIT
SAR
ADC
CONTROL
LOGIC &
I2C
INTERFACE
SCL
SDA
AD7991/7995/7999
GND
Figure 1.
GENERAL DESCRIPTION
The AD7991/AD7995/AD7999 are 12-/10-/8-bit, low power,
successive approximation ADCs with an I²C-compatible
interface. The parts operate from a single 2.7 V to 5.5 V power
supply and feature a 2 µs conversion time. The part contains a
4-channel multiplexer and track-and-hold amplifier that can
handle input frequencies up to 11 MHz.
The AD7991/AD7995/AD7999 provides a 2-wire serial
interface compatible with I²C interfaces. The parts come in two
versions with each part having an individual I²C address. This
will allow two of the same devices be connected to the same I²C
bus. Both parts support standard, fast and high-speed I²C
interface modes
The AD7991/AD7995/AD7999 normally remain in a shutdown
state while not converting, and power up only for conversions.
The conversion process is controlled by a command mode,
where every time an I²C read operation is executed on the
AD7991/AD7995/AD7999, a conversion is performed and the
result is returned on the I²C bus.
The reference for the part is taken from VDD, this allows the
widest dynamic input range to the ADC. Thus the analog input
range to the ADC is 0V to VDD. An external reference may also
be used with this part. The external reference may be applied
through the Ain3 input.
Rev. PrB
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PRODUCT HIGHLIGHTS
1. 4 single ended analog input channels, with the option of
having 3 single ended analog input channels and 1
reference input channel.
2. I²C compatible serial Interface. Standard, Fast and Hs-
Modes
3. Automatic shutdown.
4. Reference derived from the power supply or external
reference.
5. 8-lead SOT23 Package.
Table 1 Related Devices
Device Number Resolution
Input Channels
AD7998
12
8
AD7997
10
8
AD7994
12
4
AD7993
10
4
AD7992
12
2
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