AD7995_15 Datasheet, PDF (1/28 Pages) Analog Devices – 4-Channel, 12-/10-/8-Bit ADC with IC-Compatible Interface in 8-Lead SOT-23

4-Channel, 12-/10-/8-Bit ADC with
I²C-Compatible Interface in 8-Lead SOT-23
AD7991/AD7995/AD7999
FEATURES
12-/10-/8-bit ADCs with fast conversion time: 1 μs typical
4 analog input channels/3 analog input channels 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 maximum
8-lead SOT-23 package
APPLICATIONS
System monitoring
Battery-powered systems
Data acquisition
Medical instruments
GENERAL DESCRIPTION
The AD7991/AD7995/AD7999 are 12-/10-/8-bit, low power,
successive approximation ADCs with an I²C®-compatible interface.
Each part operates from a single 2.7 V to 5.5 V power supply and
features a 1 μs conversion time. The track-and-hold amplifier
allows each part to handle input frequencies of up to 14 MHz,
and a multiplexer allows taking samples from four channels.
Each AD7991/AD7995/AD7999 provides a 2-wire serial
interface compatible with I²C interfaces. The AD7991 and
AD7995 come in two versions and each version has an
individual I²C address. This allows two of the same devices to be
connected to the same I²C bus. Both versions support standard,
fast, and high speed I²C interface modes. The AD7999 comes in
one version.
The AD7991/AD7995/AD7999 normally remain in a shutdown
state, powering up only for conversions. The conversion process
is controlled by a command mode, during which each I²C read
operation initiates a conversion and returns the result over the
I²C bus.
When four channels are used as analog inputs, the reference for
the part is taken from VDD; this allows the widest dynamic input
range to the ADC. Therefore, the analog input range to the
ADC is 0 V to VDD. An external reference, applied through the
VIN3/VREF input, can also be used with this part.
FUNCTIONAL BLOCK DIAGRAM
V_DD
V_IN0
V_IN1
V_IN2
V_IN3/V_REF
I/P
T/H
MUX
12-/10-/8-BIT
SAR
ADC
CONTROL
LOGIC AND
I²C
INTERFACE
AD7991/AD7995/AD7999
GND
Figure 1.
SCL
SDA
PRODUCT HIGHLIGHTS
1. Four single-ended analog input channels, or three single-
ended analog input channels and one reference input channel.
2. I²C-compatible serial interface. Standard, fast, and high
speed modes.
3. Automatic shutdown.
4. Reference derived from the power supply or external
reference.
5. 8-lead SOT-23 package.
Table 1. Related Devices
Device
Resolution
AD7998
12
AD7997
10
AD7994
12
AD7993
10
AD7992
12
Input Channels
8
8
4
4
2
Rev. B
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