AD7992 Analog Devices, AD7992 Datasheet - Page 14

• Manufacturer Part Number: AD7992
• Description: 2-Channel, 12-Bit ADC with I2C Compatible Interface in 10-Lead MSOP
• Manufacturer: Analog Devices

Specifications of AD7992

• Resolution (bits): 12bit
• # Chan: 2
• Sample Rate: 79kSPS
• Interface: I²C/Ser 2-Wire,Ser
• Analog Input Type: SE-Uni
• Ain Range: Uni (Vref),Uni Vdd
• Adc Architecture: SAR
• Pkg Type: SOP

AD7992
TYPICAL CONNECTION DIAGRAM
Figure 21 shows the typical connection diagram for the
AD7992. In Figure 21, the address select pin (AS) is tied to V
however AS can also be tied to AGND or left floating, allowing
the user to select up to five AD7992 devices on the same serial
bus. An external reference must be applied to the AD7992.
This reference can be in the range of 1.2 V to V
reference like the REF 19x family, ADR03, or ADR381 can be
used to supply the reference voltage to the ADC. The AD7992
can be configured to be a single-channel device with the
reference voltage applied to the V
can also be configured as a dual-channel device where the
reference voltage is taken from the supply voltage V
V
SDA and SCL form the 2-wire I
External pull-up resisters are required for both SDA and SCL
lines.
The AD7992-0 supports standard and fast I
The AD7992-1 supports standard, fast, and high speed I
interface modes. Therefore, if operating the AD7992 in either
standard or fast mode, up to five AD7992 devices can be
connected to the bus (3 × AD7992-0 and 2 × AD7992-1 or
3 × AD7992-1 and 2 × AD7992-0). In high speed mode, up to
three AD7992-1 devices can be connected to the bus.
Wake up from power-down prior to a conversion is approx-
imately 1 µs, and conversion time is approximately 2 µs. The
AD7992 enters shutdown mode again after each conversion,
which is useful in applications where power consumption is a
concern.
IN
2/REF
IN
takes on its analog input function,V
REF 19x
2
C/SMBus-compatible interface.
0.1µF
IN
2/REF
0V to REF
Figure 21. AD7992 Typical Connection Diagram, Single-Channel Mode, Mode 1
INPUT
1µF
IN
IN
pin. The AD7992
2
C interface modes.
DD
IN
V
V
IN
. A precision
2.
IN
2/REF
1
DD
, and the
AD7992
IN
2
C
GND
Rev. 0 | Page 14 of 28
DD
V
DD
;
10µF
CONVST
ALERT
SDA
SCL
AS
0.1µF
ANALOG INPUT
Figure 20 shows an equivalent circuit of the AD7992 analog
input structure. The two diodes, D1 and D2, provide ESD
protection for the analog inputs. Care must be taken to ensure
that the analog input signal does not exceed the supply rails
by more than 300 mV. This causes these diodes to become
forward-biased and start conducting current into the substrate.
These diodes can conduct a maximum current of 10 mA
without causing irreversible damage to the part.
Capacitor C1 in Figure 20 is typically about 4 pF and can
primarily be attributed to pin capacitance. Resistor R1 is a
lumped component made up of the on resistance (R
a track-and-hold switch, and also the R
plexer. The total resistor is typically about 400 Ω. C2, the ADC
sampling capacitor, has a typical capacitance of 30 pF.
V
IN
4pF
C1
SET TO REQUIRED
ADDRESS
R
P
Figure 20. Equivalent Analog Input Circuit
R
P
R
V
DD
P
D1
D2
5V SUPPLY
2-WIRE SERIAL
INTERFACE
CONVERSION PHASE - SWITCH OPEN
TRACK PHASE - SWITCH CLOSED
µC/µP
R1
ON
of the input multi-
30pF
C2
ON
) of