AD7890 Analog Devices, AD7890 Datasheet - Page 8

• Manufacturer Part Number: AD7890
• Description: LC2MOS 8-Channel, 12-Bit Serial Data Acquisition System
• Manufacturer: Analog Devices

Specifications of AD7890

• Resolution (bits): 12bit
• # Chan: 8
• Sample Rate: 117kSPS
• Interface: Ser
• Analog Input Type: SE-Bip,SE-Uni
• Ain Range: Bip 10V,Uni 2.5V,Uni 4.096V
• Adc Architecture: SAR
• Pkg Type: DIP,SOIC

AD7890
Pin No.
14
15
16
17
18
19
20
21
22
23
24
Mnemonic
SHA IN
AGND
V
V
V
V
V
V
V
V
REF OUT/REF IN
IN1
IN2
IN3
IN4
IN5
IN6
IN7
IN8
Description
Track/Hold Input. The input to the on-chip track/hold is applied to this pin. It is a high impedance input and the
input voltage range is 0 V to 2.5 V.
Analog Ground. Ground reference for track/hold, comparator, and DAC.
Analog Input Channel 1. Single-ended analog input. The analog input range on is ±10 V (AD7890-10), 0 V to
4.096 V (AD7890-4), and 0 V to 2.5 V (AD7890-2). The channel to be converted is selected using the A0, A1, and
A2 bits in the control register. The multiplexer has guaranteed break-before-make operation.
Analog Input Channel 2. Single-ended analog input. The analog input range on is ±10 V (AD7890-10), 0 V to
4.096 V (AD7890-4), and 0 V to 2.5 V (AD7890-2). The channel to be converted is selected using the A0, A1, and
A2 bits in the control register. The multiplexer has guaranteed break-before-make operation.
Analog Input Channel 3. Single-ended analog input. The analog input range on is ±10 V (AD7890-10), 0 V to
4.096 V (AD7890-4), and 0 V to 2.5 V (AD7890-2). The channel to be converted is selected using the A0, A1, and
A2 bits in the control register. The multiplexer has guaranteed break-before-make operation.
Analog Input Channel 4. Single-ended analog input. The analog input range on is ±10 V (AD7890-10), 0 V to
4.096 V (AD7890-4), and 0 V to 2.5 V (AD7890-2). The channel to be converted is selected using the A0, A1, and
A2 bits in the control register. The multiplexer has guaranteed break-before-make operation.
Analog Input Channel 5. Single-ended analog input. The analog input range on is ±10 V (AD7890-10), 0 V to
4.096 V (AD7890-4), and 0 V to 2.5 V (AD7890-2). The channel to be converted is selected using the A0, A1, and
A2 bits in the control register. The multiplexer has guaranteed break-before-make operation.
Analog Input Channel 6. Single-ended analog input. The analog input range on is ±10 V (AD7890-10), 0 V to
4.096 V (AD7890-4), and 0 V to 2.5 V (AD7890-2). The channel to be converted is selected using the A0, A1, and
A2 bits in the control register. The multiplexer has guaranteed break-before-make operation.
Analog Input Channel 7. Single-ended analog input. The analog input range on is ±10 V (AD7890-10), 0 V to
4.096 V (AD7890-4), and 0 V to 2.5 V (AD7890-2). The channel to be converted is selected using the A0, A1, and
A2 bits in the control register. The multiplexer has guaranteed break-before-make operation.
Analog Input Channel 8. Single-ended analog input. The analog input range on is ±10 V (AD7890-10), 0 V to
4.096 V (AD7890-4) and 0 V to 2.5 V (AD7890-2). The channel to be converted is selected using the A0, A1, and
A2 bits in the control register. The multiplexer has guaranteed break-before-make operation.
Voltage Reference Output/Input. The part can be used with either its own internal reference or with an external
reference source. The on-chip 2.5 V reference voltage is provided at this pin. When using this internal reference
as the reference source for the part, REF OUT should decoupled to AGND with a 0.1 μF disc ceramic capacitor.
The output impedance of this reference source is typically 2 kΩ. When using an external reference source as
the reference voltage for the part, the reference source should be connected to this pin. This overdrives the
internal reference and provides the reference source for the part. The REF IN input is buffered on-chip. The
nominal reference voltage for correct operation of the AD7890 is 2.5 V.
Rev. C | Page 8 of 28