AD7942 Analog Devices, AD7942 Datasheet - Page 8

• Manufacturer Part Number: AD7942
• Manufacturer: Analog Devices

Specifications of AD7942

• Resolution (bits): 14bit
• # Chan: 1
• Sample Rate: 250kSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: (Vref) p-p,Uni (Vref)
• Adc Architecture: SAR
• Pkg Type: CSP,SOP

AD7942
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Table 6. Pin Function Descriptions
Pin No.
1
2
3
4
5
6
7
8
9
10
1
AI = analog input, DI = digital input, DO = digital output, and P = power.
Mnemonic
REF
VDD
IN+
IN−
GND
CNV
SDO
SCK
SDI
VIO
Type
AI
P
AI
AI
P
DI
DO
DI
DI
P
1
Description
Reference Input Voltage. The V
as closely as possible to a 10 μF capacitor.
Power Supply.
Analog Input. IN+ is referred to IN−. The voltage range, that is, the difference between IN+ and IN−, is 0 V
to V
Analog Input Ground Sense. Connect IN− to the analog ground plane or to a remote sense ground.
Power Supply Ground.
Convert Input. This input pin has multiple functions. On its leading edge, CNV initiates the conversions
and selects the interface mode of the part: chain mode or CS mode. In CS mode, CNV enables the SDO pin
when low. In chain mode, the data should be read when CNV is high.
Serial Data Output. The conversion result is output on this pin. It is synchronized to SCK.
Serial Data Clock Input. When the part is selected, the conversion result is shifted out by this clock.
Serial Data Input. This input provides multiple features. It selects the interface mode of the ADC as follows:
Chain mode is selected if SDI is low during the CNV rising edge. In this mode, SDI is used as a data input to
daisy-chain the conversion results of two or more ADCs onto a single SDO line. The digital data level on
SDI is output on SDO with a delay of 14 SCK cycles.
CS mode is selected if SDI is high during the CNV rising edge. In this mode, either SDI or CNV can enable
the serial output signals when low, and if SDI or CNV is low when the conversion is complete, the busy
indicator feature is enabled.
Input/Output Interface Digital Power. Nominally at the same supply as the host interface (1.8 V, 2.5 V, 3 V, or 5 V).
REF
.
NOTES
1. PADDLE CONNECTED TO GND. THIS CONNECTION IS NOT
REQUIRED TO MEET THE ELECTRICAL PERFORMANCES.
GND
VDD
REF
IN+
IN–
Figure 4. Pin Configuration
1
2
3
4
5
Rev. B | Page 8 of 24
AD7942
REF
range is from 0.5 V to VDD. REF is referred to the GND pin. Decouple REF
10
9
8
7
6
VIO
SDI
SCK
SDO
CNV