AD7771 Datasheet, PDF (12/14 Pages) Analog Devices – 8-Ch, 24-Bit Simultaneous Sampling ADC

Preliminary Technical Data
AD7771
Table 4. Pin Description
Pin No.
1
2
3
4
5
Mnemonic
AIN0-
AIN0+
AIN1−
AIN1+
AVSS1A
6
AVDD1A
7
REF1−
8
REF1+
9
AIN2−
10
AIN2+
11
AIN3−
12
AIN3+
13
MODE0/GPIO0
14
MODE1/GPIO1
15
MODE2/GPIO2
16
MODE3/ALERT
17
CONVST_SAR
18
ALERT/CS
19
DCLK2 / SCLK
20
DCLK1 / SDI
21
DCLK0 / SDO
22
DGND
23
DREGCAP
24
IOVDD
25
DOUT3
Type
Direction Description
Analog Input
Analog Input
Analog Input
Input
Input
Input
Analog Input Channel 0
Analog Input Channel 0
Analog Input Channel 1
Analog Input Input
Supply
Supply
Supply
Reference
Supply
Input
Analog Input Channel 1
Negative Front End Analog Supply for Channels 0 to 3, typical −1.65V(Dual
Supply), and AGND (Single Supply). Connect all AVSSx pins to the same
potential
Positive Front End Analog Supply for Channels 0 to 3, typical AVSSx + 3.3V.
This pin should be connected together with AVDD1B.
Negative Reference Input for Channels 0 to 3, typical AVSSx. Connect all
REFx− pins to the same potential
Reference
Input
Positive Reference Input 1 for Channels 0 to 3, typical REF1− +2.5V
Analog Input Input
Analog Input Channel 2
Analog Input Input
Analog Input Input
Analog Input Channel 2
Analog Input Channel 3
Analog Input Input
Digital I/O
IO
Digital I/O
IO
Analog Input Channel 3
PIN Control Mode: MODE0 input pin,
SPI Control Mode: Configurable GPIO0. If this pin is not used, connect to
DGND or IOVDD.
PIN Control Mode: MODE1 input pin
Digital I/O
IO
Digital I/O
IO
Digital Input Input
Digital Input Input
Digital Input Input
Digital Input Input
Digital Output Output
Supply
Supply
Supply
Supply
Output
Supply
Digital Output IO
SPI Control Mode: Configurable GPIO1. If this pin is not used, connect to
DGND or IOVDD.
PIN Control Mode: MODE2 input pin,
SPI Control Mode: Configurable GPIO2. If this pin is not used, connect to
DGND or IOVDD.
PIN Control Mode: MODE3 input pin,
SPI Control Mode: Alert Output Pin
Pin Control Mode – ΣΔ output interface selection
SPI Control Mode - SAR Convert Start
PIN Control Mode: Alert Output Pin
SPI Control Mode: Chip Select
PIN Control Mode: DCLK frequency selection,
SPI Control Mode: SPI Clock.
PIN Control Mode: DCLK frequency selection
SPI Control Mode: SPI Data In. Connect this pin to DGND if the part is
configured in Pin Contro Mode with SPI as data output interface
PIN Control Mode: DCLK frequency selection
SPI Control Mode: SPI Data Out
Digital ground
Digital LDO output. Decouple to DGND with 1uF cap
IO Digital levels and DLDO supply, from 1.8V to 3.6V. IOVDD should not be
lower than DRegCap.
Data output pin 3. If the part is configured in daisy-chain mode, this pin acts
as an input pin.
Rev. PrC | Page 11 of 13