![](http://datasheet.mmic.net.cn/Analog-Devices-Inc/AD7327BRUZ-REEL7_datasheet_100312/AD7327BRUZ-REEL7_10.png)
Data Sheet
AD7327
Rev. B | Page 9 of 36
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
DIN
DGND
AGND
VIN0
VSS
REFIN/OUT
CS
DGND
DOUT
VDRIVE
VIN2
VDD
VCC
VIN5
VIN4
VIN1
VIN7
VIN6
VIN3
SCLK
AD7327
TOP VIEW
(Not to Scale)
05401-
003
Figure 3. TSSOP Pin Configuration
Table 5. Pin Function Descriptions
Pin No.
Mnemonic
Description
1
CS
Chip Select. Active low logic input. This input provides the dual function of initiating conversions on
2
DIN
Data In. Data to be written to the on-chip registers is provided on this input and is clocked into the
3, 19
DGND
Digital Ground. Ground reference point for all digital circuitry on th
e AD7327. The DGND and AGND
voltages ideally should be at the same potential and must not be more than 0.3 V apart, even on a
transient basis.
4
AGND
Analog Ground. Ground reference point for all analog circuitry on t
he AD7327. All analog input signals
and any external reference signal should be referred to this AGND voltage. The AGND and DGND
voltages ideally should be at the same potential and must not be more than 0.3 V apart, even on a
transient basis.
5
REFIN/OUT
Reference Input/Reference Output. The on-chip reference is available on this pin for external use to the
AD7327. The nominal internal reference voltage is 2.5 V, which appears at this pin. A 680 nF capacitor
should be placed on the reference pin (see t
he Reference section). Alternatively, the internal reference
can be disabled and an external reference applied to this input. On power-up, the external reference
mode is the default condition.
6
VSS
Negative Power Supply Voltage. This is the negative supply voltage for the analog input section.
7, 8, 14, 13, 9,
10, 12, 11
VIN0 to VIN7
Analog Input 0 to Analog Input 7. The analog inputs are multiplexed into the on-chip track-and-hold.
The analog input channel for conversion is selected by programming the channel address Bit ADD2
through Bit ADD0 in the control register. The inputs can be configured as eight single-ended inputs,
four true differential input pairs, four pseudo differential inputs, or seven pseudo differential inputs.
The configuration of the analog inputs is selected by programming the mode bits, Bit Mode 1 and
Bit Mode 0, in the control register. The input range on each input channel is controlled by program-
ming the range registers. Input ranges of ±10 V, ±5 V, ±2.5 V, and 0 V to +10 V can be selected on each
analog input channel when a +2.5 V reference voltage is used (see the
Registers section).
15
VDD
Positive Power Supply Voltage. This is the positive supply voltage for the analog input section.
16
VCC
Analog Supply Voltage, 2.7 V to 5.25 V. This is the supply voltage for the ADC core on t
he AD7327.This supply should be decoupled to AGND.
17
VDRIVE
Logic Power Supply Input. The voltage supplied at this pin determines at what voltage the interface
operates. This pin should be decoupled to DGND. The voltage at this pin may be different to that at VCC,
but it should not exceed VCC by more than 0.3 V.
18
DOUT
Serial Data Output. The conversion output data is supplied to this pin as a serial data stream. The bits
are clocked out on the falling edge of the SCLK input, and 16 SCLKs are required to access the data. The
data stream consists of three channel identification bits, the sign bit, and 12 bits of conversion data.
20
SCLK
Serial Clock, Logic Input. A serial clock input provides the SCLK used for accessing the data from the
AD7327. This clock is also used as the clock source for the conversion process.