AD7323 Analog Devices, AD7323 Datasheet - Page 28

• Manufacturer Part Number: AD7323
• Description: 500 kSPS, 4-Channel, Software Selectable True bipolar Input, 12-Bit Plus Sign A/D Converter
• Manufacturer: Analog Devices

Specifications of AD7323

• Resolution (bits): 13bit
• # Chan: 4
• Sample Rate: 500kSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni,SE-Uni
• Ain Range: Bip 10V,Bip 2.5V,Bip 5.0V,Uni 10V
• Adc Architecture: SAR
• Pkg Type: SOP

AD7323
REFERENCE
The AD7323 can operate with either the internal 2.5 V on-chip
reference or an externally applied reference. The internal
reference is selected by setting the Ref bit in the control register
to 1. On power-up, the Ref bit is 0, which selects the external
reference for the AD7323 conversion. Suitable reference sources
for the AD7323 include AD780, AD1582, ADR431, REF193,
and ADR391.
The internal reference circuitry consists of a 2.5 V band gap
reference and a reference buffer. When operating the AD7323
in internal reference mode, the 2.5 V internal reference is available
at the REFIN/OUT pin, which should be decoupled to AGND
using a 680 nF capacitor. It is recommended that the internal
reference be buffered before applying it elsewhere in the system.
The internal reference is capable of sourcing up to 90 μA.
On power-up, if the internal reference operation is required for
the ADC conversion, a write to the control register is necessary
to set the Ref bit to 1. During the control register write, the
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conversion result from the first initial conversion is invalid. The
reference buffer requires 500 μs to power up and charge the
680 nF decoupling capacitor during the power-up time.
The AD7323 is specified for a 2.5 V to 3 V reference range.
When a 3 V reference is selected, the ranges are ±12 V, ±6 V,
±3 V, and 0 V to +12 V. For these ranges, the V
must be equal to or greater than the maximum analog input
range selected (see Table 6).
V
The AD7323 has a V
the serial interface operates. V
interface to both 3 V and 5 V processors. For example, if the
AD7323 is operated with a V
powered from a 3 V supply. This allows the AD7323 to accept
large bipolar input signals with low voltage digital processing.
DRIVE
DRIVE
feature to control the voltage at which
CC
DRIVE
of 5 V, the V
allows the ADC to easily
DRIVE
DD
pin can be
and V
SS
supply