Preliminary Technical Data
FEATURES
Software Selectable True Bipolar Input,
2-Channel, 12-Bit Plus Sign ADC
AD7322*
FUNCTIONAL BLOCK DIAGRAM
•
12-Bit Plus Sign SAR ADC
•
True Bipolar Analog Inputs
•
Software Selectable Input Ranges
± 10V, ± 5V, ± 2.5V, 0 to 10V
•
Two Analog Inputs with Channel Sequencer
•
Single Ended, True Differential and Pseudo Differential
Capability.
•
High Analog Input Impedance
•
Low Power:- 6 mW
•
Full Power Signal Bandwidth: >13 MHz
•
Internal 2.5 V Reference
•
High Speed Serial Interface
•
Power Down Modes
•
14-Lead TSSOP
•
For 8 and 4 channel equivalent devices see AD7328 and
AD7324 respectively.
Figure 1.
GENERAL DESCRIPTION
The AD7322 is a 2-Channel, 12-Bit Plus Sign, 1 MSPS
Successive Approximation ADC. The ADC has a high speed
serial interface that can operate at throughput rates up to 1
MSPS.
The AD7322 can handle True Bipolar Analog input signals. The
Bipolar ranges are software selectable by programming the on
board Range Register. Bipolar input ranges include ± 10V, ± 5V,
± 2.5V. The AD7322 can also handle a 0 to 10 V uniploar input
range, which is also software selectable. Each analog input
channel can be independently programmed to one of the input
ranges by setting the appropriate bits in the Range Register.
The Analog Input Channels can be configured as Single-Ended,
Fully Differential or Pseudo Differential. Dedicated Control
Register bits are used to configure the Analog inputs. The
AD7322 contains a Channel Sequencer, allowing automatic
conversions between each analog input channel.
The ADC contains a 2.5V Internal reference. The AD7322 also
allows for external Reference operation. If a 3V external
reference is applied to the REFIN/OUT pin, the ADC can
handle a True Bipolar ± 12 V Analog input range. Minimum
V
DD
and V
SS
supplies of ± 12V are required for this ± 12 V input
range.
* Patent Pending
The Serial clock frequency, SCLK, applied to the ADC will
determine the maximum throughput rate the ADC can operate
at. The SCLK signal is used as the conversion clock and also to
transfer data to and from the ADC. The Serial interface is
SPI
TM
, QSPI
TM
, MICROWIRE
TM
and DSP compatible.
The AD7322 offers power down modes to reduce the power
consumption of the ADC at lower throughput rates.
PRODUCT HIGHLIGHTS
1. The AD7322 can accept True Bipolar Analog Input signals,
±10V, ±5V, ±2.5V and 0 to 10V unipolar signals.
2. The Two Analog Inputs can be configured as Two Single-
Ended inputs, One True Differential or One Pseudo Differential
Input. The AD7322 has high Impedance Analog Inputs.
3. The AD7322 features a High Speed Serial Interface.
Throughput Rates up to 1 MSPS can be achieved on the
AD7322.
4. Low Power, 12 mW at maximum throughput rate of 1 MSPS.
Rev. PrE
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