AD7923 Datasheet, PDF (1/20 Pages) Analog Devices – 4-Channel, 200 kSPS, 12-Bit ADC with Sequencer in 16-Lead TSSOP

a
4-Channel, 200 kSPS, 12-Bit ADC
with Sequencer in 16-Lead TSSOP
AD7923
FEATURES
Fast Throughput Rate: 200 kSPS
Specified for AV_DD of 2.7 V to 5.25 V
Low Power:
3.6 mW Max at 200 kSPS with 3 V Supply
7.5 mW Max at 200 kSPS with 5 V Supply
4 (Single-Ended) Inputs with Sequencer
Wide Input Bandwidth:
70 dB Min SNR at 50 kHz Input Frequency
Flexible Power/Serial Clock Speed Management
No Pipeline Delays
High Speed Serial Interface SPI™/QSPI™/
MICROWIRE™/DSP Compatible
Shutdown Mode: 0.5 ␮A Max
16-Lead TSSOP Package
GENERAL DESCRIPTION
The AD7923 is a 12-bit, high speed, low power, 4-channel,
successive approximation ADC. The part operates from a single
2.7 V to 5.25 V power supply and features throughput rates up
to 200 kSPS. The part contains a low noise, wide bandwidth
track-and-hold amplifier that can handle input frequencies in
excess of 8 MHz.
The conversion process and data acquisition are controlled using
CS and the serial clock signal, allowing the device to easily
interface with microprocessors or DSPs. The input signal is
sampled on the falling edge of CS and the conversion is also
initiated at this point. There are no pipeline delays associated
with the part.
The AD7923 uses advanced design techniques to achieve very low
power dissipation at maximum throughput rates. At maximum
throughput rates, the AD7923 consumes 1.2 mA maximum with 3 V
supplies, and with 5 V supplies the current consumption is 1.5 mA
maximum.
Through the configuration of the Control Register, the analog
input range for the part can be selected as 0 V to REF_IN or 0 V
to 2 ¥ REF_IN, with either straight binary or twos complement
output coding. The AD7923 features four single-ended analog
inputs with a channel sequencer to allow a preprogrammed
selection of channels to be converted sequentially.
The conversion time for the AD7923 is determined by the SCLK
frequency, as this is also used as the master clock to control the
conversion. The conversion time may be as short as 800 ns with
a 20 MHz SCLK.
FUNCTIONAL BLOCK DIAGRAM
AV_DD
REF_IN
V_IN0
•
•
•
•
•
•
•
•
•
•
•
•
•
V_IN3
T/H
I/P
MUX
12-BIT
SUCCESSIVE
APPROXIMATION
ADC
SEQUENCER
CONTROL LOGIC
AD7923
GND
SCLK
DOUT
DIN
CS
V_DRIVE
PRODUCT HIGHLIGHTS
1. High Throughput with Low Power Consumption.
The AD7923 offers up to 200 kSPS throughput rates. At the
maximum throughput rate with 3 V supplies, the AD7923
dissipates just 3.6 mW of power maximum.
2. Four Single-Ended Inputs with a Channel Sequencer.
A consecutive sequence of channels, through which the ADC
will cycle and convert on, can be selected.
3. Single-Supply Operation with V_DRIVE Function.
The AD7923 operates from a single 2.7 V to 5.25 V supply.
The V_DRIVE function allows the serial interface to connect
directly to either 3 V or 5 V processor systems independent of AV_DD.
4. Flexible Power/Serial Clock Speed Management.
The conversion rate is determined by the serial clock, allowing
the conversion time to be reduced through the serial clock speed
increase. The part also features various shutdown modes to
maximize power efficiency at lower throughput rates. Current
consumption is 0.5 mA maximum when in full shutdown.
5. No Pipeline Delay.
The part features a standard successive approximation ADC
with accurate control of the sampling instant via a CS input
and once off conversion control.
REV. 0
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