8-Channel, 200 kSPS, 12-Bit ADC
with Sequencer in 20-Lead TSSOP
Fast Throughput Rate: 200 kSPS
Specified for AVDD of 2.7 V to 5.25 V
3.6 mW Max at 200 kSPS with 3 V Supply
7.5 mW Max at 200 kSPS with 5 V Supply
8 (Single-Ended) Inputs with Sequencer
Wide Input Bandwidth:
70 dB Min SINAD at 50 kHz Input Frequency
Flexible Power/Serial Clock Speed Management
No Pipeline Delays
High Speed Serial Interface SPI™/QSPI™/
Shutdown Mode: 0.5 A Max
20-Lead TSSOP Package
The AD7927 is a 12-bit, high speed, low power, 8-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 AD7927 uses advanced design techniques to achieve very low
power dissipation at maximum throughput rates. At maximum
throughput rates, the AD7927 consumes 1.2 mA maximum
with 3 V supplies; 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 REFIN or 0 V to
2 ¥ REFIN, with either straight binary or twos complement output
coding. The AD7927 features eight single-ended analog inputs
with a channel sequencer to allow a preprogrammed selection of
channels to be converted sequentially.
The conversion time for the AD7927 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
1. High Throughput with Low Power Consumption.
The AD7927 offers up to 200 kSPS throughput rates. At the
maximum throughput rate with 3 V supplies, the AD7927
dissipates 3.6 mW of power maximum.
2. Eight 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 VDRIVE Function.
The AD7927 operates from a single 2.7 V to 5.25 V supply. The
VDRIVE function allows the serial interface to connect directly
to either 3 V or 5 V processor systems independent of AVDD.
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.
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