4-Channel, 1 MSPS, 8-/10-/12-Bit ADCs
with Sequencer in 16-Lead TSSOP
AD7904/AD7914/AD7924
Data Sheet
FEATURES
FUNCTIONAL BLOCK DIAGRAM
AVDD
REFIN
VIN0
T/H
8-/10-/12-BIT
SUCCESSIVE
APPROXIMATION
ADC
VIN1
I/P
MUX
VIN2
VIN3
SCLK
DOUT
SEQUENCER
CONTROL LOGIC
DIN
CS
AD7904/AD7914/AD7924
VDRIVE
AGND
03087-001
Fast throughput rate: 1 MSPS
Specified for AVDD of 2.7 V to 5.25 V
Low power:
6 mW maximum at 1 MSPS with 3 V supplies
13.5 mW maximum at 1 MSPS with 5 V supplies
4 single-ended inputs with sequencer
Wide input bandwidth
AD7924, 70 dB 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 µA maximum
16-lead TSSOP package
Qualified for automotive applications
Figure 1.
GENERAL DESCRIPTION
PRODUCT HIGHLIGHTS
The AD7904/AD7914/AD7924 are, respectively, 8-bit, 10-bit, and
12-bit, high speed, low power, 4-channel successive approximation ADCs. The parts operate from a single 2.7 V to 5.25 V
power supply and feature throughput rates up to 1 MSPS. The
parts contain a low noise, wide bandwidth track-and-hold
amplifier that can handle input frequencies in excess of 8 MHz.
1.
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 conversion is initiated at this
point. There are no pipeline delays associated with the part.
The AD7904/AD7914/AD7924 use advanced design techniques
to achieve very low power dissipation at maximum throughput
rates. At maximum throughput rates, the AD7904/AD7914/
AD7924 consume 2 mA maximum with 3 V supplies; with 5 V
supplies, the current consumption is 2.7 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 AD7904/AD7914/AD7924 each feature four singleended analog inputs with a channel sequencer to allow a preprogrammed selection of channels to be converted sequentially.
The conversion time for the AD7904/AD7914/AD7924 is
determined by the SCLK frequency, which is also used as the
master clock to control the conversion.
Rev. C
2.
3.
4.
5.
High Throughput with Low Power Consumption.
The AD7904/AD7914/AD7924 offer throughput rates
up to 1 MSPS. At the maximum throughput rate with 3 V
supplies, the AD7904/AD7914/AD7924 dissipate only
6 mW of power maximum.
Four Single-Ended Inputs with Channel Sequencer.
A consecutive sequence of channels can be selected,
through which the ADC will cycle and convert on.
Single-Supply Operation with VDRIVE Function.
The AD7904/AD7914/AD7924 operate from a single 2.7 V
to 5.25 V supply. The VDRIVE function allows the serial interface to connect directly to 3 V or 5 V processor systems,
independent of VDD.
Flexible Power/Serial Clock Speed Management.
The conversion rate is determined by the serial clock,
allowing the conversion time to be reduced by increasing
the serial clock speed. The parts also feature two shutdown
modes to maximize power efficiency at lower throughput
rates. Current consumption is 0.5 µA maximum when in
full shutdown.
No Pipeline Delay.
The parts feature a standard successive approximation
ADC with accurate control of the sampling instant via
the CS input and once-off conversion control.
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