4-Channel, 200 kSPS 12-Bit ADC

with Sequencer in 16-Lead TSSOP

AD7923

Rev. C

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FEATURES

Fast throughput rate: 200 kSPS

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

Shutdown mode: 0.5 μA max

16-lead TSSOP package

Qualified for automotive applications

GENERAL DESCRIPTION

The AD7923 is a 12-bit, high speed, low power, 4-channel, suc-

cessive approximation (SAR) ADC. It operates from a single

2.7 V to 5.25 V power supply and features throughput rates up to

200 kSPS. It 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 by

CS and the serial clock, allowing the device to easily interface

with microprocessors or DSPs. The input signal is sampled on

the falling edge of CS; the conversion is also initiated at this

point.

The AD7923 uses advanced design techniques to achieve very

low power dissipation at maximum throughput rates. At

maximum throughput rates, it consumes 1.2 mA maximum

with 3 V supplies and 1.5 mA maximum with 5 V supplies.

Through the configuration of the control register, the analog

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 serial

clock, SCLK, frequency, since this is used as the master clock to

control the conversion. The conversion time can be as short as

800 ns with a 20 MHz SCLK.

FUNCTIONAL BLOCK DIAGRAM

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•

•

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•

•

•

•

T/H

I/P

MUX

SEQUENCER

CONTROL LOGIC

12-BIT

SUCCESSIVE

APPROXIMATION

ADC

GND

SCLK

DOUT

DIN

CS

AD7923

Figure 1.

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.

2.

Four Single-Ended Inputs with a Channel Sequencer.

3.

directly to either 3 V or 5 V processor systems independent

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 μA

maximum when in full shutdown.

5.

No Pipeline Delay.

The part features a SAR ADC with accurate control of the

sampling instant via a CS input and once off conversion

control.