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AD7927

8-Channel, 200 kSPS, 12-Bit ADC

with Sequencer in 20-Lead TSSOP

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

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™/

MICROWIRE™/DSP Compatible

Shutdown Mode: 0.5 A Max

20-Lead TSSOP Package

GENERAL DESCRIPTION

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

2

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

•

•

•

•

•

•

•

•

•

•

•

•

•

T/H

I/P

MUX

SEQUENCER

CONTROL LOGIC

12-BIT

SUCCESSIVE

APPROXIMATION

ADC

GND

SCLK

DOUT

DIN

CS

AD7927

PRODUCT HIGHLIGHTS

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.

The AD7927 operates from a single 2.7 V to 5.25 V supply. The

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.