Differential/Single-Ended Input, Dual

2 MSPS, 12-Bit, 3-Channel SAR ADC

AD7266

Rev. B

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FEATURES

Dual 12-bit, 3-channel ADC

Throughput rate: 2 MSPS

Power consumption

9 mW at 1.5 MSPS with 3 V supplies

27 mW at 2 MSPS with 5 V supplies

Pin-configurable analog inputs

12-channel single-ended inputs

6-channel fully differential inputs

6-channel pseudo differential inputs

70 dB SNR at 50 kHz input frequency

Accurate on-chip reference: 2.5 V

±0.2% maximum @ 25°C, 20 ppm/°C maximum

Dual conversion with read 437.5 ns, 32 MHz SCLK

High speed serial interface

SPI®-/QSPI™-/MICROWIRE™-/DSP-compatible

−40°C to +125°C operation

Shutdown mode: 1 μA maximum

32-lead LFCSP and 32-lead TQFP

1 MSPS version, AD7265

GENERAL DESCRIPTION

The AD72661 is a dual, 12-bit, high speed, low power, successive

approximation ADC that operates from a single 2.7 V to 5.25 V

power supply and features throughput rates up to 2 MSPS. The

device contains two ADCs, each preceded by a 3-channel

multiplexer, and a low noise, wide bandwidth track-and-hold

amplifier that can handle input frequencies in excess of 30 MHz.

The conversion process and data acquisition use standard

control inputs allowing easy interfacing to microprocessors or

DSPs. The input signal is sampled on the falling edge of CS;

conversion is also initiated at this point. The conversion time is

determined by the SCLK frequency. There are no pipelined

delays associated with the part.

The AD7266 uses advanced design techniques to achieve very

low power dissipation at high throughput rates. With 5 V

supplies and a 2 MSPS throughput rate, the part consumes

6.2 mA maximum. The part also offers flexible power/

throughput rate management when operating in normal mode

as the quiescent current consumption is so low.

The analog input range for the part can be selected to be a 0 V

complement output coding. The AD7266 has an on-chip 2.5 V

reference that can be overdriven when an external reference is

FUNCTIONAL BLOCK DIAGRAM

12-BIT

SUCCESSIVE

APPROXIMATION

ADC

OUTPUT

DRIVERS

CONTROL

LOGIC

T/H

BUF

MUX

REF

AD7266

REF SELECT

BUF

OUTPUT

DRIVERS

12-BIT

SUCCESSIVE

APPROXIMATION

ADC

T/H

MUX

DGND

DGND

CS

SCLK

RANGE

SGL/DIFF

A0

A1

A2

Figure 1.

The AD7266 is available in a 32-lead LFCSP and a

32-lead TQFP.

PRODUCT HIGHLIGHTS

1.

Two Complete ADC Functions Allow Simultaneous

Sampling and Conversion of Two Channels.

Each ADC has three fully/pseudo differential pairs, or six

single-ended channels, as programmed. The conversion

result of both channels is simultaneously available on

separate data lines, or in succession on one data line if only

one serial port is available.

2.

High Throughput with Low Power Consumption.

The AD7266 offers a 1.5 MSPS throughput rate with 11.4 mW

maximum power dissipation when operating at 3 V.

3.

4.

No Pipeline Delay.

The part features two standard successive approximation

ADCs with accurate control of the sampling instant via a

CS input and once off conversion control.