1 MSPS, 12-Bit, Simultaneous Sampling

SAR ADC with PGA and Four Comparators

AD7262

Rev. 0

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibilityis assumedbyAnalogDevicesforitsuse,norforanyinfringementsof patentsorother

rightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

www.analog.com

Fax: 781.461.3113

©2008 Analog Devices, Inc. All rights reserved.

FEATURES

Dual simultaneous sampling 12-bit, 2-channel ADC

True differential analog inputs

Programmable gain stage: ×1, ×2, ×3, ×4, ×6, ×8, ×12, ×16,

×24, ×32, ×48, ×64, ×96, ×128

Throughput rate per ADC

1 MSPS for AD7262

500 kSPS for AD7262-5

Analog input impedance: >1 GΩ

Wide input bandwidth

−3 dB bandwidth: 1.7 MHz at gain = 2

4 on-chip comparators

SNR: 73 dB typical at gain = 2, 66 dB typical at gain = 32

Device offset calibration, system gain calibration

On-chip reference: 2.5 V

–40°C to +105°C operation

High speed serial interface

SPI/QSPI™/MICROWIRE™/DSP compatible

48-lead LFCSP and LQFP packages

GENERAL DESCRIPTION

The AD7262/AD7262-5 are dual, 12-bit, high speed, low power,

successive approximation ADCs that operate from a single 5 V

power supply. The AD7262 features throughput rates of up to

1 MSPS per on-chip ADC. The AD7262-5 features throughput

rates of up to 500 kSPS. Two complete ADC functions allow

simultaneous sampling and conversion of two channels. Each

ADC is preceded by a true differential analog input with a PGA.

There are 14 gain settings available: ×1, ×2, ×3, ×4, ×6, ×8, ×12,

×16, ×24, ×32, ×48, ×64, ×96, and ×128.

The AD7262/AD7262-5 contain four comparators. Comparator A

and Comparator B are optimized for low power, while Compara-

tor C and Comparator D have fast propagation delays. The

AD7262/AD7262-5 feature a calibration function to remove any

device offset error and programmable gain adjust registers to

allow for input path (for example, sensor) offset and gain

compensation. The AD7262/AD7262-5 have an on-chip 2.5 V

reference that can be disabled if an external reference is preferred.

The AD7262/AD7262-5 are ideally suited for monitoring small

amplitude signals from a variety of sensors. They include all the

functionality needed for monitoring the position feedback

signals from a variety of analog encoders used in motor control

systems.

FUNCTIONAL BLOCK DIAGRAM

AGND

DGND

PD1

PD2

COMP

COMP

COMP

COMP

PGA

T/H

BUF

T/H

BUF

PGA

12-BIT

SUCCESSIVE

APPROXIMATION

ADC

REF

12-BIT

SUCCESSIVE

APPROXIMATION

ADC

CONTROL

LOGIC

OUTPUT

DRIVERS

OUTPUT

DRIVERS

OUTPUT

DRIVERS

OUTPUT

DRIVERS

G3

G2

G1

G0

CAL

CS

SCLK

REFSEL

AD7262

OUTPUT

DRIVERS

OUTPUT

DRIVERS

Figure 1.

PRODUCT HIGHLIGHTS

1.

Integrated PGA with a variety of flexible gain settings to

allow detection and conversion of low level analog signals.

2.

Each PGA is followed by a dual simultaneous sampling

ADC, featuring throughput rates of 1 MSPS per ADC for

the AD7262. The conversion results of both ADCs are

simultaneously available on separate data lines or in succes-

sion on one data line if only one serial port is available.

3.

Four integrated comparators that can be used to count

signals from pole sensors in motor control applications.

4.

Internal 2.5 V reference.