FUNCTIONAL BLOCK DIAGRAM

HIGH ACCURACY

SIN COS

MULTIPLIER

UP-DOWN

COUNTER

LATCH

SERIAL INTERFACE

HIGH

DYNAMIC

RANGE V.C.O.

P.S.D. AND

FREQUENCY

SHAPING

DECODE

LOGIC

SIN

SIN LO

COS

NMC

A

B

NM

SCLK

DATA

REF

VEL

CLKOUT

DIR

ERROR

AMPLIFIER

CLK

U/D

ANGLE

CS

SIN (

–

)

COS LO

DIGITAL

ANGLE

REV. D

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reliable. However, no responsibility is assumed by Analog Devices for its

use, nor for any infringements of patents or other rights of third parties

which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of Analog Devices.

a

FEATURES

Complete Monolithic Resolver-to-Digital Converter

Incremental Encoder Emulation (1024-Line)

Absolute Serial Data (12-Bit)

Differential Inputs

12-Bit Resolution

Industrial Temperature Range

20-Lead PLCC

Low Power (50 mW)

APPLICATIONS

Industrial Motor Control

Servo Motor Control

Industrial Gauging

Encoder Emulation

Automotive Motion Sensing and Control

Factory Automation

Limit Switching

AD2S90

GENERAL DESCRIPTION

The AD2S90 is a complete 12-bit resolution tracking resolver-

to-digital converter. No external components are required to

operate the device.

The converter accepts 2 V rms

± 10% input signals in the range

3 kHz–20 kHz on the SIN, COS and REF inputs. A Type II

servo loop is employed to track the inputs and convert the input

SIN and COS information into a digital representation of the

input angle. The bandwidth of the converter is set internally at

1 kHz within the tolerances of the device. The guaranteed maxi-

mum tracking rate is 500 rps.

Angular position output information is available in two forms,

absolute serial binary and incremental A quad B.

The absolute serial binary output is 12-bit (1 in 4096). The data

output pin is high impedance when Chip Select

CS is logic HI.

This allows the connection of multiple converters onto a com-

mon bus. Absolute angular information in serial pure binary

form is accessed by

CS followed by the application of an exter-

nal clock (SCLK) with a maximum rate of 2 MHz.

The encoder emulation outputs A, B and NM continuously

produce signals equivalent to a 1024 line encoder. When de-

coded this corresponds to 12 bits of resolution. Three common

north marker pulsewidths are selected via a single pin (NMC).

An analog velocity output signal provides a representation of

velocity from a rotating resolver shaft traveling in either a clock-

wise or counterclockwise direction.

The AD2S90 operates on

±5 V dc ± 5% power supplies and is

fabricated on Analog Devices’ Linear Compatible CMOS pro-

cess (LC

combines precision bipolar circuits with low power CMOS logic

circuits.

PRODUCT HIGHLIGHTS

Complete Resolver-Digital Interface. The AD2S90 provides

the complete solution for digitizing resolver signals (12-bit reso-

lution) without the need for external components.

Dual Format Position Data. Incremental encoder emulation

in standard A QUAD B format with selectable North Marker

width. Absolute serial 12-bit angular binary position data

accessed via simple 3-wire interface.

Single High Accuracy Grade in Low Cost Package.

±10.6 arc

minutes of angular accuracy available in a 20-lead PLCC.

Low Power. Typically 50 mW power consumption.

Low Cost, Complete 12-Bit

Resolver-to-Digital Converter

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

Tel: 781/329-4700

World Wide Web Site: http://www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 1999