Analog Devices AD2S99BP, AD2S99AP Datasheet

a		Programmable
		Oscillator
		AD2S99

FEATURES

Programmable Sinusoidal Oscillator

Synthesized Synchronous Reference Output

Programmable Output Frequency Range: 2 kHz–20

“Loss-of-Signal” Indicator

20-Pin PLCC Package

Low Cost

APPLICATIONS

Excitation Source for:

Resolvers

Synchros

LVDTs

RVDTs

Pressure Transducers

Load Cells

AC Bridges

FUNCTIONAL BLOCK DIAGRAM

kHz			PUSH/	EXC	TO
			PULL
					TRANSDUCER
			O/P STAGE	EXC
FBIAS
SEL1	FREQUENCY	SINE WAVE
	SELECT	GENERATOR
SEL2
				SYNREF
		PHASE		SYNCHRONOUS
				REFERENCE
		DETECT
	AD2S99	LOGIC		LOS
		SIN	COS
		FROM
		TRANSDUCER

GENERAL DESCRIPTION

The AD2S99 programmable sinusoidal oscillator provides sine wave excitation for resolvers and a wide variety of ac transducers. The AD2S99 also provides a synchronous reference output signal (3 V p-p square wave) that is phase locked to its SIN and COS inputs. In an application, the SIN and COS inputs are connected to the transducer’s secondary windings.

The synchronous reference output compensates for temperature and cabling dependent phase shifts and eliminates the need for external preset phase compensation circuits. The synchronous reference output can be used as a zero crossing reference for resolver-to-digital converters such as Analog Devices’ AD2S80A, AD2S82A, AD2S83 and AD2S90.

The AD2S99 is packaged in a 20-pin PLCC and operates over –40°C to +85°C.

REV. B

Information furnished by Analog Devices is believed to be accurate and 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.

PRODUCT HIGHLIGHTS Dynamic Phase Compensation

The AD2S99 dynamically compensates for any phase variation in a transducer by phase locking its synchronous reference output to the transducer’s secondary windings.

Programmable Excitation Frequency

The excitation frequency is easily programmed to 2 kHz, 5 kHz, 10 kHz, or 20 kHz by using the frequency select pins. Intermediate frequencies are available by adding an external resistor.

Signal Loss Detection

The AD2S99 has the ability to detect if both the transducer secondary winding connections become disconnected from its SIN and COS inputs. The “LOS” output pin pulls high when a signal loss is detected.

Integration

The AD2S99 integrates the transducer excitation, synchronous reference, and loss of signal detection functions into a small, cost effective package.

© Analog Devices, Inc., 1995

One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A. Tel: [phone] Fax: [phone]

AD2S99–SPECIFICATIONS (VS = 64.75 V to 65.25 V @ –408C to +858C unless otherwise noted)

Parameter

Min

Typ

Max

Units

Test Conditions

FREQUENCY OUTPUT RANGE

SEL1

SEL2

2 kHz

2000

Hz

VSS

VSS

5 kHz

5000

Hz

VSS

GND

10 kHz

10000

Hz

GND

VSS

20 kHz

20000

Hz

GND

GND

ACCURACY

±10

AP Grade @ +25°C

Frequency

%

±20

%

AP Grade –40°C to +85°C

±5

%

BP Grade @ +25°C

±10

%

BP Grade –40°C to +85°C

Amplitude

±3

±10

%

AP Grade @ +25°C

±3

±20

%

AP Grade –40°C to +85°C

±5

%

BP Grade @ +25°C

±10

%

BP Grade –40°C to +85°C

Power Supply Rejection Ratio

0.002

V p-p/V

Output Variation as Function of

Change in Power Supply Voltage

ANALOG OUTPUTS

Amplitude

EXC,

EXC

2

V rms

EXC to GND,

EXC

to GND

SYNREF

±3

±200

V p-p

Square Wave

SYNREF OFFSET

mV

Current Drive Capability

EXC,

VS = ±5 V

8

mA rms

RLOAD = 500 Ω

to EXC

EXC

EXC

Capacitive Drive

1000

pF

CLOAD = 1000 pF

Total Harmonic Distortion

EXC,

EXC

–25

dB

ANALOG INPUTS SIN, COS

Amplitude

1.8

2.0

2.2

V rms

Phase Lock Range

–45

+45

Degrees

Additional Phase Delay

±10

Degrees

AP Grade

±10

Degrees

BP Grade

FREQUENCY SELECT INPUTS

SEL1, SEL21

VSS

AGND

V dc

LOS OUTPUT

IOL = 400 μA

Output Low Voltage

0.7

V dc

Output High Voltage

VDD

V dc

50 kΩ Pull Up to VDD (Open

Drain Output)

SIN, COS LOS Threshold

0.5

0.6

0.8

V rms

POWER SUPPLIES

VDD

+4.75

+5.25

V dc

VSS

–4.75

±8

–5.25

V dc

Quiescent Current IDD, ISS

±15

mA

No Load

TEMPERATURE RANGE

°C

Operating

–40

+85

Storage

–65

+150

°C

NOTES

1Frequency select pins SEL1 and SEL2 must be connected to appropriate voltage levels before power is applied. Specifications subject to change without notice.

–2–

REV. B

AD2S99

ABSOLUTE MAXIMUM RATINGS*
VDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . +7 V
VSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . –7 V
Operating Temperature . . . . . . . . . . . . . . . . .	.–40°C to +85°C
Storage Temperature . . . . . . . . . . . . . . . . . . .	–65°C to +150°C
Analog Input Voltages (SIN and COS) . . . . .	. . . . VSS – 0.3	V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. .to VDD + 0.3	V
Frequency Select (SEL1, SEL2) . . . . . . . . . .	. . . . VSS – 0.4	V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	to AGND + 0.4 V

*Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

RECOMMENDED OPERATING CONDITIONS

Power Supply Voltage (VDD to VSS) . . . . . . ±4.75 V to ±5.25 V Analog Input Voltage (SIN and COS) . . . . . . . . 2 V rms ±10%

Frequency Select (SEL1 and SEL2) . . . . . . . . . VSS to AGND Operating Temperature Range . . . . . . . . . . . . . –40°C to +85°C

ORDERING GUIDE

Model	Temperature Range	Package Option*
AD2S99AP	–40°C to +85°C	P-20A
AD2S99BP	–40°C to +85°C	P-20A

*P = PLCC.

PIN DESIGNATIONS

Pin
No.	Mnemonic			Description
1	SEL2			Frequency Select 2
2	SEL1			Frequency Select 1
3	FBIAS			External Frequency Adjust Pin
5	SIN			Resolver Output SIN
61	DGND			Digital Ground
7	COS			Resolver Output COS
10		SYNREF		Synthesized Reference Output
11		LOS		Indicates When Both the SIN and
				COS Are Below the Threshold.
12		VDD		Positive Power Supply
161	AGND			Analog Ground
17		EXC		Resolver Reference One
18				Resolver Reference Two3
		EXC
192	VSS			Negative Power Supply
202	VSS			Negative Power Supply

NOTES

1Pins 6 and 16 must be connected together.

2Pins 19 and 20 must be connected together.

3Resolver Reference two (EXC) is 180° phase advanced with respect to Resolver Reference one (EXC).

PIN CONFIGURATION

			FBIAS		SEL1		SEL2		V		V
									SS		SS
			3		2		1		20		19
NC	4												18	EXC
SIN	5				AD2S99								17	EXC
DGND	6				TOP VIEW								16	AGND
COS				(Not to Scale)										NC
	7												15
NC	8												14	NC
			9		10		11		12		13
			NC		SYNREF		LOS		V		NC
									DD

NC = NO CONNECT

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD2S99 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

WARNING!

ESD SENSITIVE DEVICE

REV. B

–3–