Programmable Oscillator

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 VP-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 –40ºC to +85ºC.

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.

APPLICATIONS

Excitation Source for:

* Resolvers

* Synchros

* LVDTs

* RVDTs

* Pressure Transducers

* Load Cells

* AC Bridges

* Programmable Sinusoidal Oscillator

* Synthesized Synchronous Reference Output

* Programmable Output Frequency Range: 2 kHz–20 kHz