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.