The AD2S99 is a programmable sinusoidal oscillator with selectable frequencies, synchronous reference output, and loss‑of‑signal detection.
The AD2S99 provides sine‑wave excitation for resolvers, synchros, LVDTs, and other AC transducers. It includes a phase‑locked synchronous reference output and a loss‑of‑signal indicator, all in a 20‑pin PLCC package that operates from –40 °C to +85 °C.
Typical applications show the oscillator driving resolver‑to‑digital converters such as the AD2S80/AD2S90 series. Frequency selection is made with SEL1/SEL2 pins, and intermediate frequencies can be obtained by adding a resistor to the FBIAS pin. The device also offers ESD protection and recommended decoupling capacitor values for stable operation.
| Frequency Output Range | 2 kHz–20 kHz |
|---|---|
| Excitation Amplitude (EXC) | 2 V rms |
| SYNREF Output | ±3 V p‑p square wave |
| Power Supply Voltage (VDD) | +4.75 to +5.25 V dc |
| Operating Temperature Range | –40 °C to +85 °C |
The LOS pin pulls high when both SIN and COS inputs fall below the loss‑of‑signal threshold, indicating a signal loss; otherwise it stays low.
SYNREF provides a 3 V p‑p square‑wave reference that is phase‑locked to the SIN and COS inputs.