AD2S99BP

Programmable Timers And Oscillators Overview

The AD2S99BP is a programmable sinusoidal oscillator designed to provide excitation for resolvers and AC transducers. It integrates sine wave generation, synchronous reference output, and loss-of-signal detection in a 20-pin PLCC package. The device operates on ±5 V supplies over a –40°C to +85°C temperature range. Key electrical parameters include an output frequency range of 2 kHz to 20 kHz, selectable via SEL1 and SEL2 pins. The EXC outputs deliver 2 V rms with a current drive capability of 8 mA rms into a 500 Ω load. The SYNREF output provides a ±3 V p-p square wave phase-locked to the SIN and COS inputs.

Programmable Timers And Oscillators Feature Summary

• Programmable excitation frequencies: 2 kHz, 5 kHz, 10 kHz, or 20 kHz via SEL1/SEL2 pins; intermediate frequencies adjustable via FBIAS pin resistor.
• Dynamic phase compensation through synthesized synchronous reference (SYNREF) output phase-locked to transducer secondary windings.
• Loss-of-Signal (LOS) detection pulls high when both SIN and COS signals fall below threshold levels.
• Integrated dual-phase EXC outputs (EXC and EXC) with 180° phase difference for direct transducer driving.

Programmable Timers And Oscillators Applications

• Excitation source for resolvers connected to Resolver-to-Digital Converters (e.g., AD2S80A, AD2S90).
• Drive signal for Synchros, LVDTs, and RVDTs requiring sinusoidal excitation.
• AC bridge circuits and pressure transducers needing stable frequency sources.
• Load cell applications utilizing AC excitation requirements.

Programmable Timers And Oscillators Procurement Notes

Verify the BP grade specification against application accuracy needs. The BP grade offers ±5% frequency accuracy at +25°C and ±10% across the full operating temperature range, compared to the AP grade's wider tolerances. Confirm the P-20A PLCC package compatibility with PCB footprints. Ensure power supply decoupling capacitors (100 nF ceramic and 4.7 μF tantalum) are placed close to the device as specified in the datasheet.

Programmable Timers And Oscillators Selection Notes

Select the AD2S99BP when precise frequency stability within ±10% over the industrial temperature range is required. Choose this model if dynamic phase compensation is necessary to eliminate external preset circuits. Verify that the 8 mA rms drive current suffices for the transducer impedance; otherwise, an external buffer amplifier like the OP279 may be needed. Ensure SEL1 and SEL2 logic levels match the desired fixed frequency or use the FBIAS pin for custom frequencies.

Programmable Timers And Oscillators Part Context

The AD2S99BP is part of the Analog Devices AD2S99 family of programmable oscillators. It serves as a companion component to various resolver-to-digital converters such as the AD2S80A, AD2S82A, AD2S83, AD2S90, and AD2S93. The BP suffix denotes the commercial/industrial temperature grade variant packaged in a 20-pin Plastic Leadless Chip Carrier (PLCC).

Programmable Timers And Oscillators Replacement Considerations

The AD2S99AP is the alternative grade within the same family, offering different accuracy specifications but identical functionality and pinout. No other direct cross-model substitutes are documented in the provided datasheet.