AD2S1205YSTZ

Overview

The AD2S1205YSTZ is a complete monolithic 12-bit resolver-to-digital converter (RDC) from Analog Devices, designed for automotive applications. It features an on-board programmable sinusoidal oscillator providing excitation for resolvers. The device accepts differential input signals of 3.15 V p-p ± 27% and utilizes a Type II tracking loop to convert Sin/Cos information into digital angle and velocity data. Key electrical parameters include a maximum tracking rate of 1250 rps at 12-bit resolution, angular accuracy of ±11 arc minutes (Y grade), and operation on a single 5.00 V ± 5% supply. It offers parallel and serial 12-bit data ports, incremental encoder emulation, and system fault detection within a 44-lead LQFP package rated for -40°C to +125°C.

Feature Summary

• Complete 12-bit RDC with integrated programmable sinusoidal oscillator for resolver excitation.
• High precision: ±11 arc minutes accuracy (Y grade) and 1250 rps maximum tracking rate.
• Dual interface options: 12-bit parallel port and 3-wire serial interface for position and velocity data.
• Built-in system fault detection for loss of signal, signal degradation, and loss of tracking.
• Automotive qualified with 4 kV ESD protection and operation from -40°C to +125°C.

Applications

• Automotive motion sensing and control systems
• Hybrid-electric vehicle powertrains
• Electric power steering (EPS)
• Integrated starter generator/alternator applications
• Industrial motor control and process control

Procurement Notes

Verify the YSTZ suffix indicates automotive qualification and tray packaging. Confirm the specific revision (Rev. A) matches design requirements. Ensure supply voltages (AVDD/DVDD) are strictly maintained between 4.75 V and 5.25 V. Check for moisture sensitivity handling requirements prior to assembly. Validate that the external clock frequency supports the desired tracking rate specifications.

Selection Notes

Select the AD2S1205YSTZ for applications requiring high-accuracy resolver feedback in harsh automotive environments. Choose this part over industrial grades if AEC-Q100 qualification is mandatory. Ensure the system can support the required 8.192 MHz ± 25% clock frequency for optimal dynamic performance. Consider the 44-lead LQFP footprint for PCB layout constraints. Verify compatibility with the 3.15 V p-p input signal range of the connected resolver.

Part Context

The AD2S1205YSTZ belongs to the AD2S1200 family of resolver-to-digital converters. The 'YSTZ' suffix specifically denotes the automotive-grade temperature rating (-40°C to +125°C) and tray packaging format. It shares functional similarities with the AD2S1200 but includes additional features like the on-board oscillator and encoder emulation. This component serves as a direct replacement for older discrete RDC solutions in modern automotive sensor interfaces.

Replacement Considerations

Public confirmed substitute part numbers include AD2S1200YSTZ and AD2S1205WSTZ. Note that WSTZ variants may differ in temperature grade or packaging. Verify pinout compatibility and software register configurations when substituting within the AD2S120x family. Cross-reference specific automotive qualification requirements if replacing non-automotive parts.

FAQ

What is the maximum tracking rate of the AD2S1205YSTZ?

The maximum tracking rate is 1250 rps at 12-bit resolution, which requires an external clock frequency of 10.24 MHz.

How is the excitation frequency programmed?

The excitation frequency is programmable to 10 kHz, 12 kHz, 15 kHz, or 20 kHz using the FS1 and FS2 logic input pins.

What fault conditions does the AD2S1205 detect?

It detects Loss of Signal (LOS), Degradation of Signal (DOS), and Loss of Tracking (LOT) via dedicated output pins.

Does the AD2S1205 provide velocity output?

Yes, it provides a 12-bit signed digital velocity output accessible via either the parallel or serial interface.