12-Bit R/D Converter with Reference Oscillator AD2S1200 GENERAL DESCRIPTION FEATURES Complete monolithic R/D converter The AD2S1200 is a complete 12-bit resolution tracking resolver- Parallel and serial 12-bit data ports to-digital converter, integrating an on-board programmable System fault detection sinusoidal oscillator that provides sine wave excitation for Absolute position and velocity outputs resolvers. An external 8.192 MHz crystal is required to provide Differential inputs a precision time reference. This clock is internally divided to 11 arc minutes of accuracy generate a 4.096 MHz clock to drive all the peripherals. 1,000 rps maximum tracking rate, 12-bit resolution The converter accepts 3.6 V p-p 10% input signals, in the Incremental encoder emulation (1,024 pulses/rev) range of 10 kHz to 20 kHz on the Sin and Cos inputs. A Type II Programmable sinusoidal oscillator on-board servo loop is employed to track the inputs and convert the input Compatible with DSP and SPI interface standards Sin and Cos information into a digital representation of the 204.8 kHz square wave output input angle and velocity. The bandwidth of the converter is set Single-supply operation (5.00 V 5%) internally to 1.7 kHz with an external 8.192 MHz crystal. The 40C to +125C temperature rating maximum tracking rate is 1,000 rps. 44-lead LQFP package 4 kV ESD protection FUNCTIONAL BLOCK DIAGRAM CLKIN (8.192MHz) REFBYP REFOUT FS1 FS2 XTALOUT INTERNAL VOLTAGE AD2S1200 (4.096MHz) CLOCK REFERENCE GENERATOR REFERENCE EXC (204.8kHz) OSCILLATOR (DAC) EXC CLOCK CPO DIVIDER SYNTHETIC DOS FAULT REFERENCE INDICATORS SinLO LOT ADC MONITOR Sin MONITOR ERROR CALCULATION/ ANGLE DEMODULATOR ERROR SIGNAL ERROR MONITOR CosLO ADC Cos DIGITAL FILTER ANGLE A ENCODER POSITION VELOCITY DIR EMULATION INTEGRATOR INTEGRATOR B NM POSITION REGISTER VELOCITY REGISTER SAMPLE MULTIPLEXER CS DATA BUS OUTPUT RD RESET RDVEL SOE DB11 DB10 DB9DB0 SO SCLK Figure 1. Rev. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Specifications subject to change without notice. No license is granted by implication Tel: 781.329.4700 www.analog.com or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Fax: 781.326.8703 2003 Analog Devices, Inc. All rights reserved. 04406-0-001AD2S1200 Triple Format Position Data: Absolute 12-bit angular APPLICATIONS binary position data accessed either via a 12-bit parallel Electric power steering port or via a 3-wire serial interface. Incremental encoder Electric vehicles emulation in standard A QUAD B format, with direction Integrated starter generator/alternator output is available. Encoder emulation Automotive motion sensing and control Digital Velocity Output: 12-bit signed digital velocity, twos complement format, accessed either via a 12-bit PRODUCT HIGHLIGHTS parallel port or via a 3-wire serial interface. Complete Resolver-to-Digital Interface: The AD2S1200 Programmable Excitation Frequency: Excitation fre- provides the complete solution for digitizing resolver quency easily programmable to 10 kHz, 12 kHz, 15 kHz, or signals (12-bit resolution) with on-board programmable 20 kHz by using the frequency select pins. sinusoidal oscillator. System Fault Detection: A fault detection circuit will Ratiometric Tracking Conversion: This technique detect any loss of resolver signals, out of range input provides continuous output position data without signals, input signal mismatch, or loss of position tracking. conversion delay. It also provides noise immunity and tolerance of harmonic distortion on the reference and input signals. Rev. 0 Page 2 of 24