1Msample/s ADCs offer simultaneous sampling and conversion for optimised motor control

National Semiconductor’s ADC122S706/655/625 12-bit simultaneous-sampling ADCs are optimised for motor-control applications.

These ADCs use two independent, 12-bit Successive-Approximation Registers (SAR) that are synchronised to sample two signals accurately at the same time. The option of a second output pin allows output at the full sample and conversion rate.

The ADC122S706 has a maximum sampling rate of 1Msample/s per channel, while the ADC122S655 and ADC122S625 offer respectively 500ksample/s and 200ksample/s.

The ADC122S625/ADC122S655 feature dual- ADC cores that are capable of simultaneously sampling each differential input. The devices have a single SPI interface that is shared by both channels. These devices are available in a 10-lead MSOP package with the conversion results outputted on a single data-output pin at a rate of 200ksample/s and 500ksample/s respectively.

In addition to the extra data-output pin, the ADC122S706 has an independent digital interface supply voltage to further ease interfacing to different logic-voltage families. The ADC122S706 features a 14-lead TSSOP package.

For duties involving current-sensing or resolver digitisation, these ADCs interface directly to resolvers or Hall-effect devices, thereby saving the costs and errors of additional external amplifiers. Optical-encoder signals can also be converted directly for accurate and cost-effective motorposition detection.

 

FEATURES Dual 12-bit SAR core Industrial temperature range: -40°C to 105°C 23mW typical power consumption 3µW power-down mode Single external reference voltage Power-supply range: 4.5V to 5.5V SPI-compatible serial interface

APPLICATIONS Current sensing for: Stepper motors 3-phase Permanent Magnet Synchronous Motors (PMSM) Induction motors Resolver front-end solution Optical motor-position detection

 

 

 

Development board ADC122S706EB is available to members of the Future Board Club. To apply for the development board, and membership of the Board Club, go to www.my-boardclub.com/manf-offers.htm This offer is free and subject to qualification.

 

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