Datasheet AD7861 (Analog Devices)

a
11-Bit Resolution Simultaneous Sampling A/D Converter AD7861 FEATURES FUNCTIONAL BLOCK DIAGRAM 11-Bit Resolution Analog-to-Digital Converter REF IN BUSY Seven Single-Ended Analog Inputs Four Input Channels Simultaneously Sampled REF OUT 2.5V A0 REFERENCE Expansion with 4 Multiplexed Inputs A1 Internal 2.5 V Reference VIN1 D0 3.2
␮
s Conversion Time per Channel VIN2 12 11-BIT SHA D11 User Definable Channel Sequencing VIN3 ADC OUTPUT REGISTERS RD Single Supply +5 V Operation CS Double Buffered Register Outputs CLKIN 6.25 MHz to 12.5 MHz Operating Clock Range AUX0 AUX1 4-1 SGND APPLICATIONS AUX2 MUX AGND AUX3 Motor Control AD7861 DGND S0 V 3-Phase Power Measurement DD S1 Cellular Phones Data Acquisition CONVST RESET M 0 M1 GENERAL DESCRIPTION PRODUCT HIGHLIGHTS
The AD7861 is a multichannel simultaneous sampling A/D
Simultaneous Sampling of Four Inputs
Converter (ADC) configured for the acquisition of voltage Four channel sample and hold amplifier (SHA) allows out of inputs in a motor control solution or three-phase power system. phase input signals to be sampled simultaneously, preserving The AD7861 combined with Analog Devices’ 16-bit fixed- the relative phase information. Sample-and-hold acquisition point digital signal processor (DSP) provides a low cost 16-bit time is 1.6 µs and conversion time per channel is 3.2 µs (using fixed-point microcontroller solution. a 12.5 MHz system clock). The input stage has been designed to accommodate the types of
Flexible Analog Channel Sequencing
signals frequently found in motor drives. The VIN1, VIN2, and AD7861 supports acquisition of 2, 3 or 4 channels per group. VIN3 channels are simultaneously sampled inputs suitable for Converted channel results are stored in registers and the data stator current acquisition. The AUX0–AUX3 channels are can be read in any order. The sampling and conversion time multiplexed and are suitable for slower moving inputs such as for two channels is 8 µs, three channels is 11.2 µs, and four temperature and bus voltage of the diode rectifier output in a channels is 14.4 µs (using a 12.5 MHz system clock). motor control application.
Single 5 V dc Operation
Low power, digital process. REV. B 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
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
which may result from its use. No license is granted by implication or
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
otherwise under any patent or patent rights of Analog Devices.
Fax: 781/326-8703 © Analog Devices, Inc., 2000