ADS7862Y/2K

The ADS7862 is a dual 12-bit, 500kHz analog-to-digital converter (A/D) with 4 fully differential input channels grouped into two pairs for high speed simultaneous signal acquisition. Inputs to the sample-and-hold amplifiers are fully differential and are maintained differential to the input of the A/D converter. This provides excellent common-mode rejection of 80dB at 50kHz, which is important in high noise environments. The ADS7862 offers parallel interface and control inputs to minimize software overhead. The output data for each channel is available as a 12-bit word. The ADS7862 is offered in an TQFP-32 package and is fully specified over the -40°C to +85°C operating range. The ADS7862 is a high speed, low power, dual 12-bit A/D converter that operates from a single +5V supply. The input channels are fully differential with a typical common-mode rejection of 80dB. The part contains dual 2µs successive approximation A/Ds, two differential sample-and-hold amplifiers, an internal +2.5V reference with REFIN and REFOUT pins and a high speed parallel interface. There are four analog inputs that are grouped into two channels (A and B) selected by the A0 input (A0 LOW selects Channels A0 and B0, while A0 HIGH selects Channels A1 and B1). Each A/D converter has two inputs (A0 and A1 and B0 and B1) that can be sampled and converted simultaneously, thus preserving the relative phase information of the signals on both analog inputs. The part accepts an analog input voltage in the range of -VREF to +VREF, centered around the internal +2.5V reference. A conversion is initiated on the ADS7862 by bringing the CONVST pin LOW for a minimum of 15ns. CONVST LOW places both sample-and-hold amplifiers in the hold state simultaneously and the conversion process is started on both channels. The BUSY output will then go HIGH and remain HIGH for the duration of the conversion cycle. Depending on the status of the A0 pin, the data will either reflect a conversion of Channel 0 (A0 LOW) or Channel 1 (A0 HIGH). The data can be read from the parallel output bus following the conversion by bringing both RD and CS LOW. Conversion time for the ADS7862 is 1.75µs when an 8MHz external clock is used. The corresponding acquisition time is 0.25µs. To achieve maximum output rate (500kHz), the read function can be performed immediately at the start of the next conversion.

Applications

• MOTOR CONTROL
• MULTI-AXIS POSITIONING SYSTEMS
• 3-PHASE POWER CONTROL

Key features

• 4 INPUT CHANNELS
• FULLY DIFFERENTIAL INPUTS
• 2µs TOTAL THROUGHPUT PER CHANNEL
• GUARANTEED NO MISSING CODES
• PARALLEL INTERFACE
• 1MHz EFFECTIVE SAMPLING RATE
• LOW POWER: 40mW