Datasheet

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SBAS253E − MAY 2003 − REVISED JULY 2006
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1
FEATURES
D Seven Simultaneously-Sampling Sample-and-Hold (S/H) Capacitors
D Fully Differential Inputs
D Flexible Digital Interface with Four Modes
− One Mode 100% Software-Compatible to VECANA01
− SPI and Two Parallel Modes
D Two Up−Down Counter Modules On-Chip
D 12-Bit System Gain Adjustment for Every Channel
D 12-Bit Accurate System Offset Adjustment for Every Channel
APPLICATIONS
D Motor Control
DESCRIPTION
The ADS7869 is a motor control front-end that includes three analog-to-digital converters (ADCs) with a total
of seven sample-and-hold capacitors and 12 fully differential input channels. There are four sign comparators
connected to four input channels. There are also three additional fully differential inputs; each input is
connected to a window comparator and a sign comparator.
In addition, the ADS7869 also offers a very flexible digital interface with a parallel port that can be configured
to different standards. Furthermore, a serial peripheral interface (SPI) and a specialized serial interface with
three data lines (VECANA01 mode) are provided. This allows the ADS7869 to interface with most digital signal
processors (DSPs) or microcontrollers. The chip is specialized for motor-control applications. For the position
sensor analysis, two up−down counters are added on the silicon. This feature ensures that the analog input
of the encoder is held at the same point of time as the counter value.
ADC
2
12−Bit
SH
2
ADC
3
12−Bit
SH
3
ADC
1
12−Bit
SH
1
MUX
2
MUX
3
MUX
1
Encoder
Counters
Flexible
Interface
Controllogic
2.5V
Ref
DAC
8−Bit
3
4