Datasheet

ADuC7033
Rev. B | Page 44 of 140
PGA
ADC
THRESHOLD
ADC
RESULT
OUTPUT
FORMAT
BUF
CHOP CHOP
ANALOG INPUT DIAGNOSTIC
CURRENT SOURCES
TWO 50µA IIN+ AND IIN–
CURRENT SOURCES.
ANALOG INPUT
DIAGNOSTIC
VOLTAGE SOURCE
VREF/136 VOLTAGE INPUT.
ANALOG INPUT
PROGRAMMABLE
CHOPPING
THE INPUTS ARE
ALTERNATELY REVERSED
THROUGH THE
CONVERSION CYCLE.
Σ-Δ ADC
THE Σ-Δ
ARCHITECTURE
ENSURES 16 BITS
NO MISSING CODES.
OUTPUT AVERAGE
AS PART OF THE CHOPPING
IMPLEMENTATION, EACH
DATA-WORD OUTPUT FROM
THE FILTER IS SUMMED AND
AVERAGED WITH ITS
PREDECESSOR.
ADC FAST OVERRANGE
GENERATES AN ADC
INTERRUPT IF THE CURRENT
INPUT IS GROSSLY
OVER-RANGED.
ADC ACCUMULATOR
ACCUMULATED THE
ADC RESULT.
PROGRAMMABLE GAIN
AMPLIFIER
THE PROGRAMMABLE
GAIN AMPLIFIER ALLOWS
EIGHT BIPOLAR INPUT
RANGES FROM ±2.3mV TO
±1.2V (INT V
REF
= +1.2V).
Σ-Δ MODULATOR
THE MODULATOR PROVIDES A
HIGH FREQUENCY 1-BIT DATA
STREAM (THE OUTPUT OF
WHICH IS ALSO CHOPPED) TO
THE DIGITAL FILTER, THE DUTY
CYCLE OF WHICH REPRESENTS
THE SAMPLED ANALOG INPUT
VOLTAGE.
IIN+
IIN–
VREF/136
GND
REG_AVDD REG_AVDD
Σ-Δ ADC
Σ-Δ
MODULATOR
PROGRAMMABLE
DIGITAL FILTER
OUTPUT
AVERAGE
OFFSET
COEFFICIENT
GAIN
COEFFICIENT
ADC
INTERRUPT
ADC RESULT
ACCUMULATOR
ADC
RESULT
ADC RESULT
COUNTER
THRESHOLD
COUNTER
ADC INTERRUPT
GENERATOR
GENERATES AN ADC
RESULT FROM ANY
ONE OF FOUR
SOURCES.
ADC RESULT COUNTER
COUNTS ADC RESULTS,
GENERATES AN INTERRUPT
ON COUNTER OVERFLOW.
THRESHOLD COUNTER
COUNTS UP IF ADC
RESULTS>THRESHOLD
COUNTS DOWN/RESET IF
ADC RESULT<THRESHOLD.
GENERATES AN INTERRUPT
ON COUNTER OVERFLOW.
BUFFER AMPLIFIER
THE BUFFER
AMPLIFIER PRESENTS
A HIGH IMPEDANCE
INPUT STAGE FOR
THE PGA DRIVING THE
Σ-Δ MODULATOR.
PRECISION REFERENCE
THE INTERNAL 5ppm/°C
REFERENCE IS ROUTED TO
THE ADC BY DEFAULT. AN
EXTERNAL REFERENCE ON
THE VREF PIN CAN ALSO
BE SELECTED.
INTERNAL
REFERENCE
VREF
PROGRAMMABLE
DIGITAL FILTER
THE SINC3 FILTER REMOVES
QUANTIZATION NOISE INTRODUCED
BY THE MODULATOR. THE UPDATE
RATE AND BANDWIDTH OF THIS
FILTER ARE PROGRAMMABLE VIA
THE ADCFLT MMR.
DIGITAL COMPARATOR
THE ADC RESULT IS
COMPARED TO A
PRESET THRESHOLD.
OUTPUT SCALING
THE OUTPUT WORD FROM
THE DIGITAL FILTER IS
SCALED BY THE CALIBRATION COEFFICIENTS BEFORE BEING
PROVIDED AS THE
CONVERSION RESULT.
06847-015
Figure 17. Current ADC, Top Level Overview