aduc7062 Analog Devices, Inc., aduc7062 Datasheet - Page 14

• Manufacturer Part Number: aduc7062
• Description: Low-power, Precision Analog Microcontroller, Dual ?-? Adcs, Flash/ee, Arm7tdmi
• Manufacturer: Analog Devices, Inc.

ADuC7060/ADuC7061/ADuC7062
TERMINOLOGY
Conversion Rate
The conversion rate specifies the rate at which an output result
is available from the ADC, once the ADC has settled.
The sigma-delta (Σ-Δ) conversion techniques used on this part
mean that while the ADC front-end signal is over sampled at a
relatively high sample rate, a subsequent digital filter is used to
decimate the output giving a valid 24-bit data conversion result
at output rates from 1 Hz to 8 kHz.
Note that when software switches from one input to another
(on the same ADC), the digital filter must first be cleared and
then allowed to average a new result. Depending on the con-
figuration of the ADC and the type of filter, this can take
multiple conversion cycles.
Integral Nonlinearity (INL)
INL is the maximum deviation of any code from a straight line
passing through the endpoints of the transfer function. The
endpoints of the transfer function are zero scale, a point ½ LSB
below the first code transition, and full scale, a point ½ LSB
above the last code transition (111 . . . 110 to 111 . . . 111).
The error is expressed as a percentage of full scale.
No Missing Codes
No missing codes is a measure of the differential nonlinearity
of the ADC. The error is expressed in bits and specifies the
number of codes (ADC results) as 2N bits, where is N = no
missing codes, guaranteed to occur through the full ADC
input range.
Offset Error
Offset error is the deviation of the first code transition ADC
input voltage from the ideal first code transition.
Offset Error Drift
Offset error drift is the variation in absolute offset error with
respect to temperature. This error is expressed as LSBs per °C.
Gain Error
Gain error is a measure of the span error of the ADC. It is a
measure of the difference between the measured and the ideal
span between any two points in the transfer function.
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Output Noise
The output noise is specified as the standard deviation (or 1 ×
Sigma) of ADC output codes distribution collected when the
ADC input voltage is at a dc voltage. It is expressed as μ rms.
The output, or rms noise, can be used to calculate the effective
resolution of the ADC as defined by the following equation:
The peak-to-peak noise is defined as the deviation of codes that
fall within 6.6 × Sigma of the distribution of ADC output codes
collected when the ADC input voltage is at dc. The peak-to-
peak noise is, therefore calculated as 6.6 × the rms noise.
The peak-to-peak noise can be used to calculate the ADC
(noise free code) resolution for which there is no code flicker
within a 6.6-Sigma limit as defined by the following equation:
Data Sheet Acronyms
ADC analog-to-digital converter
ARM advanced RISC machine
JTAG joint test action group
LSB
LVF
MCU microcontroller
MMR memory mapped register
MSB most significant byte/bit
PID
POR power-on reset
PSM power supply monitor
rms
Noise Free Code Resolution = log2(
Effective Resolution = log2(Full-Scale Range/rms Noise) bits
least significant byte/bit
low voltage flag
protected identifier
root mean square
Preliminary Technical Data
Peak
Full
−
−
to
Scale
−
Peak
Range
Noise
) bits