ADC574ASH BURR-BROWN [Burr-Brown Corporation], ADC574ASH Datasheet - Page 5

• Manufacturer Part Number: ADC574ASH
• Description: Microprocessor-Compatible ANALOG-TO-DIGITAL CONVERTER
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

DISCUSSION OF
SPECIFICATIONS
LINEARITY ERROR
Linearity error is defined as the deviation of actual code
transition values from the ideal transition values. Ideal
transition values lie on a line drawn through zero (or minus
full scale for bipolar operation) and plus full scale. The zero
value is located at an analog input value 1/2LSB before the
first code transition (000
located at an analog value 3/2LSB beyond the last code
transition (FFE
FIGURE 1. ADC574A Transfer Characteristics Terminology.
TABLE I. Input Voltages, Transition Values, and LSB Values.
Thus, for a converter connected for biopolar operation and
with a full-scale range (or span) of 20V ( 10V), the zero
value of –10V is 2.44mV below the first code transition
(000
+10V is 7.32mV above the last code transition (FFE
FFF
NO MISSING CODES
(DIFFERENTIAL LINEARITY ERROR)
A specification which guarantees no missing codes requires
that every code combination to appear in a monotonically-
increasing sequence as the analog input is increased through-
BINARY (BIN) OUTPUT
Analog Input Voltage Range
One Least Significant Bit (LSB)
Output Transition Values
FFE
7FF
H
FFD
FFF
FFE
7FE
H
7FF
802
801
800
002
001
000
(–Full Scale)
H
H
at +9.99268) (see Table I).
to 001
to 800
to FFF
H
H
H
H
H
H
H
H
H
H
H
1/2LSB
Zero
H
H
H
Offset
Error
Shifts
The Line
at –9.99756V) and the plus full-scale value of
H
to FFF
Zero
(–Full-Scale
Calibration
Transition)
Transaction)
(Bipolar
Offset
H
H
) (see Figure 1).
to 001
Analog Input
1/2LSB
Midscale Calibration (Bipolar Offset)
H
Full-Scale
Calibration
Error
Rotates
The
Line
). The full-scale value is
Midscale
(Bipolar
Zero)
+Full-Scale Calibration
Defined as:
3/2LSB
+Full-Scale
Calibration
Transition
n =12
n = 8
FSR
2
n
+Full
Scale
H
INPUT VOLTAGE RANGE AND LSB VALUES
to
5
out the range. Thus, every input code width (quantum) must
have a finite width. If an input quantum has a value of zero
(a differential linearity error of –1LSB), a missing code will
occur.
ADC574AKP, KN, KH and TH grades are guaranteed to
have no missing codes to 12-bit resolution over their re-
spective specification temperature ranges.
UNIPOLAR OFFSET ERROR
An ADC574A connected for unipolar operation has an
analog input range of 0V to plus full scale. The first output
code transition should occur at an analog input value 1/2
LSB above 0V. Unipolar offset error is defined as the
deviation of the actual transition value from the ideal value.
The unipolar offset temperature coefficient specifies the
change of this transition value versus a change in ambient
temperature.
BIPOLAR OFFSET ERROR
A/D converter specifications have historically defined bipo-
lar offset as the first transition value above the minus full-
scale value. The ADC574A specification, however, follows
the terminology defined for the 574 converter several years
ago. Thus, bipolar offset is located near the midscale value
of 0V (bipolar zero) at the output code transition 7FF
800
Bipolar offset error for the ADC574A is defined as the
deviation of the actual transition value from the ideal
transition value located 1/2LSB below 0V. The bipolar
offset temperature coefficient specifies the maximum change
of the code transition value versus a change in ambient
temperature.
FULL SCALE CALIBRATION ERROR
The last output transition (FFE
analog input value 3/2LSB below the nominal full-scale
value. The full-scale calibration error is the deviation of the
actual analog value at the last transition point from the ideal
value. The full-scale calibration temperature coefficient
specifies the maximum change of the code transition value
versus a change in ambient temperature.
POWER SUPPLY SENSITIVITY
Electrical specifications for the ADC574A assume the
application of the rated power supply voltages of +5V and
12V or 15V. The major effect of power supply voltage
+10V – 3/2LSB
0 – 1/2LSB
H
78.13mV
4.88mV
.
20V
10V
2
n
+5 – 3/2LSB
0 – 1/2LSB
39.06mV
2.44mV
10V
2
5V
n
ADC574A
+10V – 3/2LSB
+5V – 1/2LSB
H
0 to +10V
39.06mV
2.44mV
to FFF
10V
2
n
H
) occurs for an
+10V – 3/2LSB
10V – 1/2LSB
0 to +20V
78.13mV
4.88mV
20V
2
n
H
to
®