MAX1323ECM-T Maxim Integrated, MAX1323ECM-T Datasheet - Page 16

• Manufacturer Part Number: MAX1323ECM-T
• Description: Analog to Digital Converters - ADC
• Manufacturer: Maxim Integrated

Table 4 and Figure 8 show the offset binary transfer func-
tion for the MAX1319 with a 0 to +5V input range. The
FSR is two times the voltage at REF. The internal +2.500V
reference gives a +5V FSR, while an external +2V to +3V
reference allows an FSR of +4V to +6V, respectively.
Calculate the LSB size using the following equation:
This equals 0.3052mV when using the internal reference.
The input range is centered about V
nally set to +2.500V. For a custom midscale voltage,
drive REF
will follow REF
directly couples into the ADC result. Use a precision,
low-drift voltage reference with adequate bypassing to
prevent MSV from degrading ADC performance. For
maximum full-scale range, be careful not to violate the
absolute maximum voltage ratings of the analog inputs
when choosing MSV. Determine the input voltage as a
function of V
using the following equation:
526ksps, Single-Channel,
14-Bit, Parallel-Interface ADCs
Table 4. 0 to +5V Unipolar Code Table
16
BINARY OUTPUT CODE
11 1111 1111 1111 ➔
11 1111 1111 1110 ➔
10 0000 0000 0001 ➔
10 0000 0000 0000 ➔
01 1111 1111 1111 ➔
00 0000 0000 0001 ➔
00 0000 0000 0000 ➔
______________________________________________________________________________________
0x3FFE
0x3FFF
0x2001
0x2000
0x1FFF
0x0001
0x0000
MS
REF
with an external voltage source and MSV
MS
, V
1
LSB
. Noise present on MSV or REF
MSV
, and the output code in decimal
=
EQUIVALENT
2
DECIMAL
(CODE
×
OUTPUT
Unipolar 0 to +5V Device
16383
16382
8193
8192
8191
V
2
1
0
REFADC
14
10
MSV
)
, which is inter-
(V
VOLTAGE (V)
REF
= 2.5V)
4.9997
4.9994
2.5003
2.5000
2.4997
0.0003
INPUT
= V
0
REFMS
MS
Integral nonlinearity is the deviation of the values on an
actual transfer function from a straight line. For these
devices this straight line is a line drawn between the
endpoints of the transfer function, once offset and gain
errors have been nullified.
Differential nonlinearity is the difference between an
actual step width and the ideal value of 1 LSB. For
these devices, the DNL of each digital output code is
measured and the worst-case value is reported in the
Electrical Characteristics table. A DNL error specifica-
tion of less than ±1 LSB guarantees no missing codes
and a monotonic transfer function.
For the unipolar MAX1319, the ideal midscale transition
from 0x1FFF to 0x2000 occurs at MSV (see Figure 8).
The unipolar offset error is the amount of deviation
between the measured midscale transition point and
the ideal midscale transition point.
Figure 8. 0 to +5V Unipolar Transfer Function
0x3FFD
0x3FFC
0x3FFF
0x3FFE
0x2001
0x2000
0x1FFF
0x0003
0x0002
0x0001
0x0000
V
CH
_
=
0
LSB
Differential Nonlinearity (DNL)
2
×
Integral Nonlinearity (INL)
CODE
INPUT VOLTAGE (LSBs)
8190
2 x V
Unipolar Offset Error
10
(MSV)
8192
REFADC
+
8194
(
V
MSV
1 LSB =
Definitions
- 2.500V
16,381
2 x V
2
REFADC
14
16,383
2 x V
REFADC
)