LTC1654 LINER [Linear Technology], LTC1654 Datasheet - Page 9

• Manufacturer Part Number: LTC1654
• Description: Dual 14-Bit Rail-to-Rail DAC in 16-Lead SSOP Package
• Manufacturer: LINER [Linear Technology]

DEFI ITIO S
Resolution (n): Resolution is defined as the number of
digital input bits (n). It is also the number of DAC output
states (2
not imply linearity.
Full-Scale Voltage (V
when all bits are set to 1.
Voltage Offset Error (V
voltage at the output when the DAC is loaded with all zeros.
The DAC can have a true negative offset, but because the
part is operated from a single supply, the output cannot go
below 0V. If the offset is negative, the output will remain
near 0V resulting in the transfer curve shown in Figure 1.
The offset of the part is measured at the code that corre-
sponds to the maximum offset specification:
Least Significant Bit (LSB): One LSB is the ideal voltage
difference between two successive codes.
Nominal LSBs:
V
LSB = (V
LTC1654 LSB = 4.09575V/16383 = 250 V
OS
U
= V
n
) that divide the full-scale range. Resolution does
OUT
NEGATIVE
FS
OFFSET
Figure 1. Effect of Negative Offset
– V
– [(Code)(V
VOLTAGE
OUTPUT
U
OS
0V
)/(2
FS
OS
n
): This is the output of the DAC
– 1) = (V
): Normally, DAC offset is the
FS
)/(2
DAC CODE
n
– 1)]
FS
– V
OS
1654 F01
)/16383
Zero-Scale Error (ZSE): The output voltage when the
DAC is loaded with all zeros. Since this is a single supply
part, this value cannot be less than 0V.
Integral Nonlinearity (INL): End-point INL is the maxi-
mum deviation from a straight line passing through the
end points of the DAC transfer curve. Because the part
operates from a single supply and the output cannot go
below zero, the linearity is measured between full scale
and the code corresponding to the maximum offset
specification. The INL error at a given input code is
calculated as follows:
Differential Nonlinearity (DNL): DNL is the difference
between the measured change and the ideal one LSB
change between any two adjacent codes. The DNL error
between any two codes is calculated as follows:
Digital Feedthrough: The glitch that appears at the analog
output caused by AC coupling from the digital inputs when
they change state. The area of the glitch is specified in
nV • s.
INL = [V
V
DNL
OUT
V
OUT
= The output voltage of the DAC measured at the
= ( V
= The measured voltage difference between
given input code
two adjacent codes
OUT
OUT
– V
– LSB)/LSB
OS
– (V
FS
– V
OS
)(code/16383)]/LSB
LTC1654
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