LTC1655 LINER [Linear Technology], LTC1655 Datasheet - Page 6

• Manufacturer Part Number: LTC1655
• Description: 16-Bit Rail-to-Rail Micropower DAC in SO-8 Package
• Manufacturer: LINER [Linear Technology]

OPERATIO
DEFI ITIO S
LTC1655
Differential Nonlinearity (DNL): The difference between
the measured change and the ideal 1LSB change for any
two adjacent codes. The DNL error between any two codes
is calculated as follows:
Where V
two adjacent codes.
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)(sec).
Full-Scale Error (FSE): The deviation of the actual full-
scale voltage from ideal. FSE includes the effects of offset
and gain errors (see Applications Information).
Gain Error (GE): The difference between the full-scale
output of a DAC from its ideal full-scale value after offset
error has been adjusted.
Integral Nonlinearity (INL): The deviation from a straight
line passing through the endpoints of the DAC transfer
curve (Endpoint INL). Because the output cannot go below
zero, the linearity is measured between full scale and the
Serial Interface
The data on the D
on the rising edge of the clock. The MSB is loaded first. The
DAC register loads the data from the shift register when
CS/LD is pulled high. The clock is disabled internally when
CS/LD is high. Note: CLK must be low before CS/LD is
pulled low to avoid an extra internal clock pulse. The input
word must be 16 bits wide.
The buffered output of the 16-bit shift register is available
on the D
Multiple LTC1655s may be daisy-chained together by
connecting the D
while the clock and CS/LD signals remain common to all
chips in the daisy chain. The serial data is clocked to all of
6
DNL = ( V
U
OUT
OUT
pin which swings from GND to V
OUT
is the measured voltage difference between
U
U
OUT
IN
– LSB)/LSB
input is loaded into the shift register
pin to the D
IN
pin of the next chip
CC
.
lowest code that guarantees the output will be greater than
zero. The INL error at a given input code is calculated as
follows:
Where V
the given input code.
Least Significant Bit (LSB): The ideal voltage difference
between two successive codes.
Resolution (n): Defines the number of DAC output states
(2
imply linearity.
Voltage Offset Error (V
output when the DAC is loaded with all zeros. A single
supply DAC can have a true negative offset, but the output
cannot go below zero (see Applications Information).
For this reason, single supply DAC offset is measured at
the lowest code that guarantees the output will be greater
than zero.
the chips, then the CS/LD signal is pulled high to update all
of them simultaneously. The shift register and DAC regis-
ter are cleared to all 0s on power-up.
Voltage Output
The LTC1655 rail-to-rail buffered output can source or sink
5mA over the entire operating temperature range while
pulling to within 400mV of the positive supply voltage or
ground. The output stage is equipped with a deglitcher that
gives a midscale glitch of 12nV-s. At power-up, output stage
clears to 0V.
The output swings to within a few millivolts of either sup-
ply rail when unloaded and has an equivalent output resis-
tance of 40 when driving a load to the rails. The output
can drive 1000pF without going into oscillation.
n
INL = [V
LSB = 2V
) that divide the full-scale range. Resolution does not
OUT
OUT
REF
is the output voltage of the DAC measured at
/65536
– V
OS
– (V
OS
): Nominally, the voltage at the
FS
– V
OS
)(code/65535)]/LSB