DAC1210LCJ-1 National Semiconductor, DAC1210LCJ-1 Datasheet - Page 8

• Manufacturer Part Number: DAC1210LCJ-1
• Description: DAC 1-CH R-2R 12-Bit 24-Pin CDIP
• Manufacturer: National Semiconductor

Specifications of DAC1210LCJ-1

• Package: 24CDIP
• Resolution: 12 Bit
• Architecture: R-2R
• Digital Interface Type: Parallel
• Number Of Outputs Per Chip: 1
• Output Type: Current
• Full Scale Error: -0.2 %FSR
• Integral Nonlinearity Error: ±0.05 %FSR
• Maximum Settling Time: 1(Typ) us

Application Hints
1 4 Left-Justified Data Format
It is important to realize that the input registers of these
DACs are arranged to accept a left-justified data word from
the microprocessor with the most significant 8 bits coming
first (Byte 1) and the lower 4 bits second Left justification
simply means that the binary point is assumed to be located
to the left of the most significant bit Figure 3 shows how the
12 bits of DAC data should be arranged in 2 8-bit registers
of an 8-bit processor before being written to the DAC
FIGURE 3 Left-Justified Data Format
X
e
don’t care
(Continued)
FIGURE 4 16-Bit Data Bus Interface for the DAC1208 Series
XFER and WR2 grounded Byte 1 Byte 2 tied to V
TL H 5690-10
Interface Timing
8
1 5 16-Bit Data Bus Interface
The DAC1208 series provides all 12 digital input lines to
permit a direct parallel interface to a 16-bit data bus In this
instance double buffering is not always necessary (unless a
simultaneous updating of several DACs or a data transfer
via an external strobe is desired) so the 12-bit DAC register
can be wired to flow-through whereby its Q outputs always
reflect the state of its D inputs The external connections
required and the timing diagram for this single buffered ap-
plication are shown in Figure 4 Note that either left or right-
justified data from the processor can be accommodated
with a 16-bit data bus
1 6 Flow-Through Operation
Through primarily designed to provide microprocessor inter-
face compatibility the MICRO-DACs can easily be config-
ured to allow the analog output to continuously reflect the
state of an applied digital input This is most useful in appli-
CC
TL H 5690-11