DAC8408FS-REEL Analog Devices Inc, DAC8408FS-REEL Datasheet - Page 12

• Manufacturer Part Number: DAC8408FS-REEL
• Manufacturer: Analog Devices Inc

Specifications of DAC8408FS-REEL

• Number Of Channels: 4
• Resolution: 8b
• Conversion Rate: 5.26MSPS
• Interface Type: Parallel
• Single Supply Voltage (typ): 5V
• Dual Supply Voltage (typ): Not RequiredV
• Settling Time: 0.25us
• Architecture: R-2R
• Power Supply Requirement: Single
• Output Type: Current
• Integral Nonlinearity Error: ±0.5LSB
• Single Supply Voltage (min): 4.5V
• Single Supply Voltage (max): 5.5V
• Dual Supply Voltage (min): Not RequiredV
• Dual Supply Voltage (max): Not RequiredV
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 28
• Package Type: SOIC W
• Lead Free Status / Rohs Status: Not Compliant

DAC8408
SINGLE SUPPLY, VOLTAGE OUTPUT OPERATION
The DAC8408 can be connected with a single +5 V supply to
produce DAC output voltages from 0 V to +1.5 V. In Figure 8,
the DAC8408 R-2R ladder is inverted from its normal connec-
tion. A +1.500 V reference is connected to the current output pin
4 (I
output. Instead of a normal current output, the R-2R ladder out-
puts a voltage. The OP-490, consisting of four precision low
power op amps that can operate its inputs and outputs to zero
volts, buffers the DAC to produce a low impedance output volt-
age from 0 V to +1.5 V full-scale. Table III shows the code table.
With the supply and reference voltages as shown, better than 1/2
LSB differential and integral nonlinearity can be expected. To
maintain this performance level, the +5 V supply must not drop
below 4.75 V. Similarly, the reference voltage must be no higher
than 1.5 V. This is because the CMOS switches require a mini-
mum level of bias in order to maintain the linearity performance.
OUT 1A
), and the normal V
REF
input pin becomes the DAC
Figure 8. Unipolar Supply, Voltage Output DAC Operation
–12–
Table III. Single Supply Binary Code Table (Refer to Figure 8)
DAC Data Input
1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0
0 1 1 1 1 1 1 1
0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0
MSB
LSB
Analog Output
V
V
V
V
V
V
REF
REF
REF
REF
REF
REF
129
128
127
255
256
256
256
256
256
256
1
0
, +1.4941 V
, +0.7559 V
, +0.7500 V
, +0.7441 V
, +0.0059 V
, 0.0000 V
REV. A