DAC101S101QCMKX/NOPB National Semiconductor, DAC101S101QCMKX/NOPB Datasheet - Page 17

• Manufacturer Part Number: DAC101S101QCMKX/NOPB
• Description: DAC RRO 10BIT MICROPWR TSOT23-6
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of DAC101S101QCMKX/NOPB

• Settling Time: 8µs
• Number Of Bits: 10
• Data Interface: Serial
• Number Of Converters: 1
• Voltage Supply Source: Single Supply
• Power Dissipation (max): 1.41mW
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: TSOT-23-6, TSOT-6
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: DAC101S101QCMKX

2.3 BIPOLAR OPERATION
The DAC101S101 is designed for single supply operation and
thus has a unipolar output. However, a bipolar output may be
obtained with the circuit in
an output voltage range of ±5 Volts. A rail-to-rail amplifier
should be used if the amplifier supplies are limited to ±5V.
The output voltage of this circuit for any code is found to be
where D is the input code in decimal form. With V
R1 = R2,
A list of rail-to-rail amplifiers suitable for this application are
indicated in
V
O
LMC7111
LM7301
LM8261
= (V
AMP
TABLE 2. Some Rail-to-Rail Amplifiers
A
x (D / 1024) x ((R1 + R2) / R1) - V
Table
FIGURE 13. Bipolar Operation
V
2.
O
SOT23-5
SOT23-5
SOT23-5
= (10 x D / 1024) - 5V
PKGS
DIP-8
SO-8
Figure
Typ V
13. This circuit will provide
0.03 mV
0.9 mV
0.7 mV
OS
A
Typ I
x R2 / R1)
620 µA
A
25 µA
1 mA
20154117
= 5V and
SUPPLY
17
2.4 LAYOUT, GROUNDING, AND BYPASSING
For best accuracy and minimum noise, the printed circuit
board containing the DAC101S101 should have separate
analog and digital areas. The areas are defined by the loca-
tions of the analog and digital power planes. Both of these
planes should be located in the same board layer. There
should be a single ground plane. A single ground plane is
preferred if digital return current does not flow through the
analog ground area. Frequently a single ground plane design
will utilize a "fencing" technique to prevent the mixing of ana-
log and digital ground current. Separate ground planes should
only be utilized when the fencing technique is inadequate.
The separate ground planes must be connected in one place,
preferably near the DAC101S101. Special care is required to
guarantee that digital signals with fast edge rates do not pass
over split ground planes. They must always have a continu-
ous return path below their traces.
The DAC101S101 power supply should be bypassed with a
10µF and a 0.1µF capacitor as close as possible to the device
with the 0.1µF right at the device supply pin. The 10µF ca-
pacitor should be a tantalum type and the 0.1µF capacitor
should be a low ESL, low ESR type. The power supply for the
DAC101S101 should only be used for analog circuits.
Avoid crossover of analog and digital signals and keep the
clock and data lines on the component side of the board. The
clock and data lines should have controlled impedances.
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