DAC104S085CISD/NOPB National Semiconductor, DAC104S085CISD/NOPB Datasheet - Page 17

• Manufacturer Part Number: DAC104S085CISD/NOPB
• Description: IC DAC 10BIT QUAD 10-LLP
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of DAC104S085CISD/NOPB

• Settling Time: 4.5µs
• Number Of Bits: 10
• Data Interface: Serial
• Number Of Converters: 4
• Voltage Supply Source: Single Supply
• Power Dissipation (max): 2.5mW
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 10-LLP
• For Use With: DAC104S085EB - BOARD EVALUATION DAC104S085
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: DAC104S085CISDTR

An input capacitance of 1.0µF without any ESR requirement
is required at the LP3985 input, while a 1.0µF ceramic ca-
pacitor with an ESR requirement of 5mΩ to 500mΩ is required
at the output. Careful interpretation and understanding of the
capacitor specification is required to ensure correct device
operation.
Like any low dropout regulator, the LP2980 requires an output
capacitor for loop stability. This output capacitor must be at
least 1.0µF over temperature, but values of 2.2µF or more will
provide even better performance. The ESR of this capacitor
should be within the range specified in the LP2980 data sheet.
Surface-mount solid tantalum capacitors offer a good combi-
nation of small size and ESR. Ceramic capacitors are attrac-
tive due to their small size but generally have ESR values that
are too low for use with the LP2980. Aluminum electrolytic
capacitors are typically not a good choice due to their large
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 Table 2.
V
O
= (V
A
x (D / 1024) x ((R1 + R2) / R1) - V
V
O
= (10 x D / 1024) - 5V
FIGURE 8. Using the LP2980 regulator
A
x R2 / R1)
FIGURE 9. Bipolar Operation
A
= 5V and
17
2.1.4 LP2980
The LP2980 is an ultra low dropout regulator with a 0.5% or
1.0% accuracy over temperature, depending upon grade. It is
available in 3.0V, 3.3V and 5V versions, among others.
size and have ESR values that may be too high at low tem-
peratures.
2.2 BIPOLAR OPERATION
The DAC104S085 is designed for single supply operation and
thus has a unipolar output. However, a bipolar output may be
obtained with the circuit in Figure 9. This circuit will provide
an output voltage range of ±5 Volts. A rail-to-rail amplifier
should be used if the amplifier supplies are limited to ±5V.
LMC7111
LM7301
LM8261
AMP
TABLE 2. Some Rail-to-Rail Amplifiers
SOT23-5
SOT23-5
SOT23-5
PKGS
DIP-8
SO-8
20195317
20195316
Typ V
0.03 mV
0.9 mV
0.7 mV
OS
Typ I
www.national.com
620 µA
25 µA
1 mA
SUPPLY