CONV D/A 12BIT MICRO PWR TSOT236

DAC121S101CIMK/NOPB

Manufacturer Part NumberDAC121S101CIMK/NOPB
DescriptionCONV D/A 12BIT MICRO PWR TSOT236
ManufacturerNational Semiconductor
SeriesPowerWise®
DAC121S101CIMK/NOPB datasheet
 


Specifications of DAC121S101CIMK/NOPB

Settling Time12µsNumber Of Bits12
Data InterfaceDSP, MICROWIRE™, QSPI™, Serial, SPI™Number Of Converters1
Voltage Supply SourceSingle SupplyPower Dissipation (max)1.72mW
Operating Temperature-40°C ~ 105°CMounting TypeSurface Mount
Package / CaseTSOT-23-6, TSOT-6Number Of Channels1
Resolution12bInterface TypeSerial (3-Wire, SPI, QSPI, Microwire)
Single Supply Voltage (typ)3.3/5VDual Supply Voltage (typ)Not RequiredV
ArchitectureResistor-StringPower Supply RequirementSingle
Output TypeVoltageIntegral Nonlinearity Error±8LSB
Single Supply Voltage (min)2.7VSingle Supply Voltage (max)5.5V
Dual Supply Voltage (min)Not RequiredVDual Supply Voltage (max)Not RequiredV
Operating Temp Range-40C to 105COperating Temperature ClassificationIndustrial
MountingSurface MountPin Count6
Package TypeTSOTFor Use WithDAC121S101EVAL - BOARD EVALUATION DAC121S101
Lead Free Status / RoHS StatusLead free / RoHS CompliantOther namesDAC121S101CIMK
DAC121S101CIMKTR
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2.1.4 Microwire Interface
Figure 8
shows an interface between a Microwire compatible
device and the DAC121S101. Data is clocked out on the rising
edges of the SCLK signal.
FIGURE 8. Microwire Interface
2.2 USING REFERENCES AS POWER SUPPLIES
Recall the need for a quiet supply source for devices that use
their power supply voltage as a reference voltage.
2.2.2 LM4050
Available with accuracy of 0.44%, the LM4050 shunt refer-
ence is also a good choice as a power regulator for the
DAC121S101. It does not come in a 3 Volt version, but 4.096V
and 5V versions are available. It comes in a space-saving 3-
pin SOT23.
FIGURE 10. The LM4050 as a power supply
The minimum resistor value in the circuit of
be chosen such that the maximum current through the
LM4050 does not exceed its 15 mA rating. The conditions for
maximum current include the input voltage at its maximum,
the LM4050 voltage at its minimum, the resistor value at its
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Since the DAC121S101 consumes very little power, a refer-
ence source may be used as the supply voltage. The advan-
tages of using a reference source over a voltage regulator are
accuracy and stability. Some low noise regulators can also be
used for the power supply of the DAC121S101. Listed below
are a few power supply options for the DAC121S101.
2.2.1 LM4130
The LM4130 reference, with its 0.05% accuracy over tem-
perature, is a good choice as a power source for the
DAC121S101. Its primary disadvantage is the lack of 3V and
5V versions. However, the 4.096V version is useful if a 0 to
20114912
4.095V output range is desirable or acceptable. Bypassing
the LM4130 VIN pin with a 0.1µF capacitor and the VOUT pin
with a 2.2µF capacitor will improve stability and reduce output
noise. The LM4130 comes in a space-saving 5-pin SOT23.
FIGURE 9. The LM4130 as a power supply
minimum due to tolerance, and the DAC121S101 draws zero
current. The maximum resistor value must allow the LM4050
to draw more than its minimum current for regulation plus the
maximum DAC121S101 current in full operation. The condi-
tions for minimum current include the input voltage at its
minimum, the LM4050 voltage at its maximum, the resistor
value at its maximum due to tolerance, and the DAC121S101
draws its maximum current. These conditions can be sum-
marized as
R(min) = ( V
and
R(max) = ( V
where V
(min) and V
Z
voltages ± the LM4050 output tolerance over temperature, I
(max) is the maximum allowable current through the LM4050,
I
(min) is the minimum current required by the LM4050 for
Z
proper regulation, I
ply current, and I
current.
2.2.3 LP3985
The LP3985 is a low noise, ultra low dropout voltage regulator
20114914
with a 3% accuracy over temperature. It is a good choice for
applications that do not require a precision reference for the
DAC121S101. It comes in 3.0V, 3.3V and 5V versions, among
others, and sports a low 30 µV noise specification at low fre-
Figure 10
should
quencies. Since low frequency noise is relatively difficult to
filter, this specification could be important for some applica-
tions. The LP3985 comes in a space-saving 5-pin SOT23 and
5-bump micro SMD packages.
16
20114913
(max) − V
(min) / (I
(min) + I
(max))
IN
Z
A
Z
(min) − V
(max) / (I
(max) + I
(min) )
IN
Z
A
Z
(max) are the nominal LM4050 output
Z
(max) is the maximum DAC121S101 sup-
A
(min) is the minimum DAC121S101 supply
A
Z