TI1 DAC121S101QML 12-bit micro power digital-to-analog converter with railto- Datasheet

DAC121S101QML
12-Bit Micro Power Digital-to-Analog Converter with Railto-Rail Output
General Description
Features
The DAC121S101 is a full-featured, general purpose 12-bit
voltage-output digital-to-analog converter (DAC) that can operate from a single +2.7 V to 5.5 V supply and consumes just
177 µA of current at 3.6 V. The on-chip output amplifier allows
rail-to-rail output swing and the three wire serial interface operates at clock rates up to 20 MHz over the specified supply
voltage range and is compatible with standard SPI™, QSPI,
MICROWIRE and DSP interfaces.
The supply voltage for the DAC121S101 serves as its voltage
reference, providing the widest possible output dynamic
range. A power-on reset circuit ensures that the DAC output
powers up to zero volts and remains there until there is a valid
write to the device. A power-down feature reduces power
consumption to less than a microWatt.
The low power consumption and small packages of the
DAC121S101 make it an excellent choice for use in battery
operated equipment.
The DAC121S101 operates over the extended temperature
range of -55°C to +125°C.
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Total Ionizing Dose
100 krad(Si)
Single Event Latch-up
120 MeV-cm2/mg
Guaranteed Monotonicity
Low Power Operation
Rail-to-Rail Voltage Output
Power-on Reset to Zero Volts Output
SYNC Interrupt Facility
Wide power supply range (+2.7 V to +5.5 V)
Small Packages
Power Down Feature
Key Specifications
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Resolution
12 bits
DNL
+0.21, -0.10 LSB (typ)
Output Settling Time
12.5 µs (typ)
Zero Code Error
2.1 mV (typ)
Full-Scale Error
−0.04 %FS (typ)
Power Dissipation
— Normal Mode 0.52 mW (3.6 V) / 1.19 mW (5.5 V) typ
0.014 µW (3.6 V) / 0.033 µW (5.5 V) typ
— Pwr Down
Mode
Applications
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Battery-Powered Instruments
Digital Gain and Offset Adjustment
Programmable Voltage & Current Sources
Programmable Attenuators
Ordering Information
NS Part Number
SMD Part Number
NS Package Number
Package Discription
DAC121S101WGRQV
Flight Part
CMOS ELDRS-Free
5962R0722601VZA
100 krad(Si)
High Dose Rate/Anneal
Tested
WG10A
10LD Ceramic SOIC
DAC121S101WGRLV
Flight Part
CMOS ELDRS-Free
5962R0722602VZA
100 krad(Si)
Low Dose Rate Tested
WG10A
10LD Ceramic SOIC
WG10A
10LD Ceramic SOIC
DAC121S101WGMPR
Pre-flight Prototype
(Note 13)
DAC121S101CVAL
Ceramic Evaluation Board
10LD Ceramic SOIC
on Evaluation Board
See section 3.0 for dose rate environment information
SPI™ is a trademark of Motorola, Inc.
© 2012 Texas Instruments Incorporated
300180 SNAS410D
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DAC121S101QML 12-Bit Micro Power Digital-to-Analog Converter with Rail-to-Rail Output
April 25, 2012
DAC121S101QML
Connection Diagrams
10LD Ceramic SOIC
30018001
Top View
See NS Package Number WG10A
Block Diagram
30018003
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2
Operating Ratings (Note 1, Note 2)
Operating Temperature Range
Supply Voltage, VA
Any Input Voltage (Note 6)
Output Load
SCLK Frequency
(Note 1, Note 2)
Supply Voltage, VA
6.5 V
Voltage on any Input Pin
−0.3 V to (VA + 0.3 V)
Input Current at Any Pin (Note 3)
10 mA
Maximum Output Current (Note 10)
10 mA
VOUT Pin in Powerdown Mode
1.0 mA
Package Input Current (Note 3)
20 mA
Power Dissipation at TA = 25°C
See (Note 4)
Maximum Junction Temperature
175°C
Lead Temperature
Ceramic SOIC
(Soldering 10 Seconds)
260°C
Storage Temperature
−65°C to +150°C
Package Weight (Typical)
Ceramic SOIC
220 mg
ESD Tolerance (Note 5)
Class 3A (5000 V)
−55°C to +125°C
+2.7 V to 5.5 V
−0.1 V to (VA + 0.1 V)
0 to 1500 pF
Up to 20 MHz
Package Thermal Resistance
Package
θJA
(Still Air)
θJC
10-lead Ceramic SOIC
Package on 2 layer, 1oz.
PCB
214°C/W
25.7°C/W
Quality Conformance Inspection
MIL-STD-883, Method 5005 - Group A
Subgroup
Description
1
Static tests at
Temp (° C)
+25
2
Static tests at
+125
3
Static tests at
-55
4
Dynamic tests at
+25
5
Dynamic tests at
+125
6
Dynamic tests at
-55
7
Functional tests at
+25
8A
Functional tests at
+125
8B
Functional tests at
-55
9
Switching tests at
+25
10
Switching tests at
+125
11
Switching tests at
-55
12
Setting time at
+25
13
Setting time at
+125
14
Setting time at
-55
3
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DAC121S101QML
Absolute Maximum Ratings
DAC121S101QML
DAC121S101 Electrical Characteristics
DC Parameters
The following specifications apply for VA = +2.7 V to +5.5 V, RL = ∞, CL = 200 pF to GND, fSCLK = 20 MHz, input code range 48 to
4047. Boldface limits apply for TMIN ≤ TA ≤ TMAX: all other limits TA = 25°C, unless otherwise specified.
Symbol
Parameter
Conditions
Notes
Typical
(Note 8)
Min
Max
Units
Subgroups
STATIC PERFORMANCE
Resolution
(Note 9)
12
Monotonicity
(Note 9)
12
INL
Integral Non-Linearity
Over Decimal codes 48 to 4047
DNL
Differential Non-Linearity
VA = 2.7 V to 5.5 V
ZE
Zero Code Error
IOUT = 0
+2.12
FSE
Full-Scale Error
IOUT = 0
GE
Gain Error
All ones Loaded to DAC register
ZCED
TC GE
LSB
1, 2, 3
+1.0
LSB
1, 2, 3
LSB
1, 2, 3
+15
mV
1, 2, 3
−0.04
−1.0
%FSR
1, 2, 3
−0.11
±1.0
%FSR
1, 2, 3
−0.10
(Note 9)
VA = 3 V
(Note 9)
VA = 5 V
Bits
8.0
−8.0
+0.21
Zero Code Error Drift
Gain Error Tempco
±2.75
Bits
−0.7
−20
µV/°C
−0.7
ppm/°C
−1.0
ppm/°C
OUTPUT CHARACTERISTICS
IPD
SINK
Vout Pin in Powerdown
Mode
All PD Modes
(Note 9)
Output Voltage Range
ZCO
FSO
Zero Code Output
Full Scale Output
Maximum Load Capacitance
(Note 9)
mA
VA
V
VA = 3 V, IOUT = 10 µA
2.0
6
mV
1, 2, 3
VA = 3 V, IOUT = 100 µA
4
10
mV
1, 2, 3
VA = 5 V, IOUT = 10 µA
2
8
mV
1, 2, 3
VA = 5 V, IOUT = 100 µA
4
9
mV
1, 2, 3
VA = 3 V, IOUT = 10 µA
2.997
2.990
V
1, 2, 3
VA = 3 V, IOUT = 100 µA
2.991
2.985
V
1, 2, 3
VA = 5 V, IOUT = 10 µA
4.994
4.985
V
1, 2, 3
VA = 5 V, IOUT = 100 µA
4.992
4.985
V
1, 2, 3
RL = ∞
(Note 9)
RL = 2 kΩ
DC Output Impedance
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0
1.0
1500
1500
8
4
pF
pF
16
Ω
1, 2, 3
The following specifications apply for VA = +2.7 V to +5.5 V, RL = ∞, CL = 200 pF to GND, fSCLK = 20 MHz, input code range 48 to
4047. Boldface limits apply for TMIN ≤ TA ≤ TMAX: all other limits TA = 25°C, unless otherwise specified.
Symbol
Parameter
Conditions
Notes
Typical
(Note 8)
Min
Max
Units
Subgroups
6
−200
LOGIC INPUT
IIN
VIL
Input Current
Input Low Voltage
VIH
Input High Voltage
CIN
Input Capacitance
+200
nA
1, 2, 3
VA = 5 V
0.8
V
1, 2, 3
VA = 3 V
0.5
V
1, 2, 3
VA = 5 V
2.4
V
1, 2, 3
VA = 3 V
2.1
V
1, 2, 3
(Note 9)
5
pF
POWER REQUIREMENTS
IA
PC
IOUT / IA
Supply Current (output
unloaded)
Power Consumption (output
unloaded)
Power Efficiency
Normal Mode
fSCLK = 20 MHz
5.5 V
216
270
µA
1, 2, 3
3.6 V
145
200
µA
1, 2, 3
Normal Mode
fSCLK = 10 MHz
5.5 V
185
230
µA
1, 2, 3
3.6 V
132
175
µA
1, 2, 3
Normal Mode
fSCLK = 0
5.5 V
150
190
µA
1, 2, 3
3.6 V
115
160
µA
1, 2, 3
All PD Modes,
fSCLK = 20 MHz
5.5 V
22
60
µA
1, 2, 3
3.6 V
12
30
µA
1, 2, 3
All PD Modes,
fSCLK = 10 MHz
5.5 V
12
40
µA
1, 2, 3
3.6 V
6
20
µA
1, 2, 3
All PD Modes,
fSCLK = 0
5.5 V
.006
1.0
µA
1, 2, 3
3.6 V
.004
1.0
µA
1, 2, 3
Normal Mode
fSCLK = 20 MHz
5.5 V
1.19
1.49
mW
0.52
.72
mW
Normal Mode
fSCLK = 10 MHz
5.5 V
1.02
1.27
mW
0.47
.63
mW
Normal Mode
fSCLK = 0
5.5 V
0.82
1.05
mW
0.41
.58
mW
All PD Modes,
fSCLK = 20 MHz
5.5 V
0.12
.33
mW
0.07
.11
mW
All PD Modes,
fSCLK = 10 MHz
5.5 V
0.04
.22
mW
All PD Modes,
fSCLK = 0
5.5 V
3.6 V
3.6 V
3.6 V
3.6 V
3.6 V
3.6 V
ILOAD = 2 mA
(Note 9)
(Note 9)
(Note 9)
(Note 9)
(Note 9)
(Note 9)
(Note 9)
5
0.02
.08
mW
0.033
5.5
µW
0.014
3.6
µW
91
%
94
%
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DAC121S101QML
DC Parameters (Continued)
DAC121S101QML
AC and Timing Characteristics
The following specifications apply for VA = +2.7 V to +5.5 V, RL = ∞, CL = 200 pF to GND, fSCLK = 20 MHz, input code range 48 to
4047. Boldface limits apply for TMIN ≤ TA ≤ TMAX: all other limits TA = 25°C, unless otherwise specified.
Symbol
fSCLK
Parameter
SCLK Frequency
Conductions
ts
Output Voltage Settling Time
change, RL = ∞
00Fh to FF0h code
change, RL = ∞
SR
1/fSCLK
Wake-Up Time
Max
Units
Subgroups
20
MHz
9, 10, 11
12.5
15
µs
9, 10, 11
CL = 500 pF
12.5
15
µs
9, 10, 11
CL ≤ 200 pF
12.5
15
µs
9, 10, 11
CL = 500 pF
12.5
15
µs
9, 10, 11
Code change from 800h to 7FFh
Digital Feedthrough
tWU
Min
CL ≤ 200 pF
Output Slew Rate
Glitch Impulse
Typical
(Note 8)
(Note
9)
(See Figure 2)
FF0 to 00F code
Notes
VA = 5 V
(Note
9)
1
V/µs
(Note
9)
12
nV-sec
(Note
9)
0.5
nV-sec
.65
µs
(Note
9)
VA = 3 V
1.1
µs
SCLK Cycle Time
(See Figure 2)
50
ns
9, 10, 11
tH
SCLK High time
(See Figure 2)
20
ns
9, 10, 11
tL
SCLK Low Time
(See Figure 2)
20
ns
9, 10, 11
tSUCL
Set-up Time SYNC to SCLK
(See Figure 2)
Rising Edge
0
ns
9, 10, 11
tSUD
Data Set-Up Time
(See Figure 2)
6
ns
9, 10, 11
tDHD
Data Hold Time
(See Figure 2)
4.5
ns
9, 10, 11
tCS
SCLK fall to rise of SYNC
VA = 5.5 V (See Figure 2)
10
ns
9, 10, 11
VA = 2.7 V (See Figure 2)
18
ns
9, 10, 11
VA = 5.5 V (See Figure 2)
37
ns
9, 10, 11
VA = 2.7 V (See Figure 2)
36
ns
9, 10, 11
tSYNC
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SYNC High Time
6
(Note 12)
The following specifications apply for VA = +2.7 V to +5.5 V, RL = ∞, CL = 200 pF to GND, fSCLK = 20 MHz, input code range 48 to
4047.
Symbol
Parameter
Conditions
Min
Max
Units
Subgroups
POWER REQUIREMENTS
IA
Normal Mode
fSCLK = 20 MHz
5.5 V
325
µA
1
3.6 V
250
µA
1
Normal Mode
fSCLK = 10 MHz
5.5 V
300
µA
1
3.6 V
225
µA
1
Normal Mode
fSCLK = 0
5.5 V
275
µA
1
3.6 V
200
µA
1
All PD Modes,
fSCLK = 20 MHz
5.5 V
125
µA
1
3.6 V
100
µA
1
All PD Modes,
fSCLK = 10 MHz
5.5 V
115
µA
1
3.6 V
95
µA
1
All PD Modes,
fSCLK = 0
5.5 V
100
µA
1
3.6 V
100
µA
1
Min
Max
Units
Integral non-linearity
±2
LBS
Output voltage settling time
±5
µA
±10
µA
Normal Mode, VA = 3.6V fSCLK = 20 MHz
±6
µA
Normal Mode, VA = 5.5V fSCLK = 10 MHz
±10
µA
Normal Mode, VA = 3.6V fSCLK = 10 MHz
±6
µA
Normal Mode, VA = 5.5V fSCLK = 0
±8
µA
Normal Mode, VA = 3.6V fSCLK = 0
±6
µA
All PD Modes, VA = 5.5V fSCLK = 20 MHz
±2
µA
All PD Modes, VA = 3.6V fSCLK = 20 MHz
±1
µA
All PD Modes, VA = 5.5V fSCLK = 10 MHz
±1
µA
Supply Current (output unloaded)
Operating Life Test Delta Parameters
Symbol
INL
ts
TA @ 25°C
Parameter
(Note 11)
Conditions
Normal Mode, VA = 5.5V fSCLK = 20 MHz
IA
Supply Current (output unloaded)
All PD Modes, VA = 3.6V fSCLK = 10 MHz
±1
µA
All PD Modes, VA = 5.5V fSCLK = 0
±0.1
µA
All PD Modes, VA = 3.6V fSCLK = 0
±0.1
µA
7
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DAC121S101QML
Radiation Electrical Characteristics
DAC121S101QML
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed
specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test
conditions.
Note 2: All voltages are measured with respect to GND = 0 V, unless otherwise specified
Note 3: When the input voltage at any pin exceeds the power supplies (that is, less than GND, or greater than VA), the current at that pin should be limited to 10
mA. The 20 mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 10 mA to two.
Note 4: The absolute maximum junction temperature (TJmax) for this device is 175°C. The maximum allowable power dissipation is dictated by TJmax, the
junction-to-ambient thermal resistance (θJA), and the ambient temperature (TA), and can be calculated using the formula PDMAX = (TJmax − TA) / θJA. The values
for maximum power dissipation will be reached only when the device is operated in a severe fault condition (e.g., when input or output pins are driven beyond
the power supply voltages, or the power supply polarity is reversed). Obviously, such conditions should always be avoided.
Note 5: Human body model is 100 pF capacitor discharged through a 1.5 kΩ resistor. Machine model is 220 pF discharged through ZERO Ohms.
Note 6: The analog inputs are protected as shown below. Input voltage magnitudes up to VA + 300 mV or to 300 mV below GND will not damage this device.
However, errors in the conversion result can occur if any input goes above VA or below GND by more than 100 mV. For example, if VA is 2.7 VDC, ensure that
−100 mV ≤ input voltages ≤2.8 VDC to ensure accurate conversions.
30018004
Note 7: To guarantee accuracy, it is required that VA be well bypassed.
Note 8: Typical figures are at TJ = 25°C, and represent most likely parametric norms.
Note 9: This parameter is guaranteed by design and/or characterization and is not tested in production.
Note 10: Maximum Output Current may not exceed 10 mA. At VDD = 5.5 V the minimum external resistive load can be no less than 550 Ω, (360 Ω at VDD = 3.6
V).
Note 11: These parameters are worse case drift. Deltas are performed at room temperature Post OP Life. All other parameters no Deltas are required.
Note 12: Pre and post irradiation limits are identical to those listed in the “DC Parameters” and “AC and Timing Characteristics” tables, except as listed in the
“Radiation Electrical Characteristics” table. When performing post irradiation electrical measurements for any RHA level, TA = +25°C. See section 3.0 for dose
rate and test conditions.
Note 13: Military Prototype (MPR): Is a non-mission / non-flight ready electrical characteristic duplicate of a space grade product.
The MPR product classification is to enable a limited quantity of devices to customers for pre-production proto-type work only. Large quantity requirements must
be approved by the qualifying activity.
There will be NO ‘Certificate of Conformance’ supplied for MPR products. There will be NO data pack supplied for MPR products. There is NO warranty implied
for MPR products.
As a MINIMUM, product must meet the following criteria:
a) DC electrical screen at room temperature. The parts are NOT PROCESSED to TM5004 and TM5005 of MIL-STD-883.
b) Top Mark shall include ‘MPR’ in the device suffix. The parts must have the letters ‘ES’[Engineering Sample] marked on the package. The Date Code, may be
commercial or military date code format.
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8
DIFFERENTIAL NON-LINEARITY (DNL) is the measure of
the maximum deviation from the ideal step size of 1 LSB,
which is VREF / 4096 = VA / 4096.
DIGITAL FEEDTHROUGH is a measure of the energy injected into the analog output of the DAC from the digital inputs
when the DAC outputs are not updated. It is measured with a
full-scale code change on the data bus.
FULL-SCALE ERROR is the difference between the actual
output voltage with a full scale code (FFFh) loaded into the
DAC and the value of VA x 4095 / 4096.
GAIN ERROR is the deviation from the ideal slope of the
transfer function. It can be calculated from Zero and FullScale Errors as GE = FSE - ZE, where GE is Gain error, FSE
is Full-Scale Error and ZE is Zero Error.
GLITCH IMPULSE is the energy injected into the analog output when the input code to the DAC register changes. It is
specified as the area of the glitch in nanovolt-seconds.
INTEGRAL NON-LINEARITY (INL) is a measure of the deviation of each individual code from a straight line through the
input to output transfer function. The deviation of any given
code from this straight line is measured from the center of that
code value. The end point method is used. INL for this product
is specified over a limited range, per the Electrical Tables.
LEAST SIGNIFICANT BIT (LSB) is the bit that has the smallest value or weight of all bits in a word. This value is
LSB = VREF / 2n
where VREF is the supply voltage for this product, and "n" is
the DAC resolution in bits, which is 12 for the DAC121S101.
9
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DAC121S101QML
MAXIMUM LOAD CAPACITANCE is the maximum capacitance that can be driven by the DAC with output stability
maintained.
MONOTONICITY is the condition of being monotonic, where
the DAC has an output that never decreases when the input
code increases.
MOST SIGNIFICANT BIT (MSB) is the bit that has the largest
value or weight of all bits in a word. Its value is 1/2 of VA.
POWER EFFICIENCY is the ratio of the output current to the
total supply current. The output current comes from the power
supply. The difference between the supply and output currents is the power consumed by the device without a load.
SETTLING TIME is the time for the output to settle to within
1/2 LSB of the final value after the input code is updated.
WAKE-UP TIME is the time for the output to exit power-down
mode. This is the time measured from the falling edge of 16th
SCLK pulse to when the output voltage deviates from the
power-down voltage of 0 V.
ZERO CODE ERROR is the output error, or voltage, present
at the DAC output after a code of 000h has been entered.
Specification Definitions
DAC121S101QML
Transfer Characteristic
30018005
FIGURE 1. Input / Output Transfer Characteristic
Timing Diagram
30018006
FIGURE 2. DAC121S101 Timing
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10
fSCLK = 20 MHz, TA = 25C, Input Code Range 48 to 4047, unless
otherwise stated
DNL at VA = 2.7V
DNL at VA = 5.5V
30018052
30018053
INL at VA = 2.7V
INL at VA = 5.5V
30018054
30018055
DNL vs. VA
INL vs. VA
30018022
30018023
11
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DAC121S101QML
Typical Performance Characteristics
DAC121S101QML
2.7V DNL vs. fSCLK
5.5V DNL vs. fSCLK
30018050
30018051
2.7V DNL vs. Clock Duty Cycle
5.5V DNL vs. Clock Duty Cycle
30018056
30018057
2.7V DNL vs. Temperature
5.5V DNL vs. Temperature
30018026
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30018027
12
DAC121S101QML
2.7V INL vs. fSCLK
5.5V INL vs. fSCLK
30018028
30018029
2.7V INL vs. Clock Duty Cycle
5.5V INL vs. Clock Duty Cycle
30018030
30018031
2.7V INL vs. Temperature
5.5V INL vs. Temperature
30018032
30018033
13
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DAC121S101QML
Zero Code Error vs. fSCLK
Zero Code Error vs. Temperature
30018036
30018034
Full-Scale Error vs. fSCLK
Full-Scale Error vs. Temperature
30018039
30018037
Supply Current vs. VA
Supply Current vs. Temperature
30018045
30018044
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14
DAC121S101QML
5V Glitch Response
Power-On Reset
30018046
30018047
3V Wake-Up Time
5V Wake-Up Time
30018048
30018049
15
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DAC121S101QML
1.3 OUTPUT AMPLIFIER
The output buffer amplifier is a rail-to-rail type, providing an
output voltage range of 0V to VA. All amplifiers, even rail-torail types, exhibit a loss of linearity as the output approaches
the supply rails (0V and VA, in this case). For this reason,
linearity is specified over less than the full output range of the
DAC. The output capabilities of the amplifier are described in
the Electrical Tables.
1.0 Functional Description
1.1 DAC SECTION
The DAC121S101 is fabricated on a CMOS process with an
architecture that consists of switches and a resistor string that
are followed by an output buffer. The power supply serves as
the reference voltage. The input coding is straight binary with
an ideal output voltage of:
1.4 SERIAL INTERFACE
The three-wire interface is compatible with SPI, QSPI and
MICROWIRE, as well as most DSPs. See the Timing Diagram
for information on a write sequence.
A write sequence begins by bringing the SYNC line low. Once
SYNC is low, the data on the DIN line is clocked into the 16bit serial input register on the falling edges of SCLK. On the
16th falling clock edge, the last data bit is clocked in and the
programmed function (a change in the mode of operation and/
or a change in the DAC register contents) is executed. At this
point the SYNC line may be kept low or brought high. In either
case, it must be brought high for the minimum specified time
before the next write sequence as a falling edge of SYNC can
initiate the next write cycle.
Since the SYNC and DIN buffers draw more current when they
are high, they should be idled low between write sequences
to minimize power consumption.
VOUT = VA x (D / 4096)
where D is the decimal equivalent of the binary code that is
loaded into the DAC register and can take on any value between 0 and 4095.
1.2 RESISTOR STRING
The simplified resistor string is shown in Figure 3. Conceptually, this string consists of 4096 equal valued resistors with a
switch at each junction of two resistors, plus a switch to
ground. The code loaded into the DAC register determines
which switch is closed, connecting the proper node to the
amplifier. This configuration guarantees that the DAC is
monotonic.
1.5 INPUT SHIFT REGISTER
The input shift register, Figure 4, has sixteen bits. The first
two bits are "don't cares" and are followed by two bits that
determine the mode of operation (normal mode or one of
three power-down modes). The contents of the serial input
register are transferred to the DAC register on the sixteenth
falling edge of SCLK. See Timing Diagram, Figure 2.
30018007
FIGURE 3. DAC Resistor String
30018008
FIGURE 4. Input Register Contents
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16
1.6 POWER-ON RESET
The power-on reset circuit controls the output voltage during
power-up. Upon application of power the DAC register is filled
with zeros and the output voltage is 0 Volts and remains there
until a valid write sequence is made to the DAC.
30018009
FIGURE 5. ADSP-2101/2103 Interface
2.1.2 80C51/80L51 Interface
A serial interface between the DAC121S101 and the
80C51/80L51 microcontroller is shown in Figure 6. The
SYNC signal comes from a bit-programmable pin on the microcontroller. The example shown here uses port line P3.3.
This line is taken low when data is to transmitted to the
DAC121S101. Since the 80C51/80L51 transmits 8-bit bytes,
only eight falling clock edges occur in the transmit cycle. To
load data into the DAC, the P3.3 line must be left low after the
first eight bits are transmitted. A second write cycle is initiated
to transmit the second byte of data, after which port line P3.3
is brought high. The 80C51/80L51 transmit routine must recognize that the 80C51/80L51 transmits data with the LSB first
while the DAC121S101 requires data with the MSB first.
1.7 POWER-DOWN MODES
The DAC121S101 has four modes of operation. These
modes are set with two bits (DB13 and DB12) in the control
register.
TABLE 1. Modes of Operation
DB13
DB12
0
0
Normal Operation
0
1
Power-Down with 5kΩ to GND
1
0
Power-Down with 100kΩ to GND
1
1
Power-Down with Hi-Z
Operating Mode
When both DB13 and DB12 are 0, the device operates normally. For the other three possible combinations of these bits
the supply current drops to its power-down level and the output is pulled down with either a 5kΩ or a 100kΩ resistor, or is
in a high impedance state, as described in Table 1.
The bias generator, output amplifier, the resistor string and
other linear circuitry are all shut down in any of the powerdown modes. Minimum power consumption is achieved in the
power-down mode with SCLK disabled and SYNC and DIN
idled low.
30018010
FIGURE 6. 80C51/80L51 Interface
2.1.3 68HC11 Interface
A serial interface between the DAC121S101 and the 68HC11
microcontroller is shown in Figure 7. The SYNC line of the
DAC121S101 is driven from a port line (PC7 in the figure),
similar to the 80C51/80L51.
The 68HC11 should be configured with its CPOL bit as a zero
and its CPHA bit as a one. This configuration causes data on
the MOSI output to be valid on the falling edge of SCLK. PC7
is taken low to transmit data to the DAC. The 68HC11 transmits data in 8-bit bytes with eight falling clock edges. Data is
transmitted with the MSB first. PC7 must remain low after the
first eight bits are transferred. A second write cycle is initiated
to transmit the second byte of data to the DAC, after which
PC7 should be raised to end the write sequence.
2.0 Applications Information
The simplicity of the DAC121S101 implies ease of use. However, it is important to recognize that any data converter that
utilizes its supply voltage as its reference voltage will have
essentially zero PSRR (Power Supply Rejection Ratio).
Therefore, it is necessary to provide a noise-free supply voltage to the device.
2.1 DSP/MICROPROCESSOR INTERFACING
Interfacing the DAC121S101 to microprocessors and DSPs
is quite simple. The following guidelines are offered to hasten
the design process.
2.1.1 ADSP-2101/ADSP2103 Interfacing
Figure 5 shows a serial interface between the DAC121S101
and the ADSP-2101/ADSP2103. The DSP should be set to
operate in the SPORT Transmit Alternate Framing Mode. It is
programmed through the SPORT control register and should
be configured for Internal Clock Operation, Active Low Framing and 16-bit Word Length. Transmission is started by writing
a word to the Tx register after the SPORT mode has been
enabled.
30018011
FIGURE 7. 68HC11 Interface
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.
17
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DAC121S101QML
Normally, the SYNC line is kept low for at least 16 falling
edges of SCLK and the DAC is updated on the 16th SCLK
falling edge. However, if SYNC is brought high before the 16th
falling edge, the shift register is reset and the write sequence
is invalid. The DAC register is not updated and there is no
change in the mode of operation or in the output voltage.
DAC121S101QML
30018012
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.
Since the DAC121S101 consumes very little power, a reference source may be used as the supply voltage. The advantages 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.
30018014
FIGURE 10. The LM4050 as a power supply
The minimum resistor value in the circuit of Figure 10 should
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
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 conditions 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 summarized as
2.2.1 LM4130
The LM4130 reference, with its 0.05% accuracy over temperature, is a good choice as a power source for the
DAC121S101. Its primary disadvantage is the lack of 3 V and
5 V versions. However, the 4.096 V version is useful if a 0 to
4.095 V output range is desirable or acceptable. Bypassing
the LM4130 VIN pin with a 0.1 µF capacitor and the VOUT
pin with a 2.2 µF capacitor will improve stability and reduce
output noise. The LM4130 comes in a space-saving 5-pin
SOT23.
R(min) = ( VIN(max) − VZ(min) / (IA(min) + IZ(max))
and
R(max) = ( VIN(min) − VZ(max) / (IA(max) + IZ(min) )
where V Z(min) and VZ(max) are the nominal LM4050 output
voltages ± the LM4050 output tolerance over temperature, IZ
(max) is the maximum allowable current through the LM4050,
IZ(min) is the minimum current required by the LM4050 for
proper regulation, IA(max) is the maximum DAC121S101 supply current, and IA(min) is the minimum DAC121S101 supply
current.
30018013
FIGURE 9. The LM4130 as a power supply
2.2.3 LP3985
The LP3985 is a low noise, ultra low dropout voltage regulator
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 frequencies. Since low frequency noise is relatively difficult to
filter, this specification could be important for some applications. The LP3985 comes in a space-saving 5-pin SOT23 and
5-bump micro SMD packages.
2.2.2 LM4050
Available with accuracy of 0.44%, the LM4050 shunt reference is also a good choice as a power regulator for the
DAC121S101. It does not come in a 3 Volt version, but 4.096
V and 5 V versions are available. It comes in a space-saving
3-pin SOT23.
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18
DAC121S101QML
30018015
30018017
FIGURE 11. Using the LP3985 regulator
FIGURE 13. Bipolar Operation
An input capacitance of 1.0µF without any ESR requirement
is required at the LP3985 input, while a 1.0µF ceramic capacitor 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.
The output voltage of this circuit for any code is found to be
VO = (VA x (D / 4096) x ((R1 + R2) / R1) - VA x R2 / R1)
where D is the input code in decimal form. With VA = 5V and
R1 = R2,
VO = (10 x D / 4096) - 5V
2.2.4 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.
A list of rail-to-rail amplifiers suitable for this application are
indicated in Table 2.
TABLE 2. Some Rail-to-Rail Amplifiers
Typ ISUPPLY
AMP
PKGS
LMC7111
DIP-8
SOT23-5
0.9 mV
25 µA
LM7301
SO-8
SOT23-5
0.03 mV
620 µA
LM8261
SOT23-5
0.7 mV
1 mA
Typ VOS
2.4 LAYOUT, GROUNDING, AND BYPASSING
For best accuracy and minimum noise, the printed circuit
board containing the DAC121S101 should have separate
analog and digital areas. The areas are defined by the locations 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 analog 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 DAC121S101. 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 continuous return path below their traces.
The DAC121S101 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 capacitor should be a tantalum type and the 0.1µF capacitor
should be a low ESL, low ESR type. The power supply for the
DAC121S101 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.
30018016
FIGURE 12. Using the LP2980 regulator
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 combination of small size and ESR. Ceramic capacitors are attractive 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
size and have ESR values that may be too high at low temperatures.
2.3 BIPOLAR OPERATION
The DAC121S101 is designed for single supply operation and
thus has a unipolar output. However, a bipolar output may be
obtained with the circuit in Figure 13. 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.
19
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DAC121S101QML
are qualified for environments with radiation levels of 0.01 rad
(Si)/s or lower.
3.0 Radiation Environments
Careful consideration should be given to environmental conditions when using a product in a radiation environment.
3.2 Single Event Latch-Up and
Functional Interrupt
3.1 Total Ionizing Dose
One time single event latch-up (SEL) and single event functional interrupt (SEFI) testing was preformed according to
EIA/JEDEC Standard, EIA/JEDEC57. The linear energy
transfer threshold (LETth) shown in the Key Specifications
table on the front page is the maximum LET tested. A test
report is available upon request.
The products with the radiation hardness assurance (RHA)
levels listed in the Ordering Information table listed on the
front page are qualified for low dose rate environments only.
3.1.1 DAC121S101WGRQV
5962R0722601VZA
3.3 Single Event Upset
This product is tested and qualified per MIL-STD-883 Test
Method 1019, Condition A and the “Extended room temperature anneal test” where a high dose irradiation followed by a
room temperature anneal is used to simulate a dose rate of
0.027 rad(Si)/s and is qualified for environments with radiation
levels of 0.027 rad(Si)/s or lower.
A report on single event upset (SEU) is available upon request.
3.1.2 DAC121S101WGRLV
5962R0722602VZA
This product is tested and qualified per MIL-STD-883 Test
Method 1019, Condition D at a dose rate of 0.01 rad(Si)/s and
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20
Date Relased
Revision
Section
05/05/08
A
Initial Release
08/14/08
B
07/15/09
05/06/2010
24–Apr-2012
Changes
New Product Data Sheet Release
Ordering Information Table
Removed SMD reference. Added
DAC121S101WGMLS NSPN . Revision A will be
Archived.
C
Ordering Information Table, AC and
Timing Electrical Characteristics
Added SMD reference, removed MLS device.
Changed following parameter limits from Max to
Min tH, tL, tSUCL tSUD, tDHD, tCS, tSYNC, tSUCL limit
from −21 to 0, Added Delta Parameters. Added
subgroups to fSCLK, Removed the typical limits.
Changed paragraph's 1.7 and 3.0 section.
Revision B will be Archived
D
Added reference to MPR and CVAL NSPN,
Ordering Information Table, Note Section, verbiage to Note 12, Per DSCC recommendation
Operating Life Test Delta Table and
delta limits for Supply Current. Change to para 3.1,
Section 3.0 Radiation Environments
0.16 rad(Si)/s to 0.027 rad(Si)/s. Revision C will be
Archived
E
Ordering Information — Updated info on
DAC121S101WGRQV. Added footnote for MPR
device. Added New NSID DAC121S101WGRLV.
Added General Note and Added Footnote 13.
Changed wording in paragraph 3.1, added
Paragraph 3.1.1 and 3.1.2. Revision D will be
Archived
Ordering Information Table, Section 3.0
and footnotes.
21
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DAC121S101QML
Revision History
DAC121S101QML
Physical Dimensions inches (millimeters) unless otherwise noted
10-Pin Ceramic SOIC
NS Package Number WG10A
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22
DAC121S101QML
Notes
23
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DAC121S101QML 12-Bit Micro Power Digital-to-Analog Converter with Rail-to-Rail Output
Notes
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