REF200 Dual Current Source and Current Sink (Rev. B) · REF200 SBVS020B –SEPTEMBER 2000–REVISED...
Transcript of REF200 Dual Current Source and Current Sink (Rev. B) · REF200 SBVS020B –SEPTEMBER 2000–REVISED...
I
High
I
High Substrate
Mirror
In
I
Low
I
Low
Mirror
Out
Mirror
Common
1 2
1 2
8 7 6 5
1 2 3 4
100µA 100µA
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Folder
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REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
REF200 Dual Current Source and Current Sink1 Features 3 Description
The REF200 combines three circuit building-blocks1• Completely Floating: No Power Supply or Ground
on a single monolithic chip: two 100-µA currentConnectionssources and a current mirror. The sections are
• High Accuracy: 100 µA ±0.5% dielectrically isolated, making them completely• Low Temperature Coefficient: ±25 ppm/°C independent. Also, because the current sources are
two-terminal devices, they can be used equally well• Wide Voltage Compliance: 2.5 V to 40 Vas current sinks. The performance of each section is• Includes Current Mirror individually measured and laser-trimmed to achievehigh accuracy at low cost.2 ApplicationsThe sections can be pin-strapped for currents of 50
• Sensor Excitation µA, 100 µA, 200 µA, 300 µA, or 400 µA. External• Biasing Circuitry circuitry can obtain virtually any current. These and
many other circuit techniques are shown in the• Offsetting Current LoopsApplication Information section of this data sheet.• Low Voltage ReferencesThe REF200 is available in an SOIC package.• Charge-pump Circuitry
• Hybrid Microcircuits Device Information(1)
PART NUMBER PACKAGE BODY SIZE (NOM)REF200 SOIC (8) 3.91 mm × 4.90 mm
(1) For all available packages, see the package addendum at theend of the data sheet.
Functional Block Diagram
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,intellectual property matters and other important disclaimers. PRODUCTION DATA.
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
Table of Contents1 Features .................................................................. 1 8 Application and Implementation .......................... 9
8.1 Application Information.............................................. 92 Applications ........................................................... 18.2 Typical Application ................................................... 93 Description ............................................................. 18.3 System Examples ................................................... 124 Revision History..................................................... 2
9 Power Supply Recommendations ...................... 255 Pin Configuration and Functions ......................... 310 Layout................................................................... 256 Specifications......................................................... 4
10.1 Layout Guidelines ................................................. 256.1 Absolute Maximum Ratings ...................................... 410.2 Layout Example .................................................... 256.2 ESD Ratings ............................................................ 4
11 Device and Documentation Support ................. 266.3 Recommended Operating Conditions....................... 411.1 Documentation Support ....................................... 266.4 Electrical Characteristics........................................... 411.2 Community Resources.......................................... 266.5 Typical Characteristics .............................................. 511.3 Trademarks ........................................................... 267 Detailed Description .............................................. 711.4 Electrostatic Discharge Caution............................ 267.1 Overview ................................................................... 711.5 Glossary ................................................................ 267.2 Functional Block Diagram ......................................... 7
12 Mechanical, Packaging, and Orderable7.3 Feature Description................................................... 7Information ........................................................... 267.4 Device Functional Modes.......................................... 8
4 Revision HistoryNOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision A (July 2015) to Revision B Page
• Changed multiple instances of "mA" in data sheet back to "µA" (typo) ................................................................................. 1
Changes from Original (September 2000) to Revision A Page
• Added ESD Ratings and Recommended Operating Conditions tables, and Feature Description, Device FunctionalModes, Application and Implementation, Power Supply Recommendations, Layout, Device and DocumentationSupport, and Mechanical, Packaging, and Orderable Information sections........................................................................... 1
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Product Folder Links: REF200
I
I
Substrate
Mirror Input
Low
Low
Mirror Common
Mirror Output
1
2
3
4
8
7
6
5
1
2
High
High
1
2
I
I
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
5 Pin Configuration and Functions
D Package8-Pin SOICTop View
Pin FunctionsPIN
DESCRIPTIONNAME NO.I1 Low 1 Current source 1 low terminalI2 Low 2 Current source 2 low terminalMirror Common 3 Current mirror common terminalMirror Output 4 Current mirror output terminalMirror Input 5 Current mirror input terminalSubstrate 6 Substrate (Usually connected to most negative potential in the system)I2 High 7 Current source 2 high terminalI1 High 8 Current source 1 high terminal
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Product Folder Links: REF200
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
6 Specifications
6.1 Absolute Maximum Ratingsover operating free-air temperature range (unless otherwise noted) (1)
MIN MAX UNITApplied voltage –6 40 VReverse current –350 µAVoltage between any two sections ±80 VOperating temperature –40 85 °C
Tstg Storage temperature –40 125 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratingsonly, which do not imply functional operation of the device at these or any other conditions beyond those indicated under RecommendedOperating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
6.2 ESD RatingsVALUE UNIT
V(ESD) Electrostatic discharge Charged-device model (CDM), per JEDEC specification JESD22-C101 (1) ±750 V
(1) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. Manufacturing withless than 250-V CDM is possible with the necessary precautions.
6.3 Recommended Operating Conditionsover operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNITVCOMP Compliance voltage 2.5 40 VTA Specified temperature range –25 85 °C
6.4 Electrical Characteristicsat TA = 25°C, VS = 15 V (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNITCURRENT SOURCES
Current accuracy ±0.25% ±1%Current match ±0.25% ±1%Temperature drift Specified temperature range 25 ppm/°C
2.5 V to 40 V 20 100Output impedance MΩ
3.5 V to 30 V 200 500BW = 0.1 Hz to 10 Hz 1 nAp-p
Noisef = 10 kHz 20 pA/√Hz
Voltage compliance (1%) TMIN to TMAX See Typical CharacteristicsCapacitance 10 pF
CURRENT MIRROR – I = 100 µA unless otherwise notedGain 0.995 1 1.005Temperature drift 25 ppm/°CImpedance (output) 2 V to 40 V 40 100 MΩNonlinearity I = 0 µA to 250 µA 0.05%Input voltage 1.4 VOutput compliance voltage See Typical CharacteristicsFrequency response (–3 dB) Transfer 5 MHz
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Product Folder Links: REF200
1000
900
800
700
600
500
400
300
200
100
Re
ve
rse
Cu
rre
nt
(µA
)
0
0 –2 –4 –6 –8 –10 –12
Reverse Voltage (V)
Reverse Voltage
Circuit Model
12kW 7V
5kW
Safe Reverse Current
Safe Reverse Voltage
101
100.8
100.6
100.4
100.2
100
99.8
99.6
99.4
99.2
Curr
ent (µ
A)
99
0 5 10 15 20 25 30 35 40
Voltage (V)
0
100.5
100.4
100.3
100.2
100.1
100
99.9
99.8
99.7
99.6
99.5
Voltage (V)
1 2 3 4 5
Curr
ent (µ
A)
–55°C
25°C
125°C
100.1
100
99.9
99.8
99.7
99.6
99.5
–25–50 25 7550 1251000
Temperature (°C)
Curr
ent (µ
A)
85°CDrift specified by
“box method”
(See text)
600
500
400
300
200
100
0
50 10
Temperature Drift (ppm/°C)
Quantit
y (
Units
)
Distribution of three
production lots —
1284 Current Sources.
2015 25 3530 40 5045 55 6560
2 5
117
30 15 6 0 1 1
501
454
8666
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
6.5 Typical Characteristicsat TA = 25°C, VS = 15 V (unless otherwise noted)
Figure 1. Current Source Typical Drift vs Temperature Figure 2. Current Source Temperature Drift Distribution
Figure 4. Current Source Output Current vs VoltageFigure 3. Current Source Output Current vs Voltage
Figure 6. Current Source Reverse Current vs ReverseFigure 5. Current Source Current Noise (0.1 Hz to 10 Hz)Voltage
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Inp
ut
Vo
lta
ge
(V
)
0
1µA 10µA 100µA 1mA 10mA
Current
4
3
2
1
Input Voltage
Output
Compliance
Voltage
5
4
3
2
1
0
–1
–2
–3
–4
Err
or
(%)
–5
10µA 100µA 1mA
Mirror Current (A)
V =
1.25V
V = 1V
V = 1.5V
O
O
O
0
0.1
0.08
0.06
0.04
0.02
0
–0.02
–0.04
–0.06
–0.08
–0.01
Current (µA)
50 100 150 200 250
No
nlin
ea
rity
(%
of
25
0µ
A)
Data from Three
Representative Units
(Least-square fit)
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
Typical Characteristics (continued)at TA = 25°C, VS = 15 V (unless otherwise noted)
Figure 8. Mirror Transfer NonlinearityFigure 7. Mirror Gain Error vs Current
Figure 9. Mirror Input Voltage and Output Compliance Voltage vs Current
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Product Folder Links: REF200
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High
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High Substrate
Mirror
In
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Low
I
Low
Mirror
Out
Mirror
Common
1 2
1 2
8 7 6 5
1 2 3 4
100µA 100µA
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
7 Detailed Description
7.1 OverviewThe REF200 device combines three circuit building-blocks on a single monolithic chip—two 100-µA currentsources and a current mirror. The sections are dielectrically isolated, making them completely independent. Also,because the current sources are two terminal devices, they can be used equally well as current sinks. Theperformance of each section is individually measured and laser-trimmed to achieve high accuracy at low cost.
7.2 Functional Block Diagram
7.3 Feature Description
7.3.1 Temperature DriftDrift performance is specified by the box method, as illustrated in Figure 1. The upper and lower currentextremes measured over temperature define the top and bottom of the box. The sides are determined by thespecified temperature range of the device. The drift of the unit is the slope of the diagonal, typically 25 ppm/°Cfrom –25°C to +85°C.
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Product Folder Links: REF200
(Substrate)
Current
Source
(1 of 2)
4kΩ
8X
8,7
5kΩ
1kΩ
1,2
6
3
5 4
1kΩ
12kΩ
Current
Mirror
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
7.4 Device Functional ModesThe three circuit sections of the REF200 are electrically isolated from one another, using a dielectrically-isolatedfabrication process. A substrate connection is provided (pin 6), which is isolated from all circuitry. This pin shouldbe connected to a defined circuit potential to assure rated DC performance. The preferred connection is to themost negative constant potential in the system. In most analog systems, this would be –VS. For best acperformance, leave pin 6 open and leave unused sections unconnected. Figure 10 shows the simplified circuitdiagram of the REF200.
Figure 10. Simplified Circuit Diagram
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Product Folder Links: REF200
100µA
REF200
+5V
100µA
3 WireRTD
+5V
RT
D
R3 78.7
INA326
Vout
R2
698k
C2
220p
R1
2k
R1
R2
+
±
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
8 Application and Implementation
NOTEInformation in the following applications sections is not part of the TI componentspecification, and TI does not warrant its accuracy or completeness. TI’s customers areresponsible for determining suitability of components for their purposes. Customers shouldvalidate and test their design implementation to confirm system functionality.
8.1 Application InformationApplications for the REF200 are limitless. Application Bulletin AB-165 (SBOA046) shows additional REF200circuits as well as other related current source techniques. In this section, a collection of circuits are shown toillustrate some techniques.
If the current sources are subjected to reverse voltage, a protection diode may be required. A reverse voltagecircuit model of the REF200 is shown in Figure 6. If reverse voltage is limited to less than 6 V or reverse currentis limited to less than 350 µA, then no protection circuitry is required. A parallel diode (see (a) in Figure 17)protects the device by limiting the reverse voltage across the current source to approximately 0.7 V. In someapplications, a series diode may be preferable (see (b) in Figure 17), because it allows no reverse current. Thisconfiguration, however, reduces the compliance voltage range by one diode drop.
8.2 Typical ApplicationFigure 11 shows the schematic of a circuit that translates RTD resistance to a voltage level convenient for anADC input. The REF200 precision current reference provides excitation and an instrumentation amplifier scalesthe signal. The design also uses a 3-wire RTD configuration to minimize errors due to wiring resistance.
Figure 11. RTD Resistance to Voltage Converter Schematic
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100µA
REF200
+5V
100µA
3 WireRTD
+5V
RT
D
R3 78.7
INA326
VOUT
R2
698k
C2
220p
R1
2k
R1
R180.3@
-50C8.03mV
+
+
160µ V0.111V
G = 2(R2/R1)- 7.87mV +
+
200µA
- - -
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
Typical Application (continued)8.2.1 Design RequirementsThe design requirements are as follows:• Supply Voltage: 5 V• RTD temperature range: –50°C to +125°C• RTD resistance range 80.3 Ω to 147.9 Ω• Output: 0.1 V to 4.9 V
The design goals and performance are summarized in Table 1. Figure 15 depicts the measured transfer functionof the design.
Table 1. Comparison of Design Goals, Calculations, Simulation, and Measured PerformanceVOUT RTD GOAL CALCULATED SIMULATED MEASURED
VOUT maximum scale 80.3 Ω 0.1 V 0.112 V 0.117 V 0.11 3 VVOUT minimum scale 142.9 Ω 4.9 V 4.83 V 4.82 V 4.862 V
8.2.2 Detailed Design ProcedureFigure 12 and Figure 13 shows the schematic of the RTD amplifier for minimum and maximum output conditions.This circuit was designed for a –50°C to 150°C RTD temperature range. At –50°C the RTD resistance is 80.3 Ωand the voltage across it is 8.03 mV (VRTD = (100 μA) (80.3 Ω), see Figure 2). Notice that R3 develops a voltagedrop that opposes the RTD drop. The drop across R3 is used to shift amplifiers input differential voltage to aminimum level. The output is the differential input multiplied by the gain (Vout = 698 ∙ 160 μV = 0.111 V). At150°C, the RTD resistance is 148 Ω and the voltage across it is 14. 8 mV (VRTD = (100 μA × 148 Ω ). Thisproduces a differential input of 6.93 mV and an output voltage of 4.84 V (VOUT = 698 ∙ 6.93 mV = 4.84 V , seeFigure 13). For more detailed design procedures and results, refer to the reference guide, RTD to VoltageReference Design Using Instrumentation Amplifier and Current Reference (TIDU969).
Figure 12. RTD Amplifier with Minimum Output Condition
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Product Folder Links: REF200
100µA
REF200
+5V
100µA +5V
RT
D
R3 78.7
INA326
VOUT
R2
698k
C2
220p
R1
2k
R1
R1148@ 150C
14.8mV
+
4.84V
+2mV-
+
-
PCB
3 WireRTD
Large Lead R
300m
10
-1mV+
-14.8mV
+
- 10
- 1mV+
10
100µA
REF200
+5V
100µA
3 WireRTD
+5V
RT
D
R3 78.7
INA326
VOUT
R2
698k
C2
220p
R1
2k
R1
R1148@
150C 14.8mV+
+
6.93mV4.84V
G = 2(R2/R1)- 7.87mV +
200µA
+
- - -
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
Figure 13. RTD Amplifier with Maximum Output Condition
8.2.2.1 Lead Resistance Cancelation (3-Wire RTD)Figure 14 shows the 3-wire RTD configuration can be used to cancel lead resistance. The resistance in eachlead must be equal to cancel the error. Also, the two current sources in the REF200 must be equal. Notice thatthe voltage developed on the two top leads of the RTD are equal and opposite polarity so that the amplifiersinput is only from the RTD voltage. In this example, the RTD drop is 14.8 mV and the leads each have 1 mV.Notice that the 1 mV drops cancel. Finally, notice that the voltage on the 3rd lead (2 mV) creates a small shift inthe common mode voltage. In some applications, a larger resistor is intentionally added to shift the common-mode voltage. However, the INA326 has a rail-to-rail common mode range, so it can accept common-modevoltages near ground.
Figure 14. 3-Wire RTD Configuration Cancels Lead Resistance
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–VS
+VS
100µA
IOUT
100µA
50µA45
3
In Out
Com
Mirror
100µA
Bidirectional
Current Source
D4 D2
D D31
D2
D1100µA
100µA
NOTE: All diodes = 1N4148.
Bidirectional
Current Source
(a) (b) (c) (d)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
80 90 100 110 120 130 140 150
Vou
t (V
)
RTD Resistance C001
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
80 100 120 140 160
Out
put
Err
or (
%)
RTD Resistance ()
Error (0
Error (10
C002
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
8.2.3 Application Curves
Figure 16. Measured Error vs RTD ResistanceFigure 15. RTD to Vout Transfer Function
8.3 System Examples
Figure 17. Reverse Voltage Protection
Figure 18. 50-µA Current Source
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Product Folder Links: REF200
101
100
99
0 10 20 30 40 50 60 70 80
Applied Voltage (V)
Provides 2X Higher Compliance Voltage
SERIES-CONNECTED CURRENT SOURCES
CURRENT vs APPLIED VOLTAGE
Curr
ent (µ
A)
100µA
100µA
High
Low100µA/200µA
45
3
In Out
Com
Mirror
SCompliance to –V + 1.5V
+VS
100µA100µA
S–V
(b)
50 µA
100 µA
45
3
In Out
Com
Mirror
–VS
100 kΩ
50 µA
100 µA
45
3
In Out
Com
Mirror
(c)
Compliance to
–V + 5.1 VS
+VS
–VS
5.1 V
1N4689
27 kΩ
0.01 µF
100 µA
45
3
In Out
Com
Mirror
(a)
–VS
Compliance to
–V + 5 VS
+VS
100 µA50 µA
Compliance to
Ground
300µA
100µA
45
3
In Out
Com
Mirror
100µA
Compliance = 4V
(b)
400µA
100µA
45
3
In Out
Com
Mirror
100µA
Compliance = 4V
(c)(a)
200µA
100µA 100µA
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
System Examples (continued)
Figure 19. 200-µA, 300-µA, and 400-µA Floating Current Sources
Figure 20. 50-µA Current Sinks
Figure 21. Improved Low-Voltage Compliance Figure 22. 100-µA Current Source—80-V Compliance
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100µA
100µA
± ±
40kΩ
40kΩ 0.01µF
0.01µF
1N41481N4148
1N41481N4148
(e) Bidirectional 200µA
cascoded current source.
100µA
100µA40kΩ
40kΩ 0.01µF
0.01µF
(d) Floating 200µA cascoded
current source.
100µA
Load
–VS
+VS
(a) Compliance approximate
to Gnd. HV compliance
limited by FET breakdown.
100µA
Load
+VS
(b) Compliance to +V – 5V.
High
Low
100µA
–VS
33kΩ0.01µF
S
100µA
Load
+VS
(c)
–VS
27kΩ
5.1V
1N4689
NOTES: (1) FET cascoded current sources offer improved output impedance and high frequency operation. Circuit in (b)
also provides improved PSRR. (2) For current sinks (Circuits (a) and (b) only), invert circuits and use “N” channel JFETS.
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
System Examples (continued)
Figure 23. FET Cascode Circuits
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Product Folder Links: REF200
To
Other
Amps
Op Amp
V
R
+V
NOTE: (1) For N Op Amps, use Potentiometer Resistance = N • 100 .Ω
100µA
51Ω
51Ω
S
IN
B
OUT
AR
V
–V
Using Standard Potentiometer
S
V = V (–R /R )
Offset Adjustment Range = ±5mVOUT IN B A
To
Other
Amps
Op Amp
V
R
+V
100µA
S
IN
B
OUT
AR
V
–V
Using Bourns Op Amp Trimpot
S
V = –V (R /R )
Offset Adjustment Range = ±5mVOUT IN B A
(1)
100Ω
Bourns Trimpot®
(1)
®
2k Linear
100µA
Ω
100µA
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
System Examples (continued)
Figure 24. Operational Amplifier Offset Adjustment Circuits
Copyright © 2000–2015, Texas Instruments Incorporated Submit Documentation Feedback 15
Product Folder Links: REF200
R
100 µA
Reference
–V
100 µA
S
R2
0.01 µF
R
(N • R )2
1
I = N • 100 µAOUT
(1)
R
(N • R )2
1
I = N • 100 µAOUT
(1)
100 µA
0.01 µF
R2
+VS
+V
100 µA
S
OPA602
0.01 µF NR
I = (N +1) 100 µAO
R0.01 µF NR
I = (N +1) 100 µAO
R
100 µA
OPA602
0.01 µF NR
I = (N +1) 100 µAO
10 pF
(a) (b)
(d)(c)
(e)
–VS
OPA602
R NR IOUT
1 kΩ 4 kΩ 500 Aμ
1 kΩ 9 kΩ 1 mA
100 kΩ 9.9 kΩ 10 mA
EXAMPLES
FEATURES:
(1) Zero volts shunt compliance.
(2) Adjustable only to values above
reference value.
NOTE:
Current source/sink swing to the
Load Return rail is limited only
by the op amp's input common
mode range and output swing
capability. Voltage drop across R
can be tailored for any amplifier to
allow swing to zero volts from rail.
NOTE: (1) OPA602 or OPA128
EXAMPLES
R R I1 2 OUT
100 Ω 10 MΩ 1 nA
10 kΩ 1 MΩ 1 Aμ
10 kΩ 1 kΩ 1 mA
Use OPA128
I = 100 A (N + 1). Compliance » 3.5 VO
μ
with 0.1 V across R. Max I limited by FET.O
For I = 1 A, R = 0.1 , NR = 1 k .O
Ω Ω
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
System Examples (continued)
Figure 25. Adjustable Current Sources
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Product Folder Links: REF200
1N41481N4148
1N41481N4148
Bidirectional
Current Source1/2
REF200
OPA602
R
C
Triangle Output
Square Output
2 Vp-p
2 Vp-p
10 kΩ
Frequency = 1/4RC (Hz)
Frequency = 25/C (Hz)
(C is in µF and R = 10 k )Ω
7
V = Gain • 200 µA • RTDΔOUT
A B
O
C
I
–VS
+VS
RTDCable Shield
200-µA
Reference
Current
200-µA
Compensation
Current
REF200
1
ROFFSET
INA110
Instrumentation Amplifier
2 3 4
8 6 5
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
System Examples (continued)
Figure 26. RTD Excitation With Three-Wire Lead Resistance Compensation
Figure 27. Precision Triangle Waveform Generator
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Product Folder Links: REF200
–15 V
100 µA
0.1 µF
Siliconix
J109
50kΩ
IOUTFor current source,
invert circuitry and
use P-Channel FET.
100 N
1/4 OPA404
100 µA + Bridge (1)
VIN = 10 V: 100% Duty Cycle
12 Vp-p Duty Cycle Out
C
V IN
100 µA + Bridge (1)
1/4 OPA404
1/4 OPA404
60 k VIN = 0 V: 50% Duty Cycle VIN = ±10 V: 0% Duty Cycle
¦10 V VIN 10 V
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
System Examples (continued)
(1) See Figure 27.
Figure 28. Precision Duty-Cycle Modulator
Figure 29. Low Noise Current Sink
18 Submit Documentation Feedback Copyright © 2000–2015, Texas Instruments Incorporated
Product Folder Links: REF200
27 kΩ
In OutMirror
Com
20 kΩ0.01 µF
0.01 µF
100 µA
100 µA
High
300 µA
2N5116
2N4340
5 4
3
300 µA
Low
(a) Regulation (15 V to 30 V = 0.00003%/V (10 GW)
In OutMirror
Com
20 kΩ0.01 µF
100 µA
High
400 µA
2N5116
2N4340
5 4
3
400 µA
Low
(a) Regulation (15 V to 30 V = 0.000025%/V (10 GW)
100 µA
–15 V
100 µA
0.1 µF
Siliconix
J109
50 kΩ
IOUT
For current source,
invert circuitry and
use P-Channel FET.
50 kΩ0.1 µF
100 µA
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
System Examples (continued)
Figure 30. Low Noise Current Sink With Compliance Below Ground
Figure 31. Floating 300-µA and 400-µA Cascoded Current Sources
Copyright © 2000–2015, Texas Instruments Incorporated Submit Documentation Feedback 19
Product Folder Links: REF200
Compliance4 V to 30 V
High
25 mA
100 Ω
100 Aμ
+VS
40.2 Ω10 kΩ
Low
–VS
NOTE: Each amplifier 1/4 LM324Op amp power supplies are derivedwithin the circuitry, and this quiescentcurrent is included in the 25 mA.
100 Ω
100 Ω
100 Ω
10 kΩ
10 kΩ
OPA602
C
100 µA
–VS
+VS
V = –VI
100 µA
VI
V Rate Limit = 100 µA/CO
Diodes: 1N4148
or PWS740-3
Diode Bridge for
reduced V .OS
O
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
System Examples (continued)
Figure 32. Rate Limiter
Figure 33. 25-mA Floating Current Source
20 Submit Documentation Feedback Copyright © 2000–2015, Texas Instruments Incorporated
Product Folder Links: REF200
–10 –5 +5 +10
–10
–5
+5
+10
OPA602
100 µA
1N4148
1N4148
R
(50 kΩ)
VI
R
(50 kΩ)
+15 V
10 pF
VO
OPA602
1N4148
1N4148
R
(50 kΩ)
VI
R
(50 kΩ)
10 pF
VO
100 µA
–15 V
–10 –5 +5 +10
–10
–5
+5
+10
For V > –5 V: V = 0
For V < –5 V: V = –V – 5 V
(Dead to 100 µA • R)
O
O
I
I I
For V < 5 V: V = 0
For V > 5 V: V = 5 V – V
(Dead to –100 µA • R)
O
O
I
I I
OV
OV
VI
VI
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
System Examples (continued)
Figure 34. Dead-Band Circuit
Copyright © 2000–2015, Texas Instruments Incorporated Submit Documentation Feedback 21
Product Folder Links: REF200
100 µA
1 Ω
+V
V = 100 µV
S
O
OPA602
100 µA
1N4148
1N4148
R
(50 kΩ)
R
(50 kΩ)
+15 V
10 pF
OPA602
1N4148
1N4148
R
(50 kΩ)
VI
R
(50 kΩ)
10 pF
100 µA
–15 V
–10 –5 +5 +10
–10
–5
+5
+10
For V > 5 V: V = V – 5 V
For V < –5 V: V = V + 5 V
(Dead to ±100 µA • R)
O
O
I
I I
OV
VI
I
OPA602
VO
10 kΩ
10 kΩ
10 kΩ
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
System Examples (continued)
Figure 35. Double Dead-Band Circuit
Figure 36. Low-Voltage Reference
22 Submit Documentation Feedback Copyright © 2000–2015, Texas Instruments Incorporated
Product Folder Links: REF200
R
(50 kΩ)
OPA121
100 µF
VO
OPA121
V I
100 µA
1 kΩ
1N4148
V = V (V < 5 V)
V = 5 V (V > 5 V)
(V = 100 µA • R)
O
O
I I
I
LIMIT
–10 –5 +5 +10
–10
–5
+5
+10OV
VI
+7.5 V (R = 75 kΩ)
+5 V (R = 50 kΩ)
+2.5 V (R = 25 kΩ)
100 µA
with bridge(1)
OPA121
100 µF
VO
OPA121
V I
R
(50 k )Ω
1 kΩ
V = V (–5 V < V < 5 V)
V = 5 V (V > 5 V)
V = –5 V (V < –5 V)
(Bound = 100 µA • R)
O
O
O
I I
I
I
–10 –5 +5 +10
–10
–5
+5
+10OV
VI
+7.5 V (R = 75 k )Ω
+5 V (R = 50 k )Ω
+2.5 V (R = 25 k )Ω
–2.5 V (R = 25 k )Ω
+5 V (R = 50 k )Ω
+7.5 V (R = 75 k )Ω
100 µA
10 kΩ
+V
V = 1 V
S
OOPA602
0.01 µF
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
System Examples (continued)
Figure 37. Voltage Reference
(1) See Figure 17.
Figure 38. Bipolar Limiting Circuit
Figure 39. Limiting Circuit
Copyright © 2000–2015, Texas Instruments Incorporated Submit Documentation Feedback 23
Product Folder Links: REF200
100µA
V = +In – (–In)
100µA
O
–VS
INA105
+VS
–InPMI
MAT03+In
1/2OPA1013
1/2OPA1013
V
V
CENTER
O
I
W–V , +V = 100µA • RW
W–V W+V
V
5V
The
Window
0
1kΩ
–VS
VOCENTERV
VI
100µA
100µA
0.01µF
R(3)
(2)
(1)
0.01µF(1)
R(3)
+5V
1/2LM393
1/2LM393
NOTES: (1) Capacitors optional to reduce noise and switching time.(2) Programs center of threshold voltage. (3) Programs window voltage.
+VS
(2)
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
System Examples (continued)
Figure 40. Window Comparator
Figure 41. Instrumentation Amplifier With Compliance to –VS
24 Submit Documentation Feedback Copyright © 2000–2015, Texas Instruments Incorporated
Product Folder Links: REF200
REF200
VSUPPLY GND
C
R
R
R
To RTD
To INA
REF200www.ti.com SBVS020B –SEPTEMBER 2000–REVISED JULY 2015
9 Power Supply RecommendationsThe REF200 device has completely floating current sources and current mirror. The REF200 device has a widecompliance voltage range from 2.5 V to 40 V.
10 Layout
10.1 Layout GuidelinesFigure 42 illustrates an example of a printed-circuit-board (PCB) layout for a data acquisition system using theREF2030. Some key considerations are:
• Minimize trace lengths in the current source and current mirror paths to reduce impedance.• Using a solid ground plane helps distribute heat and reduces electromagnetic interference (EMI) noise pickup.• Place the external components as close to the device as possible. This configuration prevents parasitic errors
(such as the Seebeck effect) from occurring.• Do not run sensitive analog traces in parallel with digital traces. Avoid crossing digital and analog traces if
possible, and only make perpendicular crossings when absolutely necessary.
10.2 Layout Example
Figure 42. Example Layout of REF200 in a RTD Measurement System
Copyright © 2000–2015, Texas Instruments Incorporated Submit Documentation Feedback 25
Product Folder Links: REF200
REF200SBVS020B –SEPTEMBER 2000–REVISED JULY 2015 www.ti.com
11 Device and Documentation Support
11.1 Documentation Support
11.1.1 Related Documentation• RTD to Voltage Reference Design Using Instrumentation Amplifier and Current Reference, TIDU969• Implementation and Applications of Current Sources and Current Receivers, SBOA046
11.2 Community ResourcesThe following links connect to TI community resources. Linked contents are provided "AS IS" by the respectivecontributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms ofUse.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaborationamong engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and helpsolve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools andcontact information for technical support.
11.3 TrademarksE2E is a trademark of Texas Instruments.All other trademarks are the property of their respective owners.
11.4 Electrostatic Discharge CautionThese devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foamduring storage or handling to prevent electrostatic damage to the MOS gates.
11.5 GlossarySLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable InformationThe following pages include mechanical, packaging, and orderable information. This information is the mostcurrent data available for the designated devices. This data is subject to change without notice and revision ofthis document. For browser-based versions of this data sheet, refer to the left-hand navigation.
26 Submit Documentation Feedback Copyright © 2000–2015, Texas Instruments Incorporated
Product Folder Links: REF200
PACKAGE OPTION ADDENDUM
www.ti.com 24-Aug-2018
Addendum-Page 1
PACKAGING INFORMATION
Orderable Device Status(1)
Package Type PackageDrawing
Pins PackageQty
Eco Plan(2)
Lead/Ball Finish(6)
MSL Peak Temp(3)
Op Temp (°C) Device Marking(4/5)
Samples
REF200AU ACTIVE SOIC D 8 75 Green (RoHS& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR -25 to 85 REF200U
REF200AU/2K5 ACTIVE SOIC D 8 2500 Green (RoHS& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR -25 to 85 REF200U
REF200AU/2K5E4 ACTIVE SOIC D 8 2500 Green (RoHS& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR -25 to 85 REF200U
REF200AUE4 ACTIVE SOIC D 8 75 Green (RoHS& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR -25 to 85 REF200U
(1) The marketing status values are defined as follows:ACTIVE: Product device recommended for new designs.LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.PREVIEW: Device has been announced but is not in production. Samples may or may not be available.OBSOLETE: TI has discontinued the production of the device.
(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substancedo not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI mayreference these types of products as "Pb-Free".RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide basedflame retardants must also meet the <=1000ppm threshold requirement.
(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuationof the previous line and the two combined represent the entire Device Marking for that device.
(6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finishvalue exceeds the maximum column width.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on informationprovided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
PACKAGE OPTION ADDENDUM
www.ti.com 24-Aug-2018
Addendum-Page 2
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device PackageType
PackageDrawing
Pins SPQ ReelDiameter
(mm)
ReelWidth
W1 (mm)
A0(mm)
B0(mm)
K0(mm)
P1(mm)
W(mm)
Pin1Quadrant
REF200AU/2K5 SOIC D 8 2500 330.0 12.4 6.4 5.2 2.1 8.0 12.0 Q1
PACKAGE MATERIALS INFORMATION
www.ti.com 23-Jul-2015
Pack Materials-Page 1
*All dimensions are nominal
Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
REF200AU/2K5 SOIC D 8 2500 367.0 367.0 35.0
PACKAGE MATERIALS INFORMATION
www.ti.com 23-Jul-2015
Pack Materials-Page 2
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