REF3112 REF3120 REF3125 REF3130 REF3133 REF3140
SBVS046A – DECEMBER 2003 – REVISED JANUARY 2004
15ppm/°C Max, 100µA, SOT23-3 SERIES VOLTAGE REFERENCE
FEATURES
q MicroSIZE PACKAGE: SOT23-3 q LOW DROPOUT: 5mV q HIGH OUTPUT CURRENT: ±10mA q HIGH ACCURACY: 0.2% max q LOW IQ: 115µA max q EXCELLENT SPECIFIED DRIFT PERFORMANCE: 15ppm/°C (max) from 0°C to +70°C 20ppm/°C (max) from –40°C to +125°C
DESCRIPTION
The REF31xx is a family of precision, low power, low dropout, series voltage references available in the tiny SOT23-3 package. The REF31xx’s small size and low power consumption (100µA typ) make it ideal for portable and battery-powered applications. The REF31xx does not require a load capacitor, but is stable with any capacitive load and can sink/source up to 10mA of output current. Unloaded, the REF31xx can be operated on supplies down to 5mV above the output voltage. All models are specified for the wide temperature range of –40°C to +125°C.
APPLICATIONS
q PORTABLE, BATTERY-POWERED EQUIPMENT q DATA ACQUISITION SYSTEMS q MEDICAL EQUIPMENT q HAND-HELD TEST EQUIPMENT
PRODUCT REF3112 REF3120 REF3125 REF3130 REF3133 REF3140 IN 1 REF3112 REF3120 REF3125 REF3130 REF3133 REF3140 SOT23-3 VOLTAGE (V) 1.25 2.048 2.5 3.0 3.3 4.096
3
GND
OUT
2
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters.
Copyright © 2003-2004, Texas Instruments Incorporated
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ABSOLUTE MAXIMUM RATINGS(1)
Supply Voltage, V+ to V– ................................................................... 7.0V Output Short-Circuit ................................................................. Continuous Operating Temperature .................................................. –55°C to +135°C Storage Temperature ..................................................... –65°C to +150°C Junction Temperature .................................................................... +150°C Lead Temperature (soldering, 10s) ............................................... +300°C NOTES: (1) Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade device reliability. These are stress ratings only, and functional operation of the device at these, or any other conditions beyond those specified, is not implied.
ELECTROSTATIC DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
PACKAGE/ORDERING INFORMATION(1)
PACKAGE DESIGNATOR DBZ SPECIFIED TEMPERATURE RANGE –40°C to +125°C PACKAGE MARKING R31A ORDERING NUMBER REF3112AIDBZT REF3112AIDBZR REF3120AIDBZT REF3120AIDBZR REF3125AIDBZT REF3125AIDBZR REF3130AIDBZT REF3130AIDBZR REF3133AIDBZT REF3133AIDBZR REF3140AIDBZT REF3140AIDBZR TRANSPORT MEDIA, QUANTITY Tape and Reel, 250 Tape and Reel, 3000 Tape and Reel, 250 Tape and Reel, 3000 Tape and Reel, 250 Tape and Reel, 3000 Tape and Reel, 250 Tape and Reel, 3000 Tape and Reel, 250 Tape and Reel, 3000 Tape and Reel, 250 Tape and Reel, 3000
PRODUCT REF3112
PACKAGE-LEAD SO T23-3
"
REF3120
"
SOT23-3
"
DBZ
"
–40°C to +125°C
"
R31B
"
REF3125
"
SOT23-3
"
DBZ
"
–40°C to +125°C
"
R31C
"
REF3130
"
SOT23-3
"
DBZ
"
–40°C to +125°C
"
R31E
"
REF3133
"
SOT23-3
"
DBZ
"
–40°C to +125°C
"
R31F
"
REF3140
"
SOT23-3
"
DBZ
"
–40°C to +125°C
"
R31D
"
"
"
"
"
NOTES: (1) For the most current package and ordering information, see the Package Option Addendum located at the end of this data sheet.
ELECTRICAL CHARACTERISTICS
Boldface limits apply over the specified temperature range, TA = –40°C to +125°C.
At TA = +25°C, ILOAD = 0mA, VIN = 5V, unless otherwise noted. REF31xx PARAMETER CONDITIONS MIN TYP MAX UNITS
REF3112(1) - 1.25V
OUTPUT VOLTAGE Initial Accuracy NOISE Output Voltage Noise Voltage Noise VOUT 1.2475 –0.2 f = 0.1Hz to 10Hz f = 10Hz to 10kHz 1.25 1.2525 0.2 V % µVPP µVrms
17 24
REF3120 – 2.048
OUTPUT VOLTAGE Initial Accuracy NOISE Output Voltage Noise Voltage Noise VOUT 2.0439 –0.2 f = 0.1Hz to 10Hz f = 10Hz to 10kHz 2.048 2.0521 0.2 V % µVPP µVrms
27 39
REF3125 – 2.5V
OUTPUT VOLTAGE Initial Accuracy NOISE Output Voltage Noise Voltage Noise VOUT 2.4950 –0.2 f = 0.1Hz to 10Hz f = 10Hz to 10kHz 2.50 2.5050 0.2 V % µVPP µVrms
33 48
2
REF3112, 3120, 3125, 3130, 3133, 3140
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SBVS046A
ELECTRICAL CHARACTERISTICS
Boldface limits apply over the specified temperature range, TA = –40°C to +125°C.
At TA = +25°C, ILOAD = 0mA, VIN = +5V, unless otherwise noted. REF31xx PARAMETER CONDITIONS MIN TYP MAX UNITS
REF3130 – 3.0V
OUTPUT VOLTAGE Initial Accuracy NOISE Output Voltage Noise Voltage Noise VOUT 2.9940 –0.2 f = 0.1Hz to 10Hz f = 10Hz to 10kHz 3.0 3.0060 0.2 V % µVPP µVrms
39 57
REF3133 – 3.3V
OUTPUT VOLTAGE Initial Accuracy NOISE Output Voltage Noise Voltage Noise VOUT 3.2934 –0.2 f = 0.1Hz to 10Hz f = 10Hz to 10kHz 3.30 3.3066 0.2 V % µVPP µVrms
43 63
REF3140 – 4.096V
OUTPUT VOLTAGE Initial Accuracy NOISE Output Voltage Noise Voltage Noise VOUT 4.0878 –0.2 f = 0.1Hz to 10Hz f = 10Hz to 10kHz 4.096 4.1042 0.2 V % µVPP µVrms
53 78
REF3112, REF3120, REF3125, REF3130, REF3133, REF3140
OUTPUT VOLTAGE TEMP DRIFT(2) dVOUT/dT 0°C ≤ TA ≤ +70°C –40°C ≤ TA ≤ +125°C 0-1000h VREF + 0.05(1) ≤ VIN ≤ 5.5V dVOUT/dILOAD 0mA < ILOAD < 10mA, VIN = VREF + 250mV(1) –10mA < ILOAD < 0mA, VIN = VREF + 100mV(1) dT 100 25 VIN – VOUT ILOAD ISC 50 40 to 0.1% at VIN = +5V with CL = 0 IL = 0 VS IQ VREF + 0.05(1) 100 115 –40 –55 –65 5.5 115 135 +125 +135 +150 336 V µA µA °C °C °C °C/W 400 mA mA µs –10 5 50 10 ppm ppm mV mA 10 20 30 50 5 10 15 20 ppm/°C ppm/°C ppm ppm/V µV/mA µV/mA
LONG-TERM STABILITY LINE REGULATION LOAD REGULATION(3) Sourcing Sinking THERMAL HYSTERESIS(4) First Cycle Additional Cycles DROPOUT VOLTAGE(1) OUTPUT CURRENT SHORT-CIRCUIT CURRENT Sourcing Sinking TURN-ON SETTLING TIME POWER SUPPLY Voltage Quiescent Current Over Temperature TEMPERATURE RANGE Specified Range Operating Range Storage Range Thermal Resistance SOT23-3 Surface-Mount NOTES: (1) (2) (3) (4) (5) 70 20 65
θJA
Minimum supply voltage for REF3112 is 1.8V. Box Method used to determine temperature drift. Typical value of load regulation reflects measurements using force and sense contacts, see section Load Regulation. Thermal hysteresis is explained in more detail in Applications Information section of data sheet. For IL > 0, see Typical Characteristic curves.
REF3112, 3120, 3125, 3130, 3133, 3140
SBVS046A
3
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TYPICAL CHARACTERISTICS
At TA = +25°C, VIN = +5V power supply, REF3125 is used for typical characteristics, unless otherwise noted.
TEMPERATURE DRIFT (0°C to +70°C) 18 16 25
TEMPERATURE DRIFT (–40°C to +125°C)
Percentage of Units
12 10 8 6 4 2 0 0 1 2 3 4 5 6 8 9 10 11 12 13 14 15 16 Drift (ppm/°C)
Percentage of Units
14
20
15
10
5
0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Drift (ppm/°C)
OUTPUT VOLTAGE vs TEMPERATURE 0.16 0.14
Dropout Voltage (mV)
120 100 80 60 40 20 0
DROPOUT VOLTAGE vs LOAD CURRENT
0.12
Output Drift (%)
0.10 0.08 0.06 0.04 0.02 0 −0.02 −0.04 −60 −40 −20 0 20 40 60 80 100 120 140
–15
–10
–5
0
5
10
15
Temperature (°C)
Load Current (mA)
QUIESCENT CURRENT vs TEMPERATURE 120 100
OUTPUT IMPEDANCE vs FREQUENCY 100
Quiescent Current (µA)
Output Resistance (Ω)
–60 –40 –20 0 20 40 60 80 100 120 140
10
80 60 40 20 0 Temperature (°C)
1
0.1
0.01 1 10 100 1k Frequency (Hz) 10k 100k 1M
4
REF3112, 3120, 3125, 3130, 3133, 3140
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SBVS046A
TYPICAL CHARACTERISTICS (Cont.)
At TA = +25°C, VIN = +5V power supply, REF3125 is used for typical characteristics, unless otherwise noted.
PSRR vs FREQUENCY 90 2.505 2.504 2.503 +125°C
OUTPUT vs SUPPLY
Power-Supply Rejection Ratio (dB)
80 70
Output (V)
60 50 40 30 20 10 0 1 10 100 1k 10k 100k Frequency (Hz)
2.502 2.501 2.500 2.499 2.498 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 Supply (V) +25°C −40°C
OUTPUT VOLTAGE vs LOAD CURRENT 2.505 2.504 Output Voltage (V) 2.503 2.502 2.501 2.500 2.499 2.498 2.497 –15 –10 –5 0 5 10 15 +25°C −40°C
1V/div
STEP RESPONSE, CL = 0, 5V STARTUP
+125°C
5V/div
VIN
VOUT
100µs/div
Load Current (mA)
0.1Hz TO 10Hz NOISE 20 0 –20 Drift (ppm) 10µV/div –40 –60 –80 –100 –120 400ms/div 0
REF3112 LONG TERM STABILITY
100 200 300 400
500
600 700 800 900 1000
Time (Hrs)
REF3112, 3120, 3125, 3130, 3133, 3140
SBVS046A
5
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TYPICAL CHARACTERISTICS (Cont.)
At TA = +25°C, VIN = +5V power supply, REF3125 is used for typical characteristics, unless otherwise noted.
LINE TRANSIENT CL = 0pF 500mV/div 500mV/div
LINE TRANSIENT CL = 10µF
VIN
VIN
20mV/div
VOUT 20mV/div 20µs/div VOUT
100µs/div
LOAD TRANSIENT CL = 0pF, ±10mA OUTPUT PULSE VIN +10mA –10mA 200mV/div VOUT +10mA VIN
LOAD TRANSIENT CL = 1µF, ±10mA OUTPUT PULSE +10mA –10mA +10mA
50mV/div
VOUT
40µs/div
40µs/div
LOAD TRANSIENT CL = 0pF, ±1mA OUTPUT PULSE VIN +1mA –1mA VOUT
100mV/div
LOAD TRANSIENT CL = 1µF, ±1mA OUTPUT PULSE VIN +1mA –1mA 20mV/div +1mA
+1mA
VOUT
40µs/div
40µs/div
6
REF3112, 3120, 3125, 3130, 3133, 3140
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SBVS046A
THEORY OF OPERATION
The REF31xx is a family of series, CMOS, precision bandgap voltage references. The basic bandgap topology is shown in Figure 1. Transistors Q1 and Q2 are biased such that the current density of Q1 is greater than that of Q2. The difference of the two base-emitter voltages, Vbe1 – Vbe2, has a positive temperature coefficient and is forced across resistor R1. This voltage is gained up and added to the base-emitter voltage of Q2, which has a negative temperature coefficient. The resulting output voltage is virtually independent of temperature.
100µA, and the maximum quiescent current over temperature is just 135µA. The quiescent current typically changes less than 2µA over the entire supply range, as shown in Figure 3.
QUIESCENT CURRENT vs POWER SUPPLY 100.5
Quiescent Current (µA)
100.0
99.5
99.0
98.5
VBANDGAP R1
98.0 1.5 2.5 3.5 Power Supply (V) 4.5 5.5
+ + Vbe1 Vbe2
– –
Q1 I
N Q2
FIGURE 3. Supply Current vs Supply Voltage. Supply voltages below the specified levels can cause the REF31xx to momentarily draw currents greater than the typical quiescent current. This can be prevented by using a power supply with a fast rising edge and low output impedance.
FIGURE 1. Simplified Schematic of Bandgap Reference.
APPLICATION INFORMATION
The REF31xx does not require a load capacitor and is stable with any capacitive load. Figure 2 shows typical connections required for operation of the REF31xx. A supply bypass capacitor of 0.47µF is recommended.
THERMAL HYSTERESIS
Thermal hysteresis for the REF31xx is defined as the change in output voltage after operating the device at 25°C, cycling the device through the specified temperature range, and returning to 25°C. It can be expressed as:
abs VPRE – VPOST 6 VHYST = • 10 (ppm) VNOM
VIN
1 0.47µF REF31xx 3
Where: VHYST = Thermal hysteresis VPRE = Output voltage measured at 25°C pretemperature cycling VPOST = Output voltage measured after the device has been cycled through the specified temperature range of –40°C to +125°C and returned to 25°C.
VOUT
2
FIGURE 2. Typical Connections for Operating REF31xx.
TEMPERATURE DRIFT
The REF31xx is designed to exhibit minimal drift error, defined as the change in output voltage over varying temperature. The drift is calculated using the “box” method which is described by the following equation:
SUPPLY VOLTAGE
The REF31xx family of references features an extremely low dropout voltage. With the exception of the REF3112, which has a minimum supply requirement of 1.8V, these references can be operated with a supply of only 5mV above the output voltage in an unloaded condition. For loaded conditions, a typical dropout voltage versus load is shown in the typical curves. The REF31xx features a low quiescent current, which is extremely stable over changes in both temperature and supply. The typical room temperature quiescent current is
VOUTMAX – VOUTMIN • 10 6 ppm V • TemperatureRange OUT
The REF31xx features a typical drift coefficient of 5ppm from 0°C to 70°C—the primary temperature range for many applications. For the industrial temperature range of –40°C to 125°C, the REF31xx family drift increases to a typical value of 10ppm.
REF3112, 3120, 3125, 3130, 3133, 3140
SBVS046A
7
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NOISE PERFORMANCE
Typical 0.1Hz to 10Hz voltage noise can be seen in the Typical Characteristic Curve, 0.1 to 10Hz Voltage Noise. The noise voltage of the REF31xx increases with output voltage and operating temperature. Additional filtering may be used to improve output noise levels, although care should be taken to ensure the output impedance does not degrade the AC performance. LONG-TERM STABILITY Long-term stability refers to the change of the output voltage of a reference over a period of months or years. This effect lessens as time progresses, as is shown by the long-term stability curves. The typical drift value for the REF31xx is 70ppm from 0-1000 hours. This parameter is characterized by measuring 30 units at regular intervals for a period of 1000 hours. LOAD REGULATION Load regulation is defined as the change in output voltage due to changes in load current. The load regulation of the REF31xx is measured using force and sense contacts as pictured in Figure 4. The force and sense lines reduce the impact of contact and trace resistance, resulting in accurate measurement of the load regulation contributed solely by the REF31xx. For applications requiring improved load regulation, force and sense lines should be used.
APPLICATION CIRCUITS
Negative Reference Voltage
For applications requiring a negative and positive reference voltage, the REF31xx and OPA703 can be used to provide a dual supply reference from a ±5V supply. Figure 5 shows the REF3125 used to provide a ±2.5V supply reference voltage. The low drift performance of the REF31xx complement the low offset voltage and low drift of the OPA703 to provide an accurate solution for split-supply applications.
+5V
REF3125 10kΩ
+2.5V
10kΩ +5V
OPA703
–2.5V
–5V
FIGURE 5. REF3125 Combined with OPA703 to Create Positive and Negative Reference Voltages.
Output Pin Contact and Trace Resistance + VOUT – Sense Line Force Line IL Load Meter
DATA ACQUISITION
Data acquisition systems often require stable voltage references to maintain accuracy. The REF31xx family features stability and a wide range of voltages suitable for most microcontrollers and data converters. Figure 6, Figure 7, and Figure 8 show basic data acquisition systems.
FIGURE 4. Accurate Load Regulation of REF31xx.
8
REF3112, 3120, 3125, 3130, 3133, 3140
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SBVS046A
3.3V 5Ω
REF3133
V+
+ 1µF to 10µF ADS7822 VREF 0.1µF VIN +In –In GND CS DOUT DCLOCK VCC + VS
GND
1µF to 10µF Microcontroller
FIGURE 6. Basic Data Acquisition System 1.
2.5V Supply
2.5V VIN ADS8324 REF3112 VOUT = 1.25V 0.1µF GND 0V to 1.25V +In –In GND CS DOUT DCLOCK VREF VCC +
5Ω + VS 1µF to 10µF
1µF to 10µF Microcontroller
FIGURE 7. Basic Data Acquisition System 2.
5V REF3140 0.1µF VOUT = 4.096V 1kΩ +5V 1kΩ VIN THS4031 6800pF 0.22µF 500Ω –5V 10Ω 10Ω 22µF VREF ADS8381 1µF
FIGURE 8. REF3140 Provides an Accurate Reference for Driving the ADS8381.
REF3112, 3120, 3125, 3130, 3133, 3140
SBVS046A
9
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MECHANICAL DATA
MPDS108 – AUGUST 2001
DBZ (R-PDSO-G3)
PLASTIC SMALL-OUTLINE
3,04 2,80 2,05 1,78 1,03 0,89 0,60 0,45
1,40 1,20
2,64 2,10
0,51 0,37
1,12 0,89 0,100 0,013 0,55 REF 0,180 0,085
4203227/A 08/01 NOTES: A. B. C. D. All linear dimensions are in millimeters. This drawing is subject to change without notice. Dimensions are inclusive of plating. Dimensions are exclusive of mold flash and metal burr.
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