Not Recommended For
New Designs
REF3212-EP, REF3220-EP, REF3225-EP
REF3230-EP, REF3233-EP, REF3240-EP
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4 ppm/°C, 100 μA SOT23-6 SERIES VOLTAGE REFERENCES
Check for Samples: REF3212-EP, REF3220-EP, REF3225-EP, REF3230-EP, REF3233-EP, REF3240-EP
FEATURES
APPLICATIONS
•
•
•
•
•
1
•
•
•
•
•
Excellent Specified Drift Performance:
– 7ppm/°C (Max) at 0°C to 125°C
– 20ppm/°C (Max) at –40°C to 125°C
– 40ppm/°C (Max) at –55°C to 125°C
Microsize Package: SOT23-6
High Output Current: ±10 mA
High Accuracy: 0.01%
Low Quiescent Current: 100 μA
Low Dropout: 5 mV
Portable Equipment
Data Acquisition Systems
Medical Equipment
Test Equipment
GND_F
1
GND_S
2
ENABLE
3
REF3212
REF3220
REF3225
REF3230
REF3233
REF3240
6
OUT_F
5
OUT_S
4
IN
SUPPORTS DEFENSE, AEROSPACE,
AND MEDICAL APPLICATIONS
•
•
•
•
•
•
•
(1)
Controlled Baseline
One Assembly/Test Site
One Fabrication Site
Available in Military (–55°C/125°C)
Temperature Range (1)
Extended Product Life Cycle
Extended Product-Change Notification
Product Traceability
Additional temperature ranges are available - contact factory
TEMPERATURE DRIFT
(0_C to +125_C)
DROPOUT VOLTAGE
vs LOAD CURRENT
160
+125_C
Population
Dropout Voltage (mV)
140
+25_ C
120
100
−40_C
80
60
40
20
0
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7
Drift (ppm/_C)
−15
−10
−5
0
5
10
15
Load Current (mA)
1
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.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2006–2011, Texas Instruments Incorporated
REF3212-EP, REF3220-EP, REF3225-EP
REF3230-EP, REF3233-EP, REF3240-EP
Not Recommended For
New Designs
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DESCRIPTION
The REF32xx is a very low drift, micropower, low-dropout, precision voltage reference family available in the tiny
SOT23-6 package.
The small size and low power consumption (120 μA max) of the REF32xx make it ideal for portable and
battery-powered applications. This reference is stable with most capacitive loads.
The REF32xx can be operated from a supply as low as 5 mV above the output voltage, under no load conditions.
All models are specified for the wide temperature range of –55°C to 125°C.
AVAILABLE OUTPUT VOLTAGES
PRODUCT
VOLTAGE
REF3212
1.25 V
REF3220
2.048 V
REF3225
2.5 V
REF3230
3V
REF3233
3.3 V
REF3240
4.096 V
Table 1. PACKAGE/ORDERING INFORMATION (1)
(1)
(2)
2
PRODUCT
OUTPUT VOLTAGE
PACKAGE-LEAD
PACKAGE DESIGNATOR (2)
PACKAGE MARKING
REF3212AMDBVREP
1.25 V
SOT23-6
DBV
R3AM
REF3220AMDBVREP
2.048 V
SOT23-6
DBV
R3BM
REF3225AMDBVREP
2.5 V
SOT23-6
DBV
R3CM
REF3230AMDBVREP
3V
SOT23-6
DBV
R3DM
REF3233AMDBVREP
3.3 V
SOT23-6
DBV
R3EM
REF3240AMDBVREP
4.096 V
SOT23-6
DBV
R3FM
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
website at www.ti.com.
Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
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REF3212-EP,
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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.
Figure 1. PIN CONFIGURATION
SOT23-6
(TOP VIEW)
1
GND_S
2
ENABLE
3
R3 2 x
A.
GND_F
6 OUT_F
5 OUT_S
4 IN
The location of pin 1 on the REF32xx is determined by orienting the package marking as shown.
PIN DESCRIPTIONS
PIN
NO.
FUNCTION
ENABLE
NAME
3
Digital input
DESCRIPTION
GND_F
1
Analog output
GND_S
2
Analog input
Ground sense at the load
IN
4
Analog input
Positive supply voltage
OUT_F
6
Analog output
Output of Reference Voltage
OUT_S
5
Analog input
Sense connection at the load
This pin enables and disables the device
Ground connection of the device
Absolute Maximum Ratings (1)
MIN
Input voltage
Output short-circuit
Storage temperature range
Junction temperature
(2)
7.5
V
–55
125
°C
–65
(2)
°C
150
°C
150
Human-Body Model
4
Charged-Device Model
1
Machine Model
(1)
UNIT
Continuous
Operating temperature range
ESD rating
MAX
400
kV
V
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.
Long-term high-temperature storage and/or extended use at maximum recommended operating conditions may result in a reduction of
overall device life. See http://www.ti.com/ep_quality for additional information on enhanced plastic packaging.
Copyright © 2006–2011, Texas Instruments Incorporated
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REF3230-EP, REF3233-EP, REF3240-EP
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Electrical Characteristics
Boldface limits apply over the listed temperature range.
TA = 25°C, ILOAD = 0 mA, and VIN = 5 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
REF3212 (1.25 V)
VOUT
Noise
Output voltage
1.2475
1.25
1.2525
V
Initial accuracy
–0.2
0.01
0.2
%
Output voltage noise
f = 0.1 Hz to 10 Hz
17
μVPP
Voltage noise
f = 10 Hz to 10 kHz
24
μVRMS
REF3220 (2.048 V)
Output
voltage
VOUT
Initial
accuracy
Output
voltage noise
Noise
2.044
2.048
2.052
V
–0.2
0.01
0.2
%
f = 0.1 Hz to 10 Hz
27
μVPP
Voltage noise f = 10 Hz to 10 kHz
39
μVRMS
REF3225 (2.5 V)
VOUT
Noise
Output voltage
Initial accuracy
2.495
2.5
2.505
–0.2
0.01
0.2
V
%
Output voltage noise
f = 0.1 Hz to 10 Hz
33
μVPP
Voltage noise
f = 10 Hz to 10 kHz
48
μVRMS
REF3230 (3 V)
VOUT
Noise
Output voltage
2.994
3
3.006
V
Initial accuracy
–0.2
0.01
0.2
%
Output voltage noise
f = 0.1 Hz to 10 Hz
39
μVPP
Voltage noise
f = 10 Hz to 10 kHz
57
μVRMS
REF3233 (3.3 V)
VOUT
Noise
Output voltage
Initial accuracy
3.293
3.3
3.307
–0.2
0.01
0.2
V
%
Output voltage noise
f = 0.1 Hz to 10 Hz
43
μVPP
Voltage noise
f = 10 Hz to 10 kHz
63
μVRMS
REF3240 (4.096 V)
VOUT
Noise
Output voltage
4.088
4.096
4.104
V
Initial accuracy
–0.2
0.01
0.2
%
Output voltage noise
f = 0.1 Hz to 10 Hz
53
μVPP
Voltage noise
f = 10 Hz to 10 kHz
78
μVRMS
REF3212/REF3220/REF3225/REF3230/REF3233/REF3240
dVOUT/dT Output voltage temperature drift
0 tp 1000 h
Line regulation
VOUT + 0.05 (1) ≤ VIN ≤ 5.5 V
Load
regulation (2)
dT
Thermal
hysteresis (3)
VIN –
VOUT
Dropout voltage (1)
4
–55°C ≤ TA ≤ 125°C
Long-term stability
dVOUT/
dILOAD
(1)
(2)
(3)
TA = 25°C
4
7
10.5
40
55
–65
15
ppm
65
Sourcing
0 mA < ILOAD < 10 mA, VIN = VOUT + 250 mV (1)
–40
3
40
Sinking
–10 mA < ILOAD < 0 mA, VIN = VOUT + 100 mV (1)
–60
20
60
First cycle
100
Additional
cycles
25
25°C ≤ TA ≤ +125°C
5
ppm/°C
ppm/V
μV/mA
ppm
50
mV
The minimum supply voltage for the REF3212 is 1.8 V.
Load regulation is using force and sense lines; see the Load Regulation section for more information.
Thermal hysteresis procedure is explained in more detail in the Applications Information section.
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REF3212-EP,
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REF3220-EP, REF3225-EP
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Electrical Characteristics (continued)
Boldface limits apply over the listed temperature range.
TA = 25°C, ILOAD = 0 mA, and VIN = 5 V (unless otherwise noted)
PARAMETER
ILOAD
Output current
ISC
Short-circuit
current
TEST CONDITIONS
50
40
VIN
Power supply Voltage
IQ
Power supply Current
IS
Temperature
range
θJA
(4)
0.1% at VIN = 5 V with CL = 0
Reference is active
IL = 0
UNIT
mA
mA
μs
60
Reference in shutdown mode
Overtemperature shutdown
MAX
10
Sinking
Enable/shutdown (4)
VH
TYP
–10
Sourcing
Turn-on settling time
VL
MIN
VIN = VOUT + 250 mV (1)
0
0.7
1.5
VIN
VOUT +
0.05 (1)
5.5
V
V
IL = 0, ENABLE > 1.5 V
100
120
μA
–55°C ≤ TA ≤ 125°C
115
135
μA
ENABLE < 0.7 V
0.1
1
μA
Specified
–55
125
Operating
–55
125
Storage
–65
Thermal resistance, SOT23-6
°C
150
200
°C/W
If the rise time of the input voltage is less than or equal to 2ms, the ENABLE and IN pins can be tied together. For rise times greater
than 2ms, see the Supply Voltage section.
Figure 2. Operating Life Derating Chart
10000.00
Years Estimated Life
1000.00
Wirebond Voiding
Fail Mode
100.00
10.00
1.00
0.10
80
Electromigration
Fail Mode
90
100 110 120 130 140 150 160
Continuuous TJ (5C)
A.
See Datasheet for Absolute Maximum and Minimum Recommended Operating Conditions.
B.
Silicon Operating Life Design Goal is 10 years at 105°C Junction Temperature (does not include package
interconnect life).
C.
Enhanced Plastic Product Disclaimer Applies.
Copyright © 2006–2011, Texas Instruments Incorporated
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REF3230-EP, REF3233-EP, REF3240-EP
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TYPICAL CHARACTERISTICS
TA = 25°C, ILOAD = 0 mA, VIN = 5 V power supply, REF3225 is used for typical characteristics (unless otherwise noted)
Population
TEMPERATURE DRIFT
(−40_ C to +125_ C)
Population
TEMPERATURE DRIFT
(0_C to +125_C)
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Drift (ppm/_C)
Drift (ppm/_C)
OUTPUT VOLTAGE ACCURACY
vs TEMPERATURE
DROPOUT VOLTAGE
vs LOAD CURRENT
0.12
160
0.08
Dropout Voltage (mV)
Output Voltage Accuracy (%)
+125_C
140
0.04
0
−0.04
−0.08
−0.12
−50
+25_ C
120
100
−40_C
80
60
40
20
0
−25
0
+25
+50
+75
+100
+125
−15
−10
Temperature (°C )
−5
0
5
10
15
Load Current (mA)
QUIESCENT CURRENT
vs TEMPERATURE
POWER−SUPPLY REJECTION RATIO
vs FREQUENCY
100
130
90
80
70
110
PSRR (dB)
Quiescent Current (µA)
120
100
50
40
90
30
80
70
20
10
−50
−25
0
+25
+50
Temperature (_ C)
6
60
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+75
+100
+125
1
10
100
1k
10k
100k
Frequency (Hz)
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REF3212-EP,
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REF3230-EP, REF3233-EP, REF3240-EP
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TYPICAL CHARACTERISTICS (continued)
TA = 25°C, ILOAD = 0 mA, VIN = 5 V power supply, REF3225 is used for typical characteristics (unless otherwise noted)
OUTPUT VOLTAGE
vs LOAD CURRENT
1.2525
2.505
1.2520
2.504
1.2515
2.503
Output Voltage (V)
1.2510
1.2505
+125_C
1.2500
+25_ C
1.2495
1.2490
−40_ C
1.2485
2.502
2.501
+125_ C
2.500
+25_ C
2.499
2.498
−40_ C
2.497
2.496
1.2480
2.495
1.2475
2
2.5
3
3.5
4
4.5
−15
5
−10
−5
Input Voltage (V)
0
5
10
15
Load Current (mA)
0.1Hz TO 10Hz
NOISE
0.20
0.16
0.12
0.08
0.04
−0.08
−0.12
−0.20
400ms/div
−0.16
10µV/div
Population
OUTPUT VOLTAGE
INITIAL ACCURACY
0
1.5
−0.04
Output Voltage (V)
OUTPUT VOLTAGE vs INPUT VOLTAGE
(REF3212)
Output Accuracy (%)
STEP RESPONSE
CL = 0pF, 5V STARTUP
STEP RESPONSE
CL = 1µF
VIN
VIN
1V/div
1V/div
VOUT
VOUT
10µs/div
Copyright © 2006–2011, Texas Instruments Incorporated
100µs/div
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TYPICAL CHARACTERISTICS (continued)
TA = 25°C, ILOAD = 0 mA, VIN = 5 V power supply, REF3225 is used for typical characteristics (unless otherwise noted)
500mV/div
LINE TRANSIENT
CL = 10µF
VIN
VIN
VOUT
20mV/div
20mV/div
500mV/div
LINE TRANSIENT
CL = 0pF
ILOAD
VOUT
20µs/div
100µs/div
LOAD TRANSIENT
CL = 0pF, ±10mA OUTPUT PULSE
LOAD TRANSIENT
CL = 1µF, ±10mA OUTPUT PULSE
+10mA
ILOAD
+10mA
+10mA
+10mA
−10mA
−10mA
50mV/div
200mV/div
VOUT
ILOAD
VOUT
40µs/div
40µs/div
LOAD TRANSIENT
CL = 0pF, ±1mA OUTPUT PULSE
LOAD TRANSIENT
CL = 1µF, ±1mA OUTPUT PULSE
ILOAD
+1mA
+1mA
−1mA
+1mA
+1mA
−1mA
20mV/div
100mV/div
VOUT
40µs/div
8
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VOUT
40µs/div
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TYPICAL CHARACTERISTICS (continued)
TA = 25°C, ILOAD = 0 mA, VIN = 5 V power supply, REF3225 is used for typical characteristics (unless otherwise noted)
LONG−TERM STABILITY
(32 Units)
Output Voltage Stability (ppm)
200
150
100
50
0
−50
−100
−150
−200
0
200
400
600
800
1000
1200
Time (Hours)
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THEORY OF OPERATION
The REF32xx is a family of CMOS, precision bandgap voltage references. Figure 3 shows the basic bandgap
topology. Transistors Q1 and Q2 are biased so 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 amplified and added to the base-emitter voltage of Q2, which has a negative
temperature coefficient. The resulting output voltage is virtually independent of temperature.
VBANDGAP
Q1 I
+
Vbe1
-
R1
+
Vbe2
N Q2
Figure 3. Simplified Schematic of Bandgap Reference
10
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APPLICATION INFORMATION
The REF32xx does not require a load capacitor and is stable with most capacitive loads, see Load Capacitance
Guidelines. Figure 4 shows typical connections required for operation of the REF32xx. A supply bypass capacitor
of 0.47 μF is recommended.
0.47 µF
2
3
+5 V
+2.5 V
6
R 3 CM
1
5
4
Figure 4. Typical Operating Connections for the REF3225
Supply Voltage
The REF32xx family of references features an extremely low dropout voltage. With the exception of the
REF3212, which has a minimum supply requirement of 1.8 V, these references can be operated with a supply of
only 5 mV above the output voltage in an unloaded condition. For loaded conditions, a typical dropout voltage
versus load is shown in the Typical Characteristic curves.
The REF32xx also features a low quiescent current of 100 μA, with a maximum quiescent current over
temperature of just 135 μA. The quiescent current typically changes less than 2 μA over the entire supply range,
as shown in Figure 5.
110
Quiescent Current (µA)
108
106
104
102
100
98
96
94
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Power Supply (V)
Figure 5. Supply Current vs Supply Voltage
Supply voltages below the specified levels can cause the REF32xx to momentarily draw currents greater than
the typical quiescent current. This momentary current draw can be prevented by using a power supply with a fast
rising edge and low output impedance.
For optimal startup when the IN pin and ENABLE pin are tied together, keep the input voltage rise time less than
or equal to 2ms. For rise times greater than 2ms, the ENABLE pin must be kept below 0.7V until the voltage at
the IN pin has reached the minimum operating voltage. One way to control the voltage at the ENABLE pin is with
an additional RC filter, such as that shown in Figure 6. The RC filter must hold the voltage at the ENABLE pin
below the threshold voltage until the voltage at the input pin has reached the minimum operating voltage.
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1
6
2
5
3
4
VREF
VIN
R1
C1
Figure 6. Application Circuit to Control the REF32xx ENABLE Pin
The RC filter in Figure 6 can be used as a starting point for the REF3240. The values for R1 and C1 have been
calculated so that the voltage at the ENABLE pin reaches 0.7V after the input voltage has reached 4.15V;
Table 2 lists these values. For output voltage options other than 4.096V, the RC filter can be made faster.
Table 2. Recommended R1 and C1 Values for the REF3240
RISE TIME
R1 VALUE
C1 VALUE
2ms
150kΩ
100nF
5ms
150kΩ
220nF
10ms
330kΩ
220nF
20ms
390kΩ
330nF
50ms
680kΩ
470nF
100ms
680kΩ
1000nF
In this document, rise time is defined as the time until an exponential input signal reaches 90% of its final
voltage. For example, the 2ms value shown in Table 2 is valid for an end value of 5V.
If the input voltage has a different shape or the end value is not 5V, then the time until the minimum dropout
voltage has been reached should be used to decide if the IN and ENABLE pins can be tied together. Table 3 lists
these times.
Table 3. Minimum Dropout Voltage Times
DEVICE
TIME
REF3212
0.4ms
REF3220
0.5ms
REF3225
0.7ms
REF3230
0.9ms
REF3233
1.0ms
REF3240
1.6ms
Note that because the leakage current of the EN pin is in the range of a few nA, it can be disregarded in most
applications.
12
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REF3220-EP, REF3225-EP
REF3230-EP, REF3233-EP, REF3240-EP
SBVS078B – OCTOBER 2006 – REVISED AUGUST 2011
www.ti.com
Shutdown
The REF32xx can be placed in a low-power mode by pulling the ENABLE/SHUTDOWN pin low. When in
shutdown mode the output of the REF32xx becomes a resistive load to ground. The value of the load depends
on the model, and ranges from approximately 100 kΩ to 400 kΩ.
The ENABLE pin must always be driven to a valid voltage level (VL or VH) as shown in the Electrical
Characteristics section of this datasheet. To maintain the low quiescent current (100 μA typ), the ENABLE pin
was designed without an internal pull-up resistor. In applications where the shutdown feature will not be used,
connecting the ENABLE pin high (to the IN pin) will ensure enabled operation of the device.
Thermal Hysteresis
Thermal hysteresis for the REF32xx 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:
ŤVPRE * V
Ť
POST
V HYST +
106(ppm)
VNOM
(1)
ǒ
Ǔ
Where:
VHYST = Thermal hysteresis (in units of ppm)
VNOM = The specified output voltage
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
Temperature Drift
The REF32xx is designed to exhibit minimal drift error, which is defined as the change in output voltage over
varying temperature. The drift is calculated using the box method, as described by the following equation:
Drift +
ǒV V
OUT
Ǔ
* V OUTMIN
Temp Range
OUTMAX
106(ppm)
(2)
The REF32xx features a typical drift coefficient of 4 ppm/°C from 0°C to 125°C — the primary temperature range
for many applications. For the extended temperature range of –55°C to 125°C, the REF32xx family drift
increases to a typical value of 10.5 ppm/°C.
Noise Performance
Typical 0.1-Hz to 10-Hz voltage noise can be seen in the Typical Characteristic curve, 0.1-Hz to 10-Hz Voltage
Noise. The noise voltage of the REF32xx increases with output voltage and operating temperature. Additional
filtering can be used to improve output noise levels, although care should be taken to ensure the output
impedance does not degrade 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 Typical Characteristic curves. The
typical drift value for the REF32xx is 55 ppm from 0 to 1000 hours. This parameter is characterized by measuring
30 units at regular intervals for a period of 1000 hours.
Copyright © 2006–2011, Texas Instruments Incorporated
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Product Folder Link(s): REF3212-EP, REF3220-EP, REF3225-EP REF3230-EP, REF3233-EP, REF3240-EP
13
REF3212-EP, REF3220-EP, REF3225-EP
REF3230-EP, REF3233-EP, REF3240-EP
Not Recommended For
New Designs
SBVS078B – OCTOBER 2006 – REVISED AUGUST 2011
www.ti.com
Load Regulation
Load regulation is defined as the change in output voltage as a result of changes in load current. The load
regulation of the REF32xx is measured using force and sense contacts, as shown in Figure 7. The force and
sense lines can be used to effectively eliminate the impact of contact and trace resistance, resulting in accurate
voltage at the load. By connecting the force and sense lines at the load, the REF32xx compensates for the
contact and trace resistances because it measures and adjusts the voltage actually delivered at the load.
Contact and Trace Resistance
GND_F
GND_S
ENABLE
1
6
2
REF32xx 5
3
4
OUT_F
OUT_S
IN
RLOAD
0.47 mF
+5 V
Figure 7. Accurate Load Regulation of REF32xx
The GND_S pin is connected to the internal ground of the device through ESD protection diodes. Because of
that connection, the maximum differential voltage between the GND_S and GND_F pins must be kept below
200mV to prevent these dioes from unintentionally turning on.
Load Capacitance Guidelines
The REF32xx series is designed to be stable with most capacitive loads. Common load capacitance values
range between 1 μF and 47 μF. To minimize noise and provide specified performance, all models will benefit
from an ESR value above 1 Ω with capacitive loads higher than 10 μF. However, the REF3212 must have an
ESR value above 1Ω with capacitive loads higher than 10 μF to avoid oscillation.
14
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Copyright © 2006–2011, Texas Instruments Incorporated
Product Folder Link(s): REF3212-EP, REF3220-EP, REF3225-EP REF3230-EP, REF3233-EP, REF3240-EP
Not Recommended For
REF3212-EP,
New Designs
REF3220-EP, REF3225-EP
REF3230-EP, REF3233-EP, REF3240-EP
SBVS078B – OCTOBER 2006 – REVISED AUGUST 2011
www.ti.com
APPLICATION CIRCUITS
Negative Reference Voltage
For applications requiring a negative and positive reference voltage, the REF32xx and OPA735 can be used to
provide a dual-supply reference from a 5-V supply. Figure 8 shows the REF3225 used to provide a 2.5-V supply
reference voltage. The low drift performance of the REF32xx complements the low offset voltage and zero drift of
the OPA735 to provide an accurate solution for split-supply applications. Care must be taken to match the
temperature coefficients of R1 and R2.
+5 V
3
4
5
REF3225
2
6
1
+2.5 V
R1
10 kW R
2
10 kW
+5 V
OPA735
-2.5 V
-5 V
Note: Bypass capacitor is not shown.
Figure 8. REF3225 Combined With OPA735 to Create Positive and Negative Reference Voltages
Data Acquisition
Data acquisition systems often require stable voltage references to maintain accuracy. The REF32xx family
features stability and a wide range of voltages suitable for most microcontrollers and data converters. Figure 9,
Figure 10, and Figure 11 show basic data acquisition systems.
5
3.3 V
6
3
REF3233
5W
VREF
VCC
VIN
+In
CS
-In
DOUT
+
+
1
V+
0.47 mF
GND
VS
ADS7822
0.1 mF
2
4
1 mF to 10 mF
1 mF to 10 mF
Microcontroller
GND DCLOCK
Figure 9. Basic Data Acquisition System 1
Copyright © 2006–2011, Texas Instruments Incorporated
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Product Folder Link(s): REF3212-EP, REF3220-EP, REF3225-EP REF3230-EP, REF3233-EP, REF3240-EP
15
REF3212-EP, REF3220-EP, REF3225-EP
REF3230-EP, REF3233-EP, REF3240-EP
Not Recommended For
New Designs
SBVS078B – OCTOBER 2006 – REVISED AUGUST 2011
www.ti.com
2.5 V Supply
2.5 V
3
5W
VIN
4
5
REF3212 6 VOUT = 1.25 V
2
VS
ADS8324
VREF
VCC
0.1 mF
1
GND
0 V to
1.25 V
+In
CS
-In
DOUT
+
+
1 mF to 10 mF
1 mF to 10 mF
Microcontroller
GND DCLOCK
Figure 10. Basic Data Acquisition System 2
+5 V
2
1
1 kW
REF3240
3
4
5 6
VOUT = 4.096 V
10 W
0.1 mF
1 mF
22 mF
+5 V
1 kW
VIN
VREF
10 W
ADS8381
THS4031
6800 pF
0.22 mF
500 W
-5 V
Figure 11. REF3240 Provides an Accurate Reference for Driving the ADS8381
16
Submit Documentation Feedback
Copyright © 2006–2011, Texas Instruments Incorporated
Product Folder Link(s): REF3212-EP, REF3220-EP, REF3225-EP REF3230-EP, REF3233-EP, REF3240-EP
Not Recommended For
REF3212-EP,
New Designs
REF3220-EP, REF3225-EP
REF3230-EP, REF3233-EP, REF3240-EP
SBVS078B – OCTOBER 2006 – REVISED AUGUST 2011
www.ti.com
Changes from Revision A (April 2007) to Revision B
Page
•
Added Pin Descriptions table ................................................................................................................................................ 3
•
Added note to Enable/Shutdown parameter ......................................................................................................................... 5
•
Changed the minimum voltage for Enable/Shutdown with reference active from 0.75 x VIN to 1.5 ..................................... 5
•
Changed current test condition from 0.75 x VIN to 1.5 V ...................................................................................................... 5
•
Added text, two tables and one figure to Supply Voltage section ...................................................................................... 11
•
Changed pin 3 in Figure 7 from SHDN to ENABLE (typo) ................................................................................................. 14
•
Added paragraph to Load Regulation section .................................................................................................................... 14
Copyright © 2006–2011, Texas Instruments Incorporated
Submit Documentation Feedback
Product Folder Link(s): REF3212-EP, REF3220-EP, REF3225-EP REF3230-EP, REF3233-EP, REF3240-EP
17
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
REF3212AMDBVREP
NRND
SOT-23
DBV
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-55 to 125
R3AM
REF3220AMDBVREP
NRND
SOT-23
DBV
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-55 to 125
R3BM
REF3225AMDBVREP
NRND
SOT-23
DBV
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-55 to 125
R3CM
REF3230AMDBVREP
NRND
SOT-23
DBV
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-55 to 125
R3DM
REF3240AMDBVREP
NRND
SOT-23
DBV
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-55 to 125
R3FM
V62/07602-01XE
NRND
SOT-23
DBV
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-55 to 125
R3AM
V62/07602-02XE
NRND
SOT-23
DBV
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-55 to 125
R3CM
V62/07602-03XE
NRND
SOT-23
DBV
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-55 to 125
R3DM
V62/07602-04XE
NRND
SOT-23
DBV
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-55 to 125
R3FM
V62/07602-05XE
NRND
SOT-23
DBV
6
3000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-55 to 125
R3BM
(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 substance
do 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 may
reference 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
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