ETC VRE310L

VRE302
Low Cost
Precision Reference
THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 85745 • (520) 882-4000
FEATURES
• 2.500 V OUTPUT ± 0.250 mV (.01%)
PIN CONFIGURATION
• TEMPERATURE DRIFT: 0.6 ppm/°C
• LOW NOISE: 1.5µV p-p (0.1-10Hz)
• INDUSTRY STD PINOUT- 8 PIN DIP OR
SURFACE MOUNT PACKAGE
N.C.
1
+VIN
2
TEMP
3
GND
4
VRE302
TOP
VIEW
8
NOISE
7
REF. GND
6
VOUT
5
TRIM
•EXCELLENT LINE REGULATION: 6ppm/V Typ.
• OUTPUT TRIM CAPABILITY
FIGURE 1
DESCRIPTION
The VRE302 is a low cost, high precision 2.5V
reference. Packaged in the industry standard 8
pin DIP, the device is ideal for upgrading systems
that use lower performance references.
The device provides ultrastable +2.500V output
with ±0.2500 mV (.01%) initial accuracy and a
temperature coefficient of 0.6 ppm/°C.
This
improvement in accuracy is made possible by a
unique, patented multipoint laser compensation
technique developed by Thaler Corporation.
Significant improvements have been made in
other performance parameters as well, including
initial accuracy, warm-up drift, line regulation, and
long-term stability, making the VRE302 series the
most accurate reference available in the standard
8 pin DIP package.
For enhanced performance, the VRE302 has an
external trim option for users who want less than
0.01% initial error. A reference ground pin is
provided to eliminate socket contact resistance
errors.
The VRE302 is recommended for use as a
reference for 14, 16, or 18 bit D/A converters
which require an external precision reference.
The device is also ideal for calibrating scale factor
on high resolution A/D converters. The VRE302
offers superior performance over monolithic
references.
SELECTION GUIDE
Model
Initial
Error
mV
VRE302A
VRE302B
VRE302C
VRE302J
VRE302K
VRE302L
0.25
0.40
0.50
0.25
0.40
0.50
Temp.
Coeff.
ppm/°C
0.6
1.0
2.0
0.6
1.0
2.0
Temp.
Range
°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
For package option add D for DIP or S for Surface Mount
to end of model number.
VRE302DS REV. F MAY 2001
ELECTRICAL SPECIFICATIONS
VRE302
Vps =+15V, T = 25°C, RL = 10KΩ unless otherwise noted.
MODEL
A/J
PARAMETER
MIN
TYP
B/K
MAX
C/L
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
°C
°C
°C
ABSOLUTE RATINGS
Power Supply
Operating Temp. (A,B,C)
Operating Temp. (J,K,L)
Storage Temperature
Short Circuit Protection
+13.5 +15
+22
0
+70
-40
+85
-65
+150
Continuous
*
*
*
*
*
*
OUTPUT VOLTAGE
VRE302
(1)
Temp. Sensor Voltage
2.500
630
V
mV
OUTPUT VOLTAGE ERRORS
(2)
Initial Error
Warmup Drift
Tmin - Tmax (3)
Long-Term Stability
Noise (.1-10Hz) (4)
0.25
0.40
1
0.50
2
0.6
3
1.0
6
1.5
2.0
*
*
*
*
mV
ppm
ppm/°C
ppm/1000hrs
µVpp
OUTPUT CURRENT
Range
±10
*
*
mA
REGULATION
Line
Load
6
3
10
*
*
*
*
*
*
ppm/V
ppm/mA
OUTPUT ADJUSTMENT
Range
10
POWER SUPPLY CURRENTS
*
mV
(5)
VRE302 +PS
NOTES:
*
5
7
*Same as A/J Models.
1. The temp. reference TC is 2.1mV/ °C
2. The specified values are without external trim.
*
*
*
*
mA
4. The specified values are without the external
noise reduction capacitor.
5. The specified values are unloaded.
3. The temperature coefficient is determined by the box
method using the following formula:
Vmax - Vmin
x 106
T.C. =
Vnominal x (Tmax-Tmin)
VRE302DS REV. F MAY 2001
TYPICAL PERFORMANCE CURVES
VOUT vs. TEMPERATURE
Temperature oC
VRE302A
VOUT vs. TEMPERATURE
Temperature oC
VRE302J
VOUT vs. TEMPERATURE
VOUT vs. TEMPERATURE
Temperature oC
VRE302B
Temperature oC
VRE302C
VOUT vs. TEMPERATURE
VOUT vs. TEMPERATURE
Temperature oC
VRE302K
Temperature oC
VRE302L
POSITIVE OUTPUT (TYP)
QUIESCENT CURRENT VS. TEMP JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Temperature oC
Output Current (mA)
PSRR VS. FREQUENCY
Frequency
(Hz)
VRE302DS REV. F MAY 2001
DISCUSSION OF PERFORMANCE
THEORY OF OPERATION
The following discussion refers to the schematic in
figure 2 below. A FET current source is used to bias a
6.3V zener diode. The zener voltage is divided by the
resistor network R1 and R2. This voltage is then applied
to the noninverting input of the operational amplifier which
amplifies the voltage to produce a 2.500V output. The
gain is determined by the resistor networks R3 and R4:
G=1 + R4/R3. The 6.3V zener diode is used because it is
the most stable diode over time and temperature.
This network is less than 2% of the overall network
resistance so it has a negligible effect on long term
stability.
Figure 3 shows the proper connection of the VRE302
series voltage references with the optional trim resistor for
initial error. The VRE302 reference has the ground
terminal brought out on two pins (pin 4 and pin 7) which
are connected together internally. This allows the user to
achieve greater accuracy when using a socket. Voltage
references have a voltage drop across their power supply
ground pin due to quiescent current flowing through the
contact resistance. If the contact resistance was constant
with time and temperature, this voltage drop could be
trimmed out. When the reference is plugged into a socket,
this source of error can be as high as 20ppm. By
connecting pin 4 to the power supply ground and pin 7 to
a high impedance ground point in the measurement
circuit, the error due to the contact resistance can be
eliminated. If the unit is soldered into place, the contact
resistance is sufficiently small that it does not effect
performance. Pay careful attention to the circuit layout to
avoid noise pickup and voltage drops in the lines.
The current source provides a closely regulated zener
current, which determines the slope of the references’
voltage vs. temperature function. By trimming the zener
current a lower drift over temperature can be achieved.
But since the voltage vs. temperature function is nonlinear
this compensation technique is not well suited for wide
temperature ranges.
Thaler Corporation has developed a nonlinear
compensation network of thermistors and resistors that is
used in the VRE series voltage references. This
proprietary network eliminates most of the nonlinearity in
the voltage vs. temperature function. By adjusting the
slope, Thaler Corporation produces a very stable voltage
over wide temperature ranges.
VRE302
FIGURE 2
EXTERNAL CONNECTIONS
+ VIN
V TEMP OUT
2
3
8
OPTIONAL
NOISE REDUCTION
CAPACITOR
6
VRE302
CN
1µF
5
7
FIGURE 3
+ VOUT
4
10kΩ
OPTIONAL
FINE TRIM
ADJUSTMENT
REF. GND
VRE302DS REV. F MAY 2001
MECHANICAL
FIGURE 3
D
D1
INCHES
D2
E1
E2
PIN 1 IDENTIFIER
E
MILLIMETER
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
D2
.018
.023
0.46
0.58
B
.098
.102
2.48
2.59
E
.507
.513
12.8
13.0
B1
.046
.051
1.14
1.29
E1
.397
.403
10.0
10.2
C
.107
.113
2.71
2.89
E2
.264
.270
6.70
6.85
C1
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
C2
.052
.058
1.32
1.47
Q
.020
.030
.508
.762
S
.045
.055
1.14
1.39
D
.397
.403
10.0
10.2
D1
.372
.380
9.44
9.65
E1
P
BASE
SEATING
B
MILLIMETER
MIN
Q
A
INCHES
DIM
C1
C2
C
S
B1
FIGURE 4
INCHES
MILLIMETER
INCHES
MILLIMETER
DIM
MIN
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
E
.397
.403
10.0
10.2
B
.018
.022
.457
.558
E1
.264
.270
6.70
6.85
B1
.046
.051
1.14
1.29
G1
.290
.310
7.36
7.87
B2
.098
.102
2.48
2.59
L
.195
.215
4.95
5.46
C
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
D
.397
.403
10.0
10.2
Q
.055
.065
1.39
1.65
D1
.372
.380
9.44
9.65
S
.045
.055
1.14
1.39
VRE302DS REV. F MAY 2001
VRE302-6
Low Cost
Precision Reference
THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 85745 • (520) 882-4000
FEATURES
• 2.048 V OUTPUT ± 0.205 mV (.01%)
PIN CONFIGURATION
• TEMPERATURE DRIFT: 0.6 ppm/°C
• LOW NOISE: 1.5µV p-p (0.1-10Hz)
• INDUSTRY STD PINOUT- 8 PIN DIP OR
SURFACE MOUNT PACKAGE
N.C.
1
+VIN
2
TEMP
3
GND
4
VRE302-6
TOP
VIEW
8
NOISE
7
REF. GND
6
VOUT
5
TRIM
•EXCELLENT LINE REGULATION: 6ppm/V Typ.
• OUTPUT TRIM CAPABILITY
FIGURE 1
DESCRIPTION
The VRE302-6 is a low cost, high precision 2.5V
reference. Packaged in the industry standard 8
pin DIP, the device is ideal for upgrading systems
that use lower performance references.
The device provides ultrastable +2.048V output
with ±0.205 mV (.01%) initial accuracy and a
temperature coefficient of 0.6 ppm/°C.
This
improvement in accuracy is made possible by a
unique, patented multipoint laser compensation
technique developed by Thaler Corporation.
Significant improvements have been made in
other performance parameters as well, including
initial accuracy, warm-up drift, line regulation, and
long-term stability, making the VRE302-6 series
the most accurate reference available in the
standard 8 pin DIP package.
For enhanced performance, the VRE302-6 has an
external trim option for users who want less than
0.01% initial error. A reference ground pin is
provided to eliminate socket contact resistance
errors.
The VRE302-6 is recommended for use as a
reference for 14, 16, or 18 bit D/A converters
which require an external precision reference.
The device is also ideal for calibrating scale factor
on high resolution A/D converters. The VRE3026 offers superior performance over monolithic
references.
SELECTION GUIDE
Model
VRE302-6A
VRE302-6B
VRE302-6C
VRE302-6J
VRE302-6K
VRE302-6L
Initial
Error
mV
Temp.
Coeff.
ppm/°C
Temp.
Range
°C
0.20
0.35
0.40
0.20
0.35
0.40
0.6
1.0
2.0
0.6
1.0
2.0
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
For package option add D for DIP or S for Surface Mount
to end of model number.
VRE302-6DS REV. B MAY 2001
ELECTRICAL SPECIFICATIONS
VRE302-6
Vps =+15V, T = 25°C, RL = 10KΩ unless otherwise noted.
MODEL
A/J
PARAMETER
MIN
TYP
B/K
MAX
C/L
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
°C
°C
°C
ABSOLUTE RATINGS
Power Supply
Operating Temp. (A,B,C)
Operating Temp. (J,K,L)
Storage Temperature
Short Circuit Protection
+13.5 +15
+22
0
+70
-40
+85
-65
+150
Continuous
*
*
*
*
*
*
OUTPUT VOLTAGE
VRE302-6
(1)
Temp. Sensor Voltage
2.048
630
V
mV
OUTPUT VOLTAGE ERRORS
(2)
Initial Error
Warmup Drift
Tmin - Tmax (3)
Long-Term Stability
Noise (.1-10Hz) (4)
0.20
0.35
1
0.40
2
0.6
3
1.0
6
1.5
2.0
*
*
*
*
mV
ppm
ppm/ °C
ppm/1000hrs
µVpp
OUTPUT CURRENT
Range
±10
*
*
mA
REGULATION
Line
Load
6
3
10
*
*
*
*
*
*
ppm/V
ppm/mA
OUTPUT ADJUSTMENT
Range
10
POWER SUPPLY CURRENTS
*
mV
(5)
VRE302-6 +PS
NOTES:
*
5
7
*Same as A/J Models.
1. The temp. reference TC is 2.1mV/ °C
2. The specified values are without external trim.
*
*
*
*
mA
4. The specified values are without the external
noise reduction capacitor.
5. The specified values are unloaded.
3. The temperature coefficient is determined by the box
method using the following formula:
Vmax - Vmin
x 106
T.C. =
Vnominal x (Tmax-Tmin)
VRE302-6DS REV. B MAY 2001
TYPICAL PERFORMANCE CURVES
VOUT vs. TEMPERATURE
Temperature oC
VRE302-6A
VOUT vs. TEMPERATURE
Temperature oC
VRE302-6J
VOUT vs. TEMPERATURE
Temperature oC
VRE302-6B
Temperature oC
VRE302-6C
VOUT vs. TEMPERATURE
VOUT vs. TEMPERATURE
Temperature oC
VRE302-6K
QUIESCENT CURRENT VS. TEMP JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Temperature oC
VOUT vs. TEMPERATURE
Output Current (mA)
Temperature oC
VRE302-6L
PSRR VS. FREQUENCY
Frequency
(Hz)
VRE302-6DS REV. B MAY 2001
DISCUSSION OF PERFORMANCE
THEORY OF OPERATION
The following discussion refers to the schematic in
figure 2 below. A FET current source is used to bias a
6.3V zener diode. The zener voltage is divided by the
resistor network R1 and R2. This voltage is then applied
to the noninverting input of the operational amplifier which
amplifies the voltage to produce a 2.048V output. The
gain is determined by the resistor networks R3 and R4:
G=1 + R4/R3. The 6.3V zener diode is used because it is
the most stable diode over time and temperature.
This network is less than 2% of the overall network
resistance so it has a negligible effect on long term
stability.
Figure 3 shows the proper connection of the VRE302-6
series voltage references with the optional trim resistor for
initial error. The VRE302-6 reference has the ground
terminal brought out on two pins (pin 4 and pin 7) which
are connected together internally. This allows the user to
achieve greater accuracy when using a socket. Voltage
references have a voltage drop across their power supply
ground pin due to quiescent current flowing through the
contact resistance. If the contact resistance was constant
with time and temperature, this voltage drop could be
trimmed out. When the reference is plugged into a socket,
this source of error can be as high as 20ppm. By
connecting pin 4 to the power supply ground and pin 7 to
a high impedance ground point in the measurement
circuit, the error due to the contact resistance can be
eliminated. If the unit is soldered into place, the contact
resistance is sufficiently small that it does not effect
performance. Pay careful attention to the circuit layout to
avoid noise pickup and voltage drops in the lines.
The current source provides a closely regulated zener
current, which determines the slope of the references’
voltage vs. temperature function. By trimming the zener
current a lower drift over temperature can be achieved.
But since the voltage vs. temperature function is nonlinear
this compensation technique is not well suited for wide
temperature ranges.
Thaler Corporation has developed a nonlinear
compensation network of thermistors and resistors that is
used in the VRE series voltage references. This
proprietary network eliminates most of the nonlinearity in
the voltage vs. temperature function. By adjusting the
slope, Thaler Corporation produces a very stable voltage
over wide temperature ranges.
VRE302-6
FIGURE 2
EXTERNAL CONNECTIONS
+ VIN
2
V TEMP OUT
3
8
OPTIONAL
NOISE REDUCTION
CAPACITOR
6
VRE302-6
CN
1µF
5
7
FIGURE 3
+ VOUT
4
10kΩ
OPTIONAL
FINE TRIM
ADJUSTMENT
REF. GND
VRE302-6DS REV. B MAY 2001
MECHANICAL
FIGURE 3
D
D1
INCHES
D2
E1
E2
PIN 1 IDENTIFIER
E
MILLIMETER
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
D2
.018
.023
0.46
0.58
B
.098
.102
2.48
2.59
E
.507
.513
12.8
13.0
B1
.046
.051
1.14
1.29
E1
.397
.403
10.0
10.2
C
.107
.113
2.71
2.89
E2
.264
.270
6.70
6.85
C1
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
C2
.052
.058
1.32
1.47
Q
.020
.030
.508
.762
S
.045
.055
1.14
1.39
D
.397
.403
10.0
10.2
D1
.372
.380
9.44
9.65
E1
P
BASE
SEATING
B
MILLIMETER
MIN
Q
A
INCHES
DIM
C1
C2
C
S
B1
FIGURE 4
INCHES
MILLIMETER
INCHES
MILLIMETER
DIM
MIN
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
E
.397
.403
10.0
10.2
B
.018
.022
.457
.558
E1
.264
.270
6.70
6.85
B1
.046
.051
1.14
1.29
G1
.290
.310
7.36
7.87
B2
.098
.102
2.48
2.59
L
.195
.215
4.95
5.46
C
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
D
.397
.403
10.0
10.2
Q
.055
.065
1.39
1.65
D1
.372
.380
9.44
9.65
S
.045
.055
1.14
1.39
VRE302-6DS REV. B MAY 2001
VRE303
Low Cost
Precision Reference
THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 85745 • (520) 882-4000
FEATURES
• 3.000 V OUTPUT ± 0.300 mV (.01%)
PIN CONFIGURATION
• TEMPERATURE DRIFT: 0.6 ppm/°C
• LOW NOISE: 1.5µV p-p (0.1-10Hz)
• INDUSTRY STD PINOUT- 8 PIN DIP OR
SURFACE MOUNT PACKAGE
N/C
1
+VIN
2
TEMP
3
GND
4
VRE303
TOP
VIEW
8
NOISE
REDUCTION
7
REF. GND
6
VOUT
5
TRIM
•EXCELLENT LINE REGULATION: 6ppm/V Typ.
• OUTPUT TRIM CAPABILITY
FIGURE 1
DESCRIPTION
The VRE303 is a low cost, high precision 3.0V
reference. Packaged in the industry standard 8
pin DIP, the device is ideal for upgrading systems
that use lower performance references.
The device provides ultrastable +3.000V output
with ±0.3000 mV (.01%) initial accuracy and a
temperature coefficient of 0.6 ppm/°C.
This
improvement in accuracy is made possible by a
unique, patented multipoint laser compensation
technique developed by Thaler Corporation.
Significant improvements have been made in
other performance parameters as well, including
initial accuracy, warm-up drift, line regulation, and
long-term stability, making the VRE303 series the
most accurate reference available in the standard
8 pin DIP package.
For enhanced performance, the VRE303 has an
external trim option for users who want less than
0.01% initial error.
For ultra low noise
applications, an external capacitor can be
attached between the noise reduction pin and the
ground pin. A reference ground pin is provided to
eliminate socket contact resistance errors.
The VRE303 is recommended for use as a
reference for 14, 16, or 18 bit D/A converters
which require an external precision reference.
The device is also ideal for calibrating scale factor
on high resolution A/D converters. The VRE303
offers superior performance over monolithic
references.
SELECTION GUIDE
Model
Initial
Error
mV
Temp.
Coeff.
ppm/°C
Temp.
Range
°C
VRE303A
VRE303B
VRE303C
VRE303J
VRE303K
VRE303L
0.30
0.48
0.60
0.30
0.48
0.60
0.6
1.0
2.0
0.6
1.0
2.0
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
For package option add D for DIP or S for Surface Mount
to end of model number.
VRE303DS REV. B MAY 2001
ELECTRICAL SPECIFICATIONS
VRE303
Vps =+15V, T = 25°C, RL = 10KΩ unless otherwise noted.
MODEL
A/J
PARAMETER
MIN
TYP
+14
0
-40
-65
+15
B/K
MAX
C/L
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
°C
°C
°C
ABSOLUTE RATINGS
Power Supply
Operating Temp. (A,B,C)
Operating Temp. (J,K,L)
Storage Temperature
Short Circuit Protection
+16
+70
+85
+150
Continuous
*
*
*
*
*
*
OUTPUT VOLTAGE
VRE303
(1)
Temp. Sensor Voltage
3.000
630
V
mV
OUTPUT VOLTAGE ERRORS
(2)
Initial Error
Warmup Drift
Tmin - Tmax (3)
Long-Term Stability
Noise (.1-10Hz) (4)
0.30
0.48
1
0.60
2
0.6
3
1.0
6
2.0
2.0
*
*
*
*
mV
ppm
ppm/°C
ppm/1000hrs
µVpp
OUTPUT CURRENT
Range
±10
*
*
mA
REGULATION
Line
Load
6
3
10
*
*
*
*
*
*
ppm/V
ppm/mA
OUTPUT ADJUSTMENT
Range
10
POWER SUPPLY CURRENTS
*
mV
(5)
VRE303 +PS
NOTES:
*
5
7
*Same as A/J Models.
1. The temp. reference TC is 2.1mV/ °C
2. The specified values are without external trim.
*
*
*
*
mA
4. The specified values are without the external
noise reduction capacitor.
5. The specified values are unloaded.
3. The temperature coefficient is determined by the box
method using the following formula:
Vmax - Vmin
x 106
T.C. =
Vnominal x (Tmax-Tmin)
VRE303DS REV. B MAY 2001
TYPICAL PERFORMANCE CURVES
VOUT vs. TEMPERATURE
Temperature oC
VRE303A
VOUT vs. TEMPERATURE
Temperature oC
VRE303J
QUIESCENT CURRENT VS. TEMP
Temperature oC
VOUT vs. TEMPERATURE
VOUT vs. TEMPERATURE
Temperature oC
VRE303B
Temperature oC
VRE303C
VOUT vs. TEMPERATURE
Temperature oC
VRE303K
JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Output Current (mA)
VOUT vs. TEMPERATURE
Temperature oC
VRE303L
PSRR VS. FREQUENCY
Frequency (Hz)
VRE303DS REV. B MAY 2001
DISCUSSION OF PERFORMANCE
THEORY OF OPERATION
This network is less than 2% of the overall network
resistance so it has a negligible effect on long term
stability.
The following discussion refers to the schematic in
figure 2 below. A FET current source is used to bias a
6.3V zener diode. The zener voltage is divided by the
resistor network R1 and R2. This voltage is then applied
to the noninverting input of the operational amplifier which
amplifies the voltage to produce a 3.000V output. The
gain is determined by the resistor networks R3 and R4:
G=1 + R4/R3. The 6.3V zener diode is used because it is
the most stable diode over time and temperature.
Figure 3 shows the proper connection of the VRE303
series voltage references with the optional trim resistor for
initial error and the optional capacitor for noise reduction.
The VRE303 reference has the ground terminal brought
out on two pins (pin 4 and pin 7) which are connected
together internally. This allows the user to achieve greater
accuracy when using a socket. Voltage references have a
voltage drop across their power supply ground pin due to
quiescent current flowing through the contact resistance.
If the contact resistance was constant with time and
temperature, this voltage drop could be trimmed out.
When the reference is plugged into a socket, this source
of error can be as high as 20ppm. By connecting pin 4 to
the power supply ground and pin 7 to a high impedance
ground point in the measurement circuit, the error due to
the contact resistance can be eliminated. If the unit is
soldered into place, the contact resistance is sufficiently
small that it does not effect performance. Pay careful
attention to the circuit layout to avoid noise pickup and
voltage drops in the lines.
The current source provides a closely regulated zener
current, which determines the slope of the references’
voltage vs. temperature function. By trimming the zener
current a lower drift over temperature can be achieved.
But since the voltage vs. temperature function is nonlinear
this compensation technique is not well suited for wide
temperature ranges.
Thaler Corporation has developed a nonlinear
compensation network of thermistors and resistors that is
used in the VRE series voltage references. This
proprietary network eliminates most of the nonlinearity in
the voltage vs. temperature function. By adjusting the
slope, Thaler Corporation produces a very stable voltage
over wide temperature ranges.
VRE303
FIGURE 2
EXTERNAL CONNECTIONS
+ VIN
V TEMP OUT
2
3
8
OPTIONAL
NOISE REDUCTION
CAPACITOR
6
VRE303
CN
1µF
5
7
FIGURE 3
+ VOUT
4
10kΩ
OPTIONAL
FINE TRIM
ADJUSTMENT
REF. GND
VRE303DS REV. B MAY 2001
MECHANICAL
FIGURE 3
D
D1
INCHES
D2
E1
E2
PIN 1 IDENTIFIER
E
MILLIMETER
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
D2
.018
.023
0.46
0.58
B
.098
.102
2.48
2.59
E
.507
.513
12.8
13.0
B1
.046
.051
1.14
1.29
E1
.397
.403
10.0
10.2
C
.107
.113
2.71
2.89
E2
.264
.270
6.70
6.85
C1
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
C2
.052
.058
1.32
1.47
Q
.020
.030
.508
.762
D
.397
.403
10.0
10.2
S
.045
.055
1.14
1.39
D1
.372
.380
9.44
9.65
E1
P
BASE
SEATING
B
MILLIMETER
MIN
Q
A
INCHES
DIM
C1
C2
C
S
B1
FIGURE 4
INCHES
MILLIMETER
INCHES
MILLIMETER
DIM
MIN
MAX
MIN
MAX
DIM
MIN
MAX MIN
MAX
A
.115
.125
2.92
3.17
E
.397
.403
10.0
10.2
B
.018
.022
.457
.558
E1
.264
.270
6.70
6.85
B1
.046
.051
1.14
1.29
G1
.290
.310
7.36
7.87
B2
.098
.102
2.48
2.59
L
.195
.215
4.95
5.46
C
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
D
.397
.403
10.0
10.2
Q
.055
.065
1.39
1.65
D1
.372
.380
9.44
9.65
S
.045
.055
1.14
1.39
VRE303DS REV. B MAY 2001
VRE304
Low Cost
Precision Reference
THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 85745 • (520) 882-4000
FEATURES
• 4.500 V OUTPUT ± 0.450 mV (.01%)
PIN CONFIGURATION
• TEMPERATURE DRIFT: 0.6 ppm/°C
• LOW NOISE: 3µV p-p (0.1-10Hz)
• INDUSTRY STD PINOUT- 8 PIN DIP OR
SURFACE MOUNT PACKAGE
N/C
1
+VIN
2
TEMP
3
GND
4
VRE304
TOP
VIEW
8
NOISE
REDUCTION
7
REF. GND
6
VOUT
5
TRIM
•EXCELLENT LINE REGULATION: 6ppm/V Typ.
• OUTPUT TRIM CAPABILITY
FIGURE 1
DESCRIPTION
The VRE304 is a low cost, high precision 4.5V
reference. Packaged in the industry standard 8
pin DIP, the device is ideal for upgrading systems
that use lower performance references.
The device provides ultrastable +4.500V output
with ±0.4500 mV (.01%) initial accuracy and a
temperature coefficient of 0.6 ppm/°C.
This
improvement in accuracy is made possible by a
unique, patented multipoint laser compensation
technique developed by Thaler Corporation.
Significant improvements have been made in
other performance parameters as well, including
initial accuracy, warm-up drift, line regulation, and
long-term stability, making the VRE304 series the
most accurate reference available in the standard
8 pin DIP package.
For enhanced performance, the VRE304 has an
external trim option for users who want less than
0.01% initial error. For ultra low noise applications,
an external capacitor can be attached between the
noise reduction pin and the ground pin.
A
reference ground pin is provided to eliminate
socket contact resistance errors.
The VRE304 is recommended for use as a
reference for 14, 16, or 18 bit D/A converters
which require an external precision reference.
The device is also ideal for calibrating scale factor
on high resolution A/D converters. The VRE304
offers superior performance over monolithic
references.
SELECTION GUIDE
Model
Initial
Error
mV
Temp.
Coeff.
ppm/°C
Temp.
Range
°C
VRE304A
VRE304B
VRE304C
VRE304J
VRE304K
VRE304L
0.45
0.70
0.90
0.45
0.70
0.90
0.6
1.0
2.0
0.6
1.0
2.0
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
For package option add D for DIP or S for Surface Mount
to end of model number.
VRE304DS REV. D MAY 2001
ELECTRICAL SPECIFICATIONS
VRE304
Vps =+15V, T = 25°C, RL = 10KΩ unless otherwise noted.
MODEL
A/J
PARAMETER
MIN
TYP
+13.5
0
-40
-65
+15
B/K
MAX
C/L
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
°C
°C
°C
ABSOLUTE RATINGS
Power Supply
Operating Temp. (A,B,C)
Operating Temp. (J,K,L)
Storage Temperature
Short Circuit Protection
+22
+70
+85
+150
Continuous
*
*
*
*
*
*
OUTPUT VOLTAGE
VRE304
(1)
Temp. Sensor Voltage
4.500
630
V
mV
OUTPUT VOLTAGE ERRORS
(2)
Initial Error
Warmup Drift
Tmin - Tmax (3)
Long-Term Stability
Noise (.1-10Hz) (4)
0.45
0.70
1
0.90
2
0.6
3
1.0
6
3
2.0
*
*
*
*
mV
ppm
ppm/°C
ppm/1000hrs
µVpp
OUTPUT CURRENT
Range
±10
*
*
mA
REGULATION
Line
Load
6
3
10
*
*
*
*
*
*
ppm/V
ppm/mA
OUTPUT ADJUSTMENT
Range
10
POWER SUPPLY CURRENTS
*
mV
(5)
VRE304 +PS
NOTES:
*
5
7
*Same as A/J Models.
1. The temp. reference TC is 2.1mV/ °C
2. The specified values are without external trim.
*
*
*
*
mA
4. The specified values are without the external
noise reduction capacitor.
5. The specified values are unloaded.
3. The temperature coefficient is determined by the box
method using the following formula:
Vmax - Vmin
x 106
T.C. =
Vnominal x (Tmax-Tmin)
VRE304DS REV. D MAY 2001
TYPICAL PERFORMANCE CURVES
VOUT vs. TEMPERATURE
Temperature oC
VRE304A
VOUT vs. TEMPERATURE
Temperature oC
VRE304J
QUIESCENT CURRENT VS. TEMP
Temperature oC
VOUT vs. TEMPERATURE
Temperature oC
VRE304B
VOUT vs. TEMPERATURE
Temperature oC
VRE304K
JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Output Current (mA)
VOUT vs. TEMPERATURE
Temperature oC
VRE304C
VOUT vs. TEMPERATURE
Temperature oC
VRE304L
PSRR VS. FREQUENCY
Frequency (Hz)
VRE304DS REV. D MAY 2001
DISCUSSION OF PERFORMANCE
THEORY OF OPERATION
The following discussion refers to the schematic in
figure 2 below. A FET current source is used to bias a
6.3V zener diode. The zener voltage is divided by the
resistor network R1 and R2. This voltage is then applied
to the noninverting input of the operational amplifier which
amplifies the voltage to produce a 4.500V output. The
gain is determined by the resistor networks R3 and R4:
G=1 + R4/R3. The 6.3V zener diode is used because it is
the most stable diode over time and temperature.
This network is less than 2% of the overall network
resistance so it has a negligible effect on long term
stability.
Figure 3 shows the proper connection of the VRE304
series voltage references with the optional trim resistor for
initial error and the optional capacitor for noise reduction.
The VRE304 reference has the ground terminal brought
out on two pins (pin 4 and pin 7) which are connected
together internally. This allows the user to achieve greater
accuracy when using a socket. Voltage references have a
voltage drop across their power supply ground pin due to
quiescent current flowing through the contact resistance.
If the contact resistance was constant with time and
temperature, this voltage drop could be trimmed out.
When the reference is plugged into a socket, this source
of error can be as high as 20ppm. By connecting pin 4 to
the power supply ground and pin 7 to a high impedance
ground point in the measurement circuit, the error due to
the contact resistance can be eliminated. If the unit is
soldered into place, the contact resistance is sufficiently
small that it does not effect performance. Pay careful
attention to the circuit layout to avoid noise pickup and
voltage drops in the lines.
The current source provides a closely regulated zener
current, which determines the slope of the references’
voltage vs. temperature function. By trimming the zener
current a lower drift over temperature can be achieved.
But since the voltage vs. temperature function is nonlinear
this compensation technique is not well suited for wide
temperature ranges.
Thaler Corporation has developed a nonlinear
compensation network of thermistors and resistors that is
used in the VRE series voltage references. This
proprietary network eliminates most of the nonlinearity in
the voltage vs. temperature function. By adjusting the
slope, Thaler Corporation produces a very stable voltage
over wide temperature ranges.
VRE304
FIGURE 2
EXTERNAL CONNECTIONS
+ VIN
V TEMP OUT
2
3
8
OPTIONAL
NOISE REDUCTION
CAPACITOR
6
VRE304
CΝ
1µF
5
7
FIGURE 3
+ VOUT
4
10kΩ
OPTIONAL
FINE TRIM
ADJUSTMENT
REF. GND
VRE304DS REV. D MAY 2001
MECHANICAL
FIGURE 3
D
D1
INCHES
D2
E1
E2
PIN 1 IDENTIFIER
E
MILLIMETER
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
D2
.018
.023
0.46
0.58
B
.098
.102
2.48
2.59
E
.507
.513
12.8
13.0
B1
.046
.051
1.14
1.29
E1
.397
.403
10.0
10.2
C
.107
.113
2.71
2.89
E2
.264
.270
6.70
6.85
C1
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
C2
.052
.058
1.32
1.47
Q
.020
.030
.508
.762
S
.045
.055
1.14
1.39
D
.397
.403
10.0
10.2
D1
.372
.380
9.44
9.65
E1
P
BASE
SEATING
B
MILLIMETER
MIN
Q
A
INCHES
DIM
C1
C2
C
S
B1
FIGURE 4
INCHES
MILLIMETER
INCHES
MILLIMETER
DIM
MIN
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
E
.397
.403
10.0
10.2
B
.018
.022
.457
.558
E1
.264
.270
6.70
6.85
B1
.046
.051
1.14
1.29
G1
.290
.310
7.36
7.87
B2
.098
.102
2.48
2.59
L
.195
.215
4.95
5.46
C
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
D
.397
.403
10.0
10.2
Q
.055
.065
1.39
1.65
D1
.372
.380
9.44
9.65
S
.045
.055
1.14
1.39
VRE304DS REV. D MAY 2001
VRE304-6
Low Cost
Precision Reference
THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 8574 5 • (520) 882 -4000
FEATURES
• 4.096 V OUTPUT ± 0.409 mV (.01%)
PIN CONFIGURATION
• TEMPERATURE DRIFT: 0.6 ppm/°C
• LOW NOISE: 3µV p-p (0.1-10Hz)
• INDUSTRY STD PINOUT- 8 PIN DIP OR
SURFACE MOUNT PACKAGE
N/C
1
+VIN
2
TEMP
3
GND
4
VRE304-6
TOP
VIEW
8
NOISE
REDUCTION
7
REF. GND
6
VOUT
5
TRIM
•EXCELLENT LINE REGULATION: 6ppm/V Typ.
• OPERATES ON +15V SUPPLY
FIGURE 1
DESCRIPTION
The VRE304-6 is a low cost, high precision
4.096V reference.
Packaged in the industry
standard 8 pin DIP, the device is ideal for
upgrading systems that use lower performance
references.
The device provides ultrastable +4.096V output
with ±0.409 mV (.01%) initial accuracy and a
temperature coefficient of 0.6 ppm/°C.
This
improvement in accuracy is made possible by a
unique, patented multipoint laser compensation
technique developed by Thaler Corporation.
Significant improvements have been made in
other performance parameters as well, including
initial accuracy, warm-up drift, line regulation, and
long-term stability, making the VRE304-6 series
the most accurate reference available in the
standard 8 pin DIP package.
For enhanced performance, the VRE304-6 has an
external trim option for users who want less than
0.01% initial error. For ultra low noise applications,
an external capacitor can be attached between the
noise reduction pin and the ground pin.
A
reference ground pin is provided to eliminate
socket contact resistance errors.
The VRE304-6 is recommended for use as a
reference for 14, 16, or 18 bit D/A converters
which require an external precision reference.
The device is also ideal for calibrating scale factor
on high resolution A/D converters. The VRE3046 offers superior performance over monolithic
references.
SELECTION GUIDE
Model
Initial
Error
mV
Temp.
Coeff.
ppm/°C
Temp.
Range
°C
VRE304-6A
VRE304-6B
VRE304-6C
VRE304-6J
VRE304-6K
VRE304-6L
0.41
0.64
0.82
0.41
0.64
0.82
0.6
1.0
2.0
0.6
1.0
2.0
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
For package option add D for DIP or S for Surface Mount
to end of model number.
VRE304-6DS REV. D JUN 1999
ELECTRICAL SPECIFICATIONS
VRE304-6
Vps =+15V, T = 25°C, RL = 10KΩ unless otherwise noted.
MODEL
A/J
PARAMETER
MIN
TYP
+13
0
-40
-65
+15
B/K
MAX
C/L
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
°C
°C
°C
ABSOLUTE RATINGS
Power Supply
Operating Temp. (A,B,C)
Operating Temp. (J,K,L)
Storage Temperature
Short Circuit Protection
+22
+70
+85
+150
Continuous
*
*
*
*
*
*
OUTPUT VOLTAGE
VRE304-6
(1)
Temp. Sensor Voltage
4.096
630
V
mV
OUTPUT VOLTAGE ERRORS
(2)
Initial Error
Warmup Drift
Tmin - Tmax (3)
Long-Term Stability
Noise (.1-10Hz) (4)
0.41
0.64
1
0.82
2
0.6
3
1.0
6
3
2.0
*
*
*
*
mV
ppm
ppm/ °C
ppm/1000hrs
µVpp
OUTPUT CURRENT
Range
±10
*
*
mA
REGULATION
Line
Load
6
3
10
*
*
*
*
*
*
ppm/V
ppm/mA
OUTPUT ADJUSTMENT
Range
10
POWER SUPPLY CURRENTS
*
mV
(5)
VRE304-6 +PS
NOTES:
*
5
7
*Same as A/J Models.
1. The temp. reference TC is 2.1mV/ °C
2. The specified values are without external trim.
*
*
*
*
mA
4. The specified values are without the external
noise reduction capacitor.
5. The specified values are unloaded.
3. The temperature coefficient is determined by the box
method using the following formula:
Vmax - Vmin
x 106
T.C. =
Vnominal x (Tmax-Tmin)
VRE304-6DS REV. D JUN 1999
TYPICAL PERFORMANCE CURVES
VOUT vs. TEMPERATURE
Temperature oC
VRE304-6A
VOUT vs. TEMPERATURE
Temperature oC
VRE304-6J
QUIESCENT CURRENT VS. TEMP
Temperature oC
VOUT vs. TEMPERATURE
Temperature oC
VRE304-6B
VOUT vs. TEMPERATURE
Temperature oC
VRE304-6K
JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Output Current (mA)
VOUT vs. TEMPERATURE
Temperature oC
VRE304-6C
VOUT vs. TEMPERATURE
Temperature oC
VRE304-6L
PSRR VS. FREQUENCY
Frequency (Hz)
VRE304-6DS REV. D JUN 1999
DISCUSSION OF PERFORMANCE
THEORY OF OPERATION
The following discussion refers to the schematic in
figure 2 below. A FET current source is used to bias a
6.3V zener diode. The zener voltage is divided by the
resistor network R1 and R2. This voltage is then applied
to the noninverting input of the operational amplifier which
amplifies the voltage to produce a 4.096V output. The
gain is determined by the resistor networks R3 and R4:
G=1 + R4/R3. The 6.3V zener diode is used because it is
the most stable diode over time and temperature.
This network is less than 2% of the overall network
resistance so it has a negligible effect on long term
stability.
Figure 3 shows the proper connection of the VRE304-6
series voltage references with the optional trim resistor for
initial error and the optional capacitor for noise reduction.
The VRE304-6 reference has the ground terminal brought
out on two pins (pin 4 and pin 7) which are connected
together internally. This allows the user to achieve greater
accuracy when using a socket. Voltage references have a
voltage drop across their power supply ground pin due to
quiescent current flowing through the contact resistance.
If the contact resistance was constant with time and
temperature, this voltage drop could be trimmed out.
When the reference is plugged into a socket, this source
of error can be as high as 20ppm. By connecting pin 4 to
the power supply ground and pin 7 to a high impedance
ground point in the measurement circuit, the error due to
the contact resistance can be eliminated. If the unit is
soldered into place, the contact resistance is sufficiently
small that it does not effect performance. Pay careful
attention to the circuit layout to avoid noise pickup and
voltage drops in the lines.
The current source provides a closely regulated zener
current, which determines the slope of the references’
voltage vs. temperature function. By trimming the zener
current a lower drift over temperature can be achieved.
But since the voltage vs. temperature function is nonlinear
this compensation technique is not well suited for wide
temperature ranges.
Thaler Corporation has developed a nonlinear
compensation network of thermistors and resistors that is
used in the VRE series voltage references. This
proprietary network eliminates most of the nonlinearity in
the voltage vs. temperature function. By adjusting the
slope, Thaler Corporation produces a very stable voltage
over wide temperature ranges.
VRE304-6
FIGURE 2
EXTERNAL CONNECTIONS
+ VIN
2
V TEMP OUT
3
8
OPTIONAL
NOISE REDUCTION
CAPACITOR
6
VRE304-6
CN
1µF
5
7
FIGURE 3
+ VOUT
4
10k?
OPTIONAL
FINE TRIM
ADJUSTMENT
REF. GND
VRE304-6DS REV. D JUN 1999
MECHANICAL SPECIFICATIONS
FIGURE 3
INCHES
MILLIMETER
MAX
INCHES
MILLIMETER
DIM
MIN
MAX
MIN
DIM
MIN
MAX
MIN
A
.110
.120
2.794 3.048
D1
.372
.380
9.45
MAX
B
.095
.105
2.413 2.667
E
.425
.435
10.80 11.05
B1
.021
.027
0.533 0.686
E1
.397
.403
10.08 10.24
C
.055
.065
1.397 1.651
E2
.264
.270
6.71
6.86
C1
.012
.020
0.305 0.508
P
.085
.095
2.16
2.41
C2
.020
.040
0.508 1.016
S
.045
.055
1.14
1.40
D
.395
.405
10.03 10.29
9.65
D
D1
E2 E1
E
1
A
P
C1
B
S
B1
C
C2
VRE304-6DS REV. D JUN 1999
MECHANICAL SPECIFICATIONS
INCHES
MILLIMETER
MILLIMETER
DIM
MIN
MAX
MIN
DIM
MIN
MAX
MIN
A
.170
.180
4.318 4.572
E
.425
.435
10.80 11.05
B
.095
.105
2.413 2.667
E1
.397
.403
10.08 10.24
B1
.016
.020
0.406 0.508
E2
.264
.270
6.71
6.86
C
.008
.011
0.203 0.279
G
.290
.310
7.36
7.87
C1
.055
.065
1.397 1.651
L
.175
.225
4.46
5.72
D
.395
.405
10.03 10.29
P
.085
.095
2.16
2.41
D1
.372
.380
S
.045
.055
1.14
1.40
9.45
MAX
INCHES
9.65
MAX
D
D1
E2 E1
E
1
P
A
C1
L
C
S
B
G
B1
VRE304-4DS REV. D JUN 1999
VRE305
Low Cost
Precision Reference
THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 85745 • (520) 882-4000
FEATURES
• 5.000 V OUTPUT ± 0.500 mV (.01%)
PIN CONFIGURATION
• TEMPERATURE DRIFT: 0.6 ppm/°C
• LOW NOISE: 3µV p-p (0.1-10Hz)
• INDUSTRY STD PINOUT- 8 PIN DIP OR
SURFACE MOUNT PACKAGE
N/C
1
+VIN
2
TEMP
3
GND
4
VRE305
TOP
VIEW
8
NOISE
REDUCTION
7
REF. GND
6
VOUT
5
TRIM
•EXCELLENT LINE REGULATION: 6ppm/V Typ.
• OUTPUT TRIM CAPABILITY
FIGURE 1
DESCRIPTION
The VRE305 is a low cost, high precision 5.0V
reference. Packaged in the industry standard 8
pin DIP, the device is ideal for upgrading systems
that use lower performance references.
The device provides ultrastable +5.000V output
with ±0.5000 mV (.01%) initial accuracy and a
temperature coefficient of 0.6 ppm/°C.
This
improvement in accuracy is made possible by a
unique, patented multipoint laser compensation
technique developed by Thaler Corporation.
Significant improvements have been made in
other performance parameters as well, including
initial accuracy, warm-up drift, line regulation, and
long-term stability, making the VRE305 series the
most accurate reference available in the standard
8 pin DIP package.
For enhanced performance, the VRE305 has an
external trim option for users who want less than
0.01% initial error.
For ultra low noise
applications, an external capacitor can be
attached between the noise reduction pin and the
ground pin. A reference ground pin is provided to
eliminate socket contact resistance errors.
The VRE305 is recommended for use as a
reference for 14, 16, or 18 bit D/A converters
which require an external precision reference.
The device is also ideal for calibrating scale factor
on high resolution A/D converters. The VRE305
offers superior performance over monolithic
references.
SELECTION GUIDE
Model
Initial
Error
mV
VRE305A
VRE305B
VRE305C
VRE305J
VRE305K
VRE305L
0.5
0.8
1.0
0.5
0.8
1.0
Temp.
Coeff.
ppm/°C
0.6
1.0
2.0
0.6
1.0
2.0
Temp.
Range
°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
For package option add D for DIP or S for Surface Mount
to end of model number.
VRE305DS REV. D MAY 2001
ELECTRICAL SPECIFICATIONS
VRE305
Vps =+15V, T = 25°C, RL = 10kΩ unless otherwise noted.
MODEL
A/J
PARAMETER
MIN
TYP
+13.5
0
-40
-65
+15
B/K
MAX
C/L
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
°C
°C
°C
ABSOLUTE RATINGS
Power Supply
Operating Temp. (A,B,C)
Operating Temp. (J,K,L)
Storage Temperature
Short Circuit Protection
+22
+70
+85
+150
Continuous
*
*
*
*
*
*
OUTPUT VOLTAGE
VRE305
(1)
Temp. Sensor Voltage
5.000
630
V
mV
OUTPUT VOLTAGE ERRORS
(2)
Initial Error
Warmup Drift
Tmin - Tmax (3)
Long-Term Stability
Noise (.1-10Hz) (4)
0.50
0.80
1
1.00
2
0.6
3
1.0
6
3
2.0
*
*
*
*
mV
ppm
ppm/°C
ppm/1000hrs
µVpp
OUTPUT CURRENT
Range
±10
*
*
mA
REGULATION
Line
Load
6
3
10
*
*
*
*
*
*
ppm/V
ppm/mA
OUTPUT ADJUSTMENT
Range
10
POWER SUPPLY CURRENTS
*
mV
(5)
VRE305 +PS
NOTES:
*
5
7
*Same as A/J Models.
1. The temp. reference TC is 2.1mV/°C
2. The specified values are without external trim.
*
*
*
*
mA
4. The specified values are without the external
noise reduction capacitor.
5. The specified values are unloaded.
3. The temperature coefficient is determined by the box
method using the following formula:
Vmax - Vmin
x 106
T.C. =
Vnominal x (Tmax-Tmin)
VRE305DS REV. D MAY 2001
TYPICAL PERFORMANCE CURVES
VOUT vs. TEMPERATURE
Temperature oC
VRE305A
VOUT vs. TEMPERATURE
Temperature oC
VRE305J
QUIESCENT CURRENT VS. TEMP
Temperature oC
VOUT vs. TEMPERATURE
Temperature oC
VRE305B
VOUT vs. TEMPERATURE
Temperature oC
VRE305K
JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Output Current (mA)
VOUT vs. TEMPERATURE
Temperature oC
VRE305C
VOUT vs. TEMPERATURE
Temperature oC
VRE305L
PSRR VS. FREQUENCY
Frequency (Hz)
VRE305DS REV. D MAY 2001
DISCUSSION OF PERFORMANCE
THEORY OF OPERATION
The following discussion refers to the schematic in
figure 2 below. A FET current source is used to bias a
6.3V zener diode. The zener voltage is divided by the
resistor network R1 and R2. This voltage is then applied
to the noninverting input of the operational amplifier which
amplifies the voltage to produce a 5.000V output. The
gain is determined by the resistor networks R3 and R4:
G=1 + R4/R3. The 6.3V zener diode is used because it is
the most stable diode over time and temperature.
This network is less than 2% of the overall network
resistance so it has a negligible effect on long term
stability.
Figure 3 shows the proper connection of the VRE305
series voltage references with the optional trim resistor for
initial error and the optional capacitor for noise reduction.
The VRE305 reference has the ground terminal brought
out on two pins (pin 4 and pin 7) which are connected
together internally. This allows the user to achieve greater
accuracy when using a socket. Voltage references have a
voltage drop across their power supply ground pin due to
quiescent current flowing through the contact resistance.
If the contact resistance was constant with time and
temperature, this voltage drop could be trimmed out.
When the reference is plugged into a socket, this source
of error can be as high as 20ppm. By connecting pin 4 to
the power supply ground and pin 7 to a high impedance
ground point in the measurement circuit, the error due to
the contact resistance can be eliminated. If the unit is
soldered into place, the contact resistance is sufficiently
small that it does not effect performance. Pay careful
attention to the circuit layout to avoid noise pickup and
voltage drops in the lines.
The current source provides a closely regulated zener
current, which determines the slope of the references’
voltage vs. temperature function. By trimming the zener
current a lower drift over temperature can be achieved.
But since the voltage vs. temperature function is nonlinear
this compensation technique is not well suited for wide
temperature ranges.
Thaler Corporation has developed a nonlinear
compensation network of thermistors and resistors that is
used in the VRE series voltage references. This
proprietary network eliminates most of the nonlinearity in
the voltage vs. temperature function. By adjusting the
slope, Thaler Corporation produces a very stable voltage
over wide temperature ranges.
VRE305
FIGURE 2
EXTERNAL CONNECTIONS
+ VIN
V TEMP OUT
2
3
8
OPTIONAL
NOISE REDUCTION
CAPACITOR
6
VRE305
CN
1µF
5
7
FIGURE 3
+ VOUT
4
10KΩ
OPTIONAL
FINE TRIM
ADJUSTMENT
REF. GND
VRE305DS REV. D MAY 2001
MECHANICAL
FIGURE 3
D
D1
INCHES
D2
E1
E2
E
PIN 1 IDENTIFIER
MILLIMETER
MILLIMETER
MIN
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
D2
.018
.023
0.46
0.58
B
.098
.102
2.48
2.59
E
.507
.513
12.8
13.0
B1
.046
.051
1.14
1.29
E1
.397
.403
10.0
10.2
C
.107
.113
2.71
2.89
E2
.264
.270
6.70
6.85
C1
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
C2
.052
.058
1.32
1.47
Q
.020
.030
.508
.762
S
.045
.055
1.14
1.39
D
.397
.403
10.0
10.2
D1
.372
.380
9.44
9.65
E1
Q
A
INCHES
DIM
P
BASE
SEATING
C1
C2
B
S
C
B1
FIGURE 4
INCHES
MILLIMETER
INCHES
MILLIMETER
DIM
MIN
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
E
.397
.403
10.0
10.2
B
.018
.022
.457
.558
E1
.264
.270
6.70
6.85
B1
.046
.051
1.14
1.29
G1
.290
.310
7.36
7.87
B2
.098
.102
2.48
2.59
L
.195
.215
4.95
5.46
C
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
D
.397
.403
10.0
10.2
Q
.055
.065
1.39
1.65
D1
.372
.380
9.44
9.65
S
.045
.055
1.14
1.39
VRE305DS REV. D MAY 2001
VRE306
Low Cost
Precision Reference
THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 85745 • (520) 882-4000
FEATURES
• 6.000 V OUTPUT ± 0.600 mV (.01%)
PIN CONFIGURATION
• TEMPERATURE DRIFT: 0.6 ppm/°C
• LOW NOISE: 4µV p-p (0.1-10Hz)
• INDUSTRY STD PINOUT- 8 PIN DIP OR
SURFACE MOUNT PACKAGE
N/C
1
+VIN
2
TEMP
3
GND
4
VRE306
TOP
VIEW
8
NOISE
REDUCTION
7
REF. GND
6
VOUT
5
TRIM
•EXCELLENT LINE REGULATION: 6ppm/V Typ.
• OUTPUT TRIM CAPABILITY
FIGURE 1
DESCRIPTION
The VRE306 is a low cost, high precision 6.0V
reference. Packaged in the industry standard 8
pin DIP, the device is ideal for upgrading systems
that use lower performance references.
The device provides ultrastable +6.000V output
with ±0.6000 mV (.01%) initial accuracy and a
temperature coefficient of 0.6 ppm/°C.
This
improvement in accuracy is made possible by a
unique, patented multipoint laser compensation
technique developed by Thaler Corporation.
Significant improvements have been made in
other performance parameters as well, including
initial accuracy, warm-up drift, line regulation, and
long-term stability, making the VRE306 series the
most accurate reference available in the standard
8 pin DIP package.
For enhanced performance, the VRE306 has an
external trim option for users who want less than
0.01% initial error.
For ultra low noise
applications, an external capacitor can be
attached between the noise reduction pin and the
ground pin. A reference ground pin is provided to
eliminate socket contact resistance errors.
The VRE306 is recommended for use as a
reference for 14, 16, or 18 bit D/A converters
which require an external precision reference.
The device is also ideal for calibrating scale factor
on high resolution A/D converters. The VRE306
offers superior performance over monolithic
references.
SELECTION GUIDE
Model
Initial
Error
mV
VRE306A
VRE306C
VRE306J
VRE306K
VRE306L
0.6
1.2
0.6
1.0
1.2
Temp.
Coeff.
ppm/°C
0.6
2.0
0.6
1.0
2.0
Temp.
Range
°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
For package option add D for DIP or S for Surface Mount
to end of model number.
VRE306DS REV. B MAY 2001
ELECTRICAL SPECIFICATIONS
VRE306
Vps =+15V, T = 25°C, RL = 10KΩ unless otherwise noted.
MODEL
A/J
PARAMETER
MIN
TYP
+14
0
-40
-65
+15
B/K
MAX
C/L
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
°C
°C
°C
ABSOLUTE RATINGS
Power Supply
Operating Temp. (A,B,C)
Operating Temp. (J,K,L)
Storage Temperature
Short Circuit Protection
+16
+70
+85
+150
Continuous
*
*
*
*
*
*
OUTPUT VOLTAGE
VRE306
(1)
Temp. Sensor Voltage
6.000
630
V
mV
OUTPUT VOLTAGE ERRORS
(2)
Initial Error
Warmup Drift
Tmin - Tmax (3)
Long-Term Stability
Noise (.1-10Hz) (4)
0.60
1.00
1
1.20
2
0.6
3
1.0
6
4
2.0
*
*
*
*
mV
ppm
ppm/ °C
ppm/1000hrs
µVpp
OUTPUT CURRENT
Range
±10
*
*
mA
REGULATION
Line
Load
6
3
10
*
*
*
*
*
*
ppm/V
ppm/mA
OUTPUT ADJUSTMENT
Range
10
POWER SUPPLY CURRENTS
*
mV
(5)
VRE306 +PS
NOTES:
*
5
7
*Same as A/J Models.
1. The temp. reference TC is 2.1mV/ °C
2. The specified values are without external trim.
*
*
*
*
mA
4. The specified values are without the external
noise reduction capacitor.
5. The specified values are unloaded.
3. The temperature coefficient is determined by the box
method using the following formula:
Vmax - Vmin
x 106
T.C. =
Vnominal x (Tmax-Tmin)
VRE306DS REV. B MAY 2001
TYPICAL PERFORMANCE CURVES
VOUT vs. TEMPERATURE
Temperature oC
VRE306A
VOUT vs. TEMPERATURE
Temperature oC
VRE306J
QUIESCENT CURRENT VS. TEMP
Temperature oC
VOUT vs. TEMPERATURE
Temperature oC
VRE306B
VOUT vs. TEMPERATURE
Temperature oC
VRE306K
JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Output Current (mA)
VOUT vs. TEMPERATURE
Temperature oC
VRE306C
VOUT vs. TEMPERATURE
Temperature oC
VRE306L
PSRR VS. FREQUENCY
Frequency (Hz)
VRE306DS REV. B MAY 2001
DISCUSSION OF PERFORMANCE
THEORY OF OPERATION
The following discussion refers to the schematic in
figure 2 below. A FET current source is used to bias a
6.3V zener diode. The zener voltage is divided by the
resistor network R1 and R2. This voltage is then applied
to the noninverting input of the operational amplifier which
amplifies the voltage to produce a 6.000V output. The
gain is determined by the resistor networks R3 and R4:
G=1 + R4/R3. The 6.3V zener diode is used because it is
the most stable diode over time and temperature.
This network is less than 2% of the overall network
resistance so it has a negligible effect on long term
stability.
Figure 3 shows the proper connection of the VRE306
series voltage references with the optional trim resistor for
initial error and the optional capacitor for noise reduction.
The VRE306 reference has the ground terminal brought
out on two pins (pin 4 and pin 7) which are connected
together internally. This allows the user to achieve greater
accuracy when using a socket. Voltage references have a
voltage drop across their power supply ground pin due to
quiescent current flowing through the contact resistance.
If the contact resistance was constant with time and
temperature, this voltage drop could be trimmed out.
When the reference is plugged into a socket, this source
of error can be as high as 20ppm. By connecting pin 4 to
the power supply ground and pin 7 to a high impedance
ground point in the measurement circuit, the error due to
the contact resistance can be eliminated. If the unit is
soldered into place, the contact resistance is sufficiently
small that it does not effect performance. Pay careful
attention to the circuit layout to avoid noise pickup and
voltage drops in the lines.
The current source provides a closely regulated zener
current, which determines the slope of the references’
voltage vs. temperature function. By trimming the zener
current a lower drift over temperature can be achieved.
But since the voltage vs. temperature function is nonlinear
this compensation technique is not well suited for wide
temperature ranges.
Thaler Corporation has developed a nonlinear
compensation network of thermistors and resistors that is
used in the VRE series voltage references. This
proprietary network eliminates most of the nonlinearity in
the voltage vs. temperature function. By adjusting the
slope, Thaler Corporation produces a very stable voltage
over wide temperature ranges.
VRE306
FIGURE 2
EXTERNAL CONNECTIONS
+ VIN
V TEMP OUT
2
3
8
OPTIONAL
NOISE REDUCTION
CAPACITOR
6
VRE306
CN
1µF
5
7
FIGURE 3
+ VOUT
4
10kW
OPTIONAL
FINE TRIM
ADJUSTMENT
REF. GND
VRE306DS REV. B MAY 2001
MECHANICAL
FIGURE 3
D
D1
INCHES
D2
E1
E2
E
PIN 1 IDENTIFIER
MILLIMETER
MILLIMETER
MIN
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
D2
.018
.023
0.46
0.58
B
.098
.102
2.48
2.59
E
.507
.513
12.8
13.0
B1
.046
.051
1.14
1.29
E1
.397
.403
10.0
10.2
C
.107
.113
2.71
2.89
E2
.264
.270
6.70
6.85
C1
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
C2
.052
.058
1.32
1.47
Q
.020
.030
.508
.762
S
.045
.055
1.14
1.39
D
.397
.403
10.0
10.2
D1
.372
.380
9.44
9.65
E1
Q
A
INCHES
DIM
P
BASE
SEATING
C1
C2
B
S
C
B1
FIGURE 4
INCHES
MILLIMETER
INCHES
MILLIMETER
DIM
MIN
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
E
.397
.403
10.0
10.2
B
.018
.022
.457
.558
E1
.264
.270
6.70
6.85
B1
.046
.051
1.14
1.29
G1
.290
.310
7.36
7.87
B2
.098
.102
2.48
2.59
L
.195
.215
4.95
5.46
C
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
D
.397
.403
10.0
10.2
Q
.055
.065
1.39
1.65
D1
.372
.380
9.44
9.65
S
.045
.055
1.14
1.39
VRE306DS REV. B MAY 2001
VRE310
Low Cost
Precision Reference
THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 85745 • (520) 882-4000
FEATURES
• 10.000 V OUTPUT ± 1.000 mV (.01%)
PIN CONFIGURATION
• TEMPERATURE DRIFT: 0.6 ppm/°C
• LOW NOISE: 6µV p-p (0.1-10Hz)
• INDUSTRY STD PINOUT- 8 PIN DIP OR
SURFACE MOUNT PACKAGE
N/C
1
+VIN
2
TEMP
3
GND
4
VRE310
TOP
VIEW
8
NOISE
REDUCTION
7
REF. GND
6
VOUT
5
TRIM
•EXCELLENT LINE REGULATION: 6ppm/V Typ.
• OUTPUT TRIM CAPABILITY
FIGURE 1
DESCRIPTION
The VRE310 is a low cost, high precision 10.0V
reference. Packaged in the industry standard 8
pin DIP, the device is ideal for upgrading systems
that use lower performance references.
The device provides ultrastable +10.000V output
with ±1.000 mV (.01%) initial accuracy and a
temperature coefficient of 0.6 ppm/°C.
This
improvement in accuracy is made possible by a
unique, patented multipoint laser compensation
technique developed by Thaler Corporation.
Significant improvements have been made in
other performance parameters as well, including
initial accuracy, warm-up drift, line regulation, and
long-term stability, making the VRE310 series the
most accurate reference available in the standard
8 pin DIP package.
For enhanced performance, the VRE310 has an
external trim option for users who want less than
0.01% initial error.
For ultra low noise
applications, an external capacitor can be
attached between the noise reduction pin and the
ground pin. A reference ground pin is provided to
eliminate socket contact resistance errors.
The VRE310 is recommended for use as a
reference for 14-, 16-, or 18-bit D/A converters
which require an external precision reference.
The device is also ideal for calibrating scale factor
on high resolution A/D converters. The VRE310
offers superior performance over monolithic
references.
SELECTION GUIDE
Model
Initial
Error
mV
VRE310A
VRE310B
VRE310C
VRE310J
VRE310K
VRE310L
1.0
1.6
2.0
1.0
1.6
2.0
Temp.
Coeff.
ppm/°C
0.6
1.0
2.0
0.6
1.0
2.0
Temp.
Range
°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
For package option add D for DIP or S for Surface Mount
to end of model number.
VRE310DS REV. D MAY 2001
ELECTRICAL SPECIFICATIONS
VRE310
Vps =+15V, T = 25°C, RL = 10KΩ unless otherwise noted.
MODEL
A/J
PARAMETER
MIN
TYP
+13.5
0
-40
-65
+15
B/K
MAX
C/L
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
°C
°C
°C
ABSOLUTE RATINGS
Power Supply
Operating Temp. (A,B,C)
Operating Temp. (J,K,L)
Storage Temperature
Short Circuit Protection
+22
+70
+85
+150
Continuous
*
*
*
*
*
*
OUTPUT VOLTAGE
VRE310
(1)
Temp. Sensor Voltage
10.000
630
V
mV
OUTPUT VOLTAGE ERRORS
(2)
Initial Error
Warmup Drift
Tmin - Tmax (3)
Long-Term Stability
Noise (.1-10Hz) (4)
1.00
1.60
1
2.00
2
0.6
3
1.0
6
6
2.0
*
*
*
*
mV
ppm
ppm/°C
ppm/1000hrs
µVpp
OUTPUT CURRENT
Range
±10
*
*
mA
REGULATION
Line
Load
3
3
10
*
*
*
*
*
*
ppm/V
ppm/mA
OUTPUT ADJUSTMENT
Range
20
POWER SUPPLY CURRENTS
*
mV
(5)
VRE310 +PS
NOTES:
*
5
7
*Same as A/J Models.
1. The temp. reference TC is 2.1mV/°C
2. The specified values are without external trim.
*
*
*
*
mA
4. The specified values are without the external
noise reduction capacitor.
5. The specified values are unloaded.
3. The temperature coefficient is determined by the box
method using the following formula:
Vmax - Vmin
x 106
T.C. =
Vnominal x (Tmax-Tmin)
VRE310DS REV. D MAY 2001
TYPICAL PERFORMANCE CURVES
VOUT vs. TEMPERATURE
Temperature oC
VRE310A
VOUT vs. TEMPERATURE
Temperature oC
VRE310B
VOUT vs. TEMPERATURE
VOUT vs. TEMPERATURE
Temperature oC
VRE310J
Temperature oC
VRE310K
QUIESCENT CURRENT VS. TEMP
JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Temperature oC
Output Current (mA)
VOUT vs. TEMPERATURE
Temperature oC
VRE310C
VOUT vs. TEMPERATURE
Temperature oC
VRE310L
PSRR VS. FREQUENCY
Frequency (Hz)
VRE310DS REV. D MAY 2001
DISCUSSION OF PERFORMANCE
THEORY OF OPERATION
This network is less than 2% of the overall network
resistance so it has a negligible effect on long term
stability. By using highly stable resistors in our network,
we produce a voltage reference that also has very good
long term stability
The following discussion refers to the schematic in
figure 2 below. In operation, approximately 6.3 volts is
applied to the noninverting input of the op amp. The
voltage is amplified by the op amp to produce a 10.000V
output. The gain is determined by the networks R1 and
R2: G=1 + R2/R1. The 6.3V zener diode is used because
it is the most stable diode over time and temperature.
Figure 3 shows the proper connection of the VRE310
series voltage references with the optional trim resistor.
The VRE310 reference has the ground terminal brought
out on two pins (pin 4 and pin 7) which are connected
together internally. This allows the user to achieve greater
accuracy when using a socket. Voltage references have a
voltage drop across their power supply ground pin due to
quiescent current flowing through the contact resistance.
If the contact resistance was constant with time and
temperature, this voltage drop could be trimmed out.
When the reference is plugged into a socket, this source
of error can be as high as 20ppm. By connecting pin 4 to
the power supply ground and pin 7 to a high impedance
ground point in the measurement circuit, the error due to
the contact resistance can be eliminated. If the unit is
soldered into place, the contact resistance is sufficiently
small that it does not effect performance. Pay careful
attention to the circuit layout to avoid noise pickup and
voltage drops in the lines.
The zener operating current is derived from the
regulated output voltage through R3. This feedback
arrangement provides a closely regulated zener current.
This current determines the slope of the references'
voltage vs. temperature function. By trimming the zener
current a lower drift over temperature can be achieved.
But since the voltage vs. temperature function is nonlinear
this compensation technique is not well suited for wide
temperature ranges.
Thaler Corporation has developed a nonlinear
compensation network of thermistors and resistors that is
used in the VRE series voltage references. This
proprietary network eliminates most of the nonlinearity in
the voltage vs. temperature function. By then adjusting
the slope, Thaler Corporation produces a very stable
voltage over wide temperature ranges.
VRE310
FIGURE 2
EXTERNAL CONNECTIONS
+ VIN
V TEMP OUT
2
3
8
OPTIONAL
NOISE REDUCTION
CAPACITOR
6
VRE310
CN
1µF
5
7
FIGURE 3
+ VOUT
4
10kΩ
OPTIONAL
FINE TRIM
ADJUSTMENT
REF. GND
VRE310DS REV. D MAY 2001
MECHANICAL
FIGURE 3
D
D1
INCHES
D2
E1
E2
E
PIN 1 IDENTIFIER
MILLIMETER
MILLIMETER
MIN
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
D2
.018
.023
0.46
0.58
B
.098
.102
2.48
2.59
E
.507
.513
12.8
13.0
B1
.046
.051
1.14
1.29
E1
.397
.403
10.0
10.2
C
.107
.113
2.71
2.89
E2
.264
.270
6.70
6.85
C1
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
C2
.052
.058
1.32
1.47
Q
.020
.030
.508
.762
S
.045
.055
1.14
1.39
D
.397
.403
10.0
10.2
D1
.372
.380
9.44
9.65
E1
Q
A
INCHES
DIM
P
BASE
SEATING
C1
C2
B
S
C
B1
FIGURE 4
INCHES
MILLIMETER
INCHES
MILLIMETER
DIM
MIN
MAX
MIN
MAX
DIM
MIN
MAX
MIN
MAX
A
.115
.125
2.92
3.17
E
.397
.403
10.0
10.2
B
.018
.022
.457
.558
E1
.264
.270
6.70
6.85
B1
.046
.051
1.14
1.29
G1
.290
.310
7.36
7.87
B2
.098
.102
2.48
2.59
L
.195
.215
4.95
5.46
C
.009
.012
0.22
0.30
P
.085
.095
2.15
2.41
D
.397
.403
10.0
10.2
Q
.055
.065
1.39
1.65
D1
.372
.380
9.44
9.65
S
.045
.055
1.14
1.39
VRE310DS REV. D MAY 2001