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VRE305L [ETC]

Low Cost Precision Reference; 低成本精密基准
VRE305L
型号： VRE305L
厂家： ETC    ETC
描述：

Low Cost Precision Reference
低成本精密基准
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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  
8
7
6
1
2
3
N.C.  
+VIN  
NOISE  
REF. GND  
VOUT  
• LOW NOISE: 1.5µV p-p (0.1-10Hz)  
VRE302  
• INDUSTRY STD PINOUT- 8 PIN DIP OR  
TOP  
TEMP  
SURFACE MOUNT PACKAGE  
VIEW  
4
5
GND  
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 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.  
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.  
SELECTION GUIDE  
Temp.  
Range  
°C  
Temp.  
Coeff.  
Initial  
Error  
mV  
Model  
ppm/°C  
VRE302A  
VRE302B  
VRE302C  
VRE302J  
VRE302K  
VRE302L  
0.25  
0.40  
0.50  
0.25  
0.40  
0.50  
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 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.  
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  
B/K  
C/L  
PARAMETER  
ABSOLUTE RATINGS  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
UNITS  
Power Supply  
+13.5 +15  
+22  
+70  
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
Operating Temp. (A,B,C)  
Operating Temp. (J,K,L)  
Storage Temperature  
Short Circuit Protection  
0
°C  
°C  
°C  
-40  
-65  
+85  
+150  
Continuous  
OUTPUT VOLTAGE  
VRE302  
2.500  
630  
*
*
*
*
V
(1)  
Temp. Sensor Voltage  
mV  
OUTPUT VOLTAGE ERRORS  
(2)  
Initial Error  
0.25  
0.6  
0.40  
1.0  
0.50  
2.0  
mV  
ppm  
Warmup Drift  
1
2
3
(3)  
Tmin - Tmax  
ppm/°C  
ppm/1000hrs  
µVpp  
Long-Term Stability  
6
*
*
*
*
(4)  
Noise (.1-10Hz)  
1.5  
OUTPUT CURRENT  
Range  
±10  
*
*
mA  
REGULATION  
Line  
6
3
10  
*
*
*
*
*
*
*
*
ppm/V  
Load  
ppm/mA  
OUTPUT ADJUSTMENT  
Range  
10  
5
*
*
*
*
mV  
mA  
(5)  
POWER SUPPLY CURRENTS  
VRE302 +PS  
7
4. The specified values are without the external  
noise reduction capacitor.  
NOTES: *Same as A/J Models.  
1. The temp. reference TC is 2.1mV/ °C  
2. The specified values are without external trim.  
5. The specified values are unloaded.  
3. The temperature coefficient is determined by the box  
method using the following formula:  
Vmax - Vmin  
T.C. =  
x 106  
Vnominal x (Tmax-Tmin  
)
VRE302DS REV. F MAY 2001  
TYPICAL PERFORMANCE CURVES  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE302A  
Temperature oC  
VRE302B  
Temperature oC  
VRE302C  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE302K  
Temperature oC  
VRE302J  
Temperature oC  
VRE302L  
POSITIVE OUTPUT (TYP)  
JUNCTION TEMP. RISE VS. OUTPUT CURRENT  
QUIESCENT CURRENT VS. TEMP  
PSRR VS. FREQUENCY  
Temperature oC  
Output Current (mA)  
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
+ VOUT  
6
VRE302  
OPTIONAL  
CN  
OPTIONAL  
FINE TRIM  
10kΩ  
5
NOISE REDUCTION  
CAPACITOR  
1µF  
ADJUSTMENT  
4
7
REF. GND  
FIGURE 3  
VRE302DS REV. F MAY 2001  
MECHANICAL  
FIGURE 3  
D
D1  
INCHES  
MILLIMETER  
INCHES  
MILLIMETER  
D2  
DIM MIN  
MAX MIN MAX  
DIM  
D2  
E
MIN  
.018  
.507  
.397  
.264  
.085  
.020  
.045  
MAX MIN MAX  
.023 0.46 0.58  
.513 12.8 13.0  
.403 10.0 10.2  
.270 6.70 6.85  
.095 2.15 2.41  
.030 .508 .762  
.055 1.14 1.39  
A
.115 .125 2.92 3.17  
.098 .102 2.48 2.59  
.046 .051 1.14 1.29  
.107 .113 2.71 2.89  
.009 .012 0.22 0.30  
.052 .058 1.32 1.47  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
B
B1  
C
E1  
E2  
P
E1  
E2  
E
C1  
C2  
D
Q
S
D1  
PIN 1 IDENTIFIER  
E1  
Q
A
P
BASE  
SEATING  
C1  
C2  
B
C
S
B1  
FIGURE 4  
INCHES  
MILLIMETER  
MAX  
INCHES  
MILLIMETER  
DIM MIN MAX MIN  
DIM  
E
MIN  
.397  
.264  
.290  
.195  
.085  
.055  
.045  
MAX MIN  
MAX  
10.2  
6.85  
7.87  
5.46  
2.41  
1.65  
1.39  
A
.115 .125 2.92 3.17  
.018 .022 .457 .558  
.046 .051 1.14 1.29  
.098 .102 2.48 2.59  
.009 .012 0.22 0.30  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
.403 10.0  
.270 6.70  
.310 7.36  
.215 4.95  
.095 2.15  
.065 1.39  
.055 1.14  
B
E1  
G1  
L
B1  
B2  
C
P
D
Q
D 1  
S
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  
8
7
6
1
2
3
N.C.  
+VIN  
NOISE  
REF. GND  
VOUT  
• LOW NOISE: 1.5µV p-p (0.1-10Hz)  
VRE302-6  
• INDUSTRY STD PINOUT- 8 PIN DIP OR  
TOP  
TEMP  
SURFACE MOUNT PACKAGE  
VIEW  
4
5
GND  
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 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 VRE302-  
6 offers superior performance over monolithic  
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.  
SELECTION GUIDE  
Temp.  
Range  
°C  
Temp.  
Coeff.  
Initial  
Error  
mV  
Model  
ppm/°C  
VRE302-6A  
VRE302-6B  
VRE302-6C  
VRE302-6J  
VRE302-6K  
VRE302-6L  
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 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.  
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  
B/K  
C/L  
PARAMETER  
ABSOLUTE RATINGS  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
UNITS  
Power Supply  
+13.5 +15  
+22  
+70  
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
Operating Temp. (A,B,C)  
Operating Temp. (J,K,L)  
Storage Temperature  
Short Circuit Protection  
0
°C  
°C  
°C  
-40  
-65  
+85  
+150  
Continuous  
OUTPUT VOLTAGE  
VRE302-6  
2.048  
630  
*
*
*
*
V
(1)  
Temp. Sensor Voltage  
mV  
OUTPUT VOLTAGE ERRORS  
(2)  
Initial Error  
0.20  
0.6  
0.35  
1.0  
0.40  
2.0  
mV  
ppm  
Warmup Drift  
1
2
3
(3)  
Tmin - Tmax  
ppm/ °C  
ppm/1000hrs  
µVpp  
Long-Term Stability  
6
*
*
*
*
(4)  
Noise (.1-10Hz)  
1.5  
OUTPUT CURRENT  
Range  
±10  
*
*
mA  
REGULATION  
Line  
6
3
10  
*
*
*
*
*
*
*
*
ppm/V  
Load  
ppm/mA  
OUTPUT ADJUSTMENT  
Range  
10  
5
*
*
*
*
mV  
mA  
(5)  
POWER SUPPLY CURRENTS  
VRE302-6 +PS  
7
4. The specified values are without the external  
noise reduction capacitor.  
NOTES: *Same as A/J Models.  
1. The temp. reference TC is 2.1mV/ °C  
2. The specified values are without external trim.  
5. The specified values are unloaded.  
3. The temperature coefficient is determined by the box  
method using the following formula:  
Vmax - Vmin  
T.C. =  
x 106  
Vnominal x (Tmax-Tmin  
)
VRE302-6DS REV. B MAY 2001  
TYPICAL PERFORMANCE CURVES  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE302-6A  
Temperature oC  
VRE302-6B  
Temperature oC  
VRE302-6C  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE302-6K  
Temperature oC  
VRE302-6J  
Temperature oC  
VRE302-6L  
JUNCTION TEMP. RISE VS. OUTPUT CURRENT  
QUIESCENT CURRENT VS. TEMP  
PSRR VS. FREQUENCY  
Temperature oC  
Output Current (mA)  
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  
V TEMP OUT  
2
3
8
+ VOUT  
6
VRE302-6  
OPTIONAL  
CN  
OPTIONAL  
FINE TRIM  
10kΩ  
5
NOISE REDUCTION  
CAPACITOR  
1µF  
ADJUSTMENT  
4
7
REF. GND  
FIGURE 3  
VRE302-6DS REV. B MAY 2001  
MECHANICAL  
FIGURE 3  
D
D1  
INCHES  
MILLIMETER  
INCHES  
MILLIMETER  
D2  
DIM MIN  
MAX MIN MAX  
DIM  
D2  
E
MIN  
.018  
.507  
.397  
.264  
.085  
.020  
.045  
MAX MIN MAX  
.023 0.46 0.58  
.513 12.8 13.0  
.403 10.0 10.2  
.270 6.70 6.85  
.095 2.15 2.41  
.030 .508 .762  
.055 1.14 1.39  
A
.115 .125 2.92 3.17  
.098 .102 2.48 2.59  
.046 .051 1.14 1.29  
.107 .113 2.71 2.89  
.009 .012 0.22 0.30  
.052 .058 1.32 1.47  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
B
B1  
C
E1  
E2  
P
E1  
E2  
E
C1  
C2  
D
Q
S
D1  
PIN 1 IDENTIFIER  
E1  
Q
A
P
BASE  
SEATING  
C1  
C2  
B
C
S
B1  
FIGURE 4  
INCHES  
MILLIMETER  
MAX  
INCHES  
MILLIMETER  
DIM MIN MAX MIN  
DIM  
E
MIN  
.397  
.264  
.290  
.195  
.085  
.055  
.045  
MAX MIN  
MAX  
10.2  
6.85  
7.87  
5.46  
2.41  
1.65  
1.39  
A
.115 .125 2.92 3.17  
.018 .022 .457 .558  
.046 .051 1.14 1.29  
.098 .102 2.48 2.59  
.009 .012 0.22 0.30  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
.403 10.0  
.270 6.70  
.310 7.36  
.215 4.95  
.095 2.15  
.065 1.39  
.055 1.14  
B
E1  
G1  
L
B1  
B2  
C
P
D
Q
D 1  
S
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  
NOISE  
REDUCTION  
8
7
6
1
2
3
N/C  
+VIN  
• LOW NOISE: 1.5µV p-p (0.1-10Hz)  
VRE303  
REF. GND  
• INDUSTRY STD PINOUT- 8 PIN DIP OR  
SURFACE MOUNT PACKAGE  
TOP  
VIEW  
TEMP  
GND  
VOUT  
4
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 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.  
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.  
SELECTION GUIDE  
Temp.  
Range  
°C  
Temp.  
Coeff.  
ppm/°C  
Initial  
Error  
mV  
Model  
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 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.  
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 = 10KW unless otherwise noted.  
MODEL  
A/J  
B/K  
C/L  
PARAMETER  
ABSOLUTE RATINGS  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
UNITS  
Power Supply  
+14  
0
-40  
-65  
+15  
+16  
+70  
+85  
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
Operating Temp. (A,B,C)  
Operating Temp. (J,K,L)  
Storage Temperature  
Short Circuit Protection  
°C  
°C  
°C  
+150  
Continuous  
OUTPUT VOLTAGE  
VRE303  
Temp. Sensor Voltage  
3.000  
630  
*
*
*
*
V
mV  
(1)  
OUTPUT VOLTAGE ERRORS  
(2)  
Initial Error  
0.30  
0.6  
0.48  
1.0  
0.60  
2.0  
mV  
ppm  
ppm/°C  
ppm/1000hrs  
µVpp  
Warmup Drift  
1
2
3
(3)  
Tmin - Tmax  
Long-Term Stability  
Noise (.1-10Hz)  
6
2.0  
*
*
*
*
(4)  
OUTPUT CURRENT  
Range  
±10  
*
*
mA  
REGULATION  
Line  
Load  
6
3
10  
*
*
*
*
*
*
ppm/V  
ppm/mA  
OUTPUT ADJUSTMENT  
Range  
10  
*
*
*
*
mV  
(5)  
POWER SUPPLY CURRENTS  
VRE303 +PS  
5
7
*
*
mA  
4. The specified values are without the external  
noise reduction capacitor.  
NOTES: *Same as A/J Models.  
1. The temp. reference TC is 2.1mV/ °C  
2. The specified values are without external trim.  
5. The specified values are unloaded.  
3. The temperature coefficient is determined by the box  
method using the following formula:  
Vmax - Vmin  
T.C. =  
x 106  
Vnominal x (Tmax-Tmin  
)
VRE303DS REV. B MAY 2001  
TYPICAL PERFORMANCE CURVES  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE303A  
Temperature oC  
VRE303B  
Temperature oC  
VRE303C  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE303K  
Temperature oC  
VRE303J  
Temperature oC  
VRE303L  
JUNCTION TEMP. RISE VS. OUTPUT CURRENT  
PSRR VS. FREQUENCY  
QUIESCENT CURRENT VS. TEMP  
Temperature oC  
Output Current (mA)  
Frequency (Hz)  
VRE303DS 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 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.  
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 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
+ VOUT  
6
VRE303  
OPTIONAL  
NOISE REDUCTION  
CAPACITOR  
CN  
1µF  
OPTIONAL  
FINE TRIM  
10kW  
5
ADJUSTMENT  
4
7
REF. GND  
FIGURE 3  
VRE303DS REV. B MAY 2001  
MECHANICAL  
FIGURE 3  
D
D1  
INCHES  
MILLIMETER  
INCHES  
MILLIMETER  
D2  
DIM MIN  
MAX MIN MAX  
DIM  
D2  
E
MIN  
.018  
.507  
.397  
.264  
.085  
.020  
.045  
MAX MIN MAX  
.023 0.46 0.58  
.513 12.8 13.0  
.403 10.0 10.2  
.270 6.70 6.85  
.095 2.15 2.41  
.030 .508 .762  
.055 1.14 1.39  
A
.115 .125 2.92 3.17  
.098 .102 2.48 2.59  
.046 .051 1.14 1.29  
.107 .113 2.71 2.89  
.009 .012 0.22 0.30  
.052 .058 1.32 1.47  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
B
B1  
C
E1  
E2  
P
E1  
E2  
E
C1  
C2  
D
Q
S
D1  
PIN 1 IDENTIFIER  
E1  
Q
A
P
BASE  
SEATING  
C1  
C2  
B
C
S
B1  
FIGURE 4  
INCHES  
MILLIMETER  
MAX  
INCHES  
MILLIMETER  
MAX MIN MAX  
.403 10.0 10.2  
.270 6.70 6.85  
.310 7.36 7.87  
.215 4.95 5.46  
.095 2.15 2.41  
.065 1.39 1.65  
.055 1.14 1.39  
DIM MIN MAX MIN  
DIM  
E
MIN  
.397  
.264  
.290  
.195  
.085  
.055  
.045  
A
.115 .125 2.92 3.17  
.018 .022 .457 .558  
.046 .051 1.14 1.29  
.098 .102 2.48 2.59  
.009 .012 0.22 0.30  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
B
E1  
G1  
L
B1  
B2  
C
P
D
Q
D 1  
S
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  
NOISE  
8
7
6
1
2
3
N/C  
+VIN  
• LOW NOISE: 3µV p-p (0.1-10Hz)  
REDUCTION  
REF. GND  
VRE304  
• INDUSTRY STD PINOUT- 8 PIN DIP OR  
TOP  
TEMP  
VOUT  
SURFACE MOUNT PACKAGE  
VIEW  
4
5
GND  
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 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.  
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.  
SELECTION GUIDE  
Temp.  
Range  
°C  
Temp.  
Coeff.  
Initial  
Error  
mV  
Model  
ppm/°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 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  
For package option add D for DIP or S for Surface Mount  
to end of model number.  
noise reduction pin and the ground pin.  
A
reference ground pin is provided to eliminate  
socket contact resistance errors.  
VRE304DS REV. D MAY 2001  
ELECTRICAL SPECIFICATIONS  
VRE304  
Vps =+15V, T = 25°C, RL = 10KΩ unless otherwise noted.  
MODEL  
A/J  
B/K  
C/L  
PARAMETER  
ABSOLUTE RATINGS  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
UNITS  
Power Supply  
+13.5 +15  
+22  
+70  
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
Operating Temp. (A,B,C)  
Operating Temp. (J,K,L)  
Storage Temperature  
Short Circuit Protection  
0
°C  
°C  
°C  
-40  
-65  
+85  
+150  
Continuous  
OUTPUT VOLTAGE  
VRE304  
4.500  
630  
*
*
*
*
V
(1)  
Temp. Sensor Voltage  
mV  
OUTPUT VOLTAGE ERRORS  
(2)  
Initial Error  
0.45  
0.6  
0.70  
1.0  
0.90  
2.0  
mV  
ppm  
Warmup Drift  
1
2
3
(3)  
Tmin - Tmax  
ppm/°C  
ppm/1000hrs  
µVpp  
Long-Term Stability  
6
3
*
*
*
*
(4)  
Noise (.1-10Hz)  
OUTPUT CURRENT  
Range  
±10  
*
*
mA  
REGULATION  
Line  
6
3
10  
*
*
*
*
*
*
ppm/V  
Load  
ppm/mA  
OUTPUT ADJUSTMENT  
Range  
10  
*
*
*
*
mV  
(5)  
POWER SUPPLY CURRENTS  
VRE304 +PS  
5
7
*
*
mA  
4. The specified values are without the external  
noise reduction capacitor.  
NOTES: *Same as A/J Models.  
1. The temp. reference TC is 2.1mV/ °C  
2. The specified values are without external trim.  
5. The specified values are unloaded.  
3. The temperature coefficient is determined by the box  
method using the following formula:  
Vmax - Vmin  
T.C. =  
x 106  
Vnominal x (Tmax-Tmin  
)
VRE304DS REV. D MAY 2001  
TYPICAL PERFORMANCE CURVES  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE304A  
Temperature oC  
VRE304B  
Temperature oC  
VRE304C  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE304K  
Temperature oC  
VRE304J  
Temperature oC  
VRE304L  
JUNCTION TEMP. RISE VS. OUTPUT CURRENT  
PSRR VS. FREQUENCY  
QUIESCENT CURRENT VS. TEMP  
Temperature oC  
Output Current (mA)  
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
+ VOUT  
6
VRE304  
OPTIONAL  
CΝ  
OPTIONAL  
FINE TRIM  
10kΩ  
5
NOISE REDUCTION  
CAPACITOR  
1µF  
ADJUSTMENT  
4
7
REF. GND  
FIGURE 3  
VRE304DS REV. D MAY 2001  
MECHANICAL  
FIGURE 3  
D
D1  
INCHES  
MILLIMETER  
INCHES  
MILLIMETER  
D2  
DIM MIN  
MAX MIN MAX  
DIM  
D2  
E
MIN  
.018  
.507  
.397  
.264  
.085  
.020  
.045  
MAX MIN MAX  
.023 0.46 0.58  
.513 12.8 13.0  
.403 10.0 10.2  
.270 6.70 6.85  
.095 2.15 2.41  
.030 .508 .762  
.055 1.14 1.39  
A
.115 .125 2.92 3.17  
.098 .102 2.48 2.59  
.046 .051 1.14 1.29  
.107 .113 2.71 2.89  
.009 .012 0.22 0.30  
.052 .058 1.32 1.47  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
B
B1  
C
E1  
E2  
P
E1  
E2  
E
C1  
C2  
D
Q
S
D1  
PIN 1 IDENTIFIER  
E1  
Q
A
P
BASE  
SEATING  
C1  
C2  
B
C
S
B1  
FIGURE 4  
INCHES  
MILLIMETER  
MAX  
INCHES  
MILLIMETER  
DIM MIN MAX MIN  
DIM  
E
MIN  
.397  
.264  
.290  
.195  
.085  
.055  
.045  
MAX MIN  
MAX  
10.2  
6.85  
7.87  
5.46  
2.41  
1.65  
1.39  
A
.115 .125 2.92 3.17  
.018 .022 .457 .558  
.046 .051 1.14 1.29  
.098 .102 2.48 2.59  
.009 .012 0.22 0.30  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
.403 10.0  
.270 6.70  
.310 7.36  
.215 4.95  
.095 2.15  
.065 1.39  
.055 1.14  
B
E1  
G1  
L
B1  
B2  
C
P
D
Q
D 1  
S
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  
NOISE  
REDUCTION  
8
7
6
1
2
3
N/C  
+VIN  
• LOW NOISE: 3µV p-p (0.1-10Hz)  
VRE304-6  
REF. GND  
• INDUSTRY STD PINOUT- 8 PIN DIP OR  
SURFACE MOUNT PACKAGE  
TOP  
VIEW  
TEMP  
GND  
VOUT  
4
5
TRIM  
• EXCELLENT LINE REGULATION: 6ppm/V Typ.  
• OPERATES ON +15V SUPPLY  
FIGURE 1  
DESCRIPTION  
The VRE304-6 is a low cost, high precision  
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 VRE304-  
6 offers superior performance over monolithic  
references.  
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  
SELECTION GUIDE  
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.  
Temp.  
Range  
°C  
Temp.  
Coeff.  
ppm/°C  
Initial  
Error  
mV  
Model  
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 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  
For package option add D for DIP or S for Surface Mount  
to end of model number.  
noise reduction pin and the ground pin.  
A
reference ground pin is provided to eliminate  
socket contact resistance errors.  
VRE304-6DS REV. D JUN 1999  
ELECTRICAL SPECIFICATIONS  
VRE304-6  
Vps =+15V, T = 25°C, RL = 10KW unless otherwise noted.  
MODEL  
A/J  
B/K  
C/L  
PARAMETER  
ABSOLUTE RATINGS  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
UNITS  
Power Supply  
+13  
0
-40  
-65  
+15  
+22  
+70  
+85  
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
Operating Temp. (A,B,C)  
Operating Temp. (J,K,L)  
Storage Temperature  
Short Circuit Protection  
°C  
°C  
°C  
+150  
Continuous  
OUTPUT VOLTAGE  
VRE304-6  
Temp. Sensor Voltage  
4.096  
630  
*
*
*
*
V
mV  
(1)  
OUTPUT VOLTAGE ERRORS  
(2)  
Initial Error  
0.41  
0.6  
0.64  
1.0  
0.82  
2.0  
mV  
ppm  
ppm/ ° C  
ppm/1000hrs  
mVpp  
Warmup Drift  
1
2
3
(3)  
Tmin - Tmax  
Long-Term Stability  
Noise (.1-10Hz)  
6
3
*
*
*
*
(4)  
OUTPUT CURRENT  
Range  
±10  
*
*
mA  
REGULATION  
Line  
Load  
6
3
10  
*
*
*
*
*
*
ppm/V  
ppm/mA  
OUTPUT ADJUSTMENT  
Range  
10  
*
*
*
*
mV  
(5)  
POWER SUPPLY CURRENTS  
VRE304-6 +PS  
5
7
*
*
mA  
4. The specified values are without the external  
noise reduction capacitor.  
NOTES: *Same as A/J Models.  
1. The temp. reference TC is 2.1mV/ ° C  
2. The specified values are without external trim.  
5. The specified values are unloaded.  
3. The temperature coefficient is determined by the box  
method using the following formula:  
Vmax - Vmin  
T.C. =  
x 106  
Vnominal x (Tmax-Tmin  
)
VRE304-6DS REV. D JUN 1999  
TYPICAL PERFORMANCE CURVES  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE304-6A  
Temperature oC  
VRE304-6B  
Temperature oC  
VRE304-6C  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE304-6K  
Temperature oC  
VRE304-6J  
Temperature oC  
VRE304-6L  
JUNCTION TEMP. RISE VS. OUTPUT CURRENT  
PSRR VS. FREQUENCY  
QUIESCENT CURRENT VS. TEMP  
Temperature oC  
Output Current (mA)  
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  
V TEMP OUT  
2
3
8
+ VOUT  
6
VRE304-6  
OPTIONAL  
NOISE REDUCTION  
CAPACITOR  
CN  
1µF  
OPTIONAL  
FINE TRIM  
10k?  
5
ADJUSTMENT  
4
7
REF. GND  
FIGURE 3  
VRE304-6DS REV. D JUN 1999  
MECHANICAL SPECIFICATIONS  
FIGURE 3  
INCHES  
MILLIMETER  
INCHES  
MILLIMETER  
MAX MIN MAX  
.380 9.45 9.65  
DIM MIN MAX MIN MAX  
DIM  
D1  
E
MIN  
.372  
.425  
.397  
.264  
.085  
.045  
A
.110 .120 2.794 3.048  
.095 .105 2.413 2.667  
.021 .027 0.533 0.686  
.055 .065 1.397 1.651  
.012 .020 0.305 0.508  
.020 .040 0.508 1.016  
.395 .405 10.03 10.29  
B
.435 10.80 11.05  
.403 10.08 10.24  
B1  
C
E1  
E2  
P
.270  
.095  
.055  
6.71 6.86  
2.16 2.41  
1.14 1.40  
C1  
C2  
D
S
D
D1  
E2 E1  
E
1
A
P
C1  
B
S
B1  
C
C2  
VRE304-6DS REV. D JUN 1999  
MECHANICAL SPECIFICATIONS  
INCHES  
MILLIMETER  
INCHES  
MILLIMETER  
DIM MIN MAX MIN MAX  
DIM  
E
MIN  
.425  
.397  
.264  
.290  
.175  
.085  
.045  
MAX MIN MAX  
.435 10.80 11.05  
.403 10.08 10.24  
A
.170 .180 4.318 4.572  
.095 .105 2.413 2.667  
.016 .020 0.406 0.508  
.008 .011 0.203 0.279  
.055 .065 1.397 1.651  
.395 .405 10.03 10.29  
B
E1  
E2  
G
B1  
C
.270  
.310  
.225  
.095  
.055  
6.71 6.86  
7.36 7.87  
4.46 5.72  
2.16 2.41  
1.14 1.40  
C1  
D
L
P
D1  
.372 .380  
9.45 9.65  
S
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  
NOISE  
8
7
6
1
2
3
N/C  
+VIN  
• LOW NOISE: 3µV p-p (0.1-10Hz)  
REDUCTION  
REF. GND  
VRE305  
• INDUSTRY STD PINOUT- 8 PIN DIP OR  
TOP  
TEMP  
VOUT  
SURFACE MOUNT PACKAGE  
VIEW  
4
5
GND  
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 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.  
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.  
SELECTION GUIDE  
Temp.  
Range  
°C  
Temp.  
Coeff.  
Initial  
Error  
mV  
Model  
ppm/°C  
VRE305A  
VRE305B  
VRE305C  
VRE305J  
VRE305K  
VRE305L  
0.5  
0.8  
1.0  
0.5  
0.8  
1.0  
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 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.  
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  
B/K  
C/L  
PARAMETER  
ABSOLUTE RATINGS  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
UNITS  
Power Supply  
+13.5 +15  
+22  
+70  
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
Operating Temp. (A,B,C)  
Operating Temp. (J,K,L)  
Storage Temperature  
Short Circuit Protection  
0
°C  
°C  
°C  
-40  
-65  
+85  
+150  
Continuous  
OUTPUT VOLTAGE  
VRE305  
5.000  
630  
*
*
*
*
V
Temp. Sensor Voltage(1)  
mV  
OUTPUT VOLTAGE ERRORS  
(2)  
Initial Error  
0.50  
0.6  
0.80  
1.0  
1.00  
2.0  
mV  
ppm  
Warmup Drift  
1
2
3
(3)  
Tmin - Tmax  
ppm/°C  
ppm/1000hrs  
µVpp  
Long-Term Stability  
6
3
*
*
*
*
(4)  
Noise (.1-10Hz)  
OUTPUT CURRENT  
Range  
±10  
*
*
mA  
REGULATION  
Line  
6
3
10  
*
*
*
*
*
*
ppm/V  
Load  
ppm/mA  
OUTPUT ADJUSTMENT  
Range  
10  
*
*
*
*
mV  
(5)  
POWER SUPPLY CURRENTS  
VRE305 +PS  
5
7
*
*
mA  
4. The specified values are without the external  
noise reduction capacitor.  
NOTES: *Same as A/J Models.  
1. The temp. reference TC is 2.1mV/°C  
2. The specified values are without external trim.  
5. The specified values are unloaded.  
3. The temperature coefficient is determined by the box  
method using the following formula:  
Vmax - Vmin  
T.C. =  
x 106  
Vnominal x (Tmax-Tmin  
)
VRE305DS REV. D MAY 2001  
TYPICAL PERFORMANCE CURVES  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE305A  
Temperature oC  
VRE305B  
Temperature oC  
VRE305C  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE305K  
Temperature oC  
VRE305J  
Temperature oC  
VRE305L  
JUNCTION TEMP. RISE VS. OUTPUT CURRENT  
PSRR VS. FREQUENCY  
QUIESCENT CURRENT VS. TEMP  
Temperature oC  
Output Current (mA)  
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
+ VOUT  
6
VRE305  
OPTIONAL  
CN  
OPTIONAL  
FINE TRIM  
10KΩ  
5
NOISE REDUCTION  
CAPACITOR  
1µF  
ADJUSTMENT  
4
7
REF. GND  
FIGURE 3  
VRE305DS REV. D MAY 2001  
MECHANICAL  
FIGURE 3  
D
D1  
INCHES  
MILLIMETER  
INCHES  
MILLIMETER  
D2  
DIM MIN  
MAX MIN MAX  
DIM  
D2  
E
MIN  
.018  
.507  
.397  
.264  
.085  
.020  
.045  
MAX MIN MAX  
.023 0.46 0.58  
.513 12.8 13.0  
.403 10.0 10.2  
.270 6.70 6.85  
.095 2.15 2.41  
.030 .508 .762  
.055 1.14 1.39  
A
.115 .125 2.92 3.17  
.098 .102 2.48 2.59  
.046 .051 1.14 1.29  
.107 .113 2.71 2.89  
.009 .012 0.22 0.30  
.052 .058 1.32 1.47  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
B
B1  
C
E1  
E2  
P
E1  
E2  
E
C1  
C2  
D
Q
S
D1  
PIN 1 IDENTIFIER  
E1  
Q
A
BASE  
SEATING  
P
C1  
C2  
B
S
C
B1  
FIGURE 4  
INCHES  
MILLIMETER  
MAX  
INCHES  
MILLIMETER  
DIM MIN MAX MIN  
DIM  
E
MIN  
.397  
.264  
.290  
.195  
.085  
.055  
.045  
MAX MIN  
MAX  
10.2  
6.85  
7.87  
5.46  
2.41  
1.65  
1.39  
A
.115 .125 2.92 3.17  
.018 .022 .457 .558  
.046 .051 1.14 1.29  
.098 .102 2.48 2.59  
.009 .012 0.22 0.30  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
.403 10.0  
.270 6.70  
.310 7.36  
.215 4.95  
.095 2.15  
.065 1.39  
.055 1.14  
B
E1  
G1  
L
B1  
B2  
C
P
D
Q
D 1  
S
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  
NOISE  
8
7
6
1
2
3
N/C  
+VIN  
• LOW NOISE: 4µV p-p (0.1-10Hz)  
REDUCTION  
REF. GND  
VRE306  
• INDUSTRY STD PINOUT- 8 PIN DIP OR  
TOP  
TEMP  
VOUT  
SURFACE MOUNT PACKAGE  
VIEW  
4
5
GND  
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 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.  
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.  
SELECTION GUIDE  
Temp.  
Range  
°C  
Temp.  
Coeff.  
Initial  
Error  
mV  
Model  
ppm/°C  
VRE306A  
VRE306C  
VRE306J  
VRE306K  
VRE306L  
0.6  
1.2  
0.6  
1.0  
1.2  
0.6  
2.0  
0.6  
1.0  
2.0  
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 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.  
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  
B/K  
C/L  
PARAMETER  
ABSOLUTE RATINGS  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
UNITS  
Power Supply  
+14  
0
+15  
+16  
+70  
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
Operating Temp. (A,B,C)  
Operating Temp. (J,K,L)  
Storage Temperature  
Short Circuit Protection  
°C  
°C  
°C  
-40  
-65  
+85  
+150  
Continuous  
OUTPUT VOLTAGE  
VRE306  
6.000  
630  
*
*
*
*
V
Temp. Sensor Voltage(1)  
mV  
OUTPUT VOLTAGE ERRORS  
(2)  
Initial Error  
0.60  
1.00  
1.0  
1.20  
2.0  
mV  
ppm  
Warmup Drift  
1
2
3
(3)  
Tmin - Tmax  
0.6  
ppm/ °C  
ppm/1000hrs  
µVpp  
Long-Term Stability  
6
4
*
*
*
*
(4)  
Noise (.1-10Hz)  
OUTPUT CURRENT  
Range  
±10  
*
*
mA  
REGULATION  
Line  
6
3
10  
*
*
*
*
*
*
ppm/V  
Load  
ppm/mA  
OUTPUT ADJUSTMENT  
Range  
10  
*
*
*
*
mV  
(5)  
POWER SUPPLY CURRENTS  
VRE306 +PS  
5
7
*
*
mA  
4. The specified values are without the external  
noise reduction capacitor.  
NOTES: *Same as A/J Models.  
1. The temp. reference TC is 2.1mV/ °C  
2. The specified values are without external trim.  
5. The specified values are unloaded.  
3. The temperature coefficient is determined by the box  
method using the following formula:  
Vmax - Vmin  
T.C. =  
x 106  
Vnominal x (Tmax-Tmin  
)
VRE306DS REV. B MAY 2001  
TYPICAL PERFORMANCE CURVES  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE306A  
Temperature oC  
VRE306B  
Temperature oC  
VRE306C  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE306K  
Temperature oC  
VRE306J  
Temperature oC  
VRE306L  
JUNCTION TEMP. RISE VS. OUTPUT CURRENT  
PSRR VS. FREQUENCY  
QUIESCENT CURRENT VS. TEMP  
Temperature oC  
Output Current (mA)  
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
+ VOUT  
6
VRE306  
OPTIONAL  
CN  
OPTIONAL  
FINE TRIM  
10kW  
5
NOISE REDUCTION  
CAPACITOR  
1µF  
ADJUSTMENT  
4
7
REF. GND  
FIGURE 3  
VRE306DS REV. B MAY 2001  
MECHANICAL  
FIGURE 3  
D
D1  
INCHES  
MILLIMETER  
INCHES  
MILLIMETER  
D2  
DIM MIN  
MAX MIN MAX  
DIM  
D2  
E
MIN  
.018  
.507  
.397  
.264  
.085  
.020  
.045  
MAX MIN MAX  
.023 0.46 0.58  
.513 12.8 13.0  
.403 10.0 10.2  
.270 6.70 6.85  
.095 2.15 2.41  
.030 .508 .762  
.055 1.14 1.39  
A
.115 .125 2.92 3.17  
.098 .102 2.48 2.59  
.046 .051 1.14 1.29  
.107 .113 2.71 2.89  
.009 .012 0.22 0.30  
.052 .058 1.32 1.47  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
B
B1  
C
E1  
E2  
P
E1  
E2  
E
C1  
C2  
D
Q
S
D1  
PIN 1 IDENTIFIER  
E1  
Q
A
BASE  
SEATING  
P
C1  
C2  
B
S
C
B1  
FIGURE 4  
INCHES  
MILLIMETER  
MAX  
INCHES  
MILLIMETER  
DIM MIN MAX MIN  
DIM  
E
MIN  
.397  
.264  
.290  
.195  
.085  
.055  
.045  
MAX MIN  
MAX  
10.2  
6.85  
7.87  
5.46  
2.41  
1.65  
1.39  
A
.115 .125 2.92 3.17  
.018 .022 .457 .558  
.046 .051 1.14 1.29  
.098 .102 2.48 2.59  
.009 .012 0.22 0.30  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
.403 10.0  
.270 6.70  
.310 7.36  
.215 4.95  
.095 2.15  
.065 1.39  
.055 1.14  
B
E1  
G1  
L
B1  
B2  
C
P
D
Q
D 1  
S
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  
NOISE  
8
7
6
1
2
3
N/C  
+VIN  
• LOW NOISE: 6µV p-p (0.1-10Hz)  
REDUCTION  
REF. GND  
VRE310  
• INDUSTRY STD PINOUT- 8 PIN DIP OR  
TOP  
TEMP  
VOUT  
SURFACE MOUNT PACKAGE  
VIEW  
4
5
GND  
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 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.  
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.  
SELECTION GUIDE  
Temp.  
Range  
°C  
Temp.  
Coeff.  
Initial  
Error  
mV  
Model  
ppm/°C  
VRE310A  
VRE310B  
VRE310C  
VRE310J  
VRE310K  
VRE310L  
1.0  
1.6  
2.0  
1.0  
1.6  
2.0  
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 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.  
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  
B/K  
C/L  
PARAMETER  
ABSOLUTE RATINGS  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
MIN  
TYP  
MAX  
UNITS  
Power Supply  
+13.5 +15  
+22  
+70  
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
V
Operating Temp. (A,B,C)  
Operating Temp. (J,K,L)  
Storage Temperature  
Short Circuit Protection  
0
°C  
°C  
°C  
-40  
-65  
+85  
+150  
Continuous  
OUTPUT VOLTAGE  
VRE310  
10.000  
630  
*
*
*
*
V
Temp. Sensor Voltage(1)  
mV  
OUTPUT VOLTAGE ERRORS  
(2)  
Initial Error  
1.00  
0.6  
1.60  
1.0  
2.00  
2.0  
mV  
ppm  
Warmup Drift  
1
2
3
(3)  
Tmin - Tmax  
ppm/°C  
ppm/1000hrs  
µVpp  
Long-Term Stability  
6
6
*
*
*
*
(4)  
Noise (.1-10Hz)  
OUTPUT CURRENT  
Range  
±10  
*
*
mA  
REGULATION  
Line  
3
3
10  
*
*
*
*
*
*
ppm/V  
Load  
ppm/mA  
OUTPUT ADJUSTMENT  
Range  
20  
*
*
*
*
mV  
(5)  
POWER SUPPLY CURRENTS  
VRE310 +PS  
5
7
*
*
mA  
4. The specified values are without the external  
noise reduction capacitor.  
NOTES: *Same as A/J Models.  
1. The temp. reference TC is 2.1mV/°C  
2. The specified values are without external trim.  
5. The specified values are unloaded.  
3. The temperature coefficient is determined by the box  
method using the following formula:  
Vmax - Vmin  
T.C. =  
x 106  
Vnominal x (Tmax-Tmin  
)
VRE310DS REV. D MAY 2001  
TYPICAL PERFORMANCE CURVES  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE310A  
Temperature oC  
VRE310B  
Temperature oC  
VRE310C  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
VOUT vs. TEMPERATURE  
Temperature oC  
VRE310K  
Temperature oC  
VRE310J  
Temperature oC  
VRE310L  
JUNCTION TEMP. RISE VS. OUTPUT CURRENT  
PSRR VS. FREQUENCY  
QUIESCENT CURRENT VS. TEMP  
Temperature oC  
Output Current (mA)  
Frequency (Hz)  
VRE310DS REV. D MAY 2001  
DISCUSSION OF PERFORMANCE  
THEORY OF OPERATION  
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.  
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  
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
+ VOUT  
6
VRE310  
OPTIONAL  
CN  
OPTIONAL  
FINE TRIM  
10kΩ  
5
NOISE REDUCTION  
CAPACITOR  
1µF  
ADJUSTMENT  
4
7
REF. GND  
FIGURE 3  
VRE310DS REV. D MAY 2001  
MECHANICAL  
FIGURE 3  
D
D1  
INCHES  
MILLIMETER  
INCHES  
MILLIMETER  
D2  
DIM MIN  
MAX MIN MAX  
DIM  
D2  
E
MIN  
.018  
.507  
.397  
.264  
.085  
.020  
.045  
MAX MIN MAX  
.023 0.46 0.58  
.513 12.8 13.0  
.403 10.0 10.2  
.270 6.70 6.85  
.095 2.15 2.41  
.030 .508 .762  
.055 1.14 1.39  
A
.115 .125 2.92 3.17  
.098 .102 2.48 2.59  
.046 .051 1.14 1.29  
.107 .113 2.71 2.89  
.009 .012 0.22 0.30  
.052 .058 1.32 1.47  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
B
B1  
C
E1  
E2  
P
E1  
E2  
E
C1  
C2  
D
Q
S
D1  
PIN 1 IDENTIFIER  
E1  
Q
A
BASE  
SEATING  
P
C1  
C2  
B
S
C
B1  
FIGURE 4  
INCHES  
MILLIMETER  
MAX  
INCHES  
MILLIMETER  
DIM MIN MAX MIN  
DIM  
E
MIN  
.397  
.264  
.290  
.195  
.085  
.055  
.045  
MAX MIN  
MAX  
10.2  
6.85  
7.87  
5.46  
2.41  
1.65  
1.39  
A
.115 .125 2.92 3.17  
.018 .022 .457 .558  
.046 .051 1.14 1.29  
.098 .102 2.48 2.59  
.009 .012 0.22 0.30  
.397 .403 10.0 10.2  
.372 .380 9.44 9.65  
.403 10.0  
.270 6.70  
.310 7.36  
.215 4.95  
.095 2.15  
.065 1.39  
.055 1.14  
B
E1  
G1  
L
B1  
B2  
C
P
D
Q
D 1  
S
VRE310DS REV. D MAY 2001  

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