VRE100/101/102
Precision
Reference Supplies
THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 85745 • (520) 882-4000
FEATURES
•
VERY HIGH ACCURACY: 10.000 V OUTPUT ±0.5 mV
•
EXTREMELY LOW DRIFT: 0.5 ppm/°C 55°C to +125°C
•
LOW WARM-UP DRIFT: 1.0 ppm Typ.
•
EXCELLENT STABILITY: 6 ppm/1000 Hrs. Typ.
•
EXCELLENT LINE REGULATION: 3 ppm/V Typ.
•
HERMETIC 14-PIN CERAMIC DIP
•
MILITARY PROCESSING OPTION
•
PIN & FUNCTION COMPATIBLE WITH
AD2700, AD2710 Series
APPLICATIONS
•
PRECISION A/D and D/A CONVERTERS
•
TRANSDUCER EXCITATION
•
ACCURATE COMPARATOR THRESHOLD
REFERENCE
•
HIGH RESOLUTION SERVO SYSTEMS
•
DIGITAL VOLTMETERS
•
HIGH PRECISION TEST and
MEASUREMENT INSTRUMENTS
DESCRIPTION
VRE100 Series Precision Voltage References
provide ultrastable +10.000V (VRE100), -
10.000V (VRE101) and ±10.000V (VRE102)
outputs with ±0.5 mV initial accuracy and
temperature coefficient as low as 0.5 ppm/°C
over the full military temperature range. This
improvement in accuracy is made possible by a
unique, proprietary 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 VRE100 series the
most accurate and stable 10V reference
available.
SELECTION GUIDE
Type
VRE100C
VRE100CA
VRE100M
VRE100MA
VRE101C
VRE101CA
VRE101M
VRE101MA
VRE102C
VRE102CA
VRE102M
VRE102MA
Output
+10V
+10V
+10V
+10V
-10V
-10V
-10V
-10V
±10V
±10V
±10V
±10V
Temperature
Operating Range
-25°C to +85°C
-25°C to +85°C
-55°C to +125°C
-55°C to +125°C
-25°C to +85°C
-25°C to +85°C
-55°C to +125°C
-55°C to +125°C
-25°C to +85°C
-25°C to +85°C
-55°C to +125°C
-55°C to +125°C
Max. Volt
Deviation
0.6mV
0.3mV
1.0mV
0.5mV
0.6mV
0.3mV
1.0mV
0.5mV
0.6mV
0.3mV
1.0mV
0.5mV
VRE100/101/102 devices are available in two operating temperature ranges, -25°C to +85°C and -55°C to
+125°C, and two performance grades. All devices are packaged in 14-pin hermetic ceramic packages for
maximum long-term stability. "M" versions are screened for high reliability and quality.
Superior stability, accuracy, and quality make these references ideal for precision applications such as A/D
and D/A converters, high-accuracy test and measurement instrumentation, and transducer excitation.
VRE100DS REV. D MAY 1995
4-20
DISCUSSION OF PERFORMANCE
THEORY OF OPERATION
The following discussion refers to the schematic
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.
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. 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.
APPLICATION INFORMATION
Figure 1 shows the proper connection of the
VRE100 series voltage reference with the optional
trim resistors. When trimming the VRE102, the
positive voltage should be trimmed first since the
negative voltage tracks the positive side. Pay careful
attention to the circuit layout to avoid noise pickup
and voltage drops in the lines.
The VRE100 series voltage references have the
ground terminal brought out on two pins (pin 6 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 7 to the power supply ground and
pin 6 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 doesn't effect performance. The VRE series
voltage references can be connected with or without
the use of pin 6 and still provide performance
superior to the 2700 and 2710 series voltage
references.
VRE100
VRE102
VRE100DS REV. D MAY 1995
4-23
FPGA/CPLD
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