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VRE117/118/119
Precision
Reference Supplies
THALER CORPORATION • 2015 N. FORBES BOULEVARD • TUCSON, AZ. 85745 • (520) 882-4000
FEATURES
• VERY HIGH ACCURACY: 3.000 V OUTPUT ±200 µV
• EXTREMELY LOW DRIFT: 0.6 ppm/°C 55°C to +125°C
• LOW WARM-UP DRIFT: 1 ppm Typ.
• EXCELLENT STABILITY: 6 ppm/1000 Hrs. Typ.
• EXCELLENT LINE REGULATION: 3 ppm/V Typ.
• HERMETIC 14-PIN CERAMIC DIP
• MILITARY PROCESSING OPTION
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
VRE117 Series Precision Voltage References
provide ultrastable +3.000V (VRE117), -3.000V
(VRE118) and ±3.000V (VRE119) outputs with
±0.200 mV initial accuracy and temperature
coefficient as low as 0.6 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 VRE117 series the
most accurate and stable 3.0V reference
available.
VRE117/118/119 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.
Type
VRE117C +3.0V -25°C to +85°C 200 µV
VRE117CA +3.0V -25°C to +85°C 100 µV
VRE117M +3.0V -55°C to +125°C 400 µV
VRE117MA +3.0V -55°C to +125°C 200 µV
VRE118C -3.0V -25°C to +85°C 200 µV
VRE118CA -3.0V -25°C to +85°C 100 µV
VRE118M -3.0V -55°C to +125°C 400 µV
VRE118MA -3.0V -55°C to +125°C 200 µV
VRE119C ±3.0V -25°C to +85°C 200 µV
VRE119CA ±3.0V -25°C to +85°C 100 µV
VRE119M ±3.0V -55°C to +125°C 400 µV
VRE119MA ±3.0V -55°C to +125°C 200 µV
SELECTION GUIDE
Output
Temperature
Operating Range
Max. Volt
Deviation
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.
VRE117DS REV. C NOV 2000
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ELECTRICAL SPECIFICATIONS
Vps =±15V, T = 25°C, RL = 10k? unless otherwise noted.
VRE117/118/119
MODEL C CA M MA
PARAMETERS MIN TYP MAX MIN TYP MAX MIN TYP MAX MIN TYP MAX UNITS
ABSOLUTE MAXIMUM RATINGS
Power Supply ±13.5 ±22 * * * * * * V
Operating Temperature -25 85 * * -55 125 -55 125 °C
Storage Temperature -65 150 * * * * * * °C
Short Circuit Protection Continuous * * *
OUTPUT VOLTAGE
VRE117 +3.0 * * * V
VRE118 -3.0 * * * V
VRE119 ±3.0 * * * V
OUTPUT VOLTAGE ERRORS
Initial Error 300 200 300 200 µV
Warmup Drift 2 1 2 1 ppm
Tmin - Tmax 200 100 400 200 µV
(1)
Long-Term Stability 6 * * * ppm/1000hr.
Noise (.1-10Hz) 1.5 * * * µVpp
OUTPUT CURRENT
Range ±10 * * * mA
REGULATION
Line 3 10 * * * * * * ppm/V
Load 3 * * * ppm/mA
OUTPUT ADJUSTMENT
Range 5 * * * mV
Temperature Coefficient 1 * * * µV/°C/mV
POWER SUPPLY CURRENTS
(2)
VRE117 +PS/ -PS 5 7 * * * * * * mA
VRE119 +PS 7 9 * * * * * * mA
VRE118/119 -PS 4 6 * * * * * * mA
NOTES: *Same as C Models.
1.Using the box method, the specified value is the
maximum deviation from the output voltage at 25°C
over the specified operating temperature range.
2.The specified values are unloaded.
VRE117DS REV. C NOV 2000
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V
vs. TEMPERATURE
OUT
TYPICAL PERFORMANCE CURVES
V
V
vs. TEMPERATURE
OUT
vs. TEMPERATURE
OUT
V
vs. TEMPERATURE
OUT
Temperature oC
VRE117/118/119C
QUIESCENT CURRENT VS. TEMP
Temperature oC
QUIESCENT CURRENT VS. TEMP
Temperature oC
VRE117/118/119CA
VRE117/118/119M
VRE117/118
JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Output Current (mA)
VRE119
POSITIVE OUTPUT
JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Temperature oC
Temperature oC
VRE117/118/119MA
PSRR VS. FREQUENCY
Frequency (Hz)
PSRR VS. FREQUENCY
Temperature oC
QUIESCENT CURRENT VS. TEMP
Temperature oC
Output Current (mA)
NEGATIVE OUTPUT
JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Output Current (mA)
Frequency (Hz)
PSRR VS. FREQUENCY
Frequency (Hz)
VRE117DS REV. C NOV 2000
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DISCUSSION OF PERFORMANCE
THEORY OF OPERATION
The following discussion refers to the schematic
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.
The current source provides a closely regulated
zener current, which determines the slope of the
reference's 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 method
leaves a residual error over wide temperature
ranges.
To remove this residual error, Thaler Corporation
has developed a nonlinear compensation network of
thermistors and resistors that is used in the VRE117
series 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.
APPLICATION INFORMATION
Figure 1 shows the proper connection of the
VRE117 series voltage reference with the optional
trim resistors. When trimming the VRE119, 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 VRE117 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.
VRE117
VRE119
VRE117DS REV. C NOV 2000
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EXTERNAL CONNECTIONS
FIGURE 1
1. Optional Fine Adjust for approximately ±5mV. VRE118 trim pot center tap connects to -15V.
PIN CONFIGURATION
TOP VIEW
NC
NC
NC
-PS
NC
REF. GND
GND
14-PIN HYBRID
PACKAGE
VRE117
(VRE118)
FINE ADJ.
+3.0V (-3.0V)
FINE ADJ.
+PS (-PS)
NC
NC
NC
TOP VIEW
FINE -ADJ.
-3.0V
FINE -ADJ.
-PS
NC
REF. GND
GND
VRE119
FINE +ADJ.
+3.0V
FINE +ADJ.
+PS
NC
NC
NC
MECHANICAL
INCHES MILLIMETER
DIM MIN MAX MIN MAX DIM MIN MAX MIN MAX
E .480 .500 12.1 12.7 A .120 .155 3.0 4.0
L .195 .215 4.9 5.4 Q .015 .035 0.4 0.9
D .775 .805 19.7 20.4 Q1 N/A .030 N/A 0.7
B .016 .020 0.4 0.5 C .009 .012 0.2 0.3
B1 .038 .042 0.9 1.0 G1 .290 .310 7.3 7.8
B2 .095 .105 2.4 2.6
S .085 .105 2.1 2.6
P .004 .006 0.10 0.15
INCHES MILLIMETER
VRE117DS REV. C NOV 2000
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