CIRRUS VRE104CA

VRE104
VRE104
P r o d u c t IInnnnoovvaa t i o n FFr roomm
Precision Voltage Reference
Features
♦ Very High Accuracy: +4.5 V Output, ±0.4 mV
♦ Extremely Low Drift: 0.6 ppm/°C (-55°C to
+125°C)
♦ Excellent Stability: 6 ppm/1000 Hrs. Typical
♦ Excellent Line Regulation: 6 ppm/V Typical
♦ Wide Supply Range: ±13.5 to ±22.0 V
♦ Hermetic 14-pin Ceramic DIP
♦ Military Processing Options
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
VRE104 Series Precision Voltage References provide
ultrastable +4.5 V outputs with up to ±0.4 mV initial
accuracy and temperature coefficient as low as 0.6
ppm/°C over the full military temperature range.
These references are specifically designed to be used
with the Crystal Semiconductor line of successive-approximation type Analog to Digital Converters (ADCs).
This line of ADCs sets new standards for temperature
drift, which can only be as good as the external reference used. The VRE104 combined with an ADC will
provide the lowest drift data conversion obtainable.
VRE104 series 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 the
VRE104 ideal for all precision applications which may
require a 4.5 V reference. High-accuracy test and
measurement instrumentation, and transducer excitation are some other applications which can benefit
from the high accuracy of the VRE104.
Figure 1. Block Diagram
VRE104DS
http://www.cirrus.com
Copyright
© Cirrus
Logic, Inc. 2009
(All Rights Reserved)
APR 2009 APEX − VRE104DSREVD
VRE104
P r o d u c t I n n o v a t i o nF r o m
Selection Guide
Output (V)
Temperature
Operating Range
Volt Deviation (MAX)
VRE104C
VRE104CA
+4.5
+4.5
-25°C to +85°C
-25°C to +85°C
±0.4mV
±0.2mV
VRE101M
VRE100MA
+4.5
+4.5
-55°C to +125°C
-55°C to +125°C
±0.6mV
±0.3mV
Model
Hermetic 14-pin Ceramic DIP
Package Style HC
1. Characteristics and Specifications
ELECTRICAL Specifications
Vps =+15V, T = 25°C, RL = 10K Ω Unless Otherwise Noted.
Grade
VRE104C
Parameter
Min
Typ
VRE104CA
Max
Min
Typ
VRE104M
Max
Min
Typ
VRE104MA
Max
Min
Typ
Max
Units
ABSOLUTE MAXIMUM RATINGS
Power Supply
±13.5
±22
*
*
*
*
*
*
V
Operating Temperature
-25
+85
*
*
-55
+125
-55
+125
ºC
Storage Temperature
-65
+150
*
*
*
*
*
*
ºC
Short Circuit Protection
Continuous
*
*
*
+4.5
*
*
*
OUTPUT VOLTAGE
VRE104
V
OUTPUT VOLTAGE ERRORS
Initial Error
±800
Warmup Drift
TMIN - TMAX
±400
2
(Note1)
±800
1
400
±400
2
1
200
600
µV
ppm
300
µV
Long-Term Stability
6
*
*
*
ppm/1000hrs.
Noise (0.1 - 10Hz)
3
*
*
*
µVpp
OUTPUT CURRENT
Range
±10
*
*
*
mA
REGULATION
Line
6
10
*
*
*
*
*
*
ppm/V
Load
3
*
*
*
ppm/mA
Range
10
*
*
*
mV
Temperature Coefficient
4
*
*
*
µV/ºC/mV
OUTPUT ADJUSTMENT
POWER SUPPLY CURRENT (Note 2)
VRE104 +PS
5
7
*
*
*
*
*
*
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.
VRE104DS
VRE104
P r o d u c t I n n o v a t i o nF r o m
2. TYPICAL PERFORMANCE GRAPHS
VOUT vs. TEMPERATURE
VOUT vs. TEMPERATURE
VOUT vs. TEMPERATURE
VOUT vs. TEMPERATURE
Temperature oC
VRE104C
Temperature oC
VRE104CA
Temperature oC
VRE104M
Temperature oC
VRE104MA
QUIESCENT CURRENT VS. TEMP
JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Temperature oC
Output Current (mA)
PSRR VS. FREQUENCY
Frequency (Hz)
3. THEORY OF OPERATION
The following discussion refers to the block diagram in Figure 1. A FET current source is used to bias a 6.3 V 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 4.5 V output. The gain is determined
by the resistor networks R3 and R4: G=1 + R4/R3. The 6.3 V 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 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 method leaves a residual error over wide temperature
ranges.
To remove this residual error, a nonlinear compensation network of thermistors and resistors has been developed
that is used in the VRE104 series references. This proprietary network eliminates most of the nonlinearity in the
voltage vs. temperature function. By then adjusting the slope, the VRE104 series 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.
VRE104DS
VRE104
P r o d u c t I n n o v a t i o nF r o m
4. APPLICATION INFORMATION
The proper connection of the VRE104 series voltage references is shown below with the optional trim resistors. Pay
careful attention to the circuit layout to avoid noise pickup and voltage drops in the lines.
The VRE104 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 20 ppm. 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 does not effect performance.
VRE104 Used With Crystal Semiconductor ADC
Suggested Reading: Crystal Semiconductor Application Note “Voltage References for the CS501X/CS25IIX Series of A/D Converters"
EXTERNAL CONNECTIONS
1. Optional Fine Adjust for approximately ±10mV.
PIN CONFIGURATION
TOP VIEW
NC
FINE ADJ.
NC
+4.5V
FINE ADJ.
NC
NC
VRE104
+PS
NC
NC
REF. GND
NC
GND
NC
VRE104DS
VRE104
P r o d u c t I n n o v a t i o nF r o m
Contacting Cirrus Logic Support
For all Apex Precision Power product questions and inquiries, call toll free 800-546-2739 in North America.
For inquiries via email, please contact [email protected]
International customers can also request support by contacting their local Cirrus Logic Sales Representative.
To find the one nearest to you, go to www.cirrus.com
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VRE104DS