CIRRUS VRE205M

VRE205
VRE205
P r o d u c t IInnnnoovvaa t i o n FFr roomm
Precision Voltage Reference
Features
DESCRIPTION
♦ Very High Accuracy: ±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 V to ±22 V
♦ Hermetic 20-terminal Ceramic LCC
♦ 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
VRE205 Series Precision Voltage References provides
ultrastable ±5 V outputs with ±0.4 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. Significant
improvements have been made in other performance
parameters as well, including initial accuracy, warm-up
drift, line regulation, and longterm stability, making the
VRE205 series the most accurate and stable 5 V references available.
VRE205 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 20-terminal ceramic LCC packages
for maximum long-term stability. “M” versions are
screened for high reliability and quality.
Figure 1. BLOCK DIAGRAM
11
Selection Guide
Output (V)
Temperature
Operating Range
Volt Deviation (Max)
VRE205C
VRE205CA
±5V
±5V
-25°C to +85°C
-25°C to +85°C
0.4mV
0.2mV
VRE205M
VRE205MA
±5V
±5V
-55°C to +125°C
-55°C to +125°C
0.6mV
0.3mV
Model
VRE205DS
http://www.cirrus.com
Copyright © Cirrus Logic, Inc. 2009
(All Rights Reserved)
20-terminal Ceramic LCC
Package Style HD
JUL 20091
APEX − VRE205DSREVG
VRE205
P r o d u c t I n n o v a t i o nF r o m
1. Characteristics and Specifications
ELECTRICAL Specifications
Vps =+15V, T = +25°C, RL = 10K Ω Unless Otherwise Noted.
Model
Parameter
C
Min
Typ
CA
Max
Min
+13.5
+22
Operating Temperature
-25
Storage Temperature
-65
Typ
M
Max
Min
*
*
+85
*
+150
*
Typ
MA
Max
Min
*
*
*
-55
*
*
Typ
Max
Units
*
*
V
+125
-55
+125
ºC
*
*
*
ºC
ABSOLUTE MAXIMUM RATINGS
Power Supply
Short Circuit Protection
Continuous
*
*
*
±5
*
*
*
OUTPUT VOLTAGE
VRE205
V
OUTPUT VOLTAGE ERRORS
Initial Error
±800
Warmup Drift
TMIN - TMAX
±400
2
(Note1)
±800
1
400
±400
2
200
1
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)
VRE205 +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.
2
VRE205DS
VRE205
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
VRE205C
Temperature oC
VRE205CA
Temperature oC
VRE205M
Temperature oC
VRE205MA
QUIESCENT CURRENT VS. TEMP
Temperature oC
JUNCTION TEMP. RISE VS. OUTPUT CURRENT
Output Current (mA)
PSRR VS. FREQUENCY
Frequency (Hz)
3. THEORY OF OPERATION
The following discussion refers to the schematic 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 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 compensation technique is not well suited for wide temperature ranges.
A nonlinear compensation network of thermistors and resistors is used in the VRE series voltage. This proprietary
network eliminates most of the nonlinearity in the voltage vs. temperature function. By then adjusting the slope, a
very stable voltage over wide temperature ranges is produced. 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.
VRE205DS
3
VRE205
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 VRE205 series voltage references with the optional trim resistor is shown below. Pay
careful attention to the circuit layout to avoid noise pickup and voltage drops in the lines.
The VRE205 series voltage references have the ground terminal brought out on two pins (pin 9 and pin 10) 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 10 to the power supply ground and pin 9 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.
PIN CONFIGURATION
EXTERNAL CONNECTIONS
3
+15V
1
20
19
18
5
17
6
16
7
15
8
Ref. Gnd.
2
4
9 10
11
12 13
NC NC NC VOUT NC
18 17 16 15 14
13 NC
NC 19
NC 20
VOUT = +5V
14
10KΩ
NC
1
NC
2
NC
3
12 NC
VRE205
11 TRIM
TOP VIEW
10 GND
Δ
4
9
5
NC VIN
6
7
REF GND
8
NC NC NC
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
IMPORTANT NOTICE
Cirrus Logic, Inc. and its subsidiaries ("Cirrus") believe that the information contained in this document is accurate and reliable. However, the information is subject
to change without notice and is provided "AS IS" without warranty of any kind (express or implied). Customers are advised to obtain the latest version of relevant
information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale
supplied at the time of order acknowledgment, including those pertaining to warranty, indemnification, and limitation of liability. No responsibility is assumed by Cirrus
for the use of this information, including use of this information as the basis for manufacture or sale of any items, or for infringement of patents or other rights of third
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does not extend to other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale.
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VRE205DS