VRE3025 ETC1 [List of Unclassifed Manufacturers], VRE3025 Datasheet - Page 6

• Manufacturer Part Number: VRE3025
• Description: Low Cost Precision Reference
• Manufacturer: ETC1 [List of Unclassifed Manufacturers]

TEMPERATURE PERFORMANCE
initial
temperature are important to the user.
instrument manufacturers, a voltage reference with a
temperature coefficient less than 1ppm/ C makes it
possible to not have to perform a system temperature
calibration, a slow and costly process.
and box), the box method is used commonly used. A box
is formed by the min/max limits for the nominal output
voltage over the operating temperature range.
equation follows:
method of test and provides a closer estimate of actual
error than the other methods.
guarantees limits for the temperature error but does not
specify the exact shape and slope of the device under
test.
acquisition system over the industrial temperature range
(-40 C to +85 C), will need a voltage reference with a
temperature coefficient (TC) of 1.0ppm/ C if the reference
is allowed to contribute an error equivalent to 1LSB. For
1/2LSB equivalent error from the reference you would
need a voltage reference with a temperature coefficient of
0.5ppm/ C. Figure 4 shows the required reference TC vs.
delta T change from 25 C for resolution ranging from 8
bits to 20 bits.
The VRE3025 is designed for applications where the
Of the three TC specification methods (slope, butterfly,
This method corresponds more accurately to the
A designer who needs a 14-bit accurate data
T
error
.
C
.
at
V
nominal
room
V
10000
1000
max
0.01
100
0.1
10
1
temperature
T
1
max
V
Reference TC vs. T change from 25°C for 1 LSB change
min
T
min
The box method
and
10
drift
For many
6
over
The
10
THERMAL HYSTERISIS
change.
change and return to the initial temperature, they do not
always have the same initial voltage. Thermal hysterisis
is difficult to correct and is a major error source in
systems that experience temperature changes greater
than 25 C. Reference vendors are starting to include this
important specification in their datasheets.
A change in output voltage as a result of a temperature
When references experience a temperature
100
8 BIT
10 BIT
12 BIT
14 BIT
16 BIT
18 BIT
20 BIT
VRE3025DS REV.D JULY 2000