AD680
+V
IN
TEMPERATURE PERFORMANCE
V
OUT
C
L
1000pF
V
L
V
OUT
249Ω
00813-012
0.1μF
AD680
V
OUT
0V
The AD680 is designed for reference applications where tem-
perature performance is important. Extensive temperature
testing and characterization ensure that the device’s performance
is maintained over the specified temperature range.
Some confusion exists in the area of defining and specifying
reference voltage error over temperature. Historically, references
have been characterized using a maximum deviation per degree
centigrade, that is, ppm/°C. However, because of nonlinearities
in temperature characteristics that originated in standard Zener
references (such as “S” type characteristics), most manufac-
turers now use a maximum limit error band approach to specify
devices. This technique involves measuring the output at three
or more different temperatures to specify an output voltage
error band.
2.501
Figure 12. Capacitive Load Transient Response Test Circuit
1,000 pF, 0 mA to 10 mA load.
2V
100
5mV
5μs
V
L
90
SLOPE = TC
=
V
MAX
– V
MIN
(T
MAX
– T
MIN
)
×
2.5V
×
10
–6
2.501 – 2.498
(85°C – (–40°C))
×
2.5V
×
10
–6
V
OUT
VOLTS (V)
2.500
=
2.499
= 9.6ppm/°C
10
0%
00813-013
2.498
–50
–30
LOAD REGULATION
the AD680.
1V
100
–10 0
20
40
60
TEMPERATURE (°C)
80
100
Figure 15. Typical AD680AN/AD680AR Temperature Drift
1mV
100μs
V
L
90
AD680AR and illustrates the test methodology. The box in
ing temperature extremes, and on the top and bottom by the
maximum and minimum output voltages measured over the
operating temperature range.
The maximum height of the box for the appropriate temperature
range and device grade is shown in Table 4. Duplication of these
results requires a combination of high accuracy and stable tem-
perature control in a test system. Evaluation of the AD680 will
produce a curve similar to that in Figure 15, but output readings
could vary depending upon the test equipment used.
00813-014
V
OUT
10
0%
Table 4. Maximum Output Change in mV
Device Grade
AD680JN/AD680JR
AD680JT
AD680AN
Maximum Output Change (mV)
0°C to 70°C
−40°C to +85°C
4.375
Not applicable
5.250
Not applicable
Not applicable
6.250
Figure 14. Typical Load Regulation Characteristics
Rev. H | Page 8 of 12
00813-015
Figure 13. Output Response with Capacitive Load
AD [ ANALOG DEVICES ]
