Datasheet

ADR4520/ADR4525/ADR4530/ADR4533/ADR4540/ADR4550 Data Sheet
Rev. B | Page 34 of 37
Measuring thermal hysteresis over the full operating temperature
range is not reflective of a typical operating environment in
most applications. Instead, smaller temperature variations are
more normal. The ADR4520/ADR4525/ADR4530/ADR4533/
ADR4540/ADR4550 were tested over 20 different temperature
cycles of increasing magnitude, centered at +25°C, starting with
+25 ±5°C and going up to the full operating temperature range
of −40°C to +125°C. The results are shown in Figure 91.
For a temperature delta of 100°C (that is, +25 ±50°C) the
thermal hysteresis is less than 20 ppm for both the full cycle and
the half cycle. Above this range, the thermal hysteresis increases
significantly. These results show that the standard specification,
which covers the full operating temperature range, is close to
the worst case performance.
0 20
40 60 80 100 120 140 160
–40
–20
0
20
40
60
80
100
THERMAL HYSTERESIS (ppm)
TEMPERATURE DE
LTA (°C)
HALF LOOP
FUL
L LOO
P
10203-805
Figure 92. Thermal Hysteresis for Increasing Temperature Range
HUMIDITY SENSITIVITY
The ADR4520/ADR4525/ADR4530/ADR4533/ADR4540/
ADR4550 is packaged in a SOIC plastic package and has a
moisture sensitivity level of MSL-1, per the JEDEC standard.
However, moisture absorption from the air into the package
changes the internal mechanical stresses on the die causing
shifts in the output voltage. Figure 92 shows the effects of a step
change in relative humidity on the output voltage over time.
The humidity chamber is maintained at an ambient temperature of
+25°C, while the relative humidity undergoes a step change from
20% to 80% at time zero. The relative humidity is maintained at
80% for the duration of the testing. Note that the output voltage
shifts quickly compared to the overall settling time, following
the step change in relative humidity.
Figure 93 shows the effects of 10% increases in relative humidity
from 30% to 70% and back to 30%. Note that after the relative
humidity returns to 30%, the output voltage is settling back to
its starting point.
0
100 200 300 400
500 600
ELAPSED TIME (Hours)
–400
–300
–200
–100
0
100
200
300
400
CHANGE IN OUTPUT VOLTAGE (ppm)
SAMPLE 1
SAMPLE 2
SAMPLE 3
V
SY
= 5V
27 UNITS
T
A
= 25°C
RELATIVE HUMIDITY STEP
FROM 20%
TO 80%
10203-803
Figure 93 Change in Output Voltage vs. Time After Humidity Step Change
(20% to 80% Relative Humidity)
0 100 200 300 400 500 600
ELAPSED TIME (Hours)
–200
–150
–100
–50
0
50
100
150
200
CHANGE IN OUTPUT VOLTAGE (ppm)
SAMPLE 1
SAMPLE 2
SAMPLE 3
V
SY
= 5V
27 UNITS
T
A
= 25°C
RELATIVE HUMIDITY STEP FROM
30% TO 70% TO 30%, 10% STEPS
10203-804
Figure 94 Change in Output Voltage vs. Time for 10% Humidity Steps
(30% to 70% to 30% Relative Humidity in 10% Steps)
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