Datasheet

LTC6652
13
6652fe
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applications inForMation
Figure 12a. MS8 Long-Term Drift
Long-Term Drift
Long-term drift cannot be extrapolated from accelerated
high temperature testing. This erroneous technique gives
drift numbers that are wildly optimistic. The only way
long-term drift can be determined is to measure it over
the time interval of interest. The LTC6652 long-term drift
data was collected on more than 100 parts that were sol-
dered into PC boards similar to a “real world” application.
The boards were then placed into a constant temperature
oven with T
A
= 35°C, their outputs were scanned regularly
and measured with an 8.5 digit DVM. Long-term drift is
shown below in Figure 12.
Figure 12b. LS8 Long-Term Drift
Hysteresis
The hysteresis data shown in Figure 13 represents the
worst-case data collected on parts from –40°C to 125°C.
The output is capable of dissipating relatively high power,
i.e., for the LTC6652-2.5, P
D
= 10.7V • 5.5mA = 58.85mW.
The thermal resistance of the MS8 package is 200°C/W
and this dissipation causes a 11.8°C internal rise. This
could increase the junction temperature above 125°C and
may cause the output to shift due to thermal hysteresis.
Figure 13a. MS8 Hysteresis Plot –40°C to 125°C Figure 13b. LS8 Hysteresis Plot –40°C to 125°C
HOURS
0
ppm
60
80
600
6652 F12b
40
–20
20
200 400 800 1000
–40
0
LTC6652-2.5 LS8 PACKAGE
4 TYPICAL PARTS
T
A
= 30°C
HOURS
0
ppm
60
80
900
6652 F12a
40
–20
20
300 600 1200 1500
–40
0
LTC6652-2.5 MS8 PACKAGE
3 TYPICAL PARTS
T
A
= 35°C
DISTRIBUTION (ppm)
–110 –80 –50 –20 0 5020 80
0
NUMBER OF UNITS
2
3
4
5
9
7
6652 F13b
8
6
110
1
25°C TO 125°C TO 25°C 25°C TO –40°C TO 25°C
DISTRIBUTION (ppm)
–250 –150 –50
0
NUMBER OF UNITS
5
10
15
35
25
6652 F13a
30
20
15050
25°C TO 125°C TO 25°C 25°C TO –40°C TO 25°C