LT1460-5 Linear Technology, LT1460-5 Datasheet - Page 8

• Manufacturer Part Number: LT1460-5
• Description: Micropower Precision Series Reference
• Manufacturer: Linear Technology

LT1460-5
This motion is repeated for a number of cycles and the
relative output deviation is noted. The result shown in
Figure 7a is for two LT1460S8-5s mounted vertically and
Figure 7b is for two LT1460S8-5s mounted horizontally.
The parts oriented in Figure 7a impart less stress into the
package because stress is absorbed in the leads. Figures
7a and 7b show the deviation to be between 250 V and
500 V and implies a 50ppm and 100ppm change respec-
tively. This corresponds to a 13- to 14-bit system and is
8
APPLICATIONS
–2
–2
2
0
4
2
0
4
0
0
Figure 8a. Same Two LT1460S8-5s in Figure 7a, but
With Slots
Figure 7a. Two Typical LT1460S8-5s, Vertical
Orientation Without Slots
1
2
3
4
10
Figure 6. Flexure Numbers
10
U
FLEXURE NUMBER
FLEXURE NUMBER
INFORMATION
U
LONG DIMENSION
20
20
W
SLOT
30
30
1460-5 F06
U
1460-5 F07a
1460-5 F08a
40
40
not a problem for most 10- to 12-bit systems unless the
system has a calibration. In this case, as with temperature
hysteresis, this low level can be important and even more
careful techniques are required.
The most effective technique to improve PC board stress
is to cut slots in the board around the reference to serve as
a strain relief. These slots can be cut on three sides of the
reference and the leads can exit on the fourth side. This
“tongue” of PC board material can be oriented in the long
direction of the board to further reduce stress transferred
to the reference.
The results of slotting the PC boards of Figures 7a and
7b are shown in Figures 8a and 8b. In this example the
slots can improve the output shift from about 100ppm to
nearly zero.
–2
–2
2
0
2
0
4
4
0
0
Figure 8b. Same Two LT1460S8-5s in Figure 7b, but
With Slots
Figure 7b. Two Typical LT1460S8-5s, Horizontal
Orientation Without Slots
10
10
FLEXURE NUMBER
FLEXURE NUMBER
LONG DIMENSION
20
20
SLOT
30
30
1460-5 F07b
1460-5 F08b
40
40