LT1461ACS8 LINER [Linear Technology], LT1461ACS8 Datasheet - Page 11

• Manufacturer Part Number: LT1461ACS8
• Description: Micropower Precision Low Dropout Series Voltage Reference Family
• Manufacturer: LINER [Linear Technology]

APPLICATIO S I FOR ATIO
relative output deviation is noted. The result shown in
Figure 5a is for two LT1461S8-2.5s mounted vertically and
Figure 5b is for two LT1461S8-2.5s mounted horizontally.
The parts oriented in Figure 5a impart less stress into the
package because stress is absorbed in the leads. Figures
5a and 5b show the deviation to be between 125 V and
250 V and implies a 50ppm and 100ppm change respec-
tively. This corresponds to a 13- to 14-bit system and is
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.
–1
–1
1
0
2
2
1
0
0
0
Figure 5a. Two Typical LT1461S8-2.5s,
Vertical Orientation Without Slots
Figure 5b. Two Typical LT1461S8-2.5s,
Horizontal Orientation Without Slots
10
10
U
FLEXURE NUMBER
FLEXURE NUMBER
U
LONG DIMENSION
LONG DIMENSION
20
20
W
30
30
U
1461 F05a
1461 F05b
40
40
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 5a and
5b are shown in Figures 6a and 6b. In this example the
slots can improve the output shift from about 100ppm to
nearly zero.
Figure 6a. Same Two LT1461S8-2.5s in Figure 5a, but with Slots
Figure 6b. Same Two LT1461S8-2.5s in Figure 5b, but with Slots
–1
–1
1
0
1
0
2
2
0
0
10
10
FLEXURE NUMBER
FLEXURE NUMBER
20
20
SLOT
SLOT
30
30
LT1461
11
1461 F06b
1461 F06a
40
40