LT1460 LINER [Linear Technology], LT1460 Datasheet - Page 17

• Manufacturer Part Number: LT1460
• Description: Micropower Precision Series Reference Family
• Manufacturer: LINER [Linear Technology]

APPLICATIO S I FOR ATIO
Table 1 gives the maximum output capacitance for vari-
ous load currents and output voltages to avoid instability.
Load capacitors with low ESR (effective series resistance)
cause more ringing than capacitors with higher ESR such
as polarized aluminum or tantalum capacitors.
Table 1. Maximum Output Capacitance
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 LT1460S3 long-term
drift data was taken on over 100 parts that were soldered
into PC boards similar to a “real world” application. The
boards were then placed into a constant temperature oven
with T
measured with an 8.5 digit DVM. Figure 12 shows typical
long-term drift of the LT1460S3s.
VOLTAGE
OPTION
2.5V
3.3V
10V
3V
5V
A
= 30°C, their outputs were scanned regularly and
–100
–150
I
– 50
150
100
OUT
50
0
>10µF
>10µF
>10µF
>10µF
>10µF
Figure 12. Typical Long-Term Drift
0
= 100µA
100
200
U
300
I
OUT
400
>10µF
>10µF
>10µF
>10µF
U
1µF
HOURS
= 1mA
500
600
700
I
OUT
W
800
0.15µF
2µF
2µF
1µF
1µF
= 10mA I
900
1460 F12
1000
OUT
U
0.68µF
0.68µF
0.68µF
0.68µF
0.1µF
= 20mA
Hysteresis
Hysteresis data shown in Figure 13 and Figure 14 represents
the worst-case data taken on parts from 0°C to 70°C and
from –40°C to 85°C. The device is capable of dissipating
relatively high power, i.e., for the LT1460S3-2.5, PD =
17.5V • 20mA = 350mW. The thermal resistance of the
SOT-23 package is 325°C/W and this dissipation causes
a 114°C internal rise producing a junction temperature of
T
cause the output to shift due to thermal hysteresis. For
highest performance in precision applications, do not
let the LT1460S3’s junction temperature exceed 85°C.
J
= 25°C + 114°C = 139°C. This elevated temperature will
12
10
18
16
14
8
6
4
0
6
5
4
3
2
0
2
9
8
7
1
–240
–600
WORST-CASE HYSTERESIS
ON 40 UNITS
WORST-CASE HYSTERESIS
ON 34 UNITS
–500
–200
Figure 14. –40°C to 85°C Hysteresis
Figure 13. 0°C to 70°C Hysteresis
–160
–400
85°C TO 25°C
–120
–300
70°C TO 25°C
–200
– 80
HYSTERESIS (ppm)
HYSTERESIS (ppm)
–100
–40
0
0
100
40
0°C TO 25°C
–40°C TO 25°C
200
80
120
300
LT1460
160
400
200
500
17
1460 F13
1460 F14
240
600
1460f