LT1460 View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LT1460 Datasheet PDF : 26 Pages
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LT1460
Applications Information
The LT1460S3 family of references are designed to be
stable with a large range of capacitive loads. With no
capacitive load, these references are ideal for fast settling
or applications where PC board space is a premium. The
test circuit shown in Figure 12 is used to measure the
response time and stability of various load currents and
load capacitors. This circuit is set for the 2.5V option. For
other voltage options, the input voltage must be scaled
up and the output voltage generator offset voltage must
be adjusted. The 1V step from 2.5V to 1.5V produces a
current step of 10mA or 1mA for RL = 100Ω or RL = 1k.
Figure 13 shows the response of the reference to these
VIN = 2.5V
CIN
0.1µF
VOUT
RL
LT1460S3-2.5
CL
VGEN
Figure 12. Response Time Test Circuit
2.5V
1.5V
1460 F12
1mA and 10mA load steps with no load capacitance, and
Figure 14 shows a 1mA and 10mA load step with a 0.1µF
output capacitor. Figure 15 shows the response to a 1mA
load step with CL = 1µF and 4.7µF.
The frequency compensation of the LT1460S3 version is
slightly different than that of the other packages. Additional
care must be taken when choosing load capacitance in an
application circuit.
Table 1 gives the maximum output capacitance for vari-
ous load currents and output voltages of the LT1460S3 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.
VGEN
2.5V
1.5V
VOUT
1mA
VGEN
2.5V
1.5V
VOUT
10mA
VOUT
1mA
100µs/DIV
1460 F14
VOUT
10mA
Figure 14. CL = 0.1µF
1µs/DIV
1460 F13
Figure 13. CL = 0µF
VGEN
VOUT
VOUT
2.5V
1.5V
1µA
4.7µA
100µs/DIV
1460 F15
Figure 15. IOUT = 1mA
1460fc
17
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