Datasheet

LT6654
13
6654fd
For more information www.linear.com/LT6654
Bypass and Load Capacitors
The LT6654 voltage references should have an input by-
pass capacitor of 0.1µF or larger, however the bypassing
o
n o
ther components nearby is sufficient. In high voltage
applications, V
IN
> 30V, an output short-circuit to ground
can create an input voltage transient that could exceed the
maximum input voltage rating. To prevent this worst-case
condition, an RC input line filter of 10µs (i.e. 10Ω and 1µF)
is recommended. These references also require an output
capacitor for stability. The optimum output capacitance for
most applications is 1µF, although larger values work as
well. This capacitor affects the turn-on and settling time
for the output to reach its final value.
Figure 1 shows the turn-on time for the LT6654-2.5 with a
0.1µF input bypass and 1µF load capacitor. Figure 2 shows
the output response to a 0.5V transient on V
IN
with the
same capacitors.
The test circuit of Figure 3 is used to measure the stability
with various load currents. With R
L
= 1k, the 1V step pro-
duces a current step of 1mA. Figure 4 shows the response
to a ±
0.5mA load. Figure 5 is the output response to a
sourcing step from 4mA to 5mA, and Figure 6 is the output
response of a sinking step from 4mA to 5mA.
applicaTions inForMaTion
Figure 1. Turn-On Characteristics of LT6654-2.5
LT6654-2.5
C
IN
0.1µF
V
IN
3V
C
L
1µF
V
GEN
1k
6654 F03
1V
OUTIN
GND
Figure 2. Output Response to 0.5V Ripple on V
IN
Figure 3. Load Current Response Time Test Circuit
20µs/DIV
GND
GND
V
IN
1V/DIV
V
OUT
1V/DIV
6654 F01
C
LOAD
= 1µF
50µs/DIV
V
IN
0.5V/DIV
3V/DC
V
OUT
2mV/DIV/AC
2.5V/DC
6654 F02
C
LOAD
= 1µF