LT6003/LT6004/LT6005
APPLICATIONS INFORMATION
10M
10M
V
CC
249k
249k
249k
249k
–
–
+
A3
1/4 LT6005
A4
–
–
INB
INA
GND
LT6700-2
OUTB OUTA
1/4 LT6005
+
V
V
S
CC
V
IN
100mV/DIV
10M
10M
V
OUT
50mV/DIV
V
CC
COMP
B
1M
OUT
S
10k
A
–
S1
A2
–
COMP
OUT
5V/DIV
V
OUT
1/4 LT6005
200k
A1
+
600345 F04b
1/4 LT6005
2ms/DIV
+
0.1µF
V
IN
S1: FAIRCHILD FSA1157
V
= 1.8V TO 5V
CC
I
= 10µA, RISING TO 20µA
CC
WITH LARGE SIGNAL
ADAPTIVE FILTER IMPROVES INHERENT TRADE-OFF OF SETTLING TIME VS NOISE FILTERING. SMALL SIGNAL DC STEPS
SETTLE WITH A 20ms TIME CONSTANT FOR AN 8Hz NOISE BANDWIDTH. LARGE STEP SIGNALS (>10mV) CAUSE S1 TO
TURN ON, SPEEDING UP THE TIME CONSTANT TO 1ms, FOR IMPROVED SETTLING. AS THE OUTPUT SETTLES BACK TO
WITHIN 10mV, 51 TURNS OFF AGAIN, RESTORING THE 20ms TIME CONSTANT, FOR IMPROVED FILTERING.
600345 F04
Figure 4. Adaptive Filter
V
S
R2
390k
R1
1M
V
S
LT1389-1.25
+
–
LT6003
I
LOAD
600345 F05
V
LOAD
1.25V
R1
I
=
LOAD
LOAD
V
= V
+ 2V
S
LOAD
Figure 5. Precision 1.25µA Current Source
600345fd
15
LINEAR_DIMENSIONS [ Linear Dimensions ]
