LT6003/LT6004/LT6005

16

600345f

APPLICATIONS INFORMATION

Figure 4. Adaptive Filter

S1

S

B

A

S1: FAIRCHILD FSA1157

WITH LARGE SIGNAL

0.1

µF

600345 F04

A2

1/4 LT6005

10M

A3

1/4 LT6005

249k

200k

249k

10M

10M

10k

10M

A4

1/4 LT6005

249k

249k

LT6700-2

GND

OUTB

OUTA

A1

1/4 LT6005

1M

ADAPTIVE FILTER IMPROVES INHERENT TRADEOFF 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.

100mV/DIV

50mV/DIV

5V/DIV

2ms/DIV

600345 F04b

Figure 5. Precision 1.25µA Current Source

600345 F05

LT6003

R1

1M

LOAD

1.25V

R1

R2

390k

LT1389-1.25