5

LTC1264

µF

capacitor to an adequate analog ground. The filter’s power

supplies should be isolated from other digital or high

voltage analog supplies. A low noise linear supply is

recommended. Using a switching power supply will lower

the signal-to-noise ratio of the filter. The supply during

power-up should have a slew rate less than 1V/

µs. When

Figures 1 and 2 show typical connections for dual and

single supply operation.

AGND (Pin 6): Analog Ground Pin. The filter performance

depends on the quality of the analog signal ground. For

either dual or single supply operation, an analog ground

plane surrounding the package is recommended. The

analog ground plane should be connected to any digital

ground at a single point. For dual supply operation, Pin 6

should be connected to the analog ground plane. For

single supply operation, Pin 6 should be biased at 1/2

supply and should be bypassed to the analog ground plane

with at least a 1

µF capacitor (Figure 2). For single 5V

biased at 2V. This minimizes passband gain and phase

variations.

Figure 2. Single Supply Ground Plane Connections

Figure 1. Dual Supply Ground Plane Connections

1

µF

1264 F02

200

Ω

LTC1264

CLOCK

SOURCE

ANALOG

GROUND

PLANE

24

23

22

21

20

*

19

18

17

*

16

15

14

13

1

2

3

4

6

7

9

10

11

12

DIGITAL

GROUND

PLANE

5k

5k

17, 20 SHOULD BE TIED TO PIN 6

STAR

SYSTEM

GROUND

+

0.1

µF

–7.5V

1264 F01

200

Ω

7.5V

LTC1264

CLOCK

SOURCE

0.1

µF

ANALOG

GROUND

PLANE

24

23

22

21

20

19

18

17

16

15

14

13

1

2

3

4

5

6

7

8

9

10

11

12

STAR

SYSTEM

GROUND

DIGITAL

GROUND

PLANE

*

PI FU CTIO S