–6–

ADXL150/ADXL250

REV. 0

TIME –

s

20

02468

10

12

14

16

18

20

15

10

5

0

–5

–10

–15

–20

NOISE FROM INTERNAL CLOCK

Figure 9. Typical Output Noise Voltage with Spikes

Generated by Internal Clock

TIME – ms

SELF-TEST

OUTPUT

(0.2V/DIV)

SELF-TEST

INPUT

(2V/DIV)

02468

10

12

14

16

18

20

Figure 10. Typical Self-Test Response

FREQUENCY – Hz

2.00

1.75

0.25

2k

10

100

1k

1.50

1.25

0.75

0.50

1.00

2.25

2.50

Figure 11. Noise Spectral Density

SUPPLY VOLTAGE – Volts

0.6

0.8

4.0

5.0

1.0

1.2

1.4

1.6

4.5

5.5

6.0

Figure 12. Noise vs. Supply Voltage

FREQUENCY – kHz

30

25

0

100

10000

1000

20

15

10

5

Figure 13. Baseband Error Graph

Figure 13 shows the mV rms error in the output signal if there is

a noise on the power supply pin of 1 mV rms at the internal

clock frequency or its odd harmonics. This is a baseband noise

and can be at any frequency in the 1 kHz passband or at dc.