−2

−1

0

1

2

−50

0

50

100

150

200

250

300

350

400

450

SYNC pin transition

Time (µs)

VOUTP, VOUTN

DC mode

Full Scale Step

G000

0

10

20

30

40

50

60

-

-

-

-

-

-

0

5

10

15

20

25

30

35

40

45

50

Output Frequency (kHz)

CLK = 4.096MHz

Excludes I/V Filter Rolloff

OUTPUT FREQUENCY RESPONSE

DAC1282

SBAS490

– DECEMBER 2011

www.ti.com

Figure 46 shows the step response time of the dc mode. The step response of sine and digital data mode have

similar settling times. Note that additional filter components in the signal path may also affect the response time.

Figure 46. DC Mode Step Response

FREQUENCY RESPONSE

The DAC internal signal generator is capable of output signal frequencies from 0.489 Hz to 250 Hz. Frequencies

outside of this range are also possible by driving the DAC directly with an external digital input (bitstream).

However, the DAC low-pass filters the digital input and results in a sinx/x frequency response. The

–3 dB signal

bandwidth of the DAC filter is 8.2 kHz. Figure 47 illustrates the DAC1282 frequency response. Note that

high-order noise-shaped digital inputs may limit the useable frequency range as a result of rising noise.

Figure 47. DAC Frequency Response

28

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© 2011, Texas Instruments Incorporated

Product Folder Link(s): DAC1282