PCM1723 datasheet(12/22 Pages) TI2

12 / 22 page

PCM1723

SBAS057A

www.ti.com

The performance of the internal low-pass filter from DC to

24kHz is shown in Figure 10. The higher frequency rolloff

of the filter is shown in Figure 11. If an application has the

PCM1723 driving a wideband amplifier, it is recommended

to use an external low-pass filter. A simple 3rd-order filter

is shown in Figure 12. For some applications, a passive RC

filter or 2nd-order filter may be adequate.

Reset

The PCM1723 has both internal power-on reset circuit and

the RSTB pin (pin 9) that accepts an external forced reset by

RSTB = LOW. For internal power on reset, initialize (reset)

is done automatically at power on VDD >2.2V (typ). During

internal reset = LOW, the output of the DAC is invalid and

the analog outputs are forced to VCC/2. Figure 13 illustrates

the timing of internal power on reset.

The PCM1723 accepts an external forced reset when

RSTB = L. During RSTB = L, the output of the DAC is

invalid and the analog outputs are forced to VCC/2 after

internal initialize (1024 system clocks count after RSTB = H).

Figure 14 illustrates the timing of RSTB pin reset.

FIGURE 12. 3rd-Order Low-Pass Filter.

10k

Ω

10k

Ω

10k

Ω

1500pF

100pF

680pF

SIN

–

–90

–180

–270

–360

100

10k

100k

GAIN vs FREQUENCY

Frequency (Hz)

–14

–34

–54

–74

–94

Gain

Phase

OPA604

FIGURE 11. Low-Pass Filter Wideband Frequency Response.

FIGURE 10. Low-Pass Filter Frequency Response.

–5

–10

–15

–20

–25

–30

–35

–40

–45

–50

–55

100

10k

100k

10M

Frequency (Hz)

–60

INTERNAL ANALOG FILTER FREQUENCY RESPONSE

(10Hz~10MHz)

1.0

0.5

–0.5

–1.0

Frequency (Hz)

100

10k

24k

INTERNAL ANALOG FILTER FREQUENCY RESPONSE

(20Hz~24kHz, Expanded Scale)

PCM1723 데이터시트(PDF) 12 Page - Texas Instruments

PCM1723 데이터시트(HTML) 12 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

데이터시트 다운로드

링크 URL