Reset
PCM1717 has both internal power on reset circuit and the
RSTB-pin (pin 15) which accepts 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 3 illustrates
the timing of internal power on reset.
For the RSTB-pin, PSTB-pin accepts external forced reset by
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 4 illustrates the timing of RSTB-pin reset.
2.6V
2.2V
1.8V
VCC/VDD
Reset
Reset Removal
Internal Reset
XTI Clock
1024 system (= XTI) clocks
FIGURE 3. Internal Power-On Reset Timing.
RSTB-pin
50% of VDD
(1)
tRST
Reset
Reset Removal
Internal Reset
1024 system (XTI) clocks
XTI Clock
NOTE: (1) tRST = 20ns min
FIGURE 4. RSTB-Pin Reset Timing.
®
7
PCM1717
BB [ BURR-BROWN CORPORATION ]
