WM8523GEDT WOLFSON [Wolfson Microelectronics plc], WM8523GEDT Datasheet - Page 15

• Manufacturer Part Number: WM8523GEDT
• Description: 24-bit 192kHz Stereo DAC with 2Vrms Ground Referenced Line Output
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

Production Data
POWER ON RESET CIRCUIT
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Figure 6 Internal Power on Reset Circuit Schematic
The WM8523 includes an internal Power-On-Reset circuit, as shown in Figure 6, which is used to reset
the DAC digital logic into a default state after power up. The POR circuit is powered by AVDD and has
as its inputs VMID and LINEVDD. It asserts POR low if VMID or LINEVDD are below a minimum
threshold.
Figure 7 Typical Power Timing Requirements
Figure 7 shows a typical power-up sequence where LINEVDD comes up with AVDD. When AVDD goes
above the minimum threshold, V
low and the chip is held in reset. In this condition, all writes to the control interface are ignored. After
VMID rises to V
state and writes to the control interface may take place.
On power down, PORB is asserted low whenever LINEVDD or AVDD drop below the minimum threshold
V
pora_low
.
pord_hi
and AVDD rises to V
pora
, there is enough voltage for the circuit to guarantee POR is asserted
pora_hi,
POR is released high and all registers are in their default
PD, Rev 4.1, August 2011
WM8523
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