ADP5042 Analog Devices, ADP5042 Datasheet - Page 26

• Manufacturer Part Number: ADP5042
• Description: Micro PMU with 0.8 A Buck, Two 300 mA LDOs, Supervisory, Watchdog and Manual Reset
• Manufacturer: Analog Devices

ADP5042
using a slightly longer watchdog timeout. In the program that
calls the subroutine, WDI1 is set high. The subroutine sets
WDI1 low when it is called. If the program executes without error,
WDI1 is toggled high and low with every loop of the program.
If the subroutine enters an infinite loop, WDI1 is kept low, the
watchdog times out, and the microprocessor is reset (see
Figure 65).
The second watchdog, refreshed through the WDI2 pin, is
useful in applications where safety is a very critical factor and
the system must recover from unwanted operations, for example, a
processor stuck in a continuous loop where Watchdog 1 is kept
refreshed or environmental conditions that may unset or damage
the processor port controlling the WDI1 pin. In the event of a
Watchdog 2 timeout, the ADP5042 power cycles all the supplied
rails to guarantee a clean processor start.
SUBROUTINE
PROGRAM
RETURN
SET WDI
SET WDI
START
CODE
HIGH
LOW
Figure 65. Watchdog Flow Diagram
INFINITE LOOP:
WATCHDOG
TIMES OUT
RESET
Rev. A | Page 26 of 32
PCB LAYOUT GUIDELINES
Poor layout can affect ADP5042 performance, causing electro-
magnetic interference (EMI) and electromagnetic compatibility
(EMC) problems, ground bounce, and voltage losses. Poor
layout can also affect regulation and stability. A good layout is
implemented using the following guidelines:
•
•
•
•
Place the inductor, input capacitor, and output capacitor
close to the IC using short tracks. These components carry
high switching frequencies, and large tracks act as antennas.
Route the output voltage path away from the inductor and
SW node to minimize noise and magnetic interference.
Maximize the size of ground metal on the component side
to help with thermal dissipation.
Use a ground plane with several vias connecting to the
component side ground to further reduce noise interference
on sensitive circuit nodes.
ADP5042
VIN1
V
Figure 66. Typical Applications Circuit
CC
nRSTO
VOUT1
VOUT2
WDI1
WDI2
MICROPROCESSOR
VCORE
VDDIO
RESET
I/O
I/O
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