A. Terminology:
- Primary = Essential power up sequence of all
voltage domains to full active state.
- VOPR MIN = Minimum operational voltage
level that ensures functionality as specified in ,
Recommended Operating Conditions.
- Ramp Up = Voltage supply transition time from off
condition to VOPR MIN.
- Domain_“n” = multiple instances of similar
voltage domains (that is, dual voltage IO domains,
VDDSHVn = VDDSHV0, VDDSHV1, VDDSHV2 …
VDDSHV6)
- Domain_“xxx” = different signal type/protocol
domains using same voltage supply type and level
(that is, VDDA_1P8_xx = VDDA_1P8_DSITX,
VDDA_1P8_USB, VDDA_0P8_DSITX, VDDA_0P8_USB,
etc.)
Time stamps:
Markers showing approximate elapsed times that
are dependent upon PDN feature set, component
selection and power mapping. Values shown are
typical for PDNs combining MCU and Main voltage
domains but could vary based upon PDN design.
Time Stamp definitions
and (typical values for reference only):
T0 – All 3.3-V voltages
start supply ramp-up to V
OPR MIN. (0
ms)
T1 – All 1.8-V
voltages start supply ramp-up to V
OPR
MIN. (0.5 ms)
T2 – All core voltages start supply ramp-up to
V
OPR MIN. (1.0 ms)
T3 – All RAM array
voltages start supply ramp-up to V
OPR
MIN. (1.5 ms)
T4 – OSC1 is stable and PORz/MCU_PORz are
de-asserted to release processor from reset. (11
ms)
B. Any MCU or Main dual
voltage IO domains (VDDSHVn_MCU or VDDSHVn) being
supplied by 3.3 V to support 3.3-V digital
interfaces.
C. Any MCU or Main dual
voltage IO domains (VDDSHVn_MCU or VDDSHVn) being
supplied by 1.8 V to support 1.8-V digital
interfaces.
D. VDDSHV5 supports MMC1
signaling for SD memory cards. A dual voltage
(3.3/1.8 V) power rail is required for compliant,
high-speed SD card operations. If SD card is not
needed or standard data rates with fixed 3.3-V
operation is acceptable, then domain can be
grouped with digital IO 3.3-V power rail. If a SD
card is capable of operating with fixed 1.8 V,
then domain can be grouped with digital IO 1.8-V
power rail.
E. VDDA_3P3_USB is 3.3-V
analog domain used for USB 2.0 differential
interface signaling. A low noise, analog supply is
recommended to provide best signal integrity for
USB data eye mask compliance. If USB interface is
not needed or data bit errors can be tolerated,
then domain can be grouped with 3.3-V digital IO
power rail either directly or through a supply
filter.
F. VDDA_1P8_<clk/pll/ana> are 1.8-V analog
domains supporting clock oscillator, PLL and
analog circuitry needing a low noise supply for
optimal performance. It is not recommended to
combine digital VDDSHVn_MCU and VDDSHVn IO domains
since high frequency switching noise could
negatively impact jitter performance of clock, PLL
and DLL signals. Combining analog
VDDA_1p8_<phy> domains should be avoided but
if grouped, then in-line ferrite bead supply
filtering is required.
G. VDDA_1P8_<phy>
are 1.8-V analog domains supporting multiple
serial PHY interfaces. A low noise, analog supply
is recommended to provide best signal integrity,
interface performance and spec compliance. If any
of these interfaces are not needed, data bit
errors or non-compliant operation can be
tolerated, then domains can be grouped with
digital IO 1.8-V power rail either directly or
through an in-line supply filter is
allowed.
H. VDDA_0P8_<dll/pll> are 0.8 V analog domains
supporting PLL and DLL circuitry needing a low
noise supply for optimal performance. It is not
recommended to combine these domains with any
other 0.8-V domains since high frequency switching
noise could negatively impact jitter performance
of PLL and DLL signals.
I. VDD_MCU is a digital voltage domain with a wide operational
voltage range enabling it to be grouped either with VDDAR_MCU domain or with VDD_CORE; for
the “Combined MCU and Main Domains Power-Up Sequencing,” VDD_MCU can be grouped with
VDD_CORE, and VDDAR_MCU can be grouped with VDDAR_CPU and VDDAR_CORE. If VDD_MCU is
grouped with VDD_CORE, VDD_MCU must be ramped-up from a common voltage resource with 0.8-V
VDD_CORE at T2. If VDD_MCU is not grouped with VDD_CORE, VDD_MCU must be ramped-up before
T2. In either case, the VDDAR supplies must be ramped at T3.
J. Minimum set-up and
hold times shown with respect to MCU_PORz and PORz
asserting high to latch MCU_BOOTMODEn (referenced
to MCU_VDDSHV0) and BOOTMODEn (reference to
VDDSHV2) settings into registers during power-up
sequence.
K. Minimum elapsed time
from crystal oscillator circuitry being energized
(VDDA_OSC1 at T1) until stable clock frequency is
reached depends upon on crystal oscillator,
capacitor parameters and PCB parasitic values. A
conservative 10- ms elapsed time defined by (T4 –
T1) time stamps is shown. This could be reduced
depending upon customer’s clock circuit (that is,
crystal oscillator or clock generator) and PCB
designs.
Figure 6-3 Combined MCU and Main
Domains, Primary Power-Up Sequence