Ultra Low Power Wi-Fi SoC Module

R19DS0151EK0370 Revision 3.7

Sept 20, 2024

CFR0011-120-00

Page 14

6.

Power-on Sequence

The sequence after the initial switching from power-off to power-on is shown in Figure 6. The RTC_PWR_KEY of

DA16200 is a pin that enables the RTC block. When RTC_PWR_KEY is enabled after VBAT power is supplied,

all the internal regulators are switched on automatically in the sequence pre-defined by the RTC block.

When RTC_PWR_KEY is switched on, LDOs for both XTAL and digital I/O are switched on shortly and then the

DCDC regulator is switched on according to the pre-defined interval. The enabling intervals can also be modified

in the register settings after initial power-up.

CLK_32K

VBAT

POWER_KEY

T2

T3

IO Voltage

T1

50% VBAT

50% IO

T0

50% VBAT

Figure 6. Power-on sequence

Table 15: Power-on sequence timing requirements

Name

Description

Min

Typ

Max

Unit

T0

VBAT power-on time from 10% to 90 % of VBAT

-

-

ms

T1

IO voltage and VCC supply

-

0

-

ms

T2

RTC_PWR_KEY switch-on time from 50% VBAT to 50%

POWER_KEY * (Note 1)

-

5*T0

-

ms

T3

Internal RC oscillator wake-up time

-

217

-

µs

Note 1

If the T0 = 10 ms to switch on VBAT, the recommended T2 is 50 ms for the safe booting operation. It can be

externally controlled by MCU, or it can be implemented using the RC filter at the input of RTC_PWR_KEY.

The recommended C value is 470 nF or 1

μF (not to exceed 1 μF) and R value is chosen to have T2 delay. For

example, R and C values will be 82 kΩ and 1 μF when T0 = 10 ms.