Power-Up Timing And System Reset; Power-Up Timing; System Reset; Schematic For The Analog Power Supply Pins - Espressif Systems ESP32-H2 Series Hardware Design Manuallines

D
2 Schematic Checklist
VDD33
C
ANT1
PCB_ANT
VDD33
10uF
B
GND
A
Notice:
• When use the single power supply, the recommended power supply voltage for ESP32-H2 is 3.3 V and the output
current is no less than 350 mA.
5
• It is suggested to add another 10 µF capacitor at the power entrance. If the power entrance is close to pin1 and
pin2, it can share the same 10 µF capacitor with pin1 and pin2.
• It is suggested to add an ESD protection diode at the power entrance.

2.2 Power-up Timing and System Reset

2.2.1 Power-up Timing

When ESP32-H2 uses a 3.3 V system power supply, the power rails need some time to stabilize before CHIP_EN
is pulled up and the chip is enabled. Therefore, CHIP_EN needs to be powered up after the 3.3 V rails have been
brought up. More details about the power-up timing can be found in Section 2.2.3.
Notice:
To ensure the correct power-up timing, it is advised to add an RC delay circuit at the CHIP_EN pin. The recommended
setting for the RC delay circuit is usually R = 10 kΩ and C = 1 µF. However, specific parameters should be adjusted based
on the characteristics of the actual power supply and the power-up and reset timing sequence of the chip.

2.2.2 System Reset

CHIP_EN serves as the reset pin of ESP32-H2. When CHIP_EN is at low level, the reset voltage (V
should be in the range of (–0.3
CHIP_EN trace as short as possible. Also, add a pull-up resistor as well as a capacitor to ground whenever
possible. More details can be found in Section 2.2.3.
Espressif Systems
The values of C1 and C4 vary with
the selection of the crystal.
The value of R4 varies with the
actual PCB board. R4 could be a
resistor or inductor, the initial
value is suggested to be 24 nH.
C2
10nF
GND
RF_ANT LNA_IN
1 L2 TBD
2
C11 C12
TBD TBD
GND GND GND
The values of C11, L2 and C12
vary with the actual PCB board.
C6 C7 C8 GPIO0
GPIO1
1uF 0.1uF GPIO2
GPIO3
GPIO4
GPIO5
GND GND
VDD33
Figure 3: Schematic for the Analog Power Supply Pins
C17
0.1uF
GND
4
~ 0.25 × VDD) V. To avoid reboots caused by external interferences, make the
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GND GND
Y1
C1
TBD
GND
32MHz(±10ppm)
GND
1
VDD3P3 GPIO25
2
VDD3P3 U0TXD
3
GPIO0 U0RXD
4
GPIO1 GPIO22
5
MTMS VDDPST2
6
MTDO VDDA_PMU
7
MTCK VBAT
8
MTDI CHIP_EN
U1 ESP32-H2
3
8
C4
TBD
VDD33
C10 C5
0.1uF 1uF
GND GND GPIO27
GPIO26
GND
C13
VDD33
0.1uF
24 GPIO25
23 R3 499 U0TXD
22 U0RXD
21 GPIO22
20
19
VDD33
18
VBAT R2 0
17 EN
C19
0.1uF
GND
When VBAT is powered by external
battery, R2 can be NC.
CHIP_EN:
H Activate chip;
L Disable chip.
This pin could not be float.
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ESP32-H2 Series Hardware Design Guidelines v0.5
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IL_nRST