Espressif Systems ESP8684 Series, Hardware Design Manuallines, Page: 7 / 28

2 Schematic Checklist
2.1 Power Supply
Details of using power supply pins can be found in Section Power Scheme in ESP8684 Series Datasheet .
2.1.1 Digital Power Supply
ESP8684 has pin 11 VDD3P3_RTC and pin 17 VDD3P3_CPU that supply power to RTC IO and CPU IO
respectively, in a voltage range of 3.0 V ~ 3.6 V. It is recommended to add an extra 0.1
µ
F filter capacitor close to
each digital power supply pin.
The schematic for the digital power supply pins is shown in Figure 2 .
5
5
4
4
3
3
2
2
1
1
D D
C C
B B
A A
The values of C8, L2 and C9
vary with the actual PCB board.
The values of C1 and C2 vary with
the selection of the crystal.
The value of R1 varies with the actual
PCB board.
ESP8684-MINI-1(pin-out)
NC: No component.
ESP8684H2
ESP8684H1
ESP8684H4
CHIP_EN
GPIO4
GPIO5
GPIO6
U0RXD
ANT
GPIO0
GPIO1
GPIO2
GPIO3
RF_ANT
U0TXD
GPIO2
GPIO3
CHIP_EN
GP
IO1
GP
IO0
GP
IO1
0
GP
IO6
GP
IO7
GP
IO8
GP
IO9
GPIO18
U0RXD
U0TXD
GP
IO4
GP
IO5
GPIO7
GPIO8
GPIO9
GPIO10
GPIO18
GND
VDD33
GND
GND GND GND
GND GND
GND
VDD33
GND GND GND
VDD33
GND
GND
GND
GND GND
VDD33
GND
GND
Title
Size Page Name R e v
Date: Sheet o f
Confidential and Proprietary
<02_ESP8684-MINI-1> V1.0
ESP8684-MINI-1
A4
2 2 Friday, October 29, 2021
Title
Size Page Name R e v
Date: Sheet o f
Confidential and Proprietary
<02_ESP8684-MINI-1> V1.0
ESP8684-MINI-1
A4
2 2 Friday, October 29, 2021
Title
Size Page Name R e v
Date: Sheet o f
Confidential and Proprietary
<02_ESP8684-MINI-1> V1.0
ESP8684-MINI-1
A4
2 2 Friday, October 29, 2021
C1
TBD
R
1
0
(1
%
)
R2 499(1%)
Y1
40MHz
X
IN
1
GN
D
2
X
OU
T
3
GN
D
4
L1 2.0nH(0.1nH)
C9
TBD
U2
ANT
1
VDDA3P3
2
VDDA3P3
3
GPIO0
4
GPIO1
5
GPIO2
6
C
H
IP
_
E
N
7
MT
MS
9
MTDI
1
0
VDD3P3_RTC
11
MTCK
12
MTDO
13
GPIO8
14
GPIO9
15
GPIO10
16
VDD3P3_CPU
17
U
0
R
X
D
1
9
U
0
T
X
D
2
0
X
T
AL
_
N
2
2
X
T
AL
_
P
2
3
GN
D
2
5
GP
IO3
8
V
D
D
A
2
4
V
D
D
A
2
1
GPIO18
18
C6
0.1uF/6.3V(10%)
D1
ESD
C3
1uF/6.3V(20%)
C4
10nF/6.3V(10%)
C10
VDD33
C7
0.1uF/6.3V(10%)
ANT1
PCB_ANT
1
2
U3
ESP8684-MINI-1
GND
1
3V3
3
IO9
2
3
NC
4
IO2
5
IO3
6
NC
7
NC
9
NC
10
N
C
1
5
IO1
0
1
6
N
C
1
7
IO4
1
8
IO5
1
9
NC
32
TXD0
31
RXD0
30
NC
34
NC
33
IO18
26
NC
29
NC
28
NC
27
IO7
2
1
IO8
2
2
IO0
1
2
IO1
1
3
GND
52
IO6
2
0
NC
35
N
C
2
4
E
P
AD
4
9
GND
2
GND
53
GND
51
GND
50
EN
8
GN
D
3
6
GN
D
3
7
GN
D
3
8
GN
D
3
9
GN
D
4
0
GN
D
4
1
GN
D
4
2
GN
D
4
3
GN
D
4
4
GN
D
4
5
GN
D
4
6
GN
D
4
7
GN
D
4
8
GN
D
1
4
GND
11
NC
25
C2
TBD
C8
TBD
C12
0.1uF/6.3V(10%)
L2
TBD
C5
10uF/6.3V(20%)
0.1uF/6.3V(10%)
Figure 2: Schematic for the Digital Power Supply Pins
2.1.2 Analog Power Supply
Pin 2 and 3 (both labelled VDDA3P3), pin 21 and 24 (both VDDA) are the analog power supply pins, working at
3.0 V ~ 3.6 V.
It should be noted that the sudden increase in current draw, when ESP8684 is transmitting signals, may cause a
power rail collapse. Therefore, it is highly recommended to add another 10 µ F capacitor to the power trace,
which can work in conjunction with the 0.1
µ
F capacitor. In addition, a LC filter circuit needs to be added near
VDDA3P3 pins so as to suppress high-frequency harmonics. The recommended rated current of the inductor is
500 mA or above. Refer to Figure 3 and place the appropriate decoupling capacitor near each analog power
pin.
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ESP8684 Series Hardware Design Guidelines v1.1