Ai-Thinker ESP32-A1S User manual

ESP32-A1S Specification V2.3
Copyright © 2021 Shenzhen Ai-Thinker Technology Co., Ltd All Rights Reserved
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ESP32-A1S Specification
Version V2.3
Copyright ©2021

ESP32-A1S Specification V2.3
Copyright © 2021 Shenzhen Ai-Thinker Technology Co., Ltd All Rights Reserved
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Disclaimer and copyright notice
The information in this article, including the URL for reference, is subject to change
without notice.
The document is provided "as is" without any guarantee responsibility, including any
guarantee of marketability, suitability for a specific purpose or non-infringement, and
any guarantee mentioned elsewhere in any proposal, specification or sample. This
document assumes no responsibility, including any liability for infringement of any
patent rights arising from the use of the information in this document. This document
does not grant any license to use intellectual property rights, whether express or
implied, by estoppel or other means.
The test data obtained in this article are all obtained by Ai-Thinker's laboratory tests,
and the actual results may be slightly different.
The Wi-Fi Alliance member logo is owned by the Wi-Fi Alliance.
All trademark names, trademarks and registered trademarks mentioned in this article
are the property of their respective owners and are hereby declared.
The final interpretation right belongs to Shenzhen Ai-Thinker Technology Co., Ltd.
Notice
The contents of this manual may change due to product version upgrade or other
reasons. Shenzhen Ai-Thinker Technology Co., Ltd. reserves the right to modify the
contents of this manual without any notice or prompt. This manual is only used as a
guide. Shenzhen Ai-Thinker Technology Co., Ltd. makes every effort to provide
accurate information in this manual, but Shenzhen Ai-Thinker Technology Co., Ltd.
does not guarantee that the contents of the manual are completely error-free. And
recommendations do not constitute any express or implied guarantee.

ESP32-A1S Specification V2.3
Copyright © 2021 Shenzhen Ai-Thinker Technology Co., Ltd All Rights Reserved
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Formulation / Revision / Abolition of CV
Version
Date
Formulation / Revision
Make
Verify
V2.2
2019.11.01
First development
Yiji Xie
Ning Guan
V2.3
2021.06.09
Update data
Peihong
Su
Ning Guan

ESP32-A1S Specification V2.3
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content
1. Product overview................................................................................................................... 5
1.1. Features......................................................................................错误！未定义书签。
2.Main parameters..................................................................................................................... 7
2.1.Electrical parameters................................................................................................... 7
2.2. Electrical characteristics.............................................................................................8
2.3. WIFI RF performance................................................................................................. 8
2.4. Bluetooth（BR）RF performance............................................................................ 9
2.5. Bluetooth（EDR）RF performance......................................................................... 9
2.6. BLE RF performance.................................................................................................. 9
2.7. Power consumption.................................................................................................... 9
3.Dimensions............................................................................................................................ 11
4.PIN definition......................................................................................................................... 12
5.Schematic diagram...............................................................................................................14
6.Design guide......................................................................................................................... 17
6.1. Antenna layout requirements.................................................................................. 17
6.2. Power supply............................................................................................................. 17
7.Reflow solder curve..............................................................................................................19
8.Packaging.............................................................................................. 错误！未定义书签。
9.Contact us..............................................................................................................................20

ESP32-A1S Specification V2.3
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1. Product overview
ESP32-A1S is a Wi-Fi+BT voice module developed by Shenzhen Anxinke Technology
Co., Ltd. The module's core processor chip ESP32 integrates 2.4 GHz Wi-Fi and
Bluetooth dual mode, and the module also integrates ES8388 voice codec chip,
PSRAM and Flash chip. It can be widely used in offline voice products and various IoT
hardware terminal occasions.
ESP32 chip has industry-leading low-power performance and radio frequency
performance, supports Wi-Fi IEEE802.11b/g/n protocol and Bluetooth V4.2 complete
standard, including traditional Bluetooth (BR/EDR) and low energy Bluetooth (BLE) .
The chip is equipped with an Xtensa® 32-bit LX6 dual-core processor with a computing
power of up to 600 MIPS and a working frequency of up to 240 MHz. Support
secondary development without using other microcontrollers or processors. The chip
has built-in 520 KB SRAM, 448 KB ROM, 16KB RTC SRAM, and 1 Kbit eFuse. The
chip supports a variety of low power consumption working states, which can meet the
power consumption requirements of various application scenarios.
ES8388 is a low-power, cost-effective audio codec chip. It integrates 2 ADCs and 2
DACs, microphone amplifiers, headphone amplifiers, etc., which can be widely used in
various home smart devices, smart audio, story machine solutions And so on, is the
ideal solution for voice products.
The ESP32-A1S module provides a wealth of peripheral interfaces, including UART,
PWM, SPI, I2S, I2C, ADC, DAC, SDIO and multiple GPIOs.

ESP32-A1S Specification V2.3
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Figure 1 Main chip architecture diagram
1.1. Features
Support Wi-Fi 802.11b/g/n, 1T1R mode data rate up to 150Mbps
Support Bluetooth V4.2 complete standard, including traditional Bluetooth
(BR/EDR) and low energy Bluetooth (BLE)
Support standard Class-1, Class-2 and Class-3
Xtensa® 32-bit LX6 dual-core processor, computing power up to 600 MIPS
The chip has built-in 520 KB SRAM, 448 KB ROM, 16KB RTC SRAM, and 1
Kbit eFuse
Support 2 audio input and 2 audio output, integrated microphone amplifier
and headphone amplifier
Support UART/GPIO/ADC/DAC/PWM/I2C/I2S interface
Integrate 64Mb PSRAM
Using SMD-38 package
General AT commands can be used quickly
Support secondary development, integrated Windows and Linux development
environment

ESP32-A1S Specification V2.3
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2. Main parameters
List 1 Main parameter description
Model
ESP32-A1S
Package
SMD-38
Size
31.5*19.0*3.1(±0.2)mm
Antenna
Onboard PCB antenna / compatible with IPEX antenna interface
Spectrum
range
2400 ~ 2483.5MHz
Operating
temperature
-40 ℃~ 85 ℃
Storage
environment
-40 ℃~ 125 ℃, < 90%RH
Power
supply
Supply voltage 3.0V ~ 3.6V, supply current >500mA
Interface
UART/GPIO/ADC/PWM/I2C/I2S/microphone/headphone/speaker
Serial port
rate
Support 110 ~ 4608000 bps, the default is 115200 bps
WiFi
802.11b/g/n
Bluetooth
Bluetooth 4.2 BR/EDR and BLE standards
Safety
WEP/WPA-PSK/WPA2-PSK
2.1.Electrical parameters
The ESP32-A1S module is an electrostatic sensitive device, and special precautions
must be taken when handling it.
Figure 2 ESD Anti-static mark

ESP32-A1S Specification V2.3
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2.2. Electrical characteristics
List 2 Main parameter description
2.3. WIFI RF performance
List 3 Main parameter description
Description
Typical
Unit
Working frequency
2400 - 2483.5
MHz
Output Power
11n mode HT40, PA output power is
13±2
dBm
11n mode HT20, PA output power is
13±2
dBm
In 11g mode, the PA output power is
14±2
dBm
In 11b mode, PA output power is
18±2
dBm
Receiving sensitivity
CCK, 1 Mbps
≤-96
dBm
CCK, 11 Mbps
≤-88
dBm
6 Mbps (1/2 BPSK)
≤-92
dBm
54 Mbps (3/4 64-QAM)
≤-74
dBm
HT20 (MCS7)
≤-72
dBm
HT40 (MCS7)
≤-70
dBm
Parameters
Condition
Min
Typical
Max
Unit
Voltage
VDD
3.0
3.3
3.6
V
I/O
VIL/VIH
-
-0.3/0.75VDD
-
0.25VDD/VDD+0.3
V
VOL/VOH
-
N/0.8VIO
-
0.1VIO/N
V

ESP32-A1S Specification V2.3
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2.4. Bluetooth（BR）RF performance
List 4 Main parameter description
Description
Typical
Unit
Output Power
Transmit power
Typical 8±2
dBm
Receiving sensitivity Bluetooth low energy 1M
[email protected]%BER
≤-89
dBm
2.5. Bluetooth（EDR）RF performance
List 5 Main parameter description
Description
Typical
Unit
Output Power
Transmit power
Typical 8±2
dBm
Receiving sensitivity Bluetooth low energy 1M
[email protected]%BER
≤-89
dBm
2.6. BLE RF performance
List 6 Main parameter description
Description
Typical
Unit
Output Power
Transmit power
Typical 8±2
dBm
Receiving sensitivity Bluetooth low energy 1M
[email protected]%PER
≤-94
dBm
2.7. Power consumption
The following power consumption data is based on 3.3V power supply, 25°C

ESP32-A1S Specification V2.3
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ambient temperature, and measured with an internal voltage regulator.
All measurements are done at the antenna interface without SAW filter.
All emission data is based on 50% duty cycle, measured in continuous emission
mode.
List 7 Main parameter description
Mode
Min
Typical
Max
Unit
Transmit 802.11b, CCK 1Mbps,
POUT=+19.5dBm
-
240
-
mA
Transmission 802.11g, OFDM
54Mbps, POUT = +16dBm
-
190
-
mA
Transmit 802.11n, MCS7, POUT =
+14dBm
-
180
-
mA
Receive 802.11b, the packet
length is 1024 bytes
-
95
-
mA
Receive 802.11g, the packet
length is 1024 bytes
-
95
-
mA
Receive 802.11n, the packet
length is 1024 bytes
-
93
-
mA
Modem-Sleep①
-
20
-
mA
Light-Sleep②
-
130
-
μA
Deep-Sleep③
-
5
-
μA
Power Off
-
1
-
μA

ESP32-A1S Specification V2.3
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3. Dimensions
Figure 3 Module appearance diagram (rendered diagram is for reference only, the
actual product shall prevail)
Figure 4 Module size chart

ESP32-A1S Specification V2.3
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4. PIN definition
图5管脚示意图
The ESP32-A1S module has a total of 38 interfaces. As shown in the pin diagram, the
pin function definition table is the interface definition.
List 8 ESP32-A1S Pin function definition table
No.
Name
Function Description
1
GND
Grounded
2
3V3
Power supply, recommended 3.3V, greater than 500mA
3
SENSOR_
VN
GPI39, SENSOR_VN, ADC1_CH3, ADC_H, RTC_GPIO3
4
SENSOR_
VP
GPI36, SENSOR_VP, ADC_H, ADC1_CH0, RTC_GPIO0
5
IO34
GPI34, ADC1_CH6, RTC_GPIO4
6
IO0
GPIO0, ADC2_CH1, TOUCH1, RTC_GPIO11,
CLK_OUT1, EMAC_TX_CLK
7
IO14
GPIO14, ADC2_CH6, TOUCH6, RTC_GPIO16, MTMS,
HSPICLK, HS2_CLK, SD_CLK, EMAC_TXD2
8
IO12
GPIO12, ADC2_CH5, TOUCH5, RTC_GPIO15, MTDI,
HSPIQ, HS2_DATA2, SD_DATA2, EMAC_TXD3
9
IO13
GPIO13, ADC2_CH4, TOUCH4, RTC_GPIO14, MTCK,
HSPID, HS2_DATA3, SD_DATA3, EMAC_RX_ER
10
IO15
GPIO15, ADC2_CH3, TOUCH3, MTDO, HSPICS0,

ESP32-A1S Specification V2.3
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RTC_GPIO13, HS2_CMD, SD_CMD, EMAC_RXD3
11
IO2
GPIO2, ADC2_CH2, TOUCH2, RTC_GPIO12, HSPIWP,
HS2_DATA0, SD_DATA0
12
IO4
GPIO4, ADC2_CH0, TOUCH0, RTC_GPIO10, HSPIHD,
HS2_DATA1, SD_DATA1, EMAC_TX_ER
13
HBIAS
Pull up to AVCC by internal 1K resistor
14
MIC2N
Audio chip RIN2 channel
15
MIC1N
Audio chip RIN1 channel
16
MBIAS
Pull up to AVCC by internal 1K resistor
17
MIC1P
Audio chip LIN1 channel
18
MIC2P
Audio chip LIN2 channel
19
GND
Grounded
20
GND
Grounded
21
LINEINR
Audio chip RIN2 channel
22
LINEINL
Audio chip LIN2 channel
23
NC
NC, suspended handling
24
SPORN
Audio chip ROUT1 channel
25
NC
NC, suspended handling
26
SPOLN
Audio chip LOUT1 channel
27
HPOUTL
Audio chip LOUT2 channel
28
HPOUTR
Audio chip ROUT2 channel
29
IO5
GPIO5, HS1_DATA6, VSPICS0, EMAC_RX_CLK
30
IO18
GPIO18, HS1_DATA7, VSPICLK
31
IO23
GPIO23, HS1_STROBE, VSPID
32
IO19
GPIO19, VSPIQ, U0CTS, EMAC_TXD0
33
IO22
GPIO22, VSPIWP, U0RTS, EMAC_TXD1
34
IO21
GPIO21, VSPIHD, EMAC_TX_EN
35
EN
Enable the chip, high level is effective.

ESP32-A1S Specification V2.3
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36
TXD0
GPIO1, U0TXD, CLK_OUT3, EMAC_RXD2
37
RXD0
GPIO3, U0RXD, CLK_OUT2
38
GND
Grounded
List 9 Module startup mode description
System startup mode
PIN
Default
SPI boot mode
Download start
mode
GPIO 0
pull up
1
0
GPIO 2
drop down
Irrelevant
0
Note: Some pins have been internally pulled up, please refer to the schematic
5. Schematic diagram
5.1. Module schematic

ESP32-A1S Specification V2.3
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Figure 6 Audio part schematic
Figure 7 Schematic diagram of the main chip

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5.2. Application circuit diagram
Figure 8 Application circuit diagram

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6. Design guide
6.1. Antenna layout requirements
（1）、For the installation position on the motherboard, the following two methods are
recommended：
Solution 1: Put the module on the edge of the main board, and the antenna area
extends out of the edge of the main board.
Solution 2: Put the module on the edge of the motherboard, and hollow out an area at
the antenna position on the edge of the motherboard.
（2）、
In order to meet the performance of the on-board antenna, it is forbidden to place
metal parts around the antenna, away from high-frequency components.
Figure 9 Schematic diagram of antenna layout
6.2. Power supply
（1）、Recommend 3.3V voltage, peak current above 500mA
（2）、It is recommended to use LDO for power supply; if DC-DC is used, the ripple is
recommended to be controlled within 30mV.
（3）、It is recommended to reserve the position of the dynamic response capacitor for
the DC-DC power supply circuit to optimize the output ripple when the load changes
greatly.
（4）、It is recommended to add ESD devices to the 3.3V power interface.

ESP32-A1S Specification V2.3
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Figure 10 DC-DC Step-down circuit diagram
6.3. Use of GPIO port
（1）、There are some GPIO ports on the periphery of the module. If you need to use it,
it is recommended to connect a 10-100 ohm resistor in series with the IO port. This can
suppress overshoot and make the levels on both sides more stable. It is helpful for EMI
and ESD.
（2）、For the pull-up and pull-down of special IO ports, please refer to the instructions
in the specification, which will affect the startup configuration of the module.
（3）、The IO port of the module is 3.3V. If the main control and the IO level of the
module do not match, a level conversion circuit needs to be added.
（4）、If the IO port is directly connected to a peripheral interface or terminal such as a
header, it is recommended to reserve an ESD device near the terminal on the IO trace.
Figure 11 Level conversion circuit

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7. Reflow solder curve
Figure 12 Reflow solder curve

ESP32-A1S Specification V2.3
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8. Packaging
As shown in the figure below, the packaging of ESP32-A1S is braid.
Figure 13 tape package
9. Contact us
Website：https://www.ai-thinker.com
Development DOCS：https://docs.ai-thinker.com
Forum：http://bbs.ai-thinker.com
Sample order：https://ai-thinker.en.alibaba.com/
Business：[e-mail]
Support：[e-mail]
Add：Room410, Building C, Huafeng Intelligence Innovation Port, Gushu, Xixiang, Baoan District,
Shenzhen China 518126
Tel：[phone]