ESP-WROOM-02D/02U
Datasheet
Includes:
ESP-WROOM-02D
ESP-WROOM-02U
Version 1.9
Espressif Systems
Copyright © 2022
www.espressif.com
About This Guide
This document provides introduction to the specifications of ESP-WROOM-02D and ESPWROOM-02U hardware.
Release Notes
Date
Version
Release notes
2017.11
V1.0
First release.
2018.03
V1.1
Updated the figure of ESP-WROOM-02U dimensions.
• Updated Table 1-1 and Table 1-2;
2018.08
V1.2
• Updated module dimensions;
• Added PCB pattern;
• Updated document cover.
2019.04
V1.3
2019.08
V1.4
2019.12
V1.5
2019.12
V1.6
2020.07
V1.7
2022.03
V1.8
2022.07
V1.9
• Added MSL information in table 1-2;
• Added notes in Figure 5-1 and Figure 5-2.
Updated Chapter 6 Peripheral Schematics.
• Added a note for the reflow profile;
• Added feedback links.
Updated a typo in ESP-WROOM-02D dimensions.
• Updated Note in Chapter 6;
• Updated links in Appendix.
Added a link to RF certification in Table 1-2
• Updated links in Appendix;
• Added Chapter 10 Product Handling.
Documentation Change Notification
Espressif provides email notifications to keep customers updated on changes to
technical documentation. Please subscribe at https://www.espressif.com/en/subscribe.
Certification
Download certificates for Espressif products from https://www.espressif.com/en/
certificates.
Table of Contents
1. Overview ................................................................................................................................1
2. Pin Description ......................................................................................................................3
3. Functional Description ..........................................................................................................5
3.1. CPU ..........................................................................................................................................5
3.2. Memory ....................................................................................................................................5
3.2.1.
Internal SRAM and ROM ...........................................................................................5
3.2.2.
SPI Flash ....................................................................................................................5
3.3. Crystal Oscillator ......................................................................................................................6
3.4. Interface Description ................................................................................................................6
4. Electrical Characteristics ......................................................................................................8
4.1. Electrical Characteristics ..........................................................................................................8
4.2. Wi-Fi Radio ...............................................................................................................................8
4.3. Power Consumption .................................................................................................................9
4.4. Reflow Profile .........................................................................................................................10
4.5. Electrostatic Discharge ..........................................................................................................11
5. Schematics ..........................................................................................................................12
6. Peripheral Schematics ........................................................................................................14
7. Dimensions ..........................................................................................................................15
8. Recommended PCB Land Pattern .....................................................................................17
9. U.FL Connector Dimensions ...............................................................................................19
10.Product Handling .................................................................................................................20
10.1. Storage Conditions ................................................................................................................20
10.2. Electrostatic Discharge (ESD) .................................................................................................20
10.3. Ultrasonic Vibration ................................................................................................................20
A. Appendix—Learning Resources .........................................................................................21
A.1. Must-Read Documents ..........................................................................................................21
A.2. Must-Have Resources ............................................................................................................22
1. Overview
1.
Overview
ESP-WROOM-02D and ESP-WROOM-02U are ESP8266EX-based modules developed by
Espressif. Compared to ESP-WROOM-02, the RF performance of ESP-WROOM-02D and
ESP-WROOM-02U are optimized. Besides, ESP-WROOM-02U integrates a U.FL
connector. Please see Chapter 8 for details of U.FL connector.
Table 1-1. ESP-WROOM-02D vs. ESP-WROOM-02U
Module
ESP-WROOM-02D
ESP-WROOM-02U
Core
ESP8266
ESP8266
Antenna
Onboard antenna
IPEX antenna
Dimensions
(18.00 ± 0.10) x (20.00 ± 0.10) x (3.20 ±
0.10)
(18.00 ± 0.10) x (14.30 ± 0.10) x (3.20 ±
0.10)
See Figure 6-1 for details.
See Figure 6-2 for details.
See Figure 5-1 for details.
See Figure 5-2 for details.
(unit: mm)
Schematics
📖 Note:
For more information on ESP8266EX, please refer to ESP8266EX Datasheet.
Table 1-2. ESP-WROOM-02D/ESP-WROOM-02U Specifications
Categories
Certification
Test
Wi-Fi
Items
Specifications
RF certification
See certificates from ESP-WROOM-02D and ESPWROOM-02U
Green certification
RoHS, REACH
Reliablity
HTOL/HTSL/uHAST/TCT/ESD
Wi-Fi protocols
802.11 b/g/n
Frequency range
2.4 GHz ~ 2.5 GHz (2400 MHz ~ 2483.5 MHz)
Peripheral interface
UART/HSPI/I2C/I2S/IR Remote Control
GPIO/PWM
Hardware
Espressif
Operating voltage
2.7 V ~ 3.6 V
Operating current
Average: 80 mA
Minimum current delivered by
power supply
500 mA
Operating temperature range
-40 °C ~ 85 °C
Storage temperature
-40 °C ~ 85 °C
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1. Overview
Categories
Software
Espressif
Items
Specifications
External interface
-
Moisture sensitivity level
Level 3
Wi-Fi mode
Station/SoftAP/SoftAP + Station
Security
WPA/WPA2
Encryption
WEP/TKIP/AES
Firmware upgrade
UART Download/OTA (via network)/Download and write
firmware via host
Software development
Supports Cloud Server Development/SDK for custom
firmware development
Network protocols
IPv4, TCP/UDP/HTTP/FTP
User configuration
AT Instruction Set, Cloud Server, Android/iOS app
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2. Pin Description
2.
Pin Description
Figure 2-1 shows the pin distribution of the ESP-WROOM-02D.
PCB ANTENNA
1
3V3
GND
18
2
EN
IO16
17
3
IO14
TOUT
16
4
IO12
RST
15
5
IO13
IO5
14
6
IO15
GND
13
7
IO2
TXD
12
8
IO0
RXD
11
9
GND
IO4
10
19 GND
Figure 2-1. ESP-WROOM-02D Pin Layout (Top View)
📖 Note:
The pin layout of ESP-WROOM-02U is the same with that of ESP-WROOM-02D, but it has no keepout
zone for PCB antenna.
ESP-WROOM-02D and ESP-WROOM-02U have 18 pins. Please see the pin definitions in
Table 2-1.
Table 2-1. ESP-WROOM-02U/ESP-WROOM-02D Pin Definitions
No.
Pin Name
Functional Description
3.3 V power supply (VDD)
Espressif
1
3V3
2
EN
📖 Note:
It is recommended the maximum output current a power supply
provides be of 500 mA or above.
Chip enable pin. Active high.
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2. Pin Description
No.
Pin Name
Functional Description
3
IO14
GPIO14; HSPI_CLK
4
IO12
GPIO12; HSPI_MISO
5
IO13
GPIO13; HSPI_MOSI; UART0_CTS
6
IO15
7
IO2
8
IO0
GPIO15; MTDO; HSPICS; UART0_RTS
Pull down.
GPIO2; UART1_TXD
Floating (internal pull-up) or pull up.
GPIO0
• UART download: pull down.
• Flash boot: floating or pull up.
Espressif
9
GND
GND
10
IO4
GPIO4
11
RXD
12
TXD
13
GND
GND
14
IO5
GPIO5
15
RST
Reset
16
TOUT
It can be used to test the power-supply voltage of VDD3P3 (Pin3 and
Pin4) and the input power voltage of TOUT (Pin6). These two functions
cannot be used simultaneously.
17
IO16
GPIO16; used for Deep-sleep wake-up when connected to RST pin.
18
GND
GND
UART0_RXD, receive end in UART download;
GPIO3
UART0_TXD, transmit end in UART download, floating or pull up;
GPIO1
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3. Functional Description
3.
Functional Description
3.1. CPU
The ESP8266EX integrates a Tensilica L106 32-bit RISC processor, which achieves extralow power consumption and reaches a maximum clock speed of 160 MHz. The Real-Time
Operating System (RTOS) and Wi-Fi stack allow 80% of the processing power to be
available for user application programming and development. The CPU includes the
interfaces as below:
• Programmable RAM/ROM interfaces (iBus), which can be connected with memory
controller, and can also be used to visit flash.
• Data RAM interface (dBus), which can connected with memory controller.
• AHB interface which can be used to visit the register.
3.2. Memory
3.2.1.
Internal SRAM and ROM
ESP8266EX Wi-Fi SoC integrates the memory controller and memory units including ROM
and SRAM. MCU can access the memory units through iBus, dBus, and AHB interfaces.
All memory units can be accessed upon request. A memory arbiter determines the running
sequence in the arrival order of requests.
According to our current version of SDK, the SRAM space available to users is assigned as
follows:
• RAM size < 50 kB, that is, when ESP8266EX is working in Station mode and
connects to the router, available space in the Heap + Data sector is around 50 kB.
• There is no programmable ROM in ESP8266EX, therefore, the user program must be
stored in an external SPI flash.
3.2.2.
SPI Flash
ESP8266EX supports SPI flash. Theoretically speaking, ESP8266EX can support an upto-16-MB SPI flash.
ESP-WROOM-02D and ESP-WROOM-02U currently integrate a 2-MB SPI flash. ESPWROOM-02U supports these SPI modes: Standard SPI, DIO (Dual I/O), DOUT (Dual
Output), QIO (Quad I/O) and QOUT (Quad Output).
Espressif
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3. Functional Description
3.3. Crystal Oscillator
ESP-WROOM-02U and ESP-WROOM-02D use a 26-MHz crystal oscillator. The accuracy
of the crystal oscillator should be ±10 PPM.
When using the download tool, please select the right type of crystal oscillator. In circuit
design, capacitors C1 and C2 which connect to the earth are added to the input and
output terminals of the crystal oscillator respectively. The values of the two capacitors can
be flexible, ranging from 6 pF to 22 pF, however, the specific capacitive values depend on
further testing of, and adjustment to, the overall performance of the whole circuit. Normally,
the capacitive values of C1 and C2 are within 10 pF for the 26-MHz crystal oscillator.
3.4. Interface Description
Table 3-1. Interface Description
Interface
Pin
Functional Description
HSPI
IO12 (MISO), IO13
(MOSI), IO14 (CLK),
IO15 (CS)
Connects to SPI Flash, display screen, and MCU.
PWM
IO12 (R), IO15
(G),IO13 (B)
Currently the PWM interface has four channels, but users can extend it
to eight channels. PWM interface can realize the control of LED lights,
buzzers, relays, electronic machines, etc.
IR
IO14 (IR_T), IO5
(IR_R)
The functionality of the infrared remote control interface can be realized
via software programming. The interface uses NEC coding, modulation,
and demodulation. The frequency of the modulated carrier signal is 38
kHz.
ADC
TOUT
Tests the power supply voltage of VDD3P3 (Pin3 and Pin4) and the input
power voltage of TOUT (Pin6). However, these two functions cannot be
used simultaneously. This interface is typically used in sensors.
I2C
IO14 (SCL), IO2 (SDA) Connects to external sensors and display screens, etc.
Communicates with the UART device.
Downloading: U0TXD + U0RXD or GPIO2 + U0RXD
Communicating: (UART0): U0TXD, U0RXD, MTDO (U0RTS), MTCK
(U0CTS)
UART0: TXD
(U0TXD),
UART
RXD (U0RXD), IO15
(RTS), IO13 (CTS)
UART1: IO2 (TXD)
Espressif
Debugging: UART1_TXD (GPIO2) can be used to print debugging
information.
By default, UART0 will output some printed information when you power
on ESP8266EX. If this issue influences some specific applications, users
can exchange the inner pins of UART when initializing ESP8266EX, that
is, exchange U0TXD and U0RXD with U0RTS and U0CTS. Users can
connect MTDO and MTCK to the serial port of the external MCU to
realize the communication.
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3. Functional Description
Interface
Pin
Functional Description
I2S input:
IO12 (I2SI_DATA) ;
IO13 (I2SI_BCK );
I2S
IO14 (I2SI_WS);
Collects, processes and transmits audio data.
I2S output:
IO15 (I2SO_BCK );
IO3 (I2SO_DATA);
IO2 (I2SO_WS ).
Espressif
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4. Electrical Characteristics
4.
Electrical Characteristics
📖 Note:
Unless otherwise specified, measurements are based on VDD = 3.3 V, TA = 25 °C.
4.1. Electrical Characteristics
Table 4-1. Electrical Characteristics
Parameter
Symbol
Min
Typ
Max
Unit
Operating temperature
-
–40
20
85
℃
Maximum soldering temperature
(Condition: IPC/JEDEC J-STD-020)
-
-
-
260
℃
Supply voltage
VDD
2.7
3.3
3.6
V
Input logic level low
VIL
–0.3
-
0.25 VDD
V
Input logic level high
VIH
0.75 VDD
-
VDD + 0.3
V
Output logic level low
VOL
-
-
0.1 VDD
V
Output logic level high
VOH
0.8 VDD
-
-
V
4.2. Wi-Fi Radio
Table 4-2. Wi-Fi Radio Characteristics
Description
Min
Typ
Max
Unit
Input frequency
2412
-
2483.5
MHz
Input reflection
-
-
–10
dB
Output Impedance
-
*
-
Ω
Output Power
PA output power at 72.2 Mbps
13
14
15
dBm
PA output power in 11b mode
19.5
20
20.5
dBm
Sensitivity
Espressif
DSSS, 1 Mbps
-
–98
-
dBm
CCK, 11 Mbps
-
–91
-
dBm
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4. Electrical Characteristics
Description
Min
Typ
Max
Unit
CCK, 11 Mbps
-
–91
-
dBm
6 Mbps (1/2 BPSK)
-
–93
-
dBm
54 Mbps (3/4 64-QAM)
-
–75
-
dBm
HT20, MCS7 (65 Mbps, 72.2 Mbps)
-
–72
-
dBm
Adjacent channel rejection
OFDM, 6 Mbps
-
37
-
dB
OFDM, 54 Mbps
-
21
-
dB
HT20, MCS0
-
37
-
dB
HT20, MCS7
-
20
-
dB
📖 Note:
For the module that uses an IPEX antenna, the output impedance is 50 Ω.
4.3. Power Consumption
The following power consumption data were obtained from the tests with a 3.3 V power
supply and a voltage stabilizer, in 25 °C ambient temperature. All data are based on 50%
duty cycle in continuous transmission mode.
Table 4-3. Power Consumption
Espressif
Modes
Min
Typ
Max
Unit
Tx 802.11 b, CCK 11 Mbps, POUT = +17 dBm
-
170
-
mA
Tx 802.11 g, OFDM 54 Mbps, POUT = +15 dBm
-
140
-
mA
Tx 802.11 n, MCS7, POUT = +13 dBm
-
120
-
mA
Rx 802.11 b, 1024 bytes packet length , –80 dBm
-
50
-
mA
Rx 802.11 g, 1024 bytes packet length , –70 dBm
-
56
-
mA
Rx 802.11 n, 1024 bytes packet length , –65 dBm
-
56
-
mA
Modem-sleep①
-
15
-
mA
Light-sleep②
-
0.9
-
mA
Deep-sleep③
-
20
-
μA
Power Off
-
0.5
-
μA
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4. Electrical Characteristics
📖 Notes:
① Modem-sleep is used when such applications as PWM or I2S require the CPU to be working. In cases
where Wi-Fi connectivity is maintained and data transmission is not required, the Wi-Fi Modem circuit can
be shut down to save power, according to 802.11 standards (such as U-APSD). For example, in DTIM3,
when ESP8266EX sleeps for 300 ms and wakes up for 3 ms to receive Beacon packages from AP, the
overall average current consumption is about 15 mA.
② Light-sleep is used for applications whose CPU may be suspended, such as Wi-Fi switch. In cases
where Wi-Fi connectivity is maintained and data transmission is not required, the Wi-Fi Modem circuit and
CPU can be shut down to save power, according to 802.11 standards (such as U-APSD). For example, in
DTIM3, when ESP8266EX sleeps for 300 ms and wakes up for 3 ms to receive Beacon packages from
AP, the overall average current consumption is about 0.9 mA.
③ Deep-sleep is for applications that do not require Wi-Fi connectivity but only transmit data over long time
lags, e.g., a temperature sensor that measures temperature every 100s. For example, when ESP8266EX
sleeps for 300 s then wakes up to connect to AP (taking about 0.3 ~ 1 s), the overall average current
consumption is far less than 1 mA. The current consumption of 20 μA was obtained at the voltage of 2.5
V.
Temperature (℃)
4.4. Reflow Profile
Peak Temp.
235 ~ 250℃
250
Preheating zone
150 ~ 200℃
60 ~ 120s
217
200
Reflow zone
217℃ 60 ~ 90s
Cooling zone
-1 ~ -5℃/s
Soldering time
> 30s
Ramp-up zone
1 ~ 3℃/s
100
50
25
Time (sec.)
0
0
50
100
150
200
250
Ramp-up zone — Temp.: 217℃
60 ~ 90s; Peak Temp.: 235 ~ 250℃ (