WBR3S is a low-power embedded Wi-Fi and Bluetooth LE module that Tuya has developed. It consists of a highly integrated RF chip (RTL8720CS) and several peripheral components, with an embedded Wi-Fi network protocol stack, Bluetooth LE network protocol, and robust library functions. WBR3S is embedded with a low-power 32-bit CPU, 512 KB static random-access memory (SRAM), and 4 MB flash memory, and has extensive peripherals.
WBR3S is an RTOS platform that integrates all function libraries of the Wi-Fi MAC and TCP/IP protocols. You can develop embedded Wi-Fi products as required.
The functional block diagram is shown in below Figure :

| NO. | Date | Change Description | Version After Change |
|---|---|---|---|
| 1 | 2020-07-13 | This is the first release. | V1.0.0 |
WBR3S has two rows of pins with a 2±0.1 mm pin spacing.
The WBR3S dimensions (H x W x D) are 2.8 mm x 16 mm x 24 mm。
The front and rear views of WBR3S:


Note:
The common appearance tolerance is ±0.3 mm. The tolerance of positions that involve plug-in assembly is ±0.1 mm. The thickness tolerance of a 1 mm thick PCB is ±0.1 mm.

| Pin No. | Symbol | I/O Type | Function |
|---|---|---|---|
| 1 | RST | I/O | The Reset Pin |
| 2 | ADC | AI | 10-bit precision SAR ADC(1),the Pin PB3 of IC |
| 3 | EN | I | Module enabling pin, which is connected to 3.3 V for normal use,对应IC的CHIP_EN |
| 4 | PA15 | I/O | GPIO,The pin PA15 of IC |
| 5 | PA13 | P | PWM Pin,The pin PA13 of IC |
| 6 | PA12 | I/O | PWM Pin,The pin PA12 of IC |
| 7 | PA26 | I/O | PWM Pin,The pin PA26 of IC |
| 8 | VCC | P | Power supply pin (3.3 V) |
| 9 | GND | P | Power supply reference ground pin |
| 10 | PA25 | O | GPIO,The pin PA25 of IC |
| 11 | LOG_TX | O | UART0_TXD (used to display the module internal information) |
| 12 | PB20 | I/O | GPIO,The pin PB20 of IC |
| 13 | PB21 | I/O | PWM Pin,The pin PB21 of IC |
| 14 | PA28 | I/O | PWM Pin,The pin PA28 of IC |
| 15 | RXD/PB2 | I/O | UART0_RXD (2),对应IC的PB2 |
| 16 | TXD/PB1 | I/O | UART0_TXD(2),对应IC的PB1 |
Note:P indicates power supply pins, I/O indicates input/output pins, and AI indicates analog input pins.
(1):This pin can only function as an ADC input and not a common I/O. If this pin is not used, it must be disconnected. When this pin is used as the ADC input, the input voltage range is 0 V to 1.0 V.
(2): UART0 is a user-side serial interface, which generates information when the module is powered on and starts.
| Pin No. | Symbol | I/O Type | Function |
|---|---|---|---|
| - | TEST | I | Used for the module production test |
Note:Test pins are not recommended.
| Parameter | Description | Minimum Value | Maximum Value | Unit |
|---|---|---|---|---|
| Ts | Storage temperature | -20 | 85 | ℃ |
| VBAT | Power supply voltage | 3.0 | 3.6 | V |
| Static electricity voltage (human body model) | TAMB-25℃ | - | 2 | KV |
| Static electricity voltage (machine model) | TAMB-25℃ | - | 0.5 | KV |
| Parameter | Description | Minimum Value | Typical Value | Maximum Value | Unit |
|---|---|---|---|---|---|
| Ta | Working temperature | -20 | - | 85 | ℃ |
| VBAT | Power supply voltage | 3.0 | 3.3 | 3.6 | V |
| VIL | I/O low-level input | -0.3 | - | VCC*0.25 | V |
| VIH | I/O high-level input | VCC*0.75 | - | VCC | V |
| VOL | I/O low-level output | - | - | VCC*0.1 | V |
| VoH | I/O high-level output | VCC*0.8 | - | VCC | V |
| Imax | I/O drive current | - | - | 12 | mA |
| Working Status | Mode | Rate | TX Power/Receiving | Typical Value | Unit |
|---|---|---|---|---|---|
| TX | 11b | 11Mbps | +18dBm | 250 | mA |
| TX | 11g | 54Mbps | +17dBm | 180 | mA |
| TX | 11n-HT20 | MCS7 | +16dBm | 170 | mA |
| TX | 11n-HT40 | MCS7 | +16dBm | 150 | mA |
| RX | 11b | 11Mbps | Receiving | 70 | mA |
| RX | 11g | 54Mbps | Receiving | 72 | mA |
| RX | 11n-HT20 | MCS7 | Receiving | 70 | mA |
| RX | 11n-HT40 | MCS7 | Receiving | 73 | mA |
| Working Mode | Working Status (Ta = 25°C) | Average Value | Maximum Value(Typical Value) | Unit |
|---|---|---|---|---|
| EZ | The module is in EZ mode, and the Wi-Fi indicator blinks quickly. | 57 | 184 | mA |
| AP | The module is in AP mode, and the Wi-Fi indicator blinks slowly | 203 | 392 | mA |
| Connected | The module is connected to the network, and the Wi-Fi indicator is steady on. | 55 | 98 | mA |
| Disconnected | The module is disconnected from the network, and the Wi-Fi indicator is steady off. | 53 | 59 | mA |
| Parameter | Description |
|---|---|
| Frequency band | 2.412~2.484GHz |
| Wi-Fi standard | IEEE 802.11b/g/n (Channels 1 to 14 |
| Data transmission rate | 802.11b: 1, 2, 5.5, or 11 (Mbit/s);802.11g: 6, 9, 12, 18, 24, 36, 48, or 54 (Mbit/s);802.11n: HT20 MCS0 to MCS7;802.11n: HT40 MCS0 to MCS7 |
| Antenna type | PCB antenna with a gain of 1.7 dBi at 2.4 GHz |
Performance during constant transmission at 2.4 GHz
| Parameter | Minimum Value | Typical Value | Maximum Value | Unit |
|---|---|---|---|---|
| Average RF output power, 802.11b CCK mode 11M | - | 17 | - | dBm |
| Average RF output power,802.11g OFDM Mode 54M | - | 16 | - | dBm |
| Average RF output power,802.11n HT20 Mode MCS7 | - | 15 | - | dBm |
| Average RF output power,802.11n HT40 Mode MCS7 | - | 14 | - | dBm |
| Frequency error | -10 | - | 10 | ppm |
RX sensitivity
| Parameter | Minimum Value | Typical Value | Maximum Value | Unit |
|---|---|---|---|---|
| PER<8%,802.11b DSSS Mode 11M | - | -91 | - | dBm |
| PER<10%,802.11a/g OFDM Mode 54 M | - | -75 | - | dBm |
| PER<10%,802.11n OFDM Mode HT20-MCS7 | - | -72 | - | dBm |
###Antenna Type
WBR3S uses an onboard PCB antenna.
To ensure optimal Wi-Fi performance when the Wi-Fi module uses an onboard PCB antenna, it is recommended that the antenna be at least 15 mm away from other metal parts.
To prevent adverse impact on the antenna radiation performance, avoid copper or traces along the antenna area on the PCB. Ensure that there are no substrate media above or below the antenna and that copper is at a certain distance away from the antenna to maximize the antenna radiation performance.

Module individual pin (PA15 PA12, PA13, PA25, PA28, PA26) before the chip didn’t completely work. It will be instantaneous high level pulse, But everything is ok after the chip work .For these pins, if used directly as a driver of light source or relay, the following reference processing can be done to avoid the effect of instant burr during the power on.
Pull-down a 1K resistor at the output port of the pin, then series a diode, and the VOLTAGE of GPIO will drop to about 2.7V after passing the diode.The red frame represents the original drive tube on the customer bottom plate, diode D1 and drop 1K need to be added.
If the lamp class is driven directly, then the 10K resistor is pulled down from the gate of the MOS tube. If the lamp class is not driven directly and the PWM signal is not sent until the module is formally set up, then there is no need to add the pull-down resistor and diode.
If the relay is driven, the diode can be replaced with 0 ohm according to the actual situation.

PCB mechanical dimensions:16mm (W)×24mm (L) ×3.5mm (H)。

###Side view

The default dimensional tolerance is ±0.3 mm. If a customer has other requirements, clearly specify them in the datasheet after communication.


Use an SMT placement machine to mount components to the stamp hole module that Tuya produces within 24 hours after the module is unpacked and the firmware is burned. If not, vacuum pack the module again. Bake the module before mounting components to the module.
A.SMT placement equipment
a)Reflow soldering machine
b)Automated optical inspection (AOI) equipment
c)Nozzle with a 6 mm to 8 mm diameter
B.Baking equipment
a)Cabinet oven
b)Anti-static heat-resistant trays
c)Anti-static heat-resistant gloves
Storage conditions for a delivered module are as follows:
A.The moisture-proof bag is placed in an environment where the temperature is below 30°C and the relative humidity is lower than 70%.
B.The shelf life of a dry-packaged product is six months from the date when the product is packaged and sealed.
C.The package contains a humidity indicator card (HIC).

Bake a module based on HIC status as follows when you unpack the module package:
A.If the 30%, 40%, and 50% circles are blue, bake the module for 2 consecutive hours.
B.If the 30% circle is pink, bake the module for 4 consecutive hours.
C.If the 30% and 40% circles are pink, bake the module for 6 consecutive hours.
D.If the 30%, 40%, and 50% circles are pink, bake the module for 12 consecutive hours.
Baking settings:
A.Baking temperature: 125±5°C
B.Alarm temperature: 130°C
C.SMT placement ready temperature after natural cooling: < 36°C
D.Number of drying times: 1
E.Rebaking condition: The module is not soldered within 12 hours after baking.
Do not use SMT to process modules that have unpacked for over three months. Electroless nickel immersion gold (ENIG) is used for the PCBs. If the solder pads are exposed to the air for over three months, they will be oxidized severely and dry joints or solder skips may occur. Tuya is not liable for such problems and consequences.
Before SMT placement, take electrostatic discharge (ESD) protective measures.
To reduce the reflow defect rate, draw 10% of the products for visual inspection and AOI before first SMT placement to determine a proper oven temperature and component placement method. Draw 5 to 10 modules every hour from subsequent batches for visual inspection and AOI.
Perform SMT placement based on the following reflow oven temperature curve. The highest temperature is 245°C.


| product model | MOQ(pcs) | Delivery packing method | pcs | Number of reels per carton |
|---|---|---|---|---|
| WBR3S | 4000 | Loaded with reel | 1000 | 4 |
FCC Caution: Any changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate this equipment.
This device complies with Part 15 of the FCC Rules.Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.
Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules.These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:
Radiation Exposure Statement
This equipment complies with FCC radiation exposure limits set forth for an uncontrolled rolled environment. This equipment should be installed and operated with minimum distance 20cm between the radiator and your body.
Important Note
This radio module must not installed to co-locate and operating simultaneously with other radios in host system except in accordance with FCC multi-transmitter product procedures. Additional testing and equipment authorization may be required to operating simultaneously with other radio.
The availability of some specific channels and/or operational frequency bands are country dependent and are firmware programmed at the factory to match the intended destination. The firmware setting is not accessible by the end user.
The host product manufacturer is responsible for compliance to any other FCC rules that apply to the host not covered by the modular transmitter grant of certification. The final host product still requires Part 15 Subpart B compliance testing with the modular transmitter installed.
The end user manual shall include all required regulatory information/warning as shown in this manual, including: This product must be installed and operated with a minimum distance of 20 cm between the radiator and user body.
This device have got a FCC ID:2ANDL-WBR3S.The final end product must be labeled in a visible area with the following: “Contains Transmitter Module FCC?ID: 2ANDL-WBR3S”
This device is intended only for OEM integrators under the following conditions:
1)The antenna must be installed such that 20cm is maintained between the antenna and users, and
2) The transmitter module may not be co-located with any other transmitter or antenna.
As long as 2 conditions above are met, further transmitter test will not be required. However, the OEM integrator is still responsible for testing their end-product for any additional compliance requirements required with this module installed.
Declaration of Conformity European notice

Hereby, Hangzhou Tuya?Information Technology Co., Ltd declares that this module product is in compliance with essential requirements and other relevant provisions of?Directive?2014/53/EU,2011/65/EU.A copy of the Declaration of conformity can be found at https://www.tuya.com

This product must not be disposed of as normal household waste, in accordance with EU directive for waste electrical and electronic equipment (WEEE- 2012/19/EU). Instead,it should be disposed of by returning it to the point of sale, or to a municipal recycling collection point.
The device could be used with a separation distance of?20cm to the human?body.