CB3L Module Datasheet

Last Updated on : 2023-11-06 06:10:58download

CB3L is an embedded low-power Wi-Fi module that Tuya has developed. It consists of a highly integrated RF chip BK7231N and a few peripherals. CB3L not only supports the Wi-Fi AP and STA modes, but also supports the Bluetooth LE.

Product overview

CB3L is built in with a 32-bit MCU whose running speed can be up to 120 MHz, a 2-MB flash memory, and a 256-KB RAM, to support the Tuya cloud connection. The MCU instructions specially extended for signal processing can effectively implement audio encoding and decoding. Besides, it has rich peripherals, such as PWM, UART and SPI. There are six 32-bit PWM outputs, making the chip very suitable for high-quality LED control.


  • Built in with the low-power 32-bit CPU, which can also function as an application processor
  • The clock rate: 120 MHz
  • Operating voltage: 3.0 to 3.6V
  • Peripherals: 7 GPIOs, 1 UART, and 1 ADC
  • Wi-Fi connectivity
    • 802.11 b/g/n
    • Channels 1 to 14
    • Support WEP, WPA/WPA2, WPA/WPA2 PSK (AES), WPA3 security modes
    • Up to +16 dBm output power in 802.11b mode
    • Support STA/AP/STA+AP working mode
    • Support Wi-Fi and hotspot network configuration manners for Android and iOS devices
    • Onboard PCB antenna with a gain of 2.4 dBi
    • Operating temperature: -40°C to 105°C
  • Bluetooth connectivity
    • Support the Bluetooth LE V5.2
    • Support the transmit power of 6 dBm in Bluetooth mode
    • Complete Bluetooth coexistence interface
    • Onboard PCB antenna with a gain of 2.4 dBi


  • Intelligent building
  • Smart household and home appliances
  • Smart socket and light
  • Industrial wireless control
  • Baby monitor
  • Network camera
  • Intelligent bus

Module interfaces

Dimensions and package

CB3L has two lines of pins with a spacing of 2±0.1 mm.

The CB3L dimensions are 16±0.35 mm (W)×24±0.35 mm (L) ×2.8±0.15 mm (H).
CB3L Module Datasheet

Pin definition

Pin number Symbol I/O type Function
1 RST I/O Reset pin, effective currently
2 ADC AI ADC, which corresponds to P23 of the IC
3 EN I Enabling pin, the module has been pulled up
4 P14 I/O General I/O pin
5 P26 I/O Support hardware PWM and correspond to P26 on the internal IC
6 P24 I/O Support hardware PWM and correspond to P24 on the internal IC
7 P6 I/O Support hardware PWM and correspond to P6 on the internal IC
8 VCC P Power supply pin (3.3V)
9 GND P Power supply reference ground
10 P9 I/O Support hardware PWM and correspond to P9 on the internal IC
11 TXD2 I/O UART2_TX, debug_log_Uart corresponds to P0 of the IC
12 CSN I/O The pull-up resistor is needed for the usage of customers. Do not connect it to the ground before the module is powered on. The pin corresponds to P21 of the IC.
13 P8 I/O Support hardware PWM and correspond to P8 on the internal IC
14 P7 I/O Support hardware PWM and correspond to P7 on the internal IC
15 RXD1 I/O User serial interface UART_RX, which corresponds to P10 of the IC. Do not pull it up. By default, the MCU serial port should be in low-level or high-impedance state.
16 TXD1 I/O User serial interface UART_TX, which corresponds to P11 of the IC. Do not pull it up. By default, the MCU serial port should be in low-level or high-impedance state.
  • P indicates a power supply pin and I/O indicates an input/output pin.
  • For the MCU solution, please refer to CBx Module.

Electrical parameters

Absolute electrical parameters

Parameter Description Minimum value Maximum value Unit
Ts Storage temperature -55 125 °C
VBAT Power supply voltage -0.3 3.9 V
ESD voltage (human body model) TAMB-25°C -4 4 KV
ESD voltage (machine model) TAMB-25°C -200 200 V

Normal working conditions

Parameter Description Minimum value Typical value Maximum value Unit
Ta Operating temperature -40 - 105 °C
VBAT Power supply voltage 3 3.3 3.6 V
VOL Low level output VSS - VSS+0.3 V
VOH High level output VBAT-0. 3 - VBAT V
Imax Drive current - 6 20 mA
θ Power supply slope 100 - - mV/ms

RF power consumption

Working status Mode Rate Transmit power/receive Average value Peak value (Typical value) Unit
Transmit 11b 11Mbps +16dBm 270 300 mA
Transmit 11g 54Mbps +15dBm 260 280 mA
Transmit 11n MCS7 +14dBm 253 273 mA
Receive 11b 11Mbps Constantly receive 73 82 mA
Receive 11g 54Mbps Constantly receive 75 82 mA
Receive 11n MCS7 Constantly receive 75 82 mA

Operating current

Working mode Working status, Ta = 25°C Average value Maximum value (Typical value) Unit
Connecting (Bluetooth) The module is connecting to the network fast and the Wi-Fi indicator flashes fast 70 270 mA
Connecting (AP) The module is connecting to the network via the hotspot and the Wi-Fi indicator flashes slowly 80 305 mA
Connecting (EZ) The module is connecting to the network fast and the Wi-Fi indicator flashes fast 87 380 mA
Connected The module is connected to the network and the Wi-Fi indicator is always on 39 355 mA
Disconnected The module is disconnected and the Wi-Fi indicator is always off 70 270 mA
Module disabled The EN pin of the module is pulled down. 330 - μA

RF parameters

Basic RF features

Parameter Description
Working frequency 2.412 to 2.484 GHz
Wi-Fi standard IEEE 802.11 b/g/n (channels 1 to 14)
Data transmission rate
  • 11b: 1, 2, 5.5, and 11 (Mbps)
  • 11g: 6, 9, 12, 18, 24, 36, 48, and 54 (Mbps)
  • 11n: HT20 MCS0-7
  • 11n: HT40 MCS0-7
Antenna type PCB antenna

Wi-Fi transmission performance

Parameter Minimum value Typical value Maximum value Unit
Average RF output power, 802.11b CCK Mode 11M - 16 - dBm
Average RF output power, 802.11g OFDM Mode 54M - 15 - dBm
Average RF output power, 802.11n OFDM Mode MCS7 - 14 - dBm
Frequency error -20 - 20 ppm

Wi-Fi receiving performance

Parameter Minimum value Typical value Maximum value Unit
PER<8%, RX sensitivity, 802.11b DSSS Mode 11M - -88 - dBm
PER<10%, RX sensitivity, 802.11g OFDM Mode 54M - -74 - dBm
PER<10%, RX sensitivity, 802.11n OFDM Mode MCS7 - -72 - dBm
PER<10%, RX sensitivity, Bluetooth 1M - -93 - dBm

Bluetooth transmission performance

Parameter Minimum value Typical value Maximum value Unit
Working frequency 2402 - 2480 MHz
Air rate - 1 - Mbps
Transmit power -20 6 20 dBm
Frequency error -150 - 150 KHz

Bluetooth receiving performance

Parameter Minimum value Typical value Maximum value Unit
RX sensitivity - -93 - dBm
Maximum RF signal input -10 - - dBm
Inter-modulation - - -23 dBm
Co-channel suppression ratio - 10 - dB

Antenna information

Antenna type

CB3L may use the PCB antenna.

Antenna interference reduction

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 within the antenna area on the PCB.

Packaging information and production instructions

Mechanical dimensions

CB3L Module Datasheet

Side view

CB3L Module Datasheet

Schematic diagram of the packaging

CB3L Module Datasheet

Diagram of PCB footprint-pin header

CB3L can be packaged with the SMT or pin header.
CB3L Module Datasheet

Pin header:
CB3L Module Datasheet

Production instructions

  1. For the modules that can be packaged with the SMT or in an in-line way, you can select either of them according to the PCB design solutions of customers. If a PCB is designed to be SMT-packaged, package the module with the SMT. If a PCB is designed to be in-line-packaged, package the module in an in-line way. After being unpacked, the module must be soldered within 24 hours. Otherwise, it needs to be put into the drying cupboard where the relative humidity is not greater than 10%; or it needs to be packaged again under vacuum and the exposure time needs to be recorded (the total exposure time cannot exceed 168 hours).

    • (SMT process) SMT devices:
      • Mounter
      • SPI
      • Reflow soldering machine
      • Thermal profiler
      • Automated optical inspection (AOI) equipment
    • (Wave soldering process) Wave soldering devices
      • Wave soldering equipment
      • Wave soldering fixture
      • Constant-temperature soldering iron
      • Tin bar, tin wire, and flux
      • Thermal profiler
    • Baking devices:
      • Cabinet oven
      • Anti-electrostatic and heat-resistant trays
      • Anti-electrostatic and heat-resistant gloves
  2. Storage conditions for a delivered module:

    • The moisture-proof bag must be placed in an environment in which the temperature is below 40°C and the relative humidity is lower than 90%.

    • The shelf life of a dry-packaged product is 12 months from the date when the product is packaged and sealed.

    • There is a humidity indicator card (HIC) in the packaging bag.

      CB3L Module Datasheet

  3. The module needs to be baked in the following cases:

    • The packaging bag is damaged before unpacking.
    • There is no humidity indicator card (HIC) in the packaging bag.
    • After unpacking, circles of 10% and above on the HIC become pink.
    • The total exposure time has lasted for over 168 hours since unpacking.
    • More than 12 months have passed since the sealing of the bag.
  4. Baking settings:

    • Temperature: 40°C and ≤ 5% RH for reel package and 125°C and ≤5% RH for tray package (please use the heat-resistant tray rather than a plastic container)
    • Time: 168 hours for reel package and 12 hours for tray package
    • Alarm temperature: 50°C for reel package and 135°C for tray package
    • Production-ready temperature after natural cooling: < 36°C
    • Re-baking situation: If a module remains unused for over 168 hours after being baked, it needs to be baked again.
    • If a batch of modules is not baked within 168 hours, do not use the reflow soldering or wave soldering to solder them. Because these modules are Level-3 moisture-sensitive devices, they are very likely to get damp when exposed beyond the allowable time. In this case, if they are soldered at high temperatures, it may result in device failure or poor soldering.
  5. In the whole production process, take electrostatic discharge (ESD) protective measures.

  6. To guarantee the passing rate, it is recommended that you use the SPI and AOI to monitor the quality of solder paste printing and mounting.

Recommended oven temperature curve

Select a proper soldering manner according to the process. For the SMT process, please refer to the recommended oven temperature curve of reflow soldering. For the wave soldering process, please refer to the recommended oven temperature curve of wave soldering. There are some differences between the set temperatures and the actual temperatures. All the temperatures shown in this module datasheet are obtained through actual measurements.

Mode 1: SMT process (Recommended oven temperature curve of reflow soldering)

Set oven temperatures according to the following curve.

CB3L Module Datasheet

  • A: Temperature axis
  • B: Time axis
  • C: Liquidus temperature: 217 to 220°C
  • D: Ramp-up slope: 1 to 3°C/s
  • E: Duration of constant temperature: 60 to 120s; the range of constant temperature: 150 to 200°C
  • F: Duration above the liquidus: 50 to 70s
  • G: Peak temperature: 235 to 245°C
  • H: Ramp-down slope: 1 to 4°C/s

The above curve is just an example of the solder paste SAC305. For more details about other solder pastes, please refer to Recommended oven temperature curve in the solder paste specifications.

Mode 2: Wave soldering process (Oven temperature curve of wave soldering)

Set oven temperatures according to the following temperature curve of wave soldering. The peak temperature is 260°C±5°C.

CB3L Module Datasheet
Suggestions on oven temperature curve of wave soldering Suggestions on manual soldering temperature
Preheat temperature 80 to 130°C Soldering temperature 360±20°C
Preheat time 75 to 100s Soldering time < 3s/point
Peak contact time 3 to 5s NA NA
Temperature of tin cylinder 260±5°C NA NA
Ramp-up slope ≤2°C/s NA NA
Ramp-down slope ≤6°C/s NA NA

Storage conditions

CB3L Module Datasheet

MOQ and packaging information

Product number MOQ (pcs) Shipping packaging method The number of modules per reel The number of reels per carton
CB3L 3600 Tape reel 900 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 device.

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 device has been tested and found to comply with the limits for a Class B digital device, according to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This device generates, uses, and can radiate radio frequency energy and, if not installed and used following 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 device does cause harmful interference to radio or television reception, which can be determined by turning the device off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

  • Reorient or relocate the receiving antenna.
  • Increase the separation between the device and receiver.
  • Connect the device to an outlet on a circuit different from that to which the receiver is connected.
  • Consult the dealer or an experienced radio/TV technician for help.

Radiation Exposure Statement

This device complies with FCC radiation exposure limits set forth for an uncontrolled rolled environment. This device should be installed and operated with a minimum distance of 20cm between the radiator and your body.

Important Note

This radio module must not be installed to co-locate and operate simultaneously with other radios in the host system except following FCC multi-transmitter product procedures. Additional testing and device authorization may be required to operate simultaneously with other radios.

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 with 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/warnings 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 has got an FCC ID: 2ANDL-CB3L. The end product must be labeled in a visible area with the following: “Contains Transmitter Module FCC ID: 2ANDL-CB3L”.

This device is intended only for OEM integrators under the following conditions:

The antenna must be installed such that 20cm is maintained between the antenna and users, and the transmitter module may not be co-located with any other transmitter or antenna.

As long as the 2 conditions above are met, further transmitter tests 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

CB3L Module Datasheet

Hereby, Hangzhou Tuya Information Technology Co., Ltd declares that this module product complies 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.

CB3L Module Datasheet

This product must not be disposed of as normal household waste, under the 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 a municipal recycling collection point.

The device could be used with a separation distance of 20cm to the human body.