BT2S Module Datasheet

Last Updated on : 2024-06-14 03:12:25download

BT2S is an embedded low-power Bluetooth module that Tuya has developed. It consists of a highly integrated Bluetooth chip (TLSR8250F512ET32) and several peripheral components, with an embedded Bluetooth network protocol stack and rich library functions.


BT2S contains a low-power 32-bit MCU, Bluetooth LE 5.0 component, 2.4 GHz radio component, 4-MB flash memory, and 48-KB SRAM.


  • Embedded low-power 32-bit MCU, which can also function as an application processor
  • Dominant frequency: 48 MHz
  • Working voltage: 1.8 V to 3.6 V (Under 1.8 V to 2.7 V, the module can start but the RF performance is not guaranteed. Under 2.8 V to 3.6 V, the module performance is normal.)
  • Peripherals: 5×GPIOs, 1×UART, 1×ADC
  • Bluetooth LE RF features
    • Compatible with Bluetooth LE 4.2/5.0
    • Up to 2 Mbit/s RF data rate
    • TX power: +10 dBm
    • RX sensitivity: -94 dBm at Bluetooth LE 1 Mbit/s
  • Embedded advanced encryption standard (AES) hardware encryption
  • Working temperature: -20°C to +85°C


  • Smart LED lights
  • Smart households
  • Smart low-power sensors

Module interfaces

Dimensions and footprint

BT2S has two lines of pins with a 2-mm pin spacing.
The BT2S dimensions are 15±0.35mm (W)×18±0.35mm (L) ×2.9±0.15mm(H). The PCB thickness is 0.8±0.1 mm. The BT2S are shown below:

BT2S Module Datasheet
BT2S Module Datasheet

Interface pin definition

Pin No. Symbol I/O type Function
1 3V3 P Power supply pin
2 C2 I/O Common I/O, which can be used as a PWM output of the LED drive and is connected to pin PC2 on the IC
3 GND P Power supply reference ground pin
4 C3 I/O Common I/O, which can be used as a PWM output of the LED drive and is connected to pin PC3 on the IC
5 B7 I/O UART_RX and is connected to pin PB7 on the IC
6 D2 I/O Common I/O, which can be used as a PWM output of the LED drive and is connected to pin PD2 on the IC
7 B1 I/O UART_TX and is connected to pin PB1 on the IC
8 C4 I/O SAR ADC Input, and is connected to pin PC4 on the IC
9 B5 I/O Common I/O, which can be used as a PWM output of the LED drive and is connected to pin PB5 on the IC
10 RST 1/O Reset, and is connected to pin 25 on the IC
11 B4 I/O Common I/O, which can be used as a PWM output of the LED drive and is connected to pin PB4 on the IC


  1. P indicates power supply pins, I/O indicates input/output pins, and AI indicates analog input pins.
  2. If you have special requirements on light colour controlled by PWM outputs, contact Tuya business personnel.

Electrical parameters

Absolute electrical parameters

Parameter Description Minimum value Maximum value Unit
Ts Storage temperature -65 150 °C
VCC Power supply voltage -0.3 3.9 V
ESD voltage (human body model) TAMB-25°C - 2 KV
ESD voltage (machine model) TAMB-25°C - 0.5 KV

Electrical conditions

Parameter Description Minimum value Typical value Maximum value Unit
Ta Working temperature -20 - 85 °C
VCC Working voltage 2.8 3.3 3.6 V
VIL I/O low-level input VSS - VCC*0.3 V
VIH I/O high-level input VCC*0.7 - VCC V
VOL I/O low-level output VSS - VCC*0.1 V
VOH I/O high-level output VCC*0.9 - VCC V

Working Current

Symbol Condition Minimum Value (Typical) Unit
Itx Constant transmission, 10dBm output power 23.5 mA
Irx Constant receiving 6.5 mA
IDC Connected to a mesh network(Average) 6.59 mA
IDC Connected to a mesh network(Peak) 24.9 mA
Ideepsleep1 Deep sleep mode 1 (16 KB RAM is reserved.) 1.2 μA
Ideepsleep2 Deep sleep mode 2 (No RAM is reserved.) 0.4 μA

RF features

Basic RF features

Parameter Description
Frequency band 2.4GHz ISM band
Wireless standard Bluetooth LE 4.2/5.0
Data transmission rate 1Mbps, 2Mbps
Antenna type Onboard PCB antenna

RF output power

Parameter Minimum value Typical value Maximum value Unit
Average RF output power -21 10 11.5 dBm
20 dB modulation signal bandwidth (1 Mbit/s) - 2500 - KHz
20 dB modulation signal bandwidth (2 Mbit/s) - 1400 - KHz

RF RX sensitivity

Parameter Minimum value Typical value Maximum value Unit
RX sensitivity 1Mbps - -94 - dBm
RX sensitivity 2Mbps - -91 - dBm
Frequency offset 1Mbps -250 - +300 KHz
Frequency offset 2Mbps -300 - +200 KHz
Co-channel interference suppression - -10 - dB


Antenna type

BT2S uses an onboard PCB antenna with a gain of 0.89 dBi.

Antenna interference reduction

To ensure optimal RF performance, it is recommended that the antenna be at least 15 mm away from other metal parts. If metal materials are wrapped around the antenna, the wireless signals will be reduced greatly, deteriorating the RF performance. Because BT2S is inserted into the PCB, sufficient space needs to be reserved for the antenna.

Packaging information and production instructions

Mechanical dimensions

BT2S Module Datasheet

The default dimensional tolerance is ±0.35 mm, and the tolerance for some key dimensions is ±0.1 mm.

Production instructions

  • The stamp-hole module must be mounted by the SMT machine. After being unpacked, it must be soldered within 24 hours. Otherwise, it must be put into the drying cupboard where the RH is not greater than 10%, or it needs to be packaged under vacuum again and the exposure time needs to be recorded (the total exposure time cannot exceed 168 hours).

    • SMT equipment:
      • Mounter
      • SPI
      • Reflow soldering machine
      • Oven temperature tester
      • Automated optical inspection (AOI) equipment
    • Baking equipment:
      • Cabinet oven
      • Anti-static heat-resistant pallets
      • Anti-static heat-resistant gloves
  • Storage conditions for a delivered module are as follows:

    • The moisture-proof bag must be placed in an environment where 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.
    • The package contains a humidity indicator card (HIC).
      BT2S Module Datasheet
  • The module needs to be baked in the following cases:

    • Vacuum packing bag was found to be damaged before being unpacked.
    • There is no humidity indicator card (HIC) in the vacuum packing bag.
    • After being unpacked, 10% and above circles on the HIC become pink.
    • The total exposure time has been more than 168 hours since unpacking.
    • More than 12 months have passed since the sealing date of the bag.
  • 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 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.
  • In the whole production process, take electrostatic discharge (ESD) protective measures.

  • 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

Perform mounting with the SMT based on the following reflow oven temperature curve. The highest temperature is 245°C. The reflow temperature curve is as below:

BT2S 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

    Note: 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.

Storage conditions

BT2S Module Datasheet

MOQ and packaging information

Product model MOQ (pcs) Packing method Number of modules in per reel Number of reels in per carton
BT2S 4400 Tape reel packing 1100 4

Appendix: Statement

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 into 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 operating 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-BT2S. The end product must be labeled in a visible area with the following: “Contains Transmitter Module FCC ID: 2ANDL-BT2S”.

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

BT2S Module Datasheet

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

BT2S Module Datasheet

This product must not be disposed of as normal household waste, in accordance with 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 to a municipal recycling collection point.

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