BCNU Module Datasheet

This topic describes Tuya’s proprietary BCNU Bluetooth low energy (LE) module. It consists of a highly integrated Bluetooth chip, TLSR8250, and a few peripheral circuits. It has built-in Bluetooth protocol stacks and a rich set of library functions.

Overview

The BCNU module is built around a 32-bit microcontroller unit (MCU) with 4 Mbits of flash and 48 KB of SRAM. The embedded 2.4 GHz transceiver supports Bluetooth 5.

Features

• Built-in low-power 32-bit MCU that also acts as an application processor
  • Clock rate of 48 MHz
• Operating voltage range: 3.0V to 3.6V
• Peripherals: 15 general-purpose input/output (GPIO) pins, 1 universal asynchronous receiver/transmitter (UART), and 2 analog-to-digital converter (ADC) pins
• Bluetooth LE radio frequency (RF) features
  • Compatible with Bluetooth LE 4.2/5.0
  • RF data rate of up to 2 Mbit/s
  • Transmitter (TX) power: +10 dBm
  • Receiver (RX) sensitivity: -94.5 dBm@Bluetooth LE 1 Mbit/s
  • Embedded hardware Advanced Encryption Standard (AES) encryption
  • Onboard PCB antenna with a gain of 1.1 dBi
  • Operating temperature range: -40°C to +85°C

Scope of applications

• Smart building
• Smart home and electrical appliance
• Smart socket and light
• Industrial wireless control
• Baby monitor
• Smart bus

Module interfaces

Dimensions and footprint

BCNU has three rows of pins with a 1.4±0.1mm pin spacing. The BCNU dimensions are 20.3±0.35 mm (L) × 15.8±0.35 mm (W) × 3.0±0.15 mm (H).

The following figure shows the dimensions and packaging design of the BCNU module.

Pinout

Pin No.	Symbol	I/O type	Description
1	D3	I/O	GPIO pin, corresponding to D3 (Pin 32) on the IC.
2	D7	I/O	GPIO pin, corresponding to D7 (Pin 2) on the IC.
3	C0	I/O	GPIO pin, corresponding to C0 (Pin 20) on the IC.
4	SWS	I/O	Used for firmware flashing, corresponding to SWS (Pin 5) on the IC.
5	B6	I	ADC pin, corresponding to B6 (Pin 16) on the IC.
6	A0	I/O	GPIO pin, corresponding to A0 (Pin 3) on the IC.
7	A1	I/O	GPIO pin, corresponding to A1 (Pin 4) on the IC.
8	C2	I/O	Support hardware PWM, corresponding to C2 (Pin 22) on the IC.
9	C3	I/O	Support hardware PWM, corresponding to C3 (Pin 23) on the IC.
10	D2	I/O	Support hardware PWM, corresponding to D2 (Pin 31) on the IC.
11	B4	I/O	Support hardware PWM, corresponding to B4 (Pin 14) on the IC.
12	B5	I/O	Support hardware PWM, corresponding to B5 (Pin 15) on the IC.
13	GND	P	Ground pin.
14	VCC	P	Power supply pin (3.3V).
15	B1	I/O	Uart_TXD, corresponding to B1 (Pin 6) on the IC.
16	B7	I/O	Uart_RXD, corresponding to B7 (Pin 17) on the IC.
17	C4	I/O	ADC pin, corresponding to C4 (Pin 24) on the IC.
18	RST	I/O	Reset pin. Active low.
19	C1	I/O	GPIO pin, corresponding to C1 (Pin 21) on the IC.
20	D4	I/O	GPIO pin, corresponding to D4 (Pin 1) on the IC.
21	NC	I/O	Not connected.

Electrical parameters

Absolute electrical parameters

Parameter	Description	Minimum value	Maximum value	Unit
Ts	Storage temperature	-65	150	°C
VCC	Supply voltage	-0.3	3.9	V
Electrostatic discharge voltage (human body model)	TAMB-25°C	-	2	kV
Electrostatic discharge voltage (machine model)	TAMB-25°C	-	0.5	kV

Operating conditions

Parameter	Description	Minimum value	Typical value	Maximum value	Unit
Ta	Operating temperature	-40	-	85	°C
VCC	Operating voltage	3.0	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

Power consumption in working mode

Symbol	Condition	Max (Typical) value	Unit
Itx	Continuous transmission, with an output power of 11.5 dBm	22.6	mA
Irx	Continuous reception	6.5	mA
IDC	Average value when connected over Bluetooth mesh	6.59	mA
IDC	Peak value when connected over Bluetooth mesh	24.9	mA
I deepsleep1	Deep sleep mode (16 KB RAM reserved)	1.2	μA
I deepsleep2	Deep sleep mode (RAM not reserved)	0.4	μA

RF parameters

Basic RF features

Parameter	Description
Operating frequency	2.4 GHz ISM band
Wireless standard	Bluetooth LE 4.2/5.0
Data transmission rate	1 Mbit/s and 2 Mbit/s
Antenna type	Onboard PCB antenna

RF output power

Parameter	Minimum value	Typical value	Maximum value	Unit
RF average output power	-21	10	11.5	dBm
Bandwidth of 20 dB modulation signal (1 Mbit/s)	-	2500	-	kHz

RF receiver (RX) sensitivity

Parameter	Minimum value	Typical value	Maximum value	Unit
RX sensitivity 1 Mbit/s	-	-94.5	-	dBm
Frequency offset error 1 Mbit/s	-250	-	+300	kHz
Co-channel interference suppression	-	-	-10	dB

Power-up sequence of the module

The TLSR8250 chip has requirements for the power-up sequence. During the power-up process, the system begins to start after the RST pin reaches 1.62V. At this time, the VDD pin needs to reach above 1.8V within 10 ms. The RST pin has an RC link. When the RST pin reaches 1.62V, the VDD pin of the bare module has far exceeded 1.8V.

If the power driver connected to a module with a TLSR8250 chip is charged and discharged by a large capacitor, and the module voltage is not fully discharged below 0.6V, the module might crash when restarted. The VDD_3.3V power supply pin of the module needs to be connected to a 1K dummy load to speed up discharge. The figure below shows part of the power drive link for your reference.

Antenna information

Antenna type

Onboard PCB antenna with a gain of 1.08 dBi.

Antenna interference reduction

The distance between the antenna and other metal components should be at least 15 mm to provide the best radio performance. If metal materials wrap the surroundings of the antenna, the wireless signal will be greatly attenuated, thereby deteriorating the RF performance. Allow enough space to support the RF layout when designing your product.

Footprint and production instructions

Mechanical dimensions

The PCB dimensions are 20.3±0.35 mm (L) × 15.8±0.35 mm (W) × 1.0±0.1 mm (H).

Side view

Pinout

Surface-mount technology (SMT) package

Production instructions

• For the modules that can be packaged with the surface-mount technology (SMT) or in in-line form, 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 use an in-line package, use wave soldering. Complete soldering within 24 hours after the module is unpacked. Otherwise, we recommend that you place the module in a drying cupboard with a relative humidity level below 10%, or pack the module in a vacuum again. Then, record the packing time and duration of exposure. The total exposure time cannot exceed 168 hours.

  • Instruments or devices required for the SMT process:
    • Surface mount system
    • SPI
    • Reflow soldering machine
    • Thermal profiler
    • Automated optical inspection (AOI) equipment
  • Instruments or devices required for the wave soldering process:
    • Wave soldering device
    • Wave soldering fixture
    • Constant-temperature soldering iron
    • Tin bar, tin wire, and flux
    • Thermal profiler
  • Instruments or devices required for the baking process:
    • Cabinet oven
    • Electrostatic discharge (ESD) protection and heat-resistant trays
    • ESD protection and heat-resistant gloves

• A delivered module must meet the following storage requirements:

  • 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.

  • A humidity indication card (HIC) is put in the sealed package.

    

• The module needs to be baked in the following cases:

  • The vacuum packaging bag is damaged before unpacking.
  • After unpacking, no HIC is found in the packaging bag.
  • After unpacking, the HIC indicates a humidity level of 10% or higher. In this case, the circle turns pink on the HIC.
  • The total exposure time has lasted for over 168 hours since unpacking.
  • More than 12 months have passed since the first sealing of the bag.

• The baking parameter settings are described below:

  • Baking temperature: 40°C for reel packaging with relative humidity ≤ 5%. And 125°C for tray packaging with relative humidity ≤ 5% (use a heat-resistant tray, rather than a plastic container).
  • Baking time: 168 hours for reel packaging and 12 hours for tray packaging.
  • Temperature for triggering an alert: 50°C for reel packaging and 135°C for tray packaging.
  • Production can begin after a module has cooled down to below 36°C under natural conditions.
  • 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 after exposure for more than 168 hours, do not use 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, device failure or poor soldering performance might occur.

• In the whole production process, take electrostatic discharge (ESD) protective measures.

• To guarantee the pass rate, we recommend 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 technique according to the process. For more information, refer to the recommended oven temperature curve of either reflow soldering or wave soldering. The set temperatures might deviate from the actual temperature measurements. All temperatures shown in this module datasheet are obtained through actual measurements.

Technique 1: SMT process (recommended oven temperature curve of reflow soldering)

Set the oven temperatures according to the following curve.

• A: temperature axis

• B: time axis

• C: alloy liquidus temperature from 217°C to 220°C

• D: ramp-up slope from 1°C/s to 3°C/s

• E: keep a constant temperature from 150°C to 200°C for a time period of 60s to 120s

• F: temperature above liquidus temperature for 50s to 70s

• G: peak temperature from 235°C to 245°C

• H: ramp-down slope from 1°C/s to 4°C/s

  The curve above is based on solder paste SAC305. For more information about other solder pastes, see the recommended oven temperature curve in the specified solder paste specifications.

Technique 2: Wave soldering process (oven temperature curve of wave soldering)

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

Suggestions on wave soldering		Suggestions on manual repair soldering
Preheat temperature	80°C to 130°C	Soldering temperature	360°C ± 20°C
Preheat duration	75s to 100s	Soldering duration	Less than 3s/point
Contact duration at the peak	3s to 5s	N/A	N/A
Solder tank temperature	260°C ± 5°C	N/A	N/A
Ramp-up slope	≤ 2°C/s	N/A	N/A
Ramp-down slope	≤ 6°C/s	N/A	N/A

Storage conditions

MOQ and packaging information

Product model	MOQ (pcs)	Shipping packaging	Modules per reel	Reels per carton
BCNU	4,400	Tape and reel	1,100	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 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-BCNU. The end product must be labeled in a visible area with the following: “Contains Transmitter Module FCC ID: 2ANDL-BCNU”.

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

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 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 from the human body.