BT7L Module Datasheet

BT7L is an embedded low-power Bluetooth module that Tuya has developed. Embedded with a Bluetooth network protocol stack and rich library functions, it consists of a highly integrated Bluetooth chip (TLSR8250F512ET32) and several peripheral circuits.

Overview

BT7L contains a low-power 32-bit MCU, Bluetooth 5.0, 2.4 GHz radio, 512-KB flash memory, 48-KB SRAM, and 7 reusable I/O interfaces.

Features

• Embedded low-power 32-bit MCU, which can also function as an application processor
• Clock rate: 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 PWMs, 1 I2C, and 1 UART
• Bluetooth RF features
  • Compatible with Bluetooth 5.0
  • Data transmission rate: Up to 2 Mbit/s RF data rate
  • TX power: +10 dBm
  • RX sensitivity: –94.5 dBm at Bluetooth 1 Mbit/s
  • Embedded Advanced Encryption Standard (AES) hardware encryption
  • Onboard PCB antenna
  • Working temperature: -40°C to +85°C

Applications

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

Module interfaces

Dimensions and footprint

BT7L has two lines of 14 pins with a spacing of 1.5 mm.

The BT7L dimensions (H x W x L) are 2.85±0.15mm x 15±0.35 mm x 16.5±0.35 mm. The following figures show the top and bottom views of BT7L.

Interface pin definition

Pin No.	Symbol	I/O type	Function
1	SDA	I/O	I2C data cable pin, which can be used as a common I/O pin and is connected to the PC0 pin on the internal IC
2	SCL	I/O	I2C clock cable pin, which can be used as a common I/O pin and is connected to the PC1 pin on the internal IC
3	C3	I/O	Common I/O pin, which can be used as a PWM output of the LED drive and is connected to the PC3 pin on the internal IC (By default, the pin controls the cold green light.)
4	D2	I/O	Common I/O pin, which can be used as a PWM output of the LED drive and is connected to the PD2 pin on the internal IC (By default, the pin controls the cold blue light.)
5	C2	I/O	Common I/O pin, which can be used as a PWM output of the LED drive and is connected to the PC2 pin on the internal IC (By default, the pin controls the cold warm white light.)
6	B5	I/O	Common I/O pin, which can be used as a PWM output of the LED drive and is connected to the PB5 pin on the internal IC (By default, the pin controls the cold cold white light.)
7	B4	I/O	Common I/O pin, which can be used as a PWM output of the LED drive and is connected to the PB4 pin on the internal IC (By default, the pin controls the cold red light.)
8	3V3	P	Power supply pin
9	TX	I/O	Serial interface transmission pin, which can be used as a common I/O pin and is connected to the PB1 pin on the internal IC
10	RX	I/O	Serial interface receiving a pin, which can be used as a common I/O pin and is connected to the PB7 pin on the internal IC
11	GND	P	Power supply reference ground pin
12	SW	I/O	Bluetooth chip programming pin, which is connected to the SWS pin on the internal IC
13	RST	I	Reset pin, which is connected to the RESETB pin on the internal IC (The module is embedded with a pull-up resistor.)
14	GND	P	Power supply reference ground pin

Note: P indicates a power supply pin, and I/O indicates an input/output pin. If you have any special requirements on light colour controlled by the 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℃	-	2	KV
ESD voltage (machine model)）	TAMB-25℃	-	0.5	KV

Working conditions

Parameter	Description	Minimum value	Typical value	Maximum value	Unit
Ta	Working temperature	-40	N/A	85	°C
VCC	Working voltage	1.8	3.3	3.6	V
VIL	I/O low-level input	VSS	N/A	VCC x 0.3	V
VIH	I/O high-level input	VCC x 0.7	N/A	VCC	V
VOL	I/O low-level output	VSS	N/A	VCC x 0.1	V
VOH	I/O high-level output	VCC x 0.9	N/A	VCC	V

Power consumption

Symbol	Condition	Typical value	Maximum value	Unit
Itx	Continuous TX, 10 dBm output power	16.8	18.4	mA
Itx	Continuous TX, 0 dBm output power	6.3	8.8	mA
Irx	Continuous RX	6.3	8.9	mA
IDC	Network pairing	6.8	32	mA
IDC	Connected	6.8	32	mA

RF features

Basic RF features

Parameter	Description
Working frequency	2.4 GHz ISM band
Wireless standard	Bluetooth 5.0
Data transmission rate	1 Mbit/s
Antenna type	Onboard PCB antenna

RF TX power

Parameter	Minimum value	Typical value	Maximum value	Unit
Average RF output power	–22	10	10.5	dBm
20 dB modulation signal bandwidth (1 Mbit/s)	-	2500	-	kHz
20 dB modulation signal bandwidth (1 Mbit/s)）	-	2600	-	kHz

RF RX sensitivity

Parameter	Minimum value	Typical value	Maximum value	Unit
RX sensitivity (1 Mbit/s)	N/A	–94.5	N/A	dBm
RX sensitivity (2 Mbit/s)	N/A	–90	N/A	dBm
Frequency offset error (1 Mbit/s)	–300	N/A	+300	kHz
Frequency offset error (2 Mbit/s)	–200	N/A	+200	kHz
Co-channel interference suppression	N/A	–7	N/A	dB

Antenna

Antenna type

BT7L uses an onboard PCB antenna.

Antenna interference reduction

To ensure optimal RF performance, 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.

Packaging information and production instructions

Mechanical dimensions and outline of the back pad

Top view

Bottom view

Side view

Recommended footprint

Note: The default dimensional tolerance is ±0.35 mm, and the tolerance for key dimensions is ±0.1 mm. If you have any other requirements, clearly specify them in the datasheet after communication. The area indicated as keep-out in the diagram above does not require tinning and should not have any traces routed through it.

Production instructions

1. The Tuya SMT module should be mounted by the SMT device. After being unpacked, it should be soldered within 24 hours. Otherwise, it should 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 devices:
     • Mounter
     • SPI
     • Reflow soldering machine
     • Thermal profiler
     • Automated optical inspection (AOI) equipment
   • 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 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.

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

     

3. The module needs to be baked in the following cases:
   • The packaging bag is damaged before unpacking.
   • There is no 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 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 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

Set oven temperatures according to the following temperature curve of reflow soldering. The peak temperature is 245°C.

• 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

MOQ and packing information

Product model	MOQ	Packing method	Number of modules per reel	Number of reels per carton
BT7L	4000	Tape reel packing	1000	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 to 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-BT7L. The end product must be labeled in a visible area with the following: “Contains Transmitter Module FCC ID: 2ANDL-BT7L”.

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.