BT740 Series Bluetooth Module
Overview
Every BT740 series Bluetooth module from Laird Connectivity is designed to add robust, long-range Bluetooth data connectivity to any device. Based on the market-leading Cambridge Silicon Radio (CSR) BC04 chipset, BT740 modules provide exceptionally low power consumption with outstanding Class 1 range via 18 dBm of transmit power. The modules support Bluetooth Version 2.1 specification, including Secure Simple Pairing (SSP), which improves security and enhances the ease of use for end customers. A broad range of Bluetooth profiles such as Serial Port Profile (SPP) and other vital features make BT740 modules superior to other Class 1 Bluetooth modules. Available in BT740-SA and BT740-SC variants.
Specifications
UART: Over 350 kbps
GPIO (8 configurable lines)
ADC (2 lines, 8 bit resolution)
Transmit (Max Data) – 35 mA
Multi-Point API - 7 simultaneous connections
I/O: 3.3V
| Product Type | Technology | OS/Software | System Architecture | Chipset (Wireless) | Antenna Type | Logical Interfaces | Frequency Range (Min) | Frequency Range (Max) | Bluetooth Version | Compliance | Connector | Data Rate | Transmit Power (Max) | Protocols | Range | Receive Sensitivity | Wireless Specification | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| BT740-SA | Embedded Module | Bluetooth Classic, Bluetooth 2.1 | AT Commands, Embedded Stack | Hosted | QCA (CSR) BC04 | Internal | Serial, GPIO, ADC | 2402 MHz | 2480 MHz | v2.1 | FCC, ISED, EU | SMT | Up to 2.1 Mbps | +18 dBm | AT Command Set | Up to 1 km | Better than -87 dBm | Bluetooth v2.1 Enhanced Class 1 |
| Product Type | Technology | OS/Software | System Architecture | Chipset (Wireless) | Antenna Type | Logical Interfaces | Frequency Range (Min) | Frequency Range (Max) | Antenna Options | Bluetooth Version | Compliance | Connector | Data Rate | Transmit Power (Max) | Protocols | Range | Receive Sensitivity | Wireless Specification | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| BT740-SC | Embedded Module | Bluetooth Classic, Bluetooth 2.1 | AT Commands, Embedded Stack | Hosted | QCA (CSR) BC04 | External | Serial, GPIO, ADC | 2402 MHz | 2480 MHz | u.FL Connector | v2.1 | FCC, ISED, EU | SMT | Up to 2.1 Mbps | +18 dBm | AT Command Set | Up to 1 km | Better than -87 dBm | Bluetooth v2.1 Enhanced Class 1 |
| Product Type | Technology | OS/Software | System Architecture | Chipset (Wireless) | Antenna Type | Logical Interfaces | Frequency Range (Min) | Frequency Range (Max) | Bluetooth Version | Connector | Data Rate | Transmit Power (Max) | Protocols | Range | Receive Sensitivity | Wireless Specification | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| DVK-BT740-SA | Development Kit | Bluetooth Classic, Bluetooth 2.1 | AT Commands | Hosted | QCA (CSR) BC04 | Internal | USB, PCM, RS232 | 2402 MHz | 2480 MHz | v2.1 | RS232/USB | Up to 2.1 Mbps | +18 dBm | AT Command Set | Up to 1 km | Better than -87 dBm | Bluetooth v2.1 Enhanced Class 1 |
| Product Type | Technology | OS/Software | System Architecture | Chipset (Wireless) | Antenna Type | Logical Interfaces | Frequency Range (Min) | Frequency Range (Max) | Antenna Options | Bluetooth Version | Connector | Data Rate | Transmit Power (Max) | Protocols | Range | Receive Sensitivity | Wireless Specification | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| DVK-BT740-SC | Development Kit | Bluetooth Classic, Bluetooth 2.1 | AT Commands | Hosted | QCA (CSR) BC04 | External | USB, PCM, RS232 | 2402 MHz | 2480 MHz | u.FL Connector | v2.1 | RS232/USB | Up to 2.1 Mbps | +18 dBm | AT Command Set | Up to 1 km | Better than -87 dBm | Bluetooth v2.1 Enhanced Class 1 |
Certified Antennas
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Documentation
Is it safe to run a Laird Connectivity Bluetooth module through a PCBA wash cycle?
In general, cleaning the populated modules is strongly discouraged. Residuals under the module cannot be easily removed with any cleaning process.
- Cleaning with water can lead to capillary effects where water is absorbed into the gap between the host board and the module. The combination of soldering flux residuals and encapsulated water could lead to short circuits between neighboring pads. Water could also damage any stickers or labels.
- Cleaning with alcohol or a similar organic solvent will likely flood soldering flux residuals into the RF shield, which is not accessible for post-washing inspection. The solvent could also damage any stickers or labels.
- Ultrasonic cleaning could damage the module permanently.
However, if water washing is required you will need to use deionized water. We do not recommend chemical cleaning and cannot guarantee it will not damage the modules. If you MUST clean PCB with chemicals it is recommended that you test on one board and then confirm the module still works after the process, prior to adding it to production, while understanding the above affects washing the populated PCBs can have on the module.
How is power adjusted on the B7xx?
While the power adjustment cannot be done manually, the radio automatically adjusts the Tx power based on the RSSI and Golden Receive Power Range values. For more information on this, please review the following guide: User Guide - BT740 Firmware.pdf
Do I still have to list/qualify my product with the BT SIG even if I don't use the BT logo?
Yes, you need to qualify/list any product that uses BT SIG intellectual property, even if you do not use the logo or require interoperability with other BT devices. see here for more details. Qualify Your Product | Bluetooth® Technology Website
What is the throughput of your bluetooth modules with the embedded AT command interface?
Our fully-embedded modules have a throughput of around 300-360 kbps. They have an on-board Bluetooth stack and do all of the Bluetooth processing themselves. Bluetooth 2.1 + EDR has a practical transfer rate of 2.1 Mbit/s, but this is not possible on a small embedded module that does not have a powerful PC-type processor.
For more information on the throughput of the BT740, see the following application note: BTM44X Enhanced Data Module: Throughput Analysis. The throughput analysis on the BTM44X is also relevant to the BT740.
Is a licence required to use the LC3 audio codec?
Use of the LC3 codec is included in the Bluetooth product licence when you qualify your product. No additional licence fees are required.