256 kB Flash, 8 kB SRAM — what the memory budget buys
The Texas Instruments CC2540TF256RHAR is a Bluetooth v4.0 single-mode (BLE) SoC that integrates a 2.4 GHz radio with an 8051-based MCU core. The 21 GPIO lines, SPI, USART, and USB serial interfaces give enough connectivity for environmental sensors, human-interface devices, or simple data-logging nodes without an additional host MCU.
Radio link budget: 4 dBm TX, −93 dBm sensitivity
The transmit output is rated at 4 dBm, which provides roughly 10–15 metres of reliable indoor range through standard PCB or chip antennas. The −93 dBm receiver sensitivity means the link budget holds about 97 dB from transmitter to receiver — enough to maintain a connection through a couple of interior walls. The GFSK modulation at 1 Mbps data rate is the Bluetooth v4.0 standard for BLE advertising and data channels. Current draw runs 19.6 mA to 22.1 mA in receive and 21.1 mA to 31.6 mA during transmit, which keeps a coin-cell-powered beacon alive for months depending on duty cycle.
The 40-VQFN (6x6 mm) package with exposed pad helps thermal dissipation when the radio is active in a 125°C ambient.
For designs that need a Bluetooth v4.0 SoC with the industrial temperature grade, this is a production-committable line item without obsolescence risk.