IC extends battery life for remote controls

The EZradio wireless IC from Silicon Laboratories is designed to reduce the cost and complexity of one-way wireless links used in a range of consumer, industrial and automotive systems.

The Si4010 system-on-chip (SoC) RF transmitter enables developers to optimise remote keyless entry (RKE), garage door opener, remote control, building automation and security device designs for the lowest system cost and highest performance while ensuring one-way link integrity.

The transmitter is a single-chip remote control IC requiring one external bypass capacitor, a printed circuit board, battery and external case with pushbuttons to create a complete wireless remote control.

Based on a patented crystal-less architecture, the Si4010 is said to achieve +/- 150ppm carrier frequency accuracy over the commercial temperature range and +/- 250ppm over the industrial temperature range - twice the accuracy of traditional surface acoustical wave (SAW) based transmitters - without using an external crystal.

The Si4010 transmitter SoC is best paired with Silicon Laboratories' Si431x RF receivers to enable a transmitter/receiver solution claimed to reduce the total bill of materials and save board space for one-way link systems operating in the sub-GHz range (from 27 to 960MHz).

The Si431x receivers' integration requires only two external antenna-matching components, a crystal and a bypass capacitor, while eliminating the need for costly RF SAW and IF ceramic filters.

The Si4010 SoC transmitter has automatic antenna tuning, featuring a patented tuning circuit that automatically fine-tunes the antenna for optimum transmit efficiency and constant output power.

Variations in transmit frequency due to PCB loop antenna manufacturing tolerances and environmental variations can lead to significant antenna inefficiencies and wasted power.

The Si4010's antenna-tuning circuit continuously maximises antenna efficiency by adjusting an on-chip variable capacitor to resonate with the antenna's inductance.

The Si4010 supports programmable edge rate control for on-off keying (OOK) mode to reduce harmonic emissions and comply with governmental RF regulations.

It is also claimed to outperform competing discrete solutions, offering +10dBm output power, good range and robust links.

The Si4010's low power consumption extends battery life for remote controls.

Offering a 1.8V to 3.6V supply range, ultra-low current consumption (<10nA standby current and <20mA peak current) and low-power wake-on-touch operation, the Si4010 is ideal for coin-cell battery powered applications.

Most remote controls are activated only a few times per day, which means the remote remains in standby mode most of the time until the end user presses a button.

The device's wake-on-touch GPIOs ensure no current is wasted checking for button presses while in standby mode.

The Si4010 contains an embedded 8051-compatible MCU core with 4kB of RAM, 8kB of one-time programmable (OTP) non-volatile memory, a 128-bit EEPROM and 12kB of ROM for library functions.

These ROM-based functions enable developers to easily implement complex features such as security encryption into their remote controls by using proven code to reduce risk and development time.

The MCU's on-chip digital peripherals include wake-on-touch general-purpose I/Os (GPIOs), a patented 20-bit EEPROM counter providing one million cycles of read/write endurance, an LED driver, sleep timers, a debugger and a high-speed 128-bit Advanced Encryption Standard (AES) accelerator for secure one-way links.

To accelerate the development of one-way link products, Silicon Laboratories offers a set of hardware and software tools, including: 4010-DASKF_434 evaluation kit to demonstrate RKE fob functionality; 4010-DAAKF_434 evaluation kit to demonstrate AES encryption functionality in RKE fobs; and 4010-DKKF_434 development kit providing a comprehensive Si4010 software development environment.

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