High drain and extended temperature models for lithium coin cell range
Murata has developed two high drain and extended temperature further ranges of its lithium coin cell batteries. Building on their standard and heat-resistant ranges of ‘CR’ battery sizes, the high current type, assigned suffix ‘R’, has double the maximum pulsed discharge rating of conventional models at 50mA (three seconds at 2V or higher, at 50% nominal capacity, 23C) and three times the discharge time (45 mA pulsed for three seconds, 23C). These characteristics make the parts ideal for LPWA communications devices, including LoRa and SIGFOX with their high peak current requirements. Offered in CR2032 and CR2450 sizes with 3V nominal rating, the cells have nominal capacities of 200mAh and 500mAh respectively for discharge down to 2V.
Extended temperature types designated suffix ‘X’ are offered in package sizes CR2032, CR2450, CR2477 and CR3677 and have an extended operating temperature range of -40C to +85C compared with standard types rated at -30C to +70C. The extended temperature range better matches the standard ratings of electronic parts in more challenging environments such as automotive, with a greater cost-performance figure in comparison to types rated to 125C. Stored charge loss at high temperature is smaller over time, and the CR3677X model claims to provide the highest capacity of any lithium coin cell, allowing smaller and thinner devices.
Vivek Mohan, director of IoT, Semtech Corporation, a member of the LoRa Alliance and a joint developer of LoRaWAN modules with Murata, commented “Semtech’s LoRa RFIC SX1261 needs an approximately 25mA power supply current at 3V supply voltage and 42mA at 1.8V in order to achieve an output of ARIB-T108-compliant 20mW. The LoRaWAN standard defines the maximum transmit time at three seconds. With Murata’s new high current type lithium coin cell battery, up to 50mA and three seconds of current can be used, making it a promising solution for LoRaWAN-compatible small sensor nodes”.