David writes…
Microsemi has a new radio, Zl70550, that’s clearly better than the one we were looking at. the receive current is a little higher but the sensitivity is much better. The sleep current is only 10 nA vs 500nA. The maximum transmit output power is higher at lower power consumed (more efficient) only 5.3mA at 0 dBm. Compare with the nRF51822 that consumes 10.5 mA @ 0dBm. It has 40 dBm of RSSI range with 2dB of RSSI resolution.
With a typical current consumption below 2.75 mA in transmit (–10 dBm) and below 2.4 mA in receive (–95 dBm sensitivity), and a data rate of 200 kbit/s, the ZL70550 device enables bidirectional RF links over a distance of more than 100 meters (based on antenna gain and operating environment). A sensitivity of –106 dBm can be achieved by optionally increasing the receiver current consumption (to approximately 3.2 mA), enabling FEC, and using the lowest data rate.
The device includes the Z-Star protocol, which is a powerful and highly optimized MAC that performs complete packet transmissions with acknowledgments and automatic retransmissions on failed receptions. This built-in protocol eliminates the need for processor intervention in packet processing, allowing the processor to go to a power-save state or to perform other critical application processing. Additionally, the MAC supports other user modes of operation with selectable options like CRC, FEC, and auto length.
Features
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Ultralow current of 2.4 mA in receive and 2.75 mA in transmit
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Ultralow sleep current of 10 nA
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Maximum TX output power of 0 dBm
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Maximum RX sensitivity of −106 dBm
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Wide supply range of 1.71 V to 3.6 V
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Operates between 779 MHz and 965 MHz (915-MHz ISM band in North America; 868-MHz SRD band in Europe; 779-MHz to 787-MHz band in China; 916-MHz to 930-MHz and 950-MHz to 956-MHz bands in Japan)
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Raw data rates of 200 kbit/s, 100 kbit/s, or 50 kbit/s
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Very small footprint
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Few external components (crystal, resistor, and two decoupling capacitors)
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Available in 29-pin CSP package (2 mm by 3 mm) or in 32-pin QFN package (5 mm by 5 mm)
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SPI bus slave for packet data and register access
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Built-in MAC
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Support for Microsemi Z-Star or user protocols
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Transmit and receive buffer
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Optional automatic CSMA packet transfers
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Efficient header optimized for small or large payloads
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Optional preamble, frame sync, length, FEC, and CRC
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Industrial temperature range (−40°C to 85°C)