general description
a7129 is a monolithic low-if architecture cmosfsk/gfsk trx for wireless applications in the315/433/470/868/915mhz ism bands. this device is especiallysuitable for battery-powered application and the 470mhz ~ 510mhzwireless amr (auto meter reading) in china and 868.3mhz wirelessm-bus in europe.
a7129 is one of amiccom’s mini power consumption family in sub 1ghzism band product line. a7129 is optimized for very low powerconsumption (i.e. 434mhz band, 3.8ma @ rx mode and 24 ma @ txmode,10.5dbm). in addition, a7129 can offer a very good link budgetwith a high efficient class-e power amplifier up to 12 dbm and alow phase noise receiver (- 110 dbm rx sensitivity @ 100kbps / fsk/ 433.92mhz). therefore, a7129 is very suitable for battery poweredapplication with a nice los (line-of-sight) wireless range.
a7129 incorporates a baseband modem with the programmable data ratedivider from 2k to 250kbps. for a battery powered system, a7129supports fast pll settling time (120 us), xtal settling time (600us) and on-chip regulator settling time (1 ms) to reduce averagepower consumption. the rf synthesizer contains a vco and a lownoise fractional-n pll with an output channel frequency resolutionof 366 hz. the vco frequency operates at the wanted radio frequencyto cover all rf band. since a7129 is a low-if architecture trx withprogrammable ifbw (if filter bandwidth,50khz/100khz/150khz/250khz), the rxlo shall be configured to offsetan intermediate frequency (if) to txrf regarding to the ifbwsetting.
a7129’s control registers are accessed via 3-wire or 4-wire spiinterface including tx/rf fifo, vco frequency, to chip calibrationprocedures. another one, via spi as well, is the unique strobecommand, a7129 can be controlled from power saving mode (deepsleep, sleep, idle, standby), pll mode, tx mode and rx mode. inaddition to spi, the digital connections between a7129 and mcu aregio1 and gio2 (multi-function gpio) to indicate a7129’s status sothat mcu could use either polling or interrupt for radiocontrol.
for packet handling, a7129 supports direct mode and fifo mode. indirect mode, mcu or encoder shall deliver the defined packet(preamble + sync word + payload) to gio1 or gio2/txd pin. then, inrx mode, mcu or decoder can receive the coming packet (preamble +sync word + payload) in bit sequence from gio1 or gio2/rxd pin. infifo mode, preamble is self-generated by a7129. user just needs toassign the sync word to this device by id r/w command via spi. forpayload, the built-in separated 64-bytes tx/rx fifo are used to bethis purpose to let user r/w the wanted payload. user can alsoenable additional packet features like crc for error detection, fec(hamming 7 by 4) for 1-bit data correction per code word,manchester coding, as well as data whitening for data encryption /decryption.
additional device features such as on-chip regulator, rssi forclear channel assessment, a thermal sensor, low battery detector,carrier detect, preamble detect, frame sync in fifo mode, auto-ackand auto-resend, aif (auto if function), afc (auto frequencycompensation), auto calibration (vco, if filter), pll/clkgenerator, on-chip compensated capacitors of xtal loading, and wor(wake on rx) to support the ability to periodically wake up fromsleep mode to rx mode and listen for incoming packets without mcuinteraction, can be used to simplify system development and cost.overall, a7129’s highly integrated features and low currentconsumption offer a reduced bom cost for a high performance ismbands product. all features are integrated in a small qfn 4x4 24pins package.
feature
small size (qfn 4x4, 24 pins).
frequency band: 315/433/470/510/868/915 mhz.
fsk and gfsk modulation.
programmable data rate from 2kbps to 250kbps.
programmable tx power level from – 40 dbm to 12 dbm.
on chip regulator, supports input voltage 1.9 ~ 3.6 v.
deep sleep current (0.5ua).
sleep current (1.5 ua).
ultra low current consumption
rx current consumption (agc off) 434mhz: 3.8ma.
rx current consumption (agc off) 868mhz: 4.4ma.
tx current consumption 433mhz: 24ma @ 10.5dbm.
tx current consumption 868mhz: 24ma @ 10dbm.
fast pll settling time (120 us).
supports low cost crystal (12.8 / 16 / 19.2 mhz).
agc (auto gain control) for the wide rssi dynamic range.
programmable if filter bandwidth (50khz / 100khz / 150khz /250khz).
high rx sensitivity, i.e. 490mhz.
-118dbm at 2kbps on-air data rate.
-115dbm at 50kbps on-air data rate.
-109dbm at 100kbps on-air data rate.
easy to use
support 3-wire or 4-wire spi.
unique strobe command via spi.
agc on with 9-bits rssi.
agc off with 8-bits rssi.
auto calibrations (vco, if filter, rssi).
auto if function.
auto frequency compensation.
auto crc filtering.
auto fec by (7, 4) hamming code (1 bit error correction / codeword).
auto-resend (max 15 cycles).
auto-acknowledgement.
manchester encoding.
programmable carrier sense indicator.
data whitening for payload encryption and decryption.
separated 64 bytes rx and tx fifo.
easy fifo / segment fifo / fifo extension (16k bytes toinfinite).
support fifo mode with frame sync to mcu.
support direct mode with recovery clock output to mcu.
on chip 8-bits adc.
low battery indication.
on-chip low power rc oscillator for wot and wor (wake on tx/rx)function.application
ism band data communication
wireless remote controller
rke (remote keyless entry)
building automation
home security
wireless sensor networking
energy control and management
rke (remote keyless entry)
amr (auto metering reading)

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