Index > Product > 2.4 GHz Short Range Devices > A7157
A7157
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General Description
A7157 is a low cost 2.4GHz band FSK/DSSS transceiver. It supports data rate up to 4Mbps (FSK mode) and 133.3Kbps (DSSS mode).

For packet handling, A7157 has built-in separated (512 bytes) TX/RX FIFO for data buffering and burst transmission, auto-ack and auto-resend, CRC for error packet filtering, FEC (7,4 hamming code) for 1-bit data correction per code word, RSSI for clear channel assessment, thermal sensor to monitor relative temperature, data whitening for data encryption / decryption. In addition, A7157 has built-in AES128 co-processor (Advanced Encryption Standard) for advanced data encryption or decryption which consists of the transformation of a 128-bit block into an encrypted 128-bit block. Those functions are very easy to use while developing a wireless system.

A7157’s control registers are accessed via 3-wire or 4-wire SPI interface such as TX/RF FIFO, ID register, RSSI value, frequency hopping and calibration procedures. Another one is the unique Strobe command via SPI to control power saving mode (sleep, idle, standby), TX mode and RX mode. The other connections between A7157 and MCU are GIO1 and GIO2 (multi-function GPIO) to output A7157’s status so that MCU could use either polling or interrupt scheme for radio control. Overall, it is very easy to develop a wireless application by a MCU and A7157 because of its rich and easy-to-use features.

 Package size (QFN5X5, 32 pins).
 Frequency band: 2400 ~ 2483.5MHz.
 FSK modulation.
 DSSS SF: 30.
 Sleep current (5.3 uA).
 RX current consumption: 65mA (DSSS mode).
 TX current consumption: 99mA (DSSS mode, 17dBm).
 On chip regulator, support input voltage 2 ~ 3.6 V.
 Programmable data rate: Up to 4Mbps (FSK mode) and 133.3Kbps (DSSS mode).
 Programmable TX power up to 17dBm.
 RX sensitivity: -87 dBm (FSK 4Mbps) / -100 dBm (DSSS 133.3Kbps).
 Fast PLL settling time (30 us) for frequency hopping system.
 Built-in AES128 co-processor
 AGC (Auto Gain Control) for wide RSSI dynamic range.
 AFC (Auto Frequency Compensation) for frequency drift due to temperature.
 Low Battery Detector indication.
 Easy to use.
 Support 3-wire or 4-wire SPI.
 Unique Strobe command via SPI.
 ONE register setting for new channel frequency.
 CRC Error Packet Filtering.
 Auto-acknowledgement and auto-resend.
 Separated 512Byte TX/RX FIFO.
 8-bits RSSI measurement for clear channel indication.
 Auto Calibrations.
 Auto IF function.
 FEC by (7, 4) Hamming code (1 bit error correction / code word).
 Easy FIFO / Segment FIFO.
 Support FIFO mode frame sync to MCU.
 Support direct mode with recovery clock output to MCU.
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