MICROCHIP ATA5702F1000M-WDQW

The ATA5700/ATA5702 is a highly integrated, ultra-low-power automotive access controller for PEPS and RKE applications, embedding an AVR 8-bit microcontroller in a single QFN 38 package. The device includes a high-sensitivity 3D LF receiver, a transponder front-end, and a UHF ASK/FSK RF transmitter. It combines ultra-low-power LF technology with excellent RF performance.

The low-power microcontroller is based on an AVR enhanced RISC architecture. It features rich digital peripherals, including a watchdog timer, RTC, several 8/16-bit timers, serial interfaces (SPI, TWI), and 19 GPIO ports. It is equipped with low-power memory such as SRAM, 32 KB Flash, and secure EEPROM.

In addition, the core is supported by power-saving co-processing units, including a powerful AES encryption engine and an autonomous protocol processing unit to support data communication with the LF receiver and transponder.

The high-sensitivity 3D LF receiver enables the IC to continuously listen for wake-up patterns in low-power standby mode. When the IC is awakened and active, the LF receiver serves as the receive path for data communication. Combined with an integrated, highly accurate logarithmic 3D RSSI, the LF receiver supports PEPS positioning requirements.

The RSSI control unit supports logarithmic-to-linear conversion, 3D vector sum computation, and RSSI calibration algorithms.

The ATA5702 features an RF transmitter implemented with a fractional-N PLL for high data rates, with Gaussian waveform shaping capability. The transmitter is designed for ISM bands in the 310 MHz to 318 MHz, 418 MHz to 477 MHz, and 836 MHz to 956 MHz ranges.

To support transponder functionality, the IC is prepared for battery-less emergency operation. It includes a built-in 3D transponder front-end for wireless power supply and bidirectional communication via LF antenna.

With its low-power AVR RISC microcontroller, high-performance secure AES encryption unit, power-efficient digital and analog peripherals, and sufficient memory, the ATA5700/ATA5702 is fully prepared for PEPS applications.

• System solution for immobilizer and PEPS functions
• Optional integrated open-source immobilizer software stack with automotive immobilizer support
• Supply voltage range: 2.0V to 4.2V
• Temperature range: -40°C to +85°C
• Excellent ESD protection on all pins (±4 kV HBM)
• Compact 5×7 mm² QFN 38-pin package with solderable leads
• 32 K bytes Flash
• EEPROM: 100000 write cycles at 25°C, 20-year data retention
• Secure EEPROM — flexible memory locking and protection
• SRAM
• 19 general-purpose I/Os
• 2× SPI, 2× TWI interfaces, debug wire
• 128-bit AES encryption unit
• Secure fast direct access AES key memory
• Enhanced LF debug functionality (LF receiver and transponder signal output mode)
• Low-power POR and brown-out detection
• Voltage monitor for battery monitoring
• LF frequency range: 100 kHz to 150 kHz
• 3D antenna integrated resonant frequency tuning
• 3D antenna integrated quality factor tuning
• Programmable high and low Q-factor receive modes
• Data rates: 1.95, 3.9, and 7.8 Kbit/s at 125 kHz carrier, OOK, Manchester encoding
• Programmable Manchester violation code (1/2-bit step, max. 2-bit L/H)
• Programmable wake-up receiver sensitivity, up to 10 m range
• Low supply current on all three channels (extended power-down listening mode)
• Ultra-low-power LF polling mode for extended battery life
• Fast logarithmic 9-bit digital RSSI field strength measurement on all three channels simultaneously
• High RSSI accuracy against inter-channel gain impairment due to aging, drift, and supply voltage variation via internal calibration routine
• RSSI control unit supporting log-to-linear conversion, vector sum calculation, and calibration algorithms
• Transponder operation (capacitor charging, gap detection, and load modulation) on all three channels in parallel, with or without battery
• Battery-less operation down to coupling coefficient <1%
• Bi-phase, Manchester modulation with programmable NRZ code insertion for code violation
• Autonomous codec with enhanced LF communication range: Manchester (uplink) and BPLM, QPLM telegrams (downlink)
• Data rates: 1.95 and 3.9 Kbit/s at 125 kHz carrier, OOK, Manchester and bi-phase encoding
• Power management unit
• UHF frequency range support using one 24.305 MHz crystal
• Low band — 310 to 318 MHz, 418 to 477 MHz
• High band — 836 to 956 MHz
• Programmable channel frequency with fractional-N PLL
• Programmable output power: -12 to +14.5 dBm
• Supported modulation — ASK, FSK, and GFSK (FSK deviation: ±0.375 to ±93 kHz)
• Data rate up to 80 Kbit/s (buffered, Manchester encoding)
• Loop antenna integrated resonant frequency tuning