Click here to ask about the production status of specific part numbers. MAX17851 SPI to UART Safety Monitoring Bridge General Description Benefits and Features The MAX17851 SPI to UART safety monitoring bridge Supports Maxims Battery Management UART translates communication from SPI format to universal Protocol asynchronous receiver transmitter (UART) format special- Supports ASIL D Functional Safety Requirements ly designed to interface with Maxim s Battery Management Automated On-Chip Communication Verification Data Acquisition System. The safety monitoring bridge en- with Simplified Host Reporting ables robust communication with baud rates extending up Always-On Daisy-Chain Fault Polling with Fault to 4Mbps in both single and dual daisy-chain system archi- Type and Fault Location tectures. High throughput, dual UART systems can read Integrated System Watchdog with Redundant Daisy- 96 cells of battery voltages within 1173us. Chain Controller The UART is ISO26262 compliant for automotive safety Programmable System Recovery integrity level (ASIL) D systems providing detection of Programmable Memory for Daisy-Chain message corruption, delay, loss, and insertion through the Configuration embedded UART communication lock step safety mea- Programmable Contactor Control sure state machine (LSSM). The MAX17851 self verifies Integrated Cell Balancing while Microcontroller is in all communication within the message payload to simplify Sleep Mode the software development on the host microcontroller. Safe Long Term Balancing Monitoring with Additionally, the MAX17851 monitors the host microcon- Programmable Interrupts troller communication to detect any failures. In the event UART Baud Rate Programmable Up to 4Mbps of a communication failure with the host, the MAX17851 SPI Interface Up to 10MHz first tries to automatically recover communication. If un- 1.71V to 5.5V Operation successful, it assumes control. The MAX17851 can then Ultra-Low Quiescent Current optionally re-configure the daisy chain network that allows Operating Temperature Range from -40C to +125C battery conditions to continue to be monitored. This allows (AEC-Q100) for continued safe system operation. Lastly, the MAX17851 provides contactor signalling in the event that Ordering Information appears at end of data sheet. the battery conditions fall outside of the programmed range, putting the complete system into a failsafe state. Applications Battery Management Systems (BMS) Electric and Hybrid Electric Vehicles (EV/HEV) Energy Storage Systems (ESS) 19-101190 Rev 0 8/21MAX17851 SPI to UART Safety Monitoring Bridge Simplified Application Diagram MASTER SLAVE(S) VDDL2 DCIN2 1F DCIN1 AGND 5V DC 0.1F 0.1F 0.1F VDDL1 SUPPLY ISOLATORS 470 AGND MAX178xx RXP 15pF V TXPL DCIN1 MAX17851MAX17851 TXNL 470 100k RXN BATTERY 15pF MISO DOUT MANAGEMENT MOSI DIN DEVICE 39 SCLK SCLK TXP SS CS RXPL V DCIN1 39 RXNL SYSTEM TXN 100k P IRQ ALERT EV System GPIO1 RESET GPIO3 GPIO2 GPIO4 Contactors www.maximintegrated.com Maxim Integrated 2