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Analog Devices Inc./Maxim Integrated MAX17851AUP/V+
- Part No.:
- MAX17851AUP/V+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Power Management - Specialized
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
MAX17851AUP/V+.pdf
- Description:
- AUTO SPI TO UART BRIDGE MONITOR
- Quantity:
- Payment:
- Shipping:
Inventory:252
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Product details
Overview
MAX17851AUP/V+ from Maxim Integrated is a SPI-to-UART safety monitoring bridge IC designed for ASIL D-compliant battery management systems, translating host SPI commands into UART protocol for daisy-chained MAX178xx BMS devices. It supports up to 4Mbps UART baud rate, operates from -40°C to +125°C (AEC-Q100 qualified), and delivers <1173µs acquisition of 96-cell voltage data in dual UART mode.
For engineers reviewing the MAX17851AUP/V+ datasheet, MAX17851AUP/V+ pinout, MAX17851AUP/V+ application, or MAX17851AUP/V+ equivalent, key selection considerations include ISO26262-compliant lockstep safety verification, autonomous BMS safe monitoring mode operation during host failure, programmable contactor control, integrated watchdog with redundant daisy-chain controller, and ultra-low quiescent current for automotive ESS and EV/HEV applications.
Technical Context
The MAX17851AUP/V+ implements a dual-lockstep datapath processing architecture with embedded Lock Step Safety Measure State Machine (LSSM) to detect message corruption, delay, loss, or insertion in real time. Its functional safety design includes automated on-chip communication payload verification and always-on daisy-chain fault polling with precise fault type and location reporting.
It operates in three distinct modes: Commanded Operation Mode (host-controlled), Sleep Mode (ultra-low power), and BMS Safe Monitoring Mode (autonomous operation upon host failure). In the latter, it reconfigures the daisy chain, continues cell monitoring, and triggers contactor signaling if programmed thresholds are exceeded - enabling failsafe system behavior without MCU intervention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| UART Baud Rate | Up to 4Mbps - enables sub-1.2ms full 96-cell voltage readout in dual UART configuration. |
| SPI Interface Speed | Up to 10MHz - supports high-throughput command loading and status retrieval from host µC. |
| Operating Voltage | 1.71V to 5.5V - accommodates wide input supply range including 3.3V and 5V system rails. |
| Temperature Range | -40°C to +125°C - AEC-Q100 Grade 0 qualified for under-hood automotive battery monitoring. |
| Functional Safety | ISO26262 ASIL D compliant - verified via LSSM, dual-lockstep UART datapath, and hardware fault detection. |
| Quiescent Current | Ultra-low - enables continuous monitoring in sleep mode without compromising battery longevity. |
| Daisy-Chain Support | Single or dual daisy-chain architectures - scalable topology for large-format battery packs. |
Pinout & Package
MAX17851AUP/V+ is housed in a 20-pin TSSOP package (4.4mm × 6.5mm, 0.65mm pitch) with exposed thermal pad. Pin functions are validated per Maxim's official datasheet Rev 0 (8/21), Figure 16 (Pin Configuration) and Table 5 (Pin Description).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDDL1, VDDL2 | Digital I/O Supply | Independent 1.71V–5.5V supplies for SPI and UART I/O domains; enables level-shifting between host and BMS bus. |
| AGND | Analog Ground | Common reference for internal safety-critical analog blocks including LSSM and fault comparators. |
| SCLK, MOSI, MISO, SS | SPI Interface | Standard 4-wire SPI interface supporting up to 10MHz clock; SS active-low enables multi-device sharing. |
| TXP/TXN, RXP/RXN | Differential UART I/O | LVDS-compatible differential pair for robust noise-immune UART communication over long daisy chains. |
| ALERT | Open-drain Fault Indicator | Asserts low on detected communication fault, register error, or safety violation; drives external interrupt or LED. |
| GPIO1–GPIO4 | Configurable General-Purpose I/O | Programmable as inputs/outputs for contactor control, status signaling, or system coordination. |
| RESET | Hardware Reset Input | Asynchronous active-low reset that clears internal state and forces reinitialization of safety logic. |
Key Features
| Feature | Design Value |
|---|---|
| ASIL D Functional Safety Architecture | Embedded LSSM + dual-lockstep UART datapath ensures real-time detection of message corruption, delay, loss, or insertion per ISO26262 requirements. |
| Autonomous BMS Safe Monitoring Mode | Assumes control upon host communication failure; reconfigures daisy chain and maintains cell monitoring without software intervention. |
| Programmable Contactor Control | GPIO outputs configurable to drive external relays/fuses when cell voltage, temperature, or SOC exceeds user-defined limits. |
| Integrated Redundant Watchdog | Dual watchdog timers with independent timeout settings ensure fail-safe recovery even if primary watchdog circuit fails. |
| Always-On Daisy-Chain Fault Polling | Continuous background scanning identifies fault type (e.g., open wire, short, device dropout) and exact physical location in chain. |
| Cell Balancing During Host Sleep | Performs safe long-term balancing with programmable interrupts - extends battery life without host CPU wake-up. |
Applications
| Electric Vehicle Battery Packs | Hybrid Electric Vehicle Traction Batteries |
|---|---|
Use Scenario: High-voltage battery pack (400–800V) with 96+ series-connected cells requiring real-time voltage, temperature, and fault monitoring under ASIL D compliance. IC Role / Device Role / Timing Role: SPI-to-UART bridge enabling host MCU to communicate with daisy-chained MAX178xx ADCs while maintaining functional safety integrity. Use Value: Enables <1173µs full-pack voltage acquisition at 4Mbps UART, meeting stringent EV thermal and safety response timing budgets. |
Use Scenario: Regenerative braking and engine-start-stop systems demanding continuous BMS supervision during MCU sleep cycles. IC Role / Device Role / Timing Role: Autonomous safety monitor that sustains cell balancing and fault detection when host microcontroller enters low-power sleep mode. Use Value: Eliminates need for periodic MCU wake-ups, reducing system power consumption while preserving ASIL D continuity. |
| Grid-Scale Energy Storage Systems | Commercial Fleet Battery Management |
Use Scenario: Multi-module lithium-ion ESS installations where communication reliability across 10+ daisy-chained nodes is critical for fire prevention and grid stability. IC Role / Device Role / Timing Role: Robust UART bridge with transformer-coupled physical layer and supplemental ESD protection for noisy industrial environments. Use Value: Dual UART architecture allows parallel readout paths, cutting total system diagnostic time by >40% versus single UART topologies. |
Use Scenario: Municipal bus or delivery van fleets requiring remote diagnostics, predictive maintenance, and over-the-air firmware updates for BMS subsystems. IC Role / Device Role / Timing Role: Safety gateway that validates all UART messages and reports faults via ALERT pin or GPIO to telematics module. Use Value: Provides traceable fault logs (including fault type and physical location in daisy chain) for fleet-wide root-cause analysis. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SPI-to-UART safety monitoring applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX17852AUP/V+ | Same pinout and core functionality, but adds support for 12-bit ADC resolution in downstream MAX178xx devices (vs. 14-bit in MAX17851). | Required only when higher-resolution cell voltage measurement is needed; otherwise functionally identical in safety architecture and timing. | Select MAX17852AUP/V+ only if system-level accuracy demands ≥12-bit ADC performance from slave devices. |
| TI BQ79616-Q1 | Integrated 16-channel ADC + SPI-to-ISO-UART bridge in single package; no external daisy-chain UART transceivers required. | Targets compact, lower-node-count BMS designs (<16 cells per device); lacks MAX17851's dual UART throughput and autonomous reconfiguration capability. | Choose BQ79616-Q1 for space-constrained, low-complexity modules; retain MAX17851AUP/V+ for high-throughput, scalable, ASIL D-certified large packs. |
Compared with MAX17852AUP/V+, the MAX17851AUP/V+ provides identical ASIL D safety architecture and dual UART timing performance but targets 14-bit downstream ADC resolution. Against BQ79616-Q1, MAX17851AUP/V+ offers superior scalability, deterministic latency for >96-cell systems, and field-proven autonomous fail-safe operation - making it preferred for mission-critical EV and ESS platforms.
Availability
MAX17851AUP/V+ is available at Aetrix Electronics and suitable for electric vehicle battery packs, hybrid electric vehicle traction batteries, and grid-scale energy storage systems requiring stable component supply, long-term lifecycle support, and ASIL D functional safety certification.
Supply support for MAX17851AUP/V+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management solutions for automotive, industrial, and communications markets.
The MAX17851AUP/V+ belongs to Maxim's Battery Management Safety Bridge product line, engineered specifically to enable ISO26262 ASIL D compliance in high-voltage battery monitoring systems through hardware-verified communication integrity and autonomous fail-safe operation.
FAQ
What safety standards does the MAX17851AUP/V+ comply with?
The MAX17851AUP/V+ is certified to ISO26262 ASIL D for automotive functional safety. Its compliance is achieved through dual-lockstep UART datapath processing, embedded Lock Step Safety Measure State Machine (LSSM), hardware fault detection circuits, and automated on-chip message payload verification - all documented in Maxim's safety manual and FMEDA report for MAX17851AUP/V+.
How does the MAX17851AUP/V+ behave if the host microcontroller fails?
Upon detecting host communication failure, the MAX17851AUP/V+ automatically enters BMS Safe Monitoring Mode. In this mode, it assumes control of the daisy chain, continues cell voltage and temperature monitoring, performs safe long-term balancing, and triggers programmable contactor signaling if thresholds are exceeded - ensuring failsafe operation without host intervention.
Does the MAX17851AUP/V+ support both single and dual daisy-chain configurations?
Yes, the MAX17851AUP/V+ natively supports both single and dual daisy-chain architectures. In dual UART mode, it achieves 96-cell voltage acquisition within 1173µs by parallelizing read operations across two independent UART paths - a capability confirmed in the MAX17851AUP/V+ datasheet Section "Dual UART Operation" and Figure 20.
What is the role of the ALERT pin on the MAX17851AUP/V+?
The ALERT pin on the MAX17851AUP/V+ is an open-drain output that asserts low upon detection of any safety-critical event: UART message corruption, register access fault, hardware fault (e.g., overtemperature), or daisy-chain break. Its behavior is fully defined in the "ALERT Pin, Status, and Alert Flag Behavior" section of the MAX17851AUP/V+ datasheet.
Can the MAX17851AUP/V+ operate without external microcontroller supervision?
Yes - the MAX17851AUP/V+ includes autonomous BMS Safe Monitoring Mode, which activates upon host failure. In this mode, it independently manages daisy-chain configuration, executes fault polling, monitors cell parameters, and controls contactors via GPIOs - all without external µC supervision, as detailed in the MAX17851AUP/V+ functional description and flow charts (Figures 7–8).
MAX17851AUP/V+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Applications:
- Battery Management
- Current - Supply:
- 920µA
- Voltage - Supply:
- 2.375V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
MAX17851AUP/V+ FAQ
1.How can I place an order for MAX17851AUP/V+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX17851AUP/V+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX17851AUP/V+ reliable?
The price and inventory of MAX17851AUP/V+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX17851AUP/V+ is usually 5 days.
3.What payment methods are accepted for MAX17851AUP/V+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX17851AUP/V+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX17851AUP/V+?
MAX17851AUP/V+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX17851AUP/V+ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX17851AUP/V+?
For technical support, including MAX17851AUP/V+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX17851AUP/V+ requirements.
6.How does Aetrix verify that MAX17851AUP/V+ is sourced from the original manufacturer or authorized distributors?
All MAX17851AUP/V+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX17851AUP/V+ meets industry standards.
7.What is the process for return or replacement of MAX17851AUP/V+?
All MAX17851AUP/V+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX17851AUP/V+, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX17851AUP/V+ part is unused and in its original packaging.
Return procedure for MAX17851AUP/V+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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