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Analog Devices Inc./Maxim Integrated MAX11081GUU+
- Part No.:
- MAX11081GUU+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Battery Management
- Package:
- 38-TFSOP (0.173", 4.40mm Width)
- Datasheet:
-
MAX11081GUU+.pdf
- Description:
- IC BATT MON LI-ION 1-12C 38TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,356
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Product details
Overview
MAX11081GUU+ from Maxim Integrated is a 12-channel, high-voltage battery-pack fault monitor IC designed for Li+ multicell stacks up to 72V. It provides pin-selectable overvoltage detection (3.3V–4.8V, ±25mV accuracy) and undervoltage detection (1.6V–2.8V, ±100mV accuracy), with programmable delay (3.0ms–3.32s) and 37.5mV comparator hysteresis. It operates in automotive-grade temperature range (−40°C to +105°C) and supports daisy-chained fault propagation in EV battery management systems.
For engineers reviewing the MAX11081GUU+ datasheet, MAX11081GUU+ pinout, MAX11081GUU+ application, or MAX11081GUU+ equivalent, this page delivers verified specifications, validated daisy-chain interface behavior, confirmed TSSOP-38 package mapping, and real-world fault-monitoring use cases - all grounded in Maxim's official documentation and electrical characterization data.
Technical Context
The MAX11081GUU+ implements differential cell monitoring across 12 Li+ cells using internal level-shifting and attenuation (×0.25) to reference all inputs to AGND. Its fault logic triggers only after sustained threshold violation beyond user-programmed CDLY capacitor delay, with built-in hysteresis (37.5mV) preventing chatter during marginal voltage transitions.
Daisy-chain operation relies on dual-level signaling: ALRML (VAA-referenced, 4.096kHz heartbeat) propagates downward, while ALRMU (GNDU-referenced) receives alarm status from upper modules via 3.3nF/150kΩ coupling. The integrated charge pump (CP+/CP−) generates VDDU above DCIN to enable level-shifted inter-module communication without optoisolators.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Cell Monitoring Channels | 12 independent differential inputs (C0–C12), supporting up to 12-series Li+ cells in stacked battery packs. |
| Overvoltage Threshold Range | +3.3V to +4.8V in 100mV steps, with ±25mV guaranteed accuracy over −40°C to +105°C - enables precise cell balancing guardbanding. |
| Undervoltage Threshold Range | +1.6V to +2.8V in 200mV steps, ±100mV accuracy; configurable disable via UVSEL0–UVSEL2 pins - supports deep-discharge protection or low-power sleep modes. |
| Comparator Hysteresis | 37.5mV (MAX11081-specific), preventing false alarms during slow voltage recovery or noise-induced threshold crossings. |
| Alarm Delay Programmability | 3.0ms to 3.32s via external CDLY capacitor (15nF–16.5µF ceramic), enabling design-tailored response to transient vs. persistent faults. |
| Supply Voltage Range | DCIN = +6.0V to +72V; internal 3.3V linear regulator (VAA) powers analog/digital circuitry - eliminates need for external bias supply in HV battery systems. |
| Operating Temperature | −40°C to +105°C, AEC-Q100 Type 2 qualified - validated for under-hood and traction-battery environments in EV/HEV applications. |
| Quiescent Current | 80µA in operating mode; 2µA in shutdown (SHDN = low) - extends standby life in always-on BMS monitoring nodes. |
Pinout & Package
MAX11081GUU+ is housed in a lead-free, RoHS-compliant 38-pin TSSOP package (9.7mm × 4.4mm, 0.5mm pitch), optimized for high-density battery module PCB layouts.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| DCIN (1) | High-voltage input supply | Accepts +6.0V to +72V stack voltage; powers internal 3.3V regulator (VAA) and charge pump - no external DC-DC required. |
| C0–C12 (4–16) | Differential cell voltage inputs | C0 = cell 1 minus; C12 = cell 12 plus; each adjacent pair (e.g., C1/C0) measures one cell - supports direct connection to series-connected Li+ cells. |
| OVSEL0–OVSEL3 (20–23) | Overvoltage threshold select | 4-bit binary input selecting one of 16 thresholds (3.3V–4.8V); internal pulldowns allow AGND/VAA tie-off - eliminates need for external logic. |
| UVSEL0–UVSEL2 (17–19) | Undervoltage threshold select | 3-bit input selecting one of eight thresholds (1.6V–2.8V) or disable state (000) - enables flexible low-voltage cutoff per application requirements. |
| CD (28) | Programmable delay timing | Connects to external capacitor (15nF–16.5µF) to set fault hold time before ALRML assertion - decouples timing from MCU firmware. |
| ALRML (27) | Lower-port alarm output | Heartbeat signal (4.096kHz, 50% duty) when healthy; driven high (≥2.4V) during fault - interfaces directly to host microcontroller GPIO or optocoupler input. |
| ALRMU (34) | Upper-port alarm input | Receives ALRML signal from module above via high-voltage capacitive coupling (3.3nF/150kΩ) - enables galvanically isolated daisy-chain without transformers. |
| TOPSEL (31) | Top-module identification | Must be tied to VAA for topmost device; AGND for all others - auto-configures daisy-chain hierarchy without address programming. |
| SHDN (26) | Active-low shutdown control | Pulls internal regulators/oscillators offline; reduces current to 2µA - used for power gating during system sleep or thermal shutdown. |
| CP+/CP− (37–38) | Charge-pump capacitor terminals | Drive internal level-shifter generating VDDU above DCIN - enables GNDU-referenced signaling between stacked modules without isolation components. |
Key Features
| Feature | Design Value |
|---|---|
| Daisy-chain scalability | Up to 31 devices cascaded via ALRML/ALRMU, reducing host interface signals to two wires - cuts BMS wiring harness cost and complexity in >100-cell packs. |
| Redundant fault monitoring | Designed as companion to MAX11068 measurement IC; enables independent fault-detection path for ASIL-B/C compliance in automotive BMS. |
| Hot-swap capable architecture | Internal POR and charge-pump startup sequence tolerates partial stack insertion - prevents latch-up during battery module replacement in field service. |
| Robust input protection | Cn-to-Cn+1 differential rating up to ±80V; C1-to-AGND withstands VDCIN + 0.6V - survives cell reversal, open-wire faults, and load-dump transients. |
| Low-power fault vigilance | 80µA operating current enables continuous monitoring without compromising pack standby life - critical for parked EVs and backup power systems. |
| AEC-Q100 qualified | Type 2 qualification (−40°C to +105°C) confirms reliability in automotive under-hood and traction battery environments - meets OEM BMS component requirements. |
Applications
| Electric Vehicle (EV) Traction Battery | Hybrid Electric Vehicle (HEV) 48V Mild-Hybrid System |
|---|---|
|
Use Scenario: Real-time monitoring of 96-cell (384V nominal) LiNiMnCoO₂ traction pack during charging, discharging, and regenerative braking. IC Role / Device Role / Timing Role: Fault monitor detecting individual cell overvoltage (>4.3V) or undervoltage (<2.5V) with 100ms delay to reject transients, triggering pack disconnect via contactor control. Use Value: Prevents thermal runaway by isolating faulty cells before voltage excursion exceeds safe limits; hysteresis avoids nuisance trips during fast transients. |
Use Scenario: Supervision of 12-cell (48V nominal) LFP battery in start-stop and torque-assist functions. IC Role / Device Role / Timing Role: Detects cell imbalance during high-current discharge pulses; asserts ALRML heartbeat interruption within 3.0ms to alert MCU of imminent under-voltage event. Use Value: Enables predictive energy management - MCU reduces assist torque before cell collapse, extending usable range and cycle life. |
| Energy Storage System (ESS) Rack Monitoring | Electric Bike (E-bike) Battery Pack |
|
Use Scenario: Centralized fault monitoring across 24 parallel strings of 16-series NMC cells (384V/200Ah) in grid-scale storage cabinet. IC Role / Device Role / Timing Role: Each MAX11081GUU+ monitors one string; daisy-chained ALRML signals converge at master controller for aggregated fault reporting. Use Value: Reduces sensor channel count by 95% versus discrete ADC-based monitoring - lowers BOM cost and improves system MTBF. |
Use Scenario: Compact 10-cell (36V) Li-ion pack in Class 3 e-bike with integrated BMS and Bluetooth telemetry. IC Role / Device Role / Timing Role: Provides cell-level fault flag to low-power BLE SoC; SHDN pin enables full sleep mode during storage to limit self-discharge. Use Value: Extends shelf life to >12 months without maintenance; 2µA shutdown current prevents pack depletion during seasonal storage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar battery-fault-monitoring applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX11080GUU+ | Hysteresis = 300mV (vs. 37.5mV); identical pinout, thresholds, and daisy-chain architecture. | Better suited for noisy industrial environments where aggressive hysteresis suppresses false alarms from EMI. | Select MAX11080GUU+ when system noise immunity outweighs need for fine-grained voltage resolution near thresholds. |
| TI BQ76952 | Integrated ADC, Coulomb counter, and protection FET drivers; requires external MCU for alarm logic; 48-pin WQFN package. | Full-featured standalone BMS AFE; not drop-in - demands firmware development and layout redesign. | Choose BQ76952 only when advanced telemetry (cell impedance, SOC/SOH) and active protection are required alongside fault monitoring. |
Compared with MAX11080GUU+, the MAX11081GUU+ offers 8× finer hysteresis for tighter voltage window control, while the BQ76952 adds measurement and actuation capability at the cost of increased design complexity and non-interchangeable packaging.
Availability
MAX11081GUU+ is available at Aetrix Electronics and suitable for electric vehicle traction batteries, hybrid vehicle 48V systems, and energy storage rack monitoring requiring stable component supply, AEC-Q100 compliance, and long-term lifecycle support.
Supply support for MAX11081GUU+ 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) designs precision analog, mixed-signal, and power-management ICs for demanding industrial, automotive, and communications applications.
The MAX11081GUU+ belongs to Maxim's battery management fault-monitor product line, engineered specifically for redundant, ultra-low-power, daisy-chain-capable cell supervision in high-voltage Li+ stacks - targeting functional safety and reliability in EV/HEV and grid-scale ESS.
FAQ
What is the key functional difference between MAX11081GUU+ and MAX11080GUU+?
The MAX11081GUU+ features 37.5mV comparator hysteresis, whereas the MAX11080GUU+ uses 300mV. This makes the MAX11081GUU+ significantly more sensitive to small voltage excursions near overvoltage/undervoltage thresholds - ideal for applications requiring tight fault detection windows, such as high-precision EV battery management. Both share identical pinout, thresholds, and daisy-chain functionality.
Can MAX11081GUU+ monitor fewer than 12 cells, such as an 8-cell Li+ pack?
Yes, the MAX11081GUU+ supports 8-, 10-, and 12-cell configurations. Unused cell inputs (e.g., C9–C12 in an 8-cell setup) are left unconnected per Maxim's application schematics (Figures 3–4). The device automatically detects connected cells during power-on initialization and configures comparators accordingly - no firmware or external configuration is needed.
How does the daisy-chain alarm propagation work in a multi-MAX11081GUU+ stack?
In a daisy chain, the topmost MAX11081GUU+ (TOPSEL = VAA) drives ALRML; each lower device receives ALRMU from the module above. If any device detects a fault, it inhibits heartbeat transmission downstream. The host reads ALRML from the bottom device: continuous 4.096kHz pulses indicate health; sustained high or stopped pulsing indicates upstream fault - enabling single-wire fault localization across up to 31 modules.
What is the role of the CD pin and how do I select the correct capacitor value?
CD pin sets the fault confirmation delay via external capacitor CDLY. Using the formula tDLY = (1.23V × CDLY)/6.1µA, a 100nF capacitor yields ~20ms delay. Capacitor values range from 15nF (3.0ms) to 16.5µF (3.32s); ceramic type with ≥5V rating is required. This hardware-based timing eliminates MCU polling overhead and ensures deterministic fault response.
Is MAX11081GUU+ qualified for automotive applications?
Yes, MAX11081GUU+ is AEC-Q100 qualified (Grade 2: −40°C to +105°C) and offered in automotive-grade packaging (denoted by /V+ suffix in ordering code). Its design - including thermal shutdown at +145°C, ±2kV HBM ESD rating, and robust input voltage tolerances - meets stringent automotive reliability and safety requirements for battery monitoring in EV/HEV platforms.
MAX11081GUU+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 38-TFSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Battery Monitor
- Battery Chemistry:
- Lithium Ion
- Number of Cells:
- 1 ~ 12
- Fault Protection:
- Over/Under Voltage
- Interface:
- -
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 38-TSSOP
MAX11081GUU+ FAQ
1.How can I place an order for MAX11081GUU+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX11081GUU+ 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 MAX11081GUU+ reliable?
The price and inventory of MAX11081GUU+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX11081GUU+ is usually 5 days.
3.What payment methods are accepted for MAX11081GUU+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX11081GUU+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX11081GUU+?
MAX11081GUU+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX11081GUU+ 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 MAX11081GUU+?
For technical support, including MAX11081GUU+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX11081GUU+ requirements.
6.How does Aetrix verify that MAX11081GUU+ is sourced from the original manufacturer or authorized distributors?
All MAX11081GUU+ 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 MAX11081GUU+ meets industry standards.
7.What is the process for return or replacement of MAX11081GUU+?
All MAX11081GUU+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX11081GUU+, 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 MAX11081GUU+ part is unused and in its original packaging.
Return procedure for MAX11081GUU+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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