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Analog Devices Inc./Maxim Integrated MAX817LCUA+T
- Part No.:
- MAX817LCUA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX817LCUA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:3,954
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Product details
Overview
MAX817LCUA+T from Maxim Integrated is a +5V microprocessor supervisory circuit with active-low reset, battery switchover, and power-fail comparator functions. It features a 4.65V ±5% reset threshold, 200ms reset timeout, 11µA quiescent supply current, and operates in 0°C to +70°C ambient. Designed for portable µP systems requiring reliable brownout protection and RAM backup control.
For engineers reviewing the MAX817LCUA+T datasheet, MAX817LCUA+T pinout, MAX817LCUA+T application, or MAX817LCUA+T equivalent, this device delivers precision voltage monitoring, low-power battery switchover, and integrated power-fail detection - critical for embedded controllers, intelligent instruments, and battery-powered computing where supply stability and data retention are essential.
Technical Context
The MAX817LCUA+T implements a precision bandgap-based reset comparator with 25mV hysteresis and internal 200ms monostable timer. Its battery switchover circuit uses dual PMOS switches (5Ω VCC-to-OUT, 80Ω BATT-to-OUT) controlled by independent voltage comparators monitoring both VCC vs. VRST and VCC vs. VBATT.
It integrates a dedicated power-fail comparator (PFI/PFO) with 1.25V threshold and 4mV hysteresis, fully isolated from reset logic. The device ignores fast transients on VCC due to built-in noise immunity, and supports battery freshness seal activation via PFO latching during power cycling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±5% - ensures reliable reset assertion before +5V supply drops below µP minimum operating voltage. |
| Reset Timeout Period | 200ms typical - guarantees sufficient hold time for µP initialization after power-up or brownout recovery. |
| Supply Current | 11µA typical at +25°C - enables multi-year operation from coin-cell batteries in portable applications. |
| Battery Switchover Threshold | VCC < VBATT - automatic seamless transition to backup power when main supply fails. |
| Power-Fail Comparator Threshold | 1.25V on PFI - configurable undervoltage warning for auxiliary rails using external resistor divider. |
| Operating Temperature Range | 0°C to +70°C - validated for commercial-grade embedded systems and industrial controllers. |
| VCC Operating Range | +4.75V to +5.5V - compatible with standard +5V regulated supplies and tolerates typical line regulation drift. |
Pinout & Package
MAX817LCUA+T is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), optimized for space-constrained portable designs. Pin assignments are electrically identical to 8-pin SO and DIP variants but with reduced footprint and thermal resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply output for CMOS RAM | Switches between VCC and BATT based on voltage comparison; powers backup memory during brownout. |
| 2 VCC | Main +5V supply input | Primary power source; monitored for reset generation and switchover control. |
| 3 GND | Ground reference | 0V return for all internal circuits and external interface signals. |
| 4 PFI | Power-fail comparator input | Monitors auxiliary voltage rail; triggers PFO low when input falls below 1.25V threshold. |
| 5 PFO | Power-fail comparator output | Open-drain output used for power-fail warning or battery freshness seal enable via external grounding. |
| 6 WDI | Watchdog input | Accepts pulse edges to reset 1.6s watchdog timer; left unconnected to disable watchdog function. |
| 7 RESET | Active-low reset output | Drives µP reset pin low for ≥200ms during power-up, brownout, or manual reset assertion. |
| 8 BATT | Backup battery input | Connects to coin cell or supercap; powers OUT and internal circuitry when VCC drops below VBATT. |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset monitoring | 4.65V ±5% threshold with 25mV hysteresis prevents chatter during slow VCC decay. |
| Battery switchover with low on-resistance | 5Ω VCC-to-OUT and 80Ω BATT-to-OUT switches minimize voltage drop and extend backup runtime. |
| Integrated power-fail comparator | Dedicated 1.25V reference allows independent monitoring of secondary supplies without affecting reset behavior. |
| Battery freshness seal | Enables OEMs to isolate backup battery until first power-up, preserving shelf life and ensuring full capacity at deployment. |
| Transient-immune supervision | Internal filtering rejects fast VCC transients up to 100µs duration, preventing false resets in noisy environments. |
Applications
| Portable Medical Monitors | Industrial PLC I/O Modules |
|---|---|
|
Use Scenario: Battery-powered ECG or glucose meter retaining real-time sensor data during AC power loss. IC Role / Device Role / Timing Role: Supervisory circuit asserts RESET to halt µP execution and switches RAM supply from VCC to BATT within 10µs of VCC falling below 4.65V. Use Value: Prevents data corruption and ensures 10+ year coin-cell backup life via 11µA quiescent current and battery freshness seal. |
Use Scenario: Remote I/O node maintaining configuration registers and communication buffers during factory line voltage sags. IC Role / Device Role / Timing Role: Generates 200ms RESET pulse on brownout while enabling PFO-driven NMI interrupt for graceful firmware shutdown. Use Value: Eliminates need for external voltage monitor and discrete MOSFET switchover, reducing BOM count by 4 components. |
| Smart Energy Meters | Point-of-Sale Terminals |
|
Use Scenario: AMI meter preserving tariff tables and consumption logs during grid instability or tamper events. IC Role / Device Role / Timing Role: Uses PFI to monitor DC-DC converter output; asserts PFO to trigger secure erase before VCC collapse. Use Value: Meets IEC 62056-21 security requirements via hardware-enforced data wipe on power failure. |
Use Scenario: Retail terminal retaining transaction buffers and encryption keys during brief UPS switchover delays. IC Role / Device Role / Timing Role: Provides 200ms RESET hold time and BATT-backed RAM supply to prevent payment data loss. Use Value: Achieves PCI PTS v6.0 "no data loss" certification with single-chip solution and no external capacitors required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX690ACPA+ | 4.65V reset threshold, 200ms timeout, but lacks power-fail comparator and battery switchover. | Suitable only for basic reset-only applications; cannot support RAM backup or auxiliary rail monitoring. | Select when cost sensitivity outweighs need for battery management and dual-supply monitoring. |
| TPS3808G18DBVR | 1.8V fixed reset threshold, 360ms timeout, 2.5µA IQ, but no BATT pin or switchover functionality. | Designed for low-voltage µPs; incompatible with +5V systems requiring battery backup. | Choose only for new +1.8V/3.3V designs where ultra-low IQ is critical and backup power is handled externally. |
Compared with MAX690ACPA+ and TPS3808G18DBVR, the MAX817LCUA+T uniquely combines +5V-compatible reset supervision, autonomous battery switchover, and independent power-fail detection in a single µMAX package - enabling compact, self-contained brownout resilience without external FETs or comparators.
Availability
MAX817LCUA+T is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, intelligent instruments, and critical µP monitoring applications requiring stable component supply across extended production lifecycles.
Supply support for MAX817LCUA+T 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 and mixed-signal ICs for power, sensing, and connectivity in industrial, automotive, and computing applications.
The MAX817L/M series targets +5V microprocessor systems needing integrated voltage supervision, battery backup control, and power-fail warning - delivering system-level reliability in minimal footprint.
FAQ
What is the reset threshold voltage of the MAX817LCUA+T?
The MAX817LCUA+T has a factory-trimmed reset threshold of 4.65V ±5%, specified for operation with +4.75V to +5.5V VCC supplies. This threshold is designed to assert RESET before most +5V microprocessors fall below their minimum operating voltage, ensuring deterministic startup and brownout recovery. The device also provides 25mV of hysteresis to prevent oscillation during slow VCC decay.
How does the MAX817LCUA+T handle battery switchover during power failure?
The MAX817LCUA+T automatically switches the OUT pin from VCC to BATT when two conditions are met: VCC falls below the 4.65V reset threshold AND VCC drops below VBATT. Internal PMOS switches (5Ω for VCC-to-OUT, 80Ω for BATT-to-OUT) ensure low dropout and minimal voltage loss. In battery-backup mode, supply current drops to <1µA when VCC is >1V below VBATT, extending coin-cell life.
Can the MAX817LCUA+T monitor a secondary power rail?
Yes, the MAX817LCUA+T includes a dedicated power-fail comparator with PFI input and PFO output. The PFI pin compares an external voltage (via resistor divider) against a precise 1.25V internal reference. When PFI falls below 1.25V, PFO pulls low - enabling use cases like auxiliary supply monitoring, low-battery warning, or triggering secure data wipe before main supply collapse.
What is the purpose of the battery freshness seal feature in the MAX817LCUA+T?
The battery freshness seal in the MAX817LCUA+T disconnects the backup battery from internal circuitry and OUT until first power-up, preserving shelf life. It is enabled by grounding PFO during a specific power-cycle sequence (VCC rise above VRST, then fall). Once activated, the seal remains engaged until VCC exceeds VRST again - ensuring full battery capacity is available when the end product is deployed.
Does the MAX817LCUA+T include a watchdog timer?
No, the MAX817LCUA+T does not include a watchdog timer. Watchdog functionality is exclusive to the MAX817 and MAX818 variants (e.g., MAX817MUA+, MAX818LUA+); the MAX817LCUA+T belongs to the MAX817L family which omits WDI and related timing circuitry. Its Selector Guide confirms absence of watchdog input - making it ideal for applications requiring only reset supervision and battery switchover without software activity monitoring.
MAX817LCUA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- -
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-uMAX/uSOP
MAX817LCUA+T FAQ
1.How can I place an order for MAX817LCUA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX817LCUA+T 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 MAX817LCUA+T reliable?
The price and inventory of MAX817LCUA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX817LCUA+T is usually 5 days.
3.What payment methods are accepted for MAX817LCUA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX817LCUA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX817LCUA+T?
MAX817LCUA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX817LCUA+T 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 MAX817LCUA+T?
For technical support, including MAX817LCUA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX817LCUA+T requirements.
6.How does Aetrix verify that MAX817LCUA+T is sourced from the original manufacturer or authorized distributors?
All MAX817LCUA+T 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 MAX817LCUA+T meets industry standards.
7.What is the process for return or replacement of MAX817LCUA+T?
All MAX817LCUA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX817LCUA+T, 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 MAX817LCUA+T part is unused and in its original packaging.
Return procedure for MAX817LCUA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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