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Analog Devices Inc./Maxim Integrated MAX817MESA+T
- Part No.:
- MAX817MESA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX817MESA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,886
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Product details
Overview
MAX817MESA+T from Maxim Integrated is a +5V microprocessor supervisory circuit with active-low reset, battery backup switchover, and power-fail comparator functionality. It features a 4.40V ±10% reset threshold, 200ms reset timeout, 11µA quiescent current, and operates in 0°C to +70°C temperature range. Designed for portable and battery-powered µP systems requiring reliable undervoltage monitoring and RAM backup control.
For engineers reviewing the MAX817MESA+T datasheet, MAX817MESA+T pinout, MAX817MESA+T application, or MAX817MESA+T equivalent, this device serves as a precision supply-voltage monitor and reset supervisor in space-constrained embedded systems where low-power operation, brownout immunity, and battery-freshness sealing are critical design requirements.
Technical Context
The MAX817MESA+T integrates a precision voltage comparator with 4.40V reset threshold (±10%), a 200ms internal reset timer, and a dedicated power-fail comparator (PFI/PFO) with 1.25V threshold. Its battery switchover circuit automatically connects BATT to OUT when VCC falls below both VRST and VBATT, using internal P-channel MOSFETs with 5Ω (VCC→OUT) and 80Ω (BATT→OUT) on-resistance.
It supports battery freshness sealing via PFO latching during power cycling, ignores fast transients on VCC due to built-in noise immunity, and delivers guaranteed reset assertion for VCC < 4.40V across full temperature range. No watchdog or manual reset functions - those are exclusive to MAX818/MAX819 variants.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.40V ±10% - triggers active-low RESET when VCC drops below this level, ensuring µP reset before brownout corruption. |
| Reset Timeout Period | 200ms typical - holds RESET low after VCC rises above threshold, guaranteeing stable µP initialization. |
| Supply Current | 11µA typical - enables multi-year battery life in portable equipment with minimal standby drain. |
| VCC to OUT On-Resistance | 5Ω max - minimizes voltage drop and power loss when supplying CMOS RAM from main +5V rail. |
| BATT to OUT On-Resistance | 80Ω max - limits inrush current and preserves backup battery charge during switchover events. |
| Power-Fail Threshold | 1.25V at PFI - provides configurable undervoltage warning for auxiliary supplies via external resistor divider. |
| Operating Temperature | 0°C to +70°C - validated for commercial-grade industrial and computing applications without derating. |
Pinout & Package
MAX817MESA+T is housed in an 8-pin µMAX package (3mm × 3mm, 0.8mm height), pin-compatible with 8-pin SO and DIP variants. The µMAX package enables high-density PCB layouts in portable and space-constrained designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply output for CMOS RAM | Switches between VCC and BATT based on voltage comparison; powers RAM during main supply failure. |
| 2 VCC | Main +5V supply input | Primary power source; monitored for reset generation and switchover control. |
| 3 GND | Ground reference | 0V return path for all internal circuits and external connections. |
| 4 PFI | Power-fail comparator input | Accepts external voltage divider to detect auxiliary supply undervoltage; threshold = 1.25V. |
| 5 PFO | Power-fail comparator output | Active-low open-drain output signaling PFI < 1.25V or VCC < VBATT; used for battery freshness seal enable. |
| 6 WDI | Watchdog input | Not functional in MAX817 - unused pin; must be left open or tied to GND/VCC per layout guidelines. |
| 7 RESET | Active-low reset output | Drives µP reset input low for ≥200ms during power-up, brownout, or PFO-triggered events. |
| 8 BATT | Backup battery input | Connects to Li-ion, coin cell, or SuperCap; powers OUT when VCC fails and enables battery freshness seal. |
Key Features
| Feature | Design Value |
|---|---|
| Precision 4.40V reset threshold | Guaranteed ±10% tolerance ensures reliable µP reset across voltage and temperature variations in +5V systems. |
| 200ms reset timeout delay | Internally timed interval prevents premature µP release before power stabilization and clock lock. |
| Battery backup switchover | Automatic VCC/BATT selection with sub-1V hysteresis avoids oscillation during marginal supply transitions. |
| Uncommitted power-fail comparator | Independent PFI/PFO pair allows flexible undervoltage detection of secondary rails without affecting reset logic. |
| Battery freshness seal | Latched disable of BATT leakage until first power cycle, preserving shelf life of backup batteries up to 10 years. |
Applications
| Portable Medical Monitors | Industrial Data Loggers |
|---|---|
|
Use Scenario: Battery-powered ECG or glucose meter retains real-time sensor data in volatile RAM during AC power loss or battery swap. IC Role / Device Role / Timing Role: MAX817MESA+T monitors VCC, asserts RESET to halt µP execution, and switches RAM supply from VCC to BATT within 10µs of brownout detection. Use Value: Prevents data corruption and ensures continuous logging integrity with <1µA backup current draw and no software intervention required. |
Use Scenario: Remote environmental sensor node records temperature/humidity hourly and transmits via LoRaWAN; must retain last 72 hours of data through seasonal battery depletion. IC Role / Device Role / Timing Role: MAX817MESA+T provides precise 4.40V reset threshold and battery freshness seal to preserve coin-cell charge until field deployment. Use Value: Extends usable shelf life by >300% versus direct BATT connection, while enabling deterministic reset timing during cold-start conditions. |
| POS Terminal Power Management | Smart Meter Backup Control |
|
Use Scenario: Retail point-of-sale terminal uses supercapacitor backup to complete transaction commit and EEPROM write during mains outage. IC Role / Device Role / Timing Role: MAX817MESA+T gates VCC-to-OUT path and activates BATT-to-OUT switchover at 4.40V, synchronizing with µP's NMI-driven save routine. Use Value: Eliminates need for external power-path controller IC; reduces BOM count by one component and PCB area by 25mm². |
Use Scenario: Electricity meter maintains time-of-use billing registers and tamper logs during grid failure, using primary battery only for backup-not runtime. IC Role / Device Role / Timing Role: MAX817MESA+T isolates BATT via freshness seal until first power-on, then enables switchover only when VCC < 4.40V and < VBATT simultaneously. Use Value: Achieves >15-year backup battery lifetime by limiting leakage to <1µA in backup mode and eliminating parasitic discharge paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX817LESA+T | 4.65V ±5% reset threshold instead of 4.40V ±10%; otherwise identical pinout, features, and timing. | Suitable for tighter-tolerance +5V systems where 4.65V reset aligns with regulator dropout specs. | Select MAX817LESA+T when system requires higher reset threshold to avoid nuisance resets near 4.5V. |
| MAX690ACSA+T | Legacy 4.65V reset, no power-fail comparator, no battery freshness seal, higher 25µA supply current. | Limited to basic reset supervision; lacks PFI/PFO and battery management features of MAX817MESA+T. | Choose MAX690ACSA+T only for drop-in replacement in legacy designs where feature reduction is acceptable. |
Compared with MAX817LESA+T, MAX817MESA+T offers lower reset threshold for earlier brownout response but wider tolerance; compared with MAX690ACSA+T, it adds power-fail detection and battery preservation-critical for modern portable and smart-meter applications.
Availability
MAX817MESA+T is available at Aetrix Electronics and suitable for portable medical monitors, industrial data loggers, POS terminals, and smart meters requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for MAX817MESA+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) is a semiconductor company specializing in analog, mixed-signal, and power-management ICs for industrial, computing, and communications markets.
The MAX817 family was designed specifically for +5V microprocessor supervisory functions-including reset generation, battery switchover, and power-fail warning-in compact, low-power embedded systems.
FAQ
What is the exact reset threshold voltage of the MAX817MESA+T?
The MAX817MESA+T has a nominal reset threshold of 4.40V with ±10% tolerance, meaning it asserts active-low RESET when VCC falls below 3.96V minimum and guarantees deassertion above 4.84V maximum across temperature and supply variations. This value is factory-trimmed and specified in the Electrical Characteristics table under VRST parameter.
Does the MAX817MESA+T include a watchdog timer function?
No, the MAX817MESA+T does not include a watchdog timer. Watchdog functionality is exclusive to the MAX818 and MAX819 variants. The WDI pin on MAX817MESA+T is unused and must be left open, tied to GND, or pulled to VCC-no internal watchdog circuitry is present in this part number.
Can the MAX817MESA+T be used with a lithium coin cell battery?
Yes, the MAX817MESA+T supports lithium coin cells (e.g., CR2032) on the BATT pin. Its battery switchover circuit operates with VBATT from 2.0V to 5.5V, and battery freshness seal ensures <1µA leakage when idle. For optimal shelf life, configure the seal during initial power-up per the timing sequence in Figure 3 of the datasheet.
How does the power-fail comparator (PFI/PFO) work in the MAX817MESA+T?
The PFI input compares an external voltage (via resistor divider) to an internal 1.25V reference. When PFI falls below 1.25V, PFO pulls low. This signal can trigger external logic or-when connected to MR on MAX819-initiate reset. In MAX817MESA+T, PFO is independent of reset logic and remains functional even during battery-backup mode.
What package type is used for the MAX817MESA+T?
The MAX817MESA+T uses the 8-pin µMAX package (3mm × 3mm, 0.8mm height), which is pin-compatible with 8-pin SO and DIP versions. This ultra-compact surface-mount package supports high-density PCB layouts and meets JEDEC MO-187 standards for reflow compatibility and thermal performance.
MAX817MESA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.4V
- Output:
- -
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX817MESA+T FAQ
1.How can I place an order for MAX817MESA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX817MESA+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 MAX817MESA+T reliable?
The price and inventory of MAX817MESA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX817MESA+T is usually 5 days.
3.What payment methods are accepted for MAX817MESA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX817MESA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX817MESA+T?
MAX817MESA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX817MESA+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 MAX817MESA+T?
For technical support, including MAX817MESA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX817MESA+T requirements.
6.How does Aetrix verify that MAX817MESA+T is sourced from the original manufacturer or authorized distributors?
All MAX817MESA+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 MAX817MESA+T meets industry standards.
7.What is the process for return or replacement of MAX817MESA+T?
All MAX817MESA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX817MESA+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 MAX817MESA+T part is unused and in its original packaging.
Return procedure for MAX817MESA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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