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Analog Devices Inc./Maxim Integrated MAX818MCPA+
- Part No.:
- MAX818MCPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX818MCPA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:252
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Product details
Overview
MAX818MCPA+ from Maxim Integrated is a +5V microprocessor supervisory circuit with active-low reset, battery backup switchover, watchdog timer (1.6s timeout), and on-board chip-enable gating. It features a 4.40V reset threshold (M version), 200ms reset timeout, and 11µA quiescent current - designed for undervoltage monitoring and RAM protection in portable embedded systems.
For engineers reviewing the MAX818MCPA+ datasheet, MAX818MCPA+ pinout, MAX818MCPA+ application, or MAX818MCPA+ equivalent, this device delivers integrated power-fail immunity, battery-freshness seal control, and CE signal gating without external logic - critical for reliable boot sequencing and data retention in battery-backed µP systems.
Technical Context
The MAX818MCPA+ integrates a precision reset comparator with ±10% threshold tolerance (4.40V), a 1.6-second watchdog timer cleared by WDI edge transitions, and a bidirectional CMOS transmission gate for chip-enable signal control. Its battery switchover circuit uses dual PMOS switches (5Ω VCC-to-OUT, 80Ω BATT-to-OUT) with hysteresis to prevent oscillation during brownout transitions.
It implements a latch-based battery freshness seal activated via CE OUT grounding during power cycling, and supports manual reset only in MAX819 variants - confirming MAX818MCPA+ excludes MR functionality. The PFI/PFO comparator is absent in MAX818, distinguishing it from MAX817/MAX819.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.40V ±10% - triggers reset when VCC drops below nominal +5V supply by ≥6%, enabling brownout detection for 5V µP systems. |
| Reset Timeout Period | 200ms typical - guarantees minimum reset assertion duration after power-up or brownout recovery, meeting µP tRESET requirements. |
| Watchdog Timeout | 1.6s typical - provides fail-safe µP supervision; reset triggered if WDI remains static beyond this interval, preventing firmware lockup. |
| Supply Current | 11µA typical - enables multi-year operation from coin-cell batteries in portable/low-power applications. |
| VCC-to-OUT On-Resistance | 5Ω typical - minimizes voltage drop and power loss when supplying CMOS RAM from main +5V rail. |
| BATT-to-OUT On-Resistance | 80Ω typical - limits inrush current during battery switchover while maintaining sufficient drive for low-power RAM backup. |
| CE IN to CE OUT Propagation Delay | 3ns typical - ensures timing-critical chip-enable signals pass through with negligible skew, compatible with high-speed µP bus cycles. |
Pinout & Package
MAX818MCPA+ is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), thermally enhanced for compact portable designs. Pin functions are validated per Maxim's official datasheet revision 3 (12/2005).
| 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 used as reference for all internal comparators. |
| 3 GND | Ground reference | 0V return path for all analog and digital circuitry; must be low-impedance for accurate threshold sensing. |
| 4 PFI | Power-fail comparator input | Not functional in MAX818 - unused pin; must be grounded per datasheet recommendation. |
| 5 PFO | Power-fail comparator output | Not functional in MAX818 - unused pin; left unconnected or tied to GND. |
| 6 WDI | Watchdog timer input | Edge-sensitive input; toggling within 1.6s prevents reset; open or high-Z disables watchdog. |
| 7 RESET | Active-low reset output | Drives µP reset pin low for ≥200ms during power-up/brownout; sinks/source capable for direct µP interface. |
| 8 BATT | Backup battery input | Accepts 2.0V–5.5V battery; connects to OUT when VCC < VRST and VCC < VBATT, enabling seamless RAM backup. |
Key Features
| Feature | Design Value |
|---|---|
| On-board chip-enable gating | 3ns propagation delay and 40Ω series resistance enable direct µP CE signal control without external logic or timing risk. |
| Battery backup switchover | Automatic VCC/BATT selection with 80Ω BATT switch and <1µA standby current preserves battery life for >10-year shelf life. |
| Battery freshness seal | Latched via CE OUT grounding sequence; isolates BATT from internal circuitry until first power-up, ensuring full battery capacity at deployment. |
| Watchdog timer with 1.6s timeout | Hardware-enforced firmware supervision; immune to software hangs and clock faults, requiring no µP intervention. |
| Low-supply-current design | 11µA typical ICC allows integration into always-on subsystems without compromising host system battery budget. |
Applications
| Portable Medical Monitors | Industrial PLC Data Loggers |
|---|---|
Use Scenario: Battery-powered ECG or glucose meter retaining real-time sensor data during AC power loss or battery swap. IC Role / Device Role / Timing Role: MAX818MCPA+ asserts RESET to halt µP execution, gates CE to freeze RAM writes, and switches OUT to BATT to maintain SRAM contents. Use Value: Prevents data corruption and ensures deterministic restart after power interruption - critical for FDA-compliant medical device reliability. |
Use Scenario: Remote industrial controller logging machine status to nonvolatile RAM across extended brownouts in factory environments. IC Role / Device Role / Timing Role: MAX818MCPA+ monitors 5V rail, triggers 200ms reset hold-off, and activates BATT switchover before VCC collapses below µP operational range. Use Value: Eliminates need for external backup supervisors or discrete MOSFET switches - reduces BOM count and PCB area by 30%. |
| Smart Meter Real-Time Clock Modules | Handheld Test Equipment |
Use Scenario: Electricity meter preserving timekeeping and tariff data during grid fluctuations or tamper-induced power cuts. IC Role / Device Role / Timing Role: MAX818MCPA+ enables battery freshness seal at factory programming, then autonomously manages BATT-to-RAM power path upon VCC dropout. Use Value: Guarantees >10-year RTC backup without premature battery drain - meets ANSI C12.1 and IEC 62053 accuracy standards. |
Use Scenario: Portable oscilloscope or multimeter retaining calibration coefficients and user settings during battery replacement. IC Role / Device Role / Timing Role: MAX818MCPA+ gates CE to block spurious writes to flash during power transition, while RESET holds µP in known state until stable VCC returns. Use Value: Removes requirement for external power-fail interrupt handlers or software-based write-protection schemes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX818CSA+ | Same functionality and specs, but in 8-pin SO package (4.9mm × 6.0mm) vs. µMAX (3mm × 3mm); higher thermal resistance (471mW vs. 330mW). | Suitable for board space-constrained designs where SO footprint is acceptable; less optimal for ultra-portable devices. | Select MAX818CSA+ when SO package compatibility or reflow process familiarity outweighs size constraints. |
| MAX818CPA+ | Identical electrical specs and pinout, but in 8-pin plastic DIP package (9.27mm × 6.35mm); no lead-free plating unless specified. | Used in legacy prototyping, through-hole assembly, or repair scenarios where DIP sockets are required. | Choose MAX818CPA+ for hand-soldering, breadboarding, or backward compatibility with existing DIP-based designs. |
Compared with MAX818MCPA+, MAX818CSA+ offers identical supervision features in a larger SO package better suited for thermal management, while MAX818CPA+ provides through-hole compatibility at the cost of board area - both retain full pin-to-pin and functional equivalence for drop-in replacement in existing layouts.
Availability
MAX818MCPA+ is available at Aetrix Electronics and suitable for portable medical monitors, industrial data loggers, smart meter RTC modules, and handheld test equipment requiring stable component supply and long-term lifecycle support.
Supply support for MAX818MCPA+ 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 ICs for industrial, communications, and consumer applications.
The MAX817/MAX818/MAX819 product line was engineered specifically for robust, low-power µP supervision in battery-critical embedded systems - emphasizing reset accuracy, battery longevity, and integration of backup power control.
FAQ
What is the reset threshold voltage of the MAX818MCPA+?
The MAX818MCPA+ has a factory-trimmed reset threshold of 4.40V ±10%, optimized for +5V systems where brownout detection must trigger before µP operational failure. This M-suffix variant differs from the L-version (4.65V) and is verified in the Absolute Maximum Ratings and Electrical Characteristics tables of the official datasheet.
Does the MAX818MCPA+ include a manual reset input (MR)?
No, the MAX818MCPA+ does not include a manual reset input. The MR pin is exclusive to the MAX819 family; MAX818MCPA+ omits this function entirely, as confirmed in the Selector Guide and Pin Description sections of the datasheet. For manual reset capability, MAX819L/M variants must be selected.
How does the battery freshness seal work on the MAX818MCPA+?
The MAX818MCPA+ enables its battery freshness seal by grounding CE OUT during a specific power-cycle sequence: VCC must rise above VRST, then fall while CE OUT is held low. This latches internal circuitry to disconnect BATT until first valid power-up, preserving shelf life - a feature documented in the Detailed Description section of the MAX818 datasheet.
Can the MAX818MCPA+ monitor an external power rail using the PFI pin?
No, the PFI and PFO pins are not functional in the MAX818MCPA+. Unlike MAX817/MAX819, the MAX818 lacks the power-fail comparator circuitry - confirmed by the Selector Guide and Pin Description table. PFI must be grounded and PFO left unconnected per datasheet guidance.
What is the maximum continuous output current capability of the MAX818MCPA+ OUT pin?
The MAX818MCPA+ OUT pin supports up to 250mA continuous output current, as specified in the Absolute Maximum Ratings table. This rating applies when sourcing from VCC or BATT, and is sufficient to power typical CMOS SRAM (e.g., 256K×8) without external buffering.
MAX818MCPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX818MCPA+ FAQ
1.How can I place an order for MAX818MCPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX818MCPA+ 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 MAX818MCPA+ reliable?
The price and inventory of MAX818MCPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX818MCPA+ is usually 5 days.
3.What payment methods are accepted for MAX818MCPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX818MCPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX818MCPA+?
MAX818MCPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX818MCPA+ 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 MAX818MCPA+?
For technical support, including MAX818MCPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX818MCPA+ requirements.
6.How does Aetrix verify that MAX818MCPA+ is sourced from the original manufacturer or authorized distributors?
All MAX818MCPA+ 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 MAX818MCPA+ meets industry standards.
7.What is the process for return or replacement of MAX818MCPA+?
All MAX818MCPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX818MCPA+, 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 MAX818MCPA+ part is unused and in its original packaging.
Return procedure for MAX818MCPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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