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Analog Devices Inc./Maxim Integrated MAX817MCSA
- Part No.:
- MAX817MCSA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX817MCSA.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:26,349
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Product details
Overview
MAX817MCSA 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 reset threshold (±10%), 200ms reset timeout, 11µA quiescent supply current, and operates in 0°C to +70°C temperature range. Designed for portable µP systems requiring reliable brownout protection and RAM backup control.
For engineers reviewing the MAX817MCSA datasheet, MAX817MCSA pinout, MAX817MCSA application, or MAX817MCSA equivalent, this device delivers precision voltage monitoring, low-power battery switchover, and integrated PFI/PFO comparator functions - critical for embedded controller power integrity and nonvolatile memory retention.
Technical Context
The MAX817MCSA implements a precision bandgap-based reset comparator with 4.40V threshold and 25mV hysteresis, enabling robust immunity to fast VCC transients. Its internal PMOS switch enables seamless switchover from VCC to BATT when VCC falls below both VRST and VBATT, maintaining OUT supply to CMOS RAM.
It integrates a dedicated power-fail comparator (PFI/PFO) independent of the reset path, with 1.25V threshold and 4mV hysteresis, supporting external undervoltage detection. The device lacks watchdog timer and manual reset input - distinguishing it from MAX818/MAX819 variants in the same family.
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 restarts only after stable +5V rail recovery. |
| Reset Timeout Period | 200ms typical - guarantees minimum RESET assertion duration after power-up or brownout, meeting µP reset timing requirements. |
| Supply Current | 11µA typical - enables multi-year battery life in portable applications where standby current directly impacts system runtime. |
| VCC to OUT On-Resistance | 5Ω typical - minimizes voltage drop and power loss during main supply operation, preserving RAM supply regulation. |
| BATT to OUT On-Resistance | 80Ω typical - limits inrush and maintains safe current delivery during battery-backup mode, protecting SuperCap or Li coin cells. |
| Power-Fail Threshold | 1.25V ±50mV - allows configurable external voltage monitoring via resistor divider, supporting secondary supply fail detection. |
| Operating Temperature | 0°C to +70°C - validated for commercial-grade embedded controllers, industrial HMIs, and battery-powered instrumentation. |
Pinout & Package
MAX817MCSA is housed in an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), optimized for space-constrained portable designs. The package supports reflow soldering and provides thermal performance suitable for continuous operation at full ambient rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 OUT | Supply output for CMOS RAM | Switches between VCC and BATT based on voltage comparison; delivers regulated +5V or backup battery voltage to memory. |
| 2 VCC | Main +5V supply input | Primary power source; monitored for reset generation and used as reference for all internal comparators and switches. |
| 3 GND | Ground reference | 0V return path for all analog and digital circuitry; must be low-impedance to ensure accurate threshold sensing. |
| 4 PFI | Power-fail comparator input | Accepts external divided voltage; asserts PFO low when input falls below 1.25V, enabling custom undervoltage warning logic. |
| 5 PFO | Power-fail comparator output | Open-drain output pulled high externally; signals power failure condition or enables battery freshness seal when grounded. |
| 6 WDI | Watchdog input | Not functional in MAX817 - left unconnected or tied to VCC/GND; no watchdog timer present per Selector Guide. |
| 7 RESET | Active-low reset output | Drives µP reset pin low for ≥200ms during power-up, brownout, or PFO-triggered event; sinks 3.2mA min. |
| 8 BATT | Backup battery input | Accepts 2.0V–5.5V battery or SuperCap; powers OUT and internal circuitry when VCC is invalid, with <1µA standby draw. |
Key Features
| Feature | Design Value |
|---|---|
| Precision 4.40V reset threshold | ±10% tolerance over 0°C to +70°C ensures reliable µP reset across voltage and temperature variations without external trimming. |
| 11µA supply current | Enables >10-year shelf life with CR2032 coin cell in always-on monitoring applications, reducing battery replacement frequency. |
| 200ms reset timeout | Guarantees sufficient hold time for µP initialization sequences, eliminating race conditions during cold start or brownout recovery. |
| Independent PFI/PFO comparator | Allows simultaneous monitoring of secondary rails (e.g., +3.3V I/O supply) without interfering with primary reset path or battery switchover logic. |
| Battery switchover with hysteresis | 80Ω BATT-to-OUT switch and 20mV hysteresis prevent oscillation during VCC/VBATT crossover, ensuring clean RAM supply transition. |
Applications
| Portable Data Loggers | Industrial PLC I/O Modules |
|---|---|
|
Use Scenario: Battery-powered field instruments recording sensor data for weeks between charges. IC Role / Device Role / Timing Role: Supervisory circuit monitors main +5V rail and switches RAM to coin-cell backup during AC loss or deep discharge. Use Value: Prevents data corruption by guaranteeing 200ms RESET assertion and seamless BATT switchover before VCC collapses below 4.40V. |
Use Scenario: DIN-rail mounted I/O modules operating in factory environments with fluctuating 24VDC supplies. IC Role / Device Role / Timing Role: Provides brownout immunity and dual-rail monitoring: VCC for logic supply, PFI for isolated 5V sensor bus. Use Value: Uses PFI input to detect +5V sensor rail collapse independently, triggering PFO alert while maintaining µP reset integrity. |
| Medical Handheld Diagnostics | Smart Energy Meters |
|
Use Scenario: FDA-cleared handheld analyzers storing calibration and patient history in nonvolatile RAM. IC Role / Device Role / Timing Role: Ensures deterministic µP reset on battery insertion and prevents write errors during low-battery shutdown. Use Value: 11µA quiescent current extends single-charge operation; 4.40V threshold aligns with Li-ion discharge curve end-of-life voltage. |
Use Scenario: ANSI C12.20-compliant meters retaining tariff tables and consumption logs during grid outages. IC Role / Device Role / Timing Role: Manages SuperCap-backed RAM using BATT switchover and enables battery freshness seal to preserve capacitor lifetime. Use Value: 80Ω BATT-to-OUT resistance limits SuperCap discharge current, extending backup duration beyond 72 hours per charge cycle. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX817LCSA | 4.65V reset threshold (±5%) vs. 4.40V; otherwise identical pinout, features, and timing. | Suitable for tighter-tolerance +5V systems where 4.65V threshold better matches regulator dropout or noise margin. | Select MAX817LCSA when design requires higher reset threshold to avoid false triggers near 4.5V minimum spec. |
| MAX690ACSA | Legacy 8-pin SO supervisory with 4.65V reset, no PFI/PFO, no battery switchover; 120µA supply current. | Lacks power-fail detection and battery backup - limited to basic reset-only applications with ample board area. | Choose MAX690ACSA only if PFI/PFO and BATT functionality are unnecessary and µMAX footprint is not required. |
Compared with MAX817MCSA, MAX817LCSA offers tighter reset accuracy but less headroom for noisy rails, while MAX690ACSA sacrifices key features (PFI, BATT switchover) and consumes 11× more current - making MAX817MCSA optimal for modern compact, low-power, multi-function designs.
Availability
MAX817MCSA is available at Aetrix Electronics and suitable for portable medical devices, industrial data loggers, and smart metering systems requiring stable component supply, long-term lifecycle support, and guaranteed lead-free packaging.
Supply support for MAX817MCSA 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, automotive, and computing applications.
The MAX817 series belongs to Maxim's microprocessor supervisory product line, designed specifically to replace discrete reset generators and discrete power-monitoring circuits in space- and power-constrained +5V µP systems.
FAQ
What is the reset threshold voltage of the MAX817MCSA?
The MAX817MCSA has a factory-trimmed reset threshold of 4.40V ±10%, specified for operation across 0°C to +70°C. This value is fixed and non-adjustable - it reflects the "M" suffix designation in the part number and is validated per Electrical Characteristics table in the official datasheet. The MAX817MCSA does not support external resistor programming of the reset voltage.
Does the MAX817MCSA include a watchdog timer?
No, the MAX817MCSA does not include a watchdog timer. Per the Selector Guide and Functional Diagram in the datasheet, watchdog input (WDI) and timeout functionality are exclusive to MAX817L/M (with WDI pin present but unused) and fully implemented only in MAX818/MAX819 variants. The MAX817MCSA pin 6 (WDI) is a no-connect terminal with no internal watchdog circuitry.
Can the MAX817MCSA be used with a SuperCapacitor on the BATT pin?
Yes, the MAX817MCSA supports SuperCap backup sources on the BATT pin. Its 80Ω BATT-to-OUT switch and <1µA standby current (when VCC < VBATT − 0.2V) enable efficient energy transfer from SuperCaps rated 2.0V–5.5V. The device's switchover hysteresis prevents oscillation during gradual SuperCap discharge, making MAX817MCSA suitable for >72-hour backup in smart meters and data loggers.
What is the function of the PFI and PFO pins on the MAX817MCSA?
The PFI (Power-Fail Input) and PFO (Power-Fail Output) pins implement an independent comparator with 1.25V threshold. When PFI voltage falls below 1.25V, PFO pulls low (open-drain). This allows monitoring of secondary supplies (e.g., +3.3V rails) without affecting the primary reset path. In MAX817MCSA, PFO can also be grounded to enable the battery freshness seal, preserving backup battery life until first use.
Is the MAX817MCSA pin-compatible with other devices in the MAX817/MAX818/MAX819 family?
Yes, the MAX817MCSA is pin-compatible with all members of the MAX817/MAX818/MAX819 family in the same package (8-pin µMAX, SO, or DIP). Pin assignments for VCC, GND, RESET, BATT, OUT, PFI, PFO, and WDI are identical across variants. Functional differences (e.g., absence of watchdog or manual reset) are implemented internally - no PCB layout change is needed when substituting within the family.
MAX817MCSA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.4V
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX817MCSA FAQ
1.How can I place an order for MAX817MCSA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX817MCSA 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 MAX817MCSA reliable?
The price and inventory of MAX817MCSA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX817MCSA is usually 5 days.
3.What payment methods are accepted for MAX817MCSA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX817MCSA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX817MCSA?
MAX817MCSA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX817MCSA 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 MAX817MCSA?
For technical support, including MAX817MCSA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX817MCSA requirements.
6.How does Aetrix verify that MAX817MCSA is sourced from the original manufacturer or authorized distributors?
All MAX817MCSA 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 MAX817MCSA meets industry standards.
7.What is the process for return or replacement of MAX817MCSA?
All MAX817MCSA units undergo pre-shipment inspection (PSI). If there is an issue with MAX817MCSA, 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 MAX817MCSA part is unused and in its original packaging.
Return procedure for MAX817MCSA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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