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Analog Devices Inc./Maxim Integrated MAX815NCPA+
- Part No.:
- MAX815NCPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX815NCPA+.pdf
- Description:
- IC SUPERVISOR MPU LP 8-DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,115
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Product details
Overview
MAX815NCPA+ from Maxim Integrated is a high-accuracy, low-power microprocessor supervisory IC providing power-on reset, independent watchdog timer with 1.56s timeout, and power-fail monitoring for +5V systems. It features ±1% worst-case reset threshold accuracy (4.55V), active-low RESET output, manual reset input, and guaranteed RESET validity down to VCC = 1V. It is used in portable medical equipment and battery-powered controllers requiring reliable brownout detection and fail-safe restart.
For engineers reviewing the MAX815NCPA+ datasheet, MAX815NCPA+ pinout, MAX815NCPA+ application, or MAX815NCPA+ equivalent, key selection criteria include its fixed 4.55V reset threshold, 75µA max supply current, watchdog timeout tolerance over temperature, PFI comparator reference (2.50V), and SO-8 package compatibility with legacy DIP layouts.
Technical Context
The MAX815NCPA+ integrates a precision reset comparator with 60mV hysteresis relative to VCC, a dedicated watchdog circuit triggered by WDI transitions, and a separate power-fail comparator referenced to 2.50V. Its RESET output remains valid and actively driven below 1V VCC, enabling robust operation during deep brownouts.
Unlike the MAX814 (with LOW LINE output) or MAX816 (adjustable reset via RESET IN), the MAX815NCPA+ uses VCC as the primary reset sense node and provides WDO as an independent watchdog status flag - not tied to reset assertion timing. The 1.56s watchdog timeout is factory-trimmed and stable across -40°C to +85°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.55V ±1% - ensures reliable reset initiation for 5V systems with ±10% supply tolerance. |
| Supply Current | 75µA max at +25°C - enables multi-year operation in coin-cell–powered portable instruments. |
| Watchdog Timeout | 1.56s - provides sufficient margin for firmware execution loops while preventing lockup persistence. |
| PFI Reference Voltage | 2.50V - allows early warning of +5V rail collapse when used with external voltage divider. |
| RESET Pulse Width | 200ms min - guarantees µP initialization completes before release from reset state. |
| VCC Operating Range | 4.60V to 5.5V - supports full industrial 5V rail variation including cold-start conditions. |
| Output Drive | RESET sinks ≥3.2mA at 0.4V; WDO sources ≥300µA at VCC–1.5V - compatible with TTL/CMOS inputs without pull-ups. |
Pinout & Package
MAX815NCPA+ is housed in an 8-pin SO (Small Outline) package, pin-compatible with industry-standard SOIC-8 footprints and functionally identical to the 8-pin PDIP variant (MAX815NCPA). The package is lead-free, RoHS-compliant, and rated for 0°C to +70°C commercial operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - MR | Manual Reset Input | Active-low CMOS input with 150µA internal pull-up; triggers reset when pulled below 1.10V; debounced by 200ms internal timer. |
| 2 - VCC | Positive Power Supply | Main supply input; reset comparator monitors this node; device operates from 4.60V to 5.5V. |
| 3 - GND | Ground Reference | System ground return for all internal comparators and outputs; must be low-impedance. |
| 4 - PFI | Power-Fail Input | High-impedance input compared to 2.50V internal reference; used to monitor auxiliary rails (e.g., +12V via divider). |
| 5 - PFO | Power-Fail Output | Open-drain output active-low when PFI < 2.50V; sinks ≥1.2mA - directly interfaces µP interrupt pins. |
| 6 - WDI | Watchdog Input | Edge-sensitive CMOS input; each transition resets 1.56s timer; pulse width ≥50ns required. |
| 7 - RESET | Reset Output | Active-low push-pull output; asserted low during power-up, brownout, or MR activation; valid to VCC = 1V. |
| 8 - WDO | Watchdog Output | Active-low open-drain output; goes low on watchdog timeout or VCC < reset threshold; no minimum pulse width. |
Key Features
| Feature | Design Value |
|---|---|
| ±1% Worst-Case Reset Accuracy | Eliminates manual trimming and ensures deterministic reset behavior across voltage, temperature, and process variation. |
| Independent Watchdog with 1.56s Timeout | Prevents firmware hang without coupling to reset timing - WDO can trigger NMI or be wired to MR for auto-reset. |
| Power-Supply Glitch Immunity | Rejects transients ≤30µs at 100mV below reset threshold - avoids spurious resets in noisy industrial environments. |
| Guaranteed RESET Validity to VCC = 1V | Ensures clean, logic-defined reset signal even during deep brownout - critical for data retention in flash-based µPs. |
| 2.50V PFI Reference for +5V Systems | Enables precise early-warning detection of +5V rail collapse before µP operating limits are breached. |
Applications
| Medical Patient Monitor | Battery-Powered Data Logger |
|---|---|
|
Use Scenario: Continuous vital-sign acquisition in handheld ECG units powered by Li-ion cells. IC Role / Device Role / Timing Role: Supervises main 5V DC-DC output; asserts RESET on battery sag below 4.55V; triggers WDO if firmware stalls during sensor readout. Use Value: Prevents corrupted waveform storage by ensuring controlled shutdown before supply collapse, leveraging 200ms reset hold and 75µA quiescent current. |
Use Scenario: Remote environmental sensor node logging temperature/humidity every 10 minutes using coin-cell power. IC Role / Device Role / Timing Role: Monitors 5V system rail; uses PFI/PFO to detect early battery depletion; initiates graceful log commit upon PFO assertion. Use Value: Extends usable battery life by >18 months via ultra-low 75µA supply current and eliminates need for external supervisor biasing. |
| Industrial PLC I/O Module | Set-Top Box Power Management |
|
Use Scenario: DIN-rail mounted controller interfacing with 24V field sensors and 5V logic. IC Role / Device Role / Timing Role: Provides dual supervision: VCC reset for 5V core, and PFI-driven PFO for 24V auxiliary rail monitoring via resistor divider. Use Value: Enables fault-isolation between power domains - PFO interrupt alerts µP to isolate faulty sensor bus before VCC brownout occurs. |
Use Scenario: Consumer STB with HDMI, tuner, and embedded Linux OS requiring deterministic boot and crash recovery. IC Role / Device Role / Timing Role: Generates power-on reset; feeds WDO to µP NMI pin to force reboot on software hang; uses MR for front-panel reset button. Use Value: Reduces field returns by eliminating unresponsive "frozen UI" states - 1.56s watchdog timeout aligns with typical Linux kernel hang detection windows. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX814NCPA+ | No watchdog; includes LOW LINE output instead of WDO; same 4.55V reset, 75µA supply, SO-8 package. | Suitable where early brownout warning (LOW LINE) is prioritized over firmware hang detection. | Select MAX814NCPA+ only if watchdog functionality is unnecessary and low-line interrupt capability is required. |
| TPS3808G33DBVR | 3.3V fixed reset threshold; 1.25s watchdog; 2.5µA quiescent current; SOT-23-6 package; no PFI/PFO. | Optimized for ultra-low-power 3.3V systems; lacks power-fail monitoring and dual-supply flexibility. | Choose TPS3808G33DBVR for space-constrained 3.3V designs where PFI monitoring is omitted and 2.5µA IQ is critical. |
Compared with MAX815NCPA+, MAX814NCPA+ removes watchdog capability but adds low-line detection for predictive brownout response, while TPS3808G33DBVR trades PFI monitoring and 5V compatibility for extreme low-power operation in 3.3V-only systems.
Availability
MAX815NCPA+ is available at Aetrix Electronics and suitable for medical instrumentation, industrial control modules, and consumer set-top boxes requiring stable component supply with long-term lifecycle assurance.
Supply support for MAX815NCPA+ 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 demanding industrial, medical, and communications applications.
The MAX814/MAX815/MAX816 family was engineered specifically for high-reliability microprocessor supervision in battery-constrained and noise-prone environments, emphasizing ±1% threshold accuracy, sub-100µA supply current, and glitch-immune reset generation.
FAQ
What is the exact reset threshold voltage of the MAX815NCPA+?
The MAX815NCPA+ has a factory-trimmed reset threshold of 4.55V ±1%, specified over the full commercial temperature range (0°C to +70°C). This value is confirmed in the Electrical Characteristics table for +5V parts under the "VRT" parameter with suffix "N", and applies to VCC rising and falling conditions with 60mV hysteresis. The threshold is optimized for 5V systems with ±10% supply tolerance.
Does the MAX815NCPA+ support watchdog functionality, and how is it implemented?
Yes, the MAX815NCPA+ includes a fully independent watchdog timer with a nominal 1.56s timeout period. It is implemented via the WDI (Watchdog Input) and WDO (Watchdog Output) pins: each rising or falling edge on WDI resets the timer, and WDO goes low if no transition occurs within 1.56s. Unlike RESET, WDO has no minimum pulse width and responds immediately to VCC crossing the reset threshold.
Can the MAX815NCPA+ monitor voltages other than VCC, such as a +12V rail?
Yes, the MAX815NCPA+ can monitor auxiliary voltages using the PFI (Power-Fail Input) pin. By connecting a resistive divider from the +12V rail to GND, with the midpoint fed to PFI, the internal 2.50V comparator detects when the divided voltage falls below threshold - indicating +12V collapse. PFO then asserts low, allowing µP interrupt-driven shutdown. Figure 11 in the datasheet shows this exact configuration.
What is the minimum VCC level at which the MAX815NCPA+ guarantees valid RESET output?
The MAX815NCPA+ guarantees RESET output remains a valid logic low (≤0.4V while sinking 3.2mA) down to VCC = 1V. Below 1V, RESET becomes high-impedance, but the datasheet explicitly confirms functional validity through 1V - a key differentiator for brownout resilience in portable equipment where supply decay is gradual.
Is the MAX815NCPA+ pin-compatible with other devices in the MAX814/MAX815/MAX816 family?
Yes, the MAX815NCPA+ shares identical pinout and SO-8 (or PDIP-8) packaging with MAX814NCPA+ and MAX816NCPA+. However, functional differences exist: MAX814 provides LOW LINE instead of WDO; MAX816 replaces VCC-sensed reset with adjustable RESET IN threshold. Pin compatibility enables layout reuse, but firmware and external connections must match the specific feature set of each variant.
MAX815NCPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.55V
- Output:
- Push-Pull, Totem Pole
- 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
MAX815NCPA+ FAQ
1.How can I place an order for MAX815NCPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX815NCPA+ 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 MAX815NCPA+ reliable?
The price and inventory of MAX815NCPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX815NCPA+ is usually 5 days.
3.What payment methods are accepted for MAX815NCPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX815NCPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX815NCPA+?
MAX815NCPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX815NCPA+ 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 MAX815NCPA+?
For technical support, including MAX815NCPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX815NCPA+ requirements.
6.How does Aetrix verify that MAX815NCPA+ is sourced from the original manufacturer or authorized distributors?
All MAX815NCPA+ 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 MAX815NCPA+ meets industry standards.
7.What is the process for return or replacement of MAX815NCPA+?
All MAX815NCPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX815NCPA+, 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 MAX815NCPA+ part is unused and in its original packaging.
Return procedure for MAX815NCPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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