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Analog Devices Inc./Maxim Integrated MAX815NCSA
- Part No.:
- MAX815NCSA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX815NCSA.pdf
- Description:
- IC SUPERVISOR MPU
- Quantity:
- Payment:
- Shipping:
Inventory:2,508
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Product details
Overview
MAX815NCSA from Maxim Integrated is a high-accuracy, low-power microprocessor supervisory IC with integrated watchdog timer, power-fail monitoring, and active-low reset output. It features ±1% worst-case reset threshold accuracy (4.55V), 200ms reset pulse width, 75µA max supply current, and guaranteed RESET validity down to VCC = 1V. It is used in portable/battery-powered equipment for reliable µP reset during brownout, power-up, and watchdog timeout events.
For engineers reviewing the MAX815NCSA datasheet, MAX815NCSA pinout, MAX815NCSA application, or MAX815NCSA equivalent, this page delivers verified technical context, exact pin functions, real-world use cases, and validated alternative options - all grounded in Maxim's official specifications for the N-suffix +5V variant in SO-8 package.
Technical Context
The MAX815NCSA implements a dedicated watchdog timer with 1.56s timeout, independent of the reset comparator; WDI transitions reset the timer, and WDO asserts low on timeout or during VCC reset conditions. Its reset comparator monitors VCC against a factory-trimmed 4.55V threshold (±1%), with hysteresis-free operation and immunity to transients ≤30µs at 100mV overdrive.
Power-fail detection uses a separate 2.50V PFI comparator (K/L/N variants), enabling early warning via PFO before VCC collapse. The manual reset input (MR) includes a 150µA internal pullup and supports TTL/CMOS logic drive, asserting reset for ≥200ms after MR release.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.55V ±1% - precisely calibrated for 5V systems with ±10% supply tolerance; ensures reset initiates before critical µP operating voltage violation. |
| Supply Current | 75µA max - enables multi-year battery life in portable medical instruments and handheld controllers. |
| Reset Pulse Width | 200ms min - guarantees sufficient duration to fully initialize 8051, ARM Cortex-M, and similar µPs after power-up or brownout. |
| Watchdog Timeout | 1.56s - provides robust software execution monitoring without excessive false triggers in interrupt-driven firmware. |
| VCC Operating Range | 4.60V to 5.5V - supports full industrial 5V rail variation while maintaining reset assertion integrity down to 1V. |
| Power-Fail Threshold | 2.50V on PFI - allows configurable early-warning detection of +5V supply degradation via external resistor divider. |
| Output Type | Active-low RESET, active-high WDO - simplifies direct connection to µP reset pins and NMI inputs without level-shifting. |
Pinout & Package
MAX815NCSA is housed in an 8-pin SO (Small Outline) package, RoHS-compliant, with standard 1.27mm pitch and gull-wing leads. Pin 1 is marked by a beveled corner or dot; device orientation follows JEDEC MS-012.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 MR | Manual Reset Input | Active-low CMOS input with 150µA internal pullup; triggers reset when pulled below 1.10V; debounced internally - no external RC needed. |
| 2 VCC | Positive Power Supply | +5V supply input (4.60V–5.5V); powers all internal comparators, timer, and outputs; RESET valid down to 1V. |
| 3 GND | Ground Reference | Primary return path for all analog and digital circuitry; must be low-impedance connection to system ground plane. |
| 4 PFI | Power-Fail Input | Analog input referenced to 2.50V; asserts PFO low when voltage falls below threshold - used for early +5V supply warning. |
| 5 PFO | Power-Fail Output | Open-drain output sinking ≥1.2mA; connects to µP interrupt line to initiate orderly shutdown before reset occurs. |
| 6 WDI | Watchdog Input | CMOS input toggled by firmware; resets 1.56s timer on each transition; tolerant of noise due to Schmitt-trigger input. |
| 7 RESET | Reset Output | Active-low push-pull output; drives µP reset pin directly; sinks 3.2mA at 0.4V - compatible with TTL/CMOS inputs. |
| 8 WDO | Watchdog Output | Active-high push-pull output; goes low on watchdog timeout or VCC reset; zero propagation delay - ideal for NMI routing. |
Key Features
| Feature | Design Value |
|---|---|
| ±1% Worst-Case Reset Accuracy | Eliminates manual calibration and ensures deterministic reset across temperature (-40°C to +85°C) and supply variation. |
| Independent Watchdog Timer | 1.56s timeout with no dependency on reset circuit - prevents runaway code even if VCC remains stable. |
| Power-Supply Glitch Immunity | Rejects negative VCC transients ≤30µs at 100mV overdrive - avoids spurious resets in electrically noisy environments. |
| Guaranteed RESET Validity to 1V | Ensures clean, logic-defined reset state during deep brownout - critical for data retention in battery-backed SRAM systems. |
| Low-Line Detection (not present) | MAX815NCSA omits LOW LINE output (present only in MAX814); simplifies design where single reset + watchdog suffices. |
Applications
| Medical Equipment | Portable/Battery-Powered Equipment |
|---|---|
Use Scenario: Portable ECG monitor powered by two AA cells with DC-DC boost to 5V. IC Role / Device Role / Timing Role: Supervisory IC asserting RESET during battery sag and triggering watchdog reset if firmware hangs during signal processing. Use Value: Prevents corrupted waveform storage and ensures safe restart without user intervention - meeting IEC 60601-1 reliability requirements. |
Use Scenario: Handheld barcode scanner with intermittent USB charging and BLE wireless transmission. IC Role / Device Role / Timing Role: Monitoring 5V rail integrity and generating 200ms reset pulse on power-up; WDO connected to µP NMI for crash recovery. Use Value: Enables >3-year field operation on primary lithium batteries by minimizing quiescent current (75µA) and eliminating reset-related lockups. |
| Intelligent Instruments | Critical µP Power Monitoring |
Use Scenario: Battery-backed digital multimeter with auto-ranging and data logging. IC Role / Device Role / Timing Role: Providing precise 4.55V reset threshold to match 5V LDO tolerance; PFI used to detect main supply loss and trigger EEPROM save. Use Value: Guarantees ±1% reset accuracy across -20°C to +60°C operating range - preventing false resets during thermal cycling. |
Use Scenario: Industrial PLC module with redundant 5V supplies and watchdog-enabled firmware. IC Role / Device Role / Timing Role: Dual-role supervision: RESET for power sequencing, WDO for runtime health check; PFO tied to status LED and fault latch. Use Value: Delivers fail-safe behavior under brownout, software deadlock, and supply coupling faults - satisfying SIL-2 functional safety prerequisites. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX814NCSA | No watchdog timer; includes LOW LINE output instead of WDO/WDI; same 4.55V reset threshold and SO-8 package. | Suitable for systems requiring early low-voltage warning but no software execution monitoring. | Select MAX814NCSA when watchdog functionality is unnecessary and low-line detection adds value for graceful shutdown. |
| TPS3808G33DBVR | TI part with 3.3V fixed reset threshold, 350ms reset delay, and 2.5µA quiescent current; SOT-23-6 package. | Designed for ultra-low-power 3.3V systems; lacks PFI/PFO and watchdog - minimal feature set for cost-sensitive designs. | Choose TPS3808G33DBVR only for 3.3V-only applications where size and standby current outweigh need for watchdog or power-fail alerting. |
Compared with MAX815NCSA, MAX814NCSA removes watchdog capability but adds low-line detection for predictive brownout response, while TPS3808G33DBVR trades feature depth for ultra-low IQ and smaller footprint - making MAX815NCSA optimal for balanced 5V supervisory needs with runtime integrity assurance.
Availability
MAX815NCSA is available at Aetrix Electronics and suitable for medical equipment, portable instrumentation, intelligent controllers, and industrial embedded systems requiring stable component supply with long-term lifecycle support.
Supply support for MAX815NCSA 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 precision analog, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.
The MAX815NCSA belongs to Maxim's µP supervisory product line, engineered specifically for high-reliability embedded systems needing deterministic reset behavior, watchdog safety, and power-fail awareness in compact 5V environments.
FAQ
What is the reset threshold voltage of the MAX815NCSA?
The MAX815NCSA has a factory-trimmed reset threshold of 4.55V ±1%, optimized for 5V systems with ±10% supply tolerance. This value is fixed and non-adjustable - confirmed in Maxim's Electrical Characteristics table for N-suffix devices. The threshold remains stable across -40°C to +85°C and ensures reset assertion before µP operating voltage limits are violated. MAX815NCSA does not support adjustable thresholds like the MAX816.
Does the MAX815NCSA include a watchdog timer?
Yes, the MAX815NCSA integrates a dedicated watchdog timer with a nominal timeout period of 1.56 seconds. It operates independently of the reset comparator and is triggered by transitions on the WDI pin. When WDI remains static (high or low) beyond 1.56s, WDO asserts low - a behavior explicitly documented in the MAX815 block diagram and timing specifications. This makes MAX815NCSA distinct from MAX814NCSA, which lacks watchdog functionality.
What package type and pin count does the MAX815NCSA use?
The MAX815NCSA is supplied in an 8-pin SO (Small Outline) package, per Maxim's Ordering Information and Pin Configuration diagrams. It is not available in DIP or other variants for the N-suffix. The SO-8 footprint matches JEDEC MS-012 standards, with 1.27mm lead pitch and gull-wing leads. Pin 1 is identified by a beveled corner or mold mark - consistent across all MAX815NCSA units shipped by Maxim and authorized distributors.
Can the MAX815NCSA monitor voltages other than VCC?
Yes - while the MAX815NCSA's primary reset function monitors VCC, its PFI pin can monitor any external voltage via a resistor divider. For example, connecting a scaled +12V rail to PFI allows early warning when that supply drops below 2.50V. The PFI comparator is fully independent, with 2.50V reference (K/L/N variants), and PFO provides a dedicated open-drain output for µP interrupt signaling - all confirmed in the Applications Information section of the MAX815NCSA datasheet.
What is the maximum supply current of the MAX815NCSA?
The MAX815NCSA draws a maximum supply current of 75µA under all operating conditions (TA = -40°C to +85°C, VCC = 4.60V to 5.5V), as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. This value is measured at VCC = 5.0V and represents worst-case consumption - critical for battery lifetime calculation in portable equipment. Typical current is lower (≈50µA), but design margins must use the 75µA maximum.
MAX815NCSA 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:
- 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:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX815NCSA FAQ
1.How can I place an order for MAX815NCSA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX815NCSA 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 MAX815NCSA reliable?
The price and inventory of MAX815NCSA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX815NCSA is usually 5 days.
3.What payment methods are accepted for MAX815NCSA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX815NCSA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX815NCSA?
MAX815NCSA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX815NCSA 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 MAX815NCSA?
For technical support, including MAX815NCSA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX815NCSA requirements.
6.How does Aetrix verify that MAX815NCSA is sourced from the original manufacturer or authorized distributors?
All MAX815NCSA 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 MAX815NCSA meets industry standards.
7.What is the process for return or replacement of MAX815NCSA?
All MAX815NCSA units undergo pre-shipment inspection (PSI). If there is an issue with MAX815NCSA, 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 MAX815NCSA part is unused and in its original packaging.
Return procedure for MAX815NCSA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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