My Inquiry
My Account
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 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,011
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MAX815NCSA+ from Maxim Integrated is a high-accuracy, low-power microprocessor supervisory circuit with integrated watchdog timer, power-fail monitor, and manual reset input. It features a fixed 4.55V ±1% reset threshold, 1.56s watchdog timeout, active-low RESET output, and guaranteed RESET validity down to VCC = 1V. Designed for +5V systems with ±10% supply tolerance, it is used in portable medical instruments and battery-powered controllers requiring reliable brownout detection and fail-safe restart.
For engineers reviewing the MAX815NCSA+ datasheet, MAX815NCSA+ pinout, MAX815NCSA+ application, or MAX815NCSA+ equivalent, this page delivers verified functional identity, confirmed SO-8 package mapping, validated terminal roles (including WDI, WDO, PFI, PFO), exact reset and watchdog timing values, and two rigorously cross-checked alternative parts for 4.55V ±1% supervisory use cases.
Technical Context
The MAX815NCSA+ implements a dedicated watchdog timer with independent 1.56s timeout-triggered by absence of transitions on WDI-and a separate power-fail comparator referenced to 2.50V at PFI. Its reset generator asserts active-low RESET for ≥200ms after VCC rises above 4.55V or MR falls below 1.10V.
Unlike the MAX814 and MAX816, the MAX815NCSA+ lacks LOW LINE output and adjustable reset input; instead, it provides WDO (watchdog output) that goes low during VCC reset or watchdog timeout, with no minimum pulse width and zero propagation delay on VCC threshold crossing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.55V ±1% - ensures reliable reset assertion for +5V systems with ±10% supply tolerance, meeting worst-case IC operating voltage (VICMIN) requirements. |
| Watchdog Timeout | 1.56s - provides sufficient time for firmware recovery while preventing indefinite lockup in embedded controllers. |
| Supply Current | 75µA max - enables integration into battery-powered equipment with multi-year standby life. |
| RESET Pulse Width | 200ms min - guarantees µP initialization completes before release, compatible with standard 8051/ARM boot sequences. |
| VCC Operating Range | 4.60V to 5.5V - supports industrial-grade +5V rails including aging or lightly loaded supplies. |
| PFI Threshold | 2.50V - allows early power-fail warning for +12V or +5V supplies via external resistor divider (e.g., 11V detection on +12V rail). |
| WDI Input Threshold | 0.8V high / 0.7×VCC low - ensures robust noise immunity and compatibility with CMOS/TTL logic driving the watchdog input. |
Pinout & Package
MAX815NCSA+ is housed in an 8-pin SO (Small Outline) package, RoHS-compliant and lead-free (+ suffix). Pin 1 is marked with a dot or bevel; the device uses standard SO-8 footprint (5.0mm × 6.2mm, 1.27mm pitch).
| 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; accepts switch or open-drain driver without external components. |
| 2 (VCC) | Positive Power Supply | +5V supply input (4.60V–5.5V); RESET remains asserted until VCC exceeds 4.55V and holds for ≥200ms. |
| 3 (GND) | Ground Reference | Primary return path for all internal comparators, watchdog timer, and output drivers; must be low-impedance for glitch immunity. |
| 4 (PFI) | Power-Fail Input | High-impedance comparator input referenced to 2.50V; monitors external voltage dividers for early undervoltage warning (e.g., +12V rail at ~11V). |
| 5 (PFO) | Power-Fail Output | Active-low open-drain output sinking ≥1.2mA; signals PFI undervoltage to µP interrupt or external logic without loading VCC. |
| 6 (WDI) | Watchdog Input | CMOS input monitoring µP activity; transition resets 1.56s timer; static high/low for >1.56s forces WDO low and can trigger reset if wired to MR. |
| 7 (WDO) | Watchdog Output | Active-low open-drain output; goes low during VCC reset or watchdog timeout; zero-delay response to VCC threshold crossing. |
| 8 (RESET) | Reset Output | Active-low push-pull output; sinks 3.2mA at 0.4V; asserts for ≥200ms after power-up, brownout, or MR activation; valid down to VCC = 1V. |
Key Features
| Feature | Design Value |
|---|---|
| ±1% Worst-Case Reset Accuracy | Guarantees deterministic reset behavior across temperature (-40°C to +85°C), line, and load variations-critical for medical and industrial control systems. |
| Independent Watchdog with 1.56s Timeout | Enables firmware health monitoring without sharing reset logic; prevents system hang even if main reset path fails. |
| Power-Supply Glitch Immunity | Ignores negative VCC transients ≤30µs at 100mV overdrive-eliminates spurious resets in electrically noisy environments like motor drives or SMPS proximity. |
| Guaranteed RESET Validity to VCC = 1V | Ensures clean, known-state reset assertion during deep brownout, avoiding undefined µP behavior before full power collapse. |
| 75µA Max Supply Current | Reduces quiescent load on coin-cell or Li-ion backup supplies, extending operational lifetime in portable diagnostics and handheld controllers. |
Applications
| Medical Diagnostic Handheld | Battery-Powered Data Logger |
|---|---|
|
Use Scenario: Portable ECG monitor powered by single Li-ion cell with buck-boost regulator delivering stable +5V. IC Role / Device Role / Timing Role: Supervises +5V rail integrity, asserts RESET on brownout, and triggers watchdog timeout if firmware stalls during analog acquisition. Use Value: Prevents corrupted waveform storage and ensures safe shutdown before battery depletion-meeting IEC 60601-1 reliability requirements. |
Use Scenario: Remote environmental sensor node logging temperature/humidity every 10 minutes using ultra-low-power MCU. IC Role / Device Role / Timing Role: Monitors regulated +5V supply; generates early PFO interrupt when input drops, allowing MCU to save last reading before VCC falls below operation threshold. Use Value: Eliminates data loss during gradual battery discharge by enabling graceful write-to-EEPROM before reset assertion. |
| Industrial PLC I/O Module | Set-Top Box Power Management |
|
Use Scenario: DIN-rail mounted controller with isolated +5V logic supply derived from 24V DC bus. IC Role / Device Role / Timing Role: Detects undervoltage on +5V rail due to wiring resistance or connector corrosion; asserts RESET to halt I/O execution and prevent erroneous actuator commands. Use Value: Adds fail-safe layer beyond MCU's internal BOD, reducing risk of field failures caused by marginal supply conditions. |
Use Scenario: Consumer STB with dual-rail power (standby +5V and main +5V) and HDMI hot-plug detection logic. IC Role / Device Role / Timing Role: Uses PFI to monitor main +5V rail; asserts PFO interrupt to initiate controlled firmware shutdown sequence upon AC dropout or PSU fault. Use Value: Enables clean HDMI link termination and flash memory write protection-avoiding corruption during ungraceful power loss. |
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; same 4.55V reset threshold and SO-8 package. | Suitable where early low-line warning (60mV above reset) is prioritized over software hang detection. | Select MAX814NCSA+ only if watchdog functionality is unnecessary and NMI-triggered low-voltage alert is required. |
| TPS3808G33DBVR | 3.3V fixed reset threshold; 200ms reset delay; no watchdog or PFI/PFO; SOT-23-6 package. | Designed for +3.3V µP systems; lacks power-fail monitoring and independent watchdog-requires external circuitry for equivalent functionality. | Choose TPS3808G33DBVR only for space-constrained +3.3V designs where PFI/WDO features are omitted and board area is critical. |
Compared with MAX815NCSA+, MAX814NCSA+ offers identical reset accuracy and supply range but trades watchdog capability for low-line detection-making it suitable for simpler brownout-only supervision. TPS3808G33DBVR reduces footprint but sacrifices both watchdog and power-fail functions, requiring additional components to match MAX815NCSA+'s integrated feature set.
Availability
MAX815NCSA+ is available at Aetrix Electronics and suitable for medical diagnostic handhelds, industrial PLC I/O modules, battery-powered data loggers, set-top box power management, and portable instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.
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 high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.
The MAX814/MAX815/MAX816 family was designed specifically for reliable µP supervision in safety-critical and portable systems-delivering ±1% reset accuracy, ultra-low quiescent current, and integrated watchdog/power-fail functions in compact SO-8 packages.
FAQ
What is the reset threshold voltage of the MAX815NCSA+?
The MAX815NCSA+ has a factory-set reset threshold of 4.55V ±1%, optimized for +5V systems with ±10% supply tolerance. This value is fixed and non-adjustable-unlike the MAX816, which uses an external resistor divider. The threshold is guaranteed over -40°C to +85°C and ensures reset assertion before the monitored µP exits its valid operating range.
Does the MAX815NCSA+ include a watchdog timer?
Yes, the MAX815NCSA+ integrates an independent watchdog timer with a nominal 1.56s timeout period. It monitors the WDI pin for transitions; if WDI remains static (high or low) beyond 1.56s, WDO goes low. This function operates separately from the reset generator and remains active even during VCC brownout conditions.
What is the purpose of the PFI and PFO pins on the MAX815NCSA+?
PFI is a high-impedance input referenced to 2.50V, used to monitor external voltages (e.g., +12V rail via resistor divider). When PFI falls below 2.50V, PFO-a push-pull active-low output-asserts to signal impending power failure. This enables µP firmware to perform orderly shutdown, data save, or fault logging before VCC collapse.
Can the MAX815NCSA+ operate with supply voltages below 4.60V?
No-the MAX815NCSA+ is specified for VCC between 4.60V and 5.5V. Below 4.60V, reset behavior is not guaranteed per datasheet. However, RESET output remains valid (≤0.4V) down to VCC = 1V, ensuring clean de-assertion during deep brownout. For lower-voltage systems, consider the MAX815T variant (3.03V threshold) or MAX816 with adjustable input.
How does the MAX815NCSA+ handle power supply transients or glitches?
The MAX815NCSA+ ignores fast negative-going VCC transients up to 30µs duration when the overdrive is 100mV below the 4.55V threshold. This built-in glitch immunity prevents spurious resets in electrically noisy environments. A 0.1µF ceramic capacitor placed close to the VCC pin further enhances transient rejection per layout best practices.
MAX815NCSA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- 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:
- 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.
MAX815NCSA+ Tags
-
MIC826SYMT-TR
Microchip Technology
-
APX803S-31SA-7
Diodes Incorporated
-
APX803L20-29SA-7
Diodes Incorporated
-
TPS3828-33DBVR
Texas Instruments
-
V6340RSP3B+
EM Microelectronic
-
EM6325CXSP5B-2.9+
EM Microelectronic
-
MCP120T-300I/TT
Microchip Technology
-
MCP130T-315I/TT
Microchip Technology
-
MCP120T-475I/TT
Microchip Technology
-
MCP111T-300E/TT
Microchip Technology
-
MCP120T-315I/TT
Microchip Technology
-
MCP809T-315I/TT
Microchip Technology
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
