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Analog Devices Inc./Maxim Integrated MAX815LCSA+
- Part No.:
- MAX815LCSA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX815LCSA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,262
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Product details
Overview
MAX815LCSA+ from Maxim Integrated is a high-accuracy, low-power microprocessor supervisory circuit with integrated watchdog timer, power-fail monitoring, and active-low reset output. It features ±1% worst-case reset threshold accuracy (4.7V), 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 power-up, brownout recovery, and system-level fault detection.
For engineers reviewing the MAX815LCSA+ datasheet, MAX815LCSA+ pinout, MAX815LCSA+ application, or MAX815LCSA+ equivalent, key selection criteria include its fixed 4.7V reset threshold, independent 1.56s watchdog timeout, PFI/PFO undervoltage warning capability, manual reset input, and SO-8 package compatibility with legacy µP reset designs.
Technical Context
The MAX815LCSA+ implements a dedicated watchdog timer with 1.56s timeout triggered by WDI transitions - it resets on any high-to-low or low-to-high edge and asserts WDO low if no transition occurs within that window. Its reset generator uses a precision bandgap reference and comparator with 60mV hysteresis relative to the 4.7V trip point, ensuring immunity to fast VCC transients.
Power-fail detection is handled by a separate 2.50V PFI comparator (K/L/N suffix parts), enabling early warning via PFO before VCC reaches the reset threshold. The device operates across 4.75V–5.5V VCC, supports manual reset via MR (150µA internal pullup), and guarantees valid logic levels on RESET and WDO outputs down to VCC = 1V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.70V ±1% - precisely triggers reset when VCC falls below 4.7V, supporting 5V systems with ±5% supply tolerance. |
| Watchdog Timeout | 1.56 seconds - provides deterministic software execution monitoring; timeout asserts WDO low without delay. |
| Reset Pulse Width | 200ms minimum - ensures µP receives sufficient reset assertion time after power-up or brownout recovery. |
| Supply Current | 75µA max - enables use in always-on, battery-backed applications without significant drain. |
| VCC Operating Range | 4.75V to 5.5V - compatible with standard +5V rail designs and accommodates line/load regulation margins. |
| RESET Output Type | Active-low open-drain - sinks ≥3.2mA at 0.4V, compatible with CMOS/TTL inputs and external pull-up configurations. |
| PFI Threshold | 2.50V - enables early power-fail warning for +5V supplies using simple resistive divider on PFI pin. |
Pinout & Package
MAX815LCSA+ is housed in an 8-pin SO (Small Outline) package, RoHS-compliant and lead-free (indicated by '+' suffix). Pin spacing is 1.27mm, body width 3.9mm, and total length 4.9mm - compatible with standard SO-8 PCB footprints and reflow assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - MR | Manual Reset Input | Active-low CMOS input with 150µA internal pullup to VCC; triggers reset when pulled below 1.10V; accepts switch or logic drive. |
| 2 - VCC | Positive Power Supply | Main supply input (4.75V–5.5V); powers all internal circuits; RESET remains valid down to VCC = 1V. |
| 3 - GND | Ground Reference | Primary return path for VCC, PFI, and all outputs; must be low-impedance for noise immunity. |
| 4 - PFI | Power-Fail Input | Undervoltage sense node referenced to 2.50V; connects to voltage divider for early warning of +5V rail collapse. |
| 5 - PFO | Power-Fail Output | Active-low open-drain output; sinks ≥1.2mA when PFI < 2.50V; used to interrupt µP before reset assertion. |
| 6 - WDI | Watchdog Input | CMOS input monitoring µP activity; toggling required every ≤1.56s; 0.8V/0.7×VCC thresholds ensure noise margin. |
| 7 - RESET | Reset Output | Active-low open-drain output; asserted during power-up, brownout, or MR activation; min 200ms pulse width. |
| 8 - WDO | Watchdog Output | Active-low open-drain output; goes low on watchdog timeout or VCC reset condition; no propagation delay. |
Key Features
| Feature | Design Value |
|---|---|
| ±1% worst-case reset threshold accuracy | Eliminates manual trimming and ensures consistent reset behavior across temperature (-40°C to +85°C) and supply variation. |
| Independent watchdog with 1.56s timeout | Provides fail-safe software supervision without relying on reset circuitry - WDO asserts independently of RESET state. |
| Power-fail comparator with 2.50V reference | Enables configurable early-warning signaling via PFI/PFO, allowing µP to save data before VCC crosses reset threshold. |
| Guaranteed RESET validity to VCC = 1V | Ensures deterministic reset signaling during deep brownout or battery depletion, critical for portable medical and industrial devices. |
| 75µA max supply current | Supports long-term operation in energy-constrained systems such as handheld test instruments and remote sensors. |
Applications
| Medical Portable Monitors | Industrial PLC I/O Modules |
|---|---|
|
Use Scenario: Battery-powered ECG or SpO₂ monitor operating from single Li-ion cell with buck-boost regulator supplying +5V. IC Role / Device Role / Timing Role: Supervises +5V rail integrity, asserts RESET on brownout, and triggers WDO if firmware hangs during sensor readout. Use Value: Prevents corrupted waveform storage and ensures safe shutdown before battery voltage collapses below MCU operational range. |
Use Scenario: DIN-rail mounted I/O module with isolated +5V logic supply and field-side analog inputs. IC Role / Device Role / Timing Role: Monitors +5V logic rail via VCC; uses PFI to detect auxiliary 24V supply sag; asserts RESET and interrupts µP via PFO. Use Value: Enables graceful I/O freeze and status flagging prior to loss of digital control, avoiding spurious actuator commands. |
| Set-Top Box Power Management | Intelligent Sensor Node |
|
Use Scenario: Consumer STB with standby +5VSB rail and main +5V rail activated on IR wake-up. IC Role / Device Role / Timing Role: Generates clean power-on reset for main SoC; uses MR to force recovery after HDMI hotplug-induced firmware lockup. Use Value: Eliminates need for external RC reset networks and reduces boot failure rate during repeated wake/sleep cycles. |
Use Scenario: Wireless environmental sensor node powered by coin cell, waking periodically to sample and transmit. IC Role / Device Role / Timing Role: Provides ultra-low-current supervision of regulated +3.3V rail; WDI toggled by MCU before each BLE transmission. Use Value: Guarantees firmware restart if sleep timer or radio stack fails, extending field deployment reliability beyond 5 years. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX814LCSA+ | No watchdog timer; includes LOW LINE output instead of WDO/WDI; same 4.7V reset threshold and SO-8 package. | Suitable where early low-line warning is prioritized over software supervision; lacks fail-safe watchdog coverage. | Select MAX814LCSA+ only if watchdog functionality is unnecessary and low-line NMI signaling is required. |
| TPS3808G33DBVR | 3.3V fixed reset threshold; 200ms delay; no watchdog; 1.6µA quiescent current; SOT-23-6 package. | Designed for low-voltage systems; incompatible pinout and voltage range; not drop-in for +5V applications. | Choose TPS3808G33DBVR only for new 3.3V designs requiring ultra-low IQ; not a functional substitute for MAX815LCSA+. |
Compared with MAX814LCSA+, MAX815LCSA+ adds watchdog supervision at the cost of losing LOW LINE output; compared with TPS3808G33DBVR, it supports higher VCC, includes watchdog and PFI/PFO, but consumes more current and requires SO-8 layout space.
Availability
MAX815LCSA+ is available at Aetrix Electronics and suitable for medical portable monitors, industrial PLC I/O modules, and set-top box power management requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.
Supply support for MAX815LCSA+ 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 robust µP supervision in mission-critical embedded systems - delivering precision reset, early power-fail warning, and independent watchdog timing in compact SO-8 packages.
FAQ
What is the reset threshold voltage of the MAX815LCSA+?
The MAX815LCSA+ has a factory-set reset threshold of 4.70V ±1%, optimized for +5V systems with ±5% supply tolerance. This value is fixed and determined by the 'L' suffix in the part number. The threshold remains stable across -40°C to +85°C and ensures reliable reset assertion before µP operational voltage limits are violated. The MAX815LCSA+ does not support adjustable reset thresholds.
Does the MAX815LCSA+ include a watchdog timer?
Yes, the MAX815LCSA+ integrates an independent watchdog timer with a nominal timeout period of 1.56 seconds. It monitors the WDI pin for transitions and asserts WDO low if no edge occurs within that window. Unlike the reset function, the watchdog operates regardless of VCC level (as long as VCC > 1V) and provides fail-safe software execution monitoring distinct from power-supply supervision.
What is the function of the PFI and PFO pins on the MAX815LCSA+?
The PFI (Power-Fail Input) pin on the MAX815LCSA+ connects to a voltage divider monitoring a supply rail (e.g., +5V or +12V), comparing it against a 2.50V internal reference. When PFI falls below 2.50V, the PFO (Power-Fail Output) pin - an open-drain output - pulls low to signal impending supply failure. This allows the µP to initiate orderly shutdown before RESET is asserted, preserving data integrity in critical applications.
Can the MAX815LCSA+ operate with supply voltages below 4.75V?
No - the MAX815LCSA+ is specified for VCC operation between 4.75V and 5.5V, as defined for 'L' suffix +5V parts. While its RESET output remains valid down to VCC = 1V, the device does not function correctly or guarantee specifications outside the 4.75V–5.5V range. For 3.3V systems, the MAX815T variant (3.03V threshold) should be used instead of the MAX815LCSA+.
Is the MAX815LCSA+ pin-compatible with other devices in the MAX814/MAX815/MAX816 family?
Yes, the MAX815LCSA+ shares identical SO-8 pinout and footprint with MAX814LCSA+ and MAX816LCSA+, including VCC, GND, MR, PFI, PFO, RESET, and unused pins. However, functional differences exist: MAX815LCSA+ uses pins 6 (WDI) and 8 (WDO), while MAX814LCSA+ uses pin 6 (LOW LINE) and MAX816LCSA+ uses pin 6 (RESET IN). Direct substitution requires verifying peripheral connections match the intended function.
MAX815LCSA+ 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:
- 4.7V
- 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
MAX815LCSA+ FAQ
1.How can I place an order for MAX815LCSA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX815LCSA+ 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 MAX815LCSA+ reliable?
The price and inventory of MAX815LCSA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX815LCSA+ is usually 5 days.
3.What payment methods are accepted for MAX815LCSA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX815LCSA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX815LCSA+?
MAX815LCSA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX815LCSA+ 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 MAX815LCSA+?
For technical support, including MAX815LCSA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX815LCSA+ requirements.
6.How does Aetrix verify that MAX815LCSA+ is sourced from the original manufacturer or authorized distributors?
All MAX815LCSA+ 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 MAX815LCSA+ meets industry standards.
7.What is the process for return or replacement of MAX815LCSA+?
All MAX815LCSA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX815LCSA+, 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 MAX815LCSA+ part is unused and in its original packaging.
Return procedure for MAX815LCSA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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