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Analog Devices Inc./Maxim Integrated MAX813LEUA+
- Part No.:
- MAX813LEUA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX813LEUA+.pdf
- Description:
- IC SUPERVISOR
- Quantity:
- Payment:
- Shipping:
Inventory:750
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Product details
Overview
The MAX813LEUA+ from Maxim Integrated is a precision microprocessor supervisory circuit in an 8-pin µMAX package, providing active-high reset output (RESET), watchdog timer with 1.6s timeout, 4.65V supply-voltage monitor, 1.25V power-fail comparator input (PFI), and debounced manual-reset input (MR). It guarantees valid RESET down to VCC = 1.2V and delivers a 200ms reset pulse width for reliable boot sequencing in industrial controllers.
For engineers reviewing the MAX813LEUA+ datasheet, MAX813LEUA+ pinout, MAX813LEUA+ application, or MAX813LEUA+ equivalent, key selection criteria include its −40°C to +85°C operating range, guaranteed reset assertion at VCC ≥ 1.2V, 1.25V PFI threshold for battery-low detection, and compatibility with 5V µP systems requiring active-high reset assertion and watchdog supervision.
Technical Context
The MAX813LEUA+ integrates four core supervisory functions on a single die: a precision voltage monitor comparing VCC against a 4.65V threshold with 40mV hysteresis, a monostable watchdog timer triggered by WDI edge transitions with 1.6s timeout, a dedicated 1.25V reference-based comparator for external power-fail or low-battery monitoring via PFI, and a TTL/CMOS-compatible MR input with internal 250µA pull-up and 150ns minimum pulse width support.
Its RESET output is actively driven high when asserted (active-high), remains valid down to VCC = 1.2V with ISOURCE = 4µA, and features guaranteed logic-low deassertion (≤0.9V) under load. Unlike MAX705 variants, it omits the active-low RESET pin and N.C. terminal, dedicating Pin 7 exclusively to RESET while retaining WDO on Pin 8 for independent watchdog signaling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±15mV - ensures reset assertion before 5V rail collapse, preventing µP execution errors during brownout |
| Reset Pulse Width | 200ms typ - provides sufficient time for µP initialization and peripheral stabilization after power-up |
| Watchdog Timeout | 1.6s ±0.65s - allows robust software loop timing margin while detecting lockup within safe system response window |
| PFI Threshold | 1.25V ±50mV - enables accurate low-battery warning or auxiliary supply monitoring with external resistor divider |
| Supply Current | 150–500µA - ultra-low quiescent draw supports long-life battery-backed applications without compromising supervision fidelity |
| VCC Operating Range | 1.2V to 5.5V - guarantees functional reset generation even during deep brownout or backup battery operation |
| Operating Temperature | −40°C to +85°C - qualified for industrial control, automotive body electronics, and outdoor embedded systems |
Pinout & Package
MAX813LEUA+ uses an 8-pin µMAX package (package code U8+1, outline 21-0036), measuring 3.0mm × 3.0mm × 0.8mm with exposed pad for thermal enhancement. The package is RoHS-compliant and lead(Pb)-free, indicated by the '+' suffix.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (MR) | Manual-Reset Input | Active-low TTL/CMOS-compatible trigger; internal 250µA pull-up enables switch or logic-line interface without external components |
| 2 (VCC) | Positive Supply Input | Primary 5V (or 1.2–5.5V) power rail connection; powers all internal comparators, timer, and outputs |
| 3 (GND) | Ground Reference | Common 0V return for all analog and digital functions; must be low-impedance for noise immunity |
| 4 (PFI) | Power-Fail Input | Non-inverting input of 1.25V comparator; connects to voltage divider for monitoring secondary supplies or battery voltage |
| 5 (PFO) | Power-Fail Output | Open-drain active-low output asserting when PFI < 1.25V; sinks current to signal early power degradation |
| 6 (WDI) | Watchdog Input | Edge-sensitive input clearing internal 1.6s timer on rising/falling transitions; floating disables watchdog |
| 7 (RESET) | Active-High Reset Output | Push-pull CMOS output asserting high during reset condition; valid down to VCC = 1.2V with 4µA source capability |
| 8 (WDO) | Watchdog Output | Open-drain active-low output asserting when watchdog times out; also pulls low during VCC brownout |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET validity at VCC = 1.2V | Enables fail-safe reset assertion during deep brownout or battery backup mode, critical for data retention and state recovery |
| 200ms reset pulse width | Ensures µP and peripherals fully initialize before release, eliminating race conditions in multi-stage boot sequences |
| Debounced MR input with 250µA pull-up | Eliminates need for external RC debounce network; supports direct pushbutton or logic-level reset triggering |
| 1.25V precision PFI threshold | Allows accurate low-battery detection or auxiliary supply monitoring using only two external resistors |
| Independent WDO output | Provides dedicated watchdog fault signaling without interfering with RESET timing or requiring MR connection |
Applications
| Industrial PLC Controller | Smart Energy Meter |
|---|---|
Use Scenario: Monitors 5V system rail and backup lithium coin cell in programmable logic controller operating across −25°C to +70°C ambient. IC Role / Device Role / Timing Role: Supervisory IC providing active-high reset assertion, watchdog supervision of firmware execution, and low-battery warning via PFI. Use Value: Prevents spurious µP resets during transient line sags and ensures graceful shutdown when backup voltage drops below 2.7V. | Use Scenario: Embedded in utility-grade electricity meter with isolated RS-485 communication and real-time clock backup. IC Role / Device Role / Timing Role: Resets metering SoC on power-up/brownout, detects main supply failure via PFI, and triggers RTC switchover using PFO interrupt. Use Value: Guarantees accurate energy accumulation during grid interruptions and preserves billing integrity through deterministic reset behavior. |
| Medical Diagnostic Handheld | Automotive Body Control Module |
Use Scenario: Powers clinical-grade handheld ultrasound device with dual-supply architecture (5V main, 3.3V logic) and Li-ion battery backup. IC Role / Device Role / Timing Role: Generates active-high reset for ARM Cortex-M4 host, monitors battery health via PFI, and supervises firmware watchdog loop. Use Value: Ensures FDA-compliant boot validation and prevents corrupted image acquisition due to undervoltage-induced µP instability. | Use Scenario: Installed in door module controlling window lift, mirror fold, and interior lighting with CAN bus interface. IC Role / Device Role / Timing Role: Provides cold-cranking tolerant reset (VCC ≥ 1.2V), detects alternator failure via PFI, and asserts watchdog timeout on firmware hang. Use Value: Maintains ASIL-B compliant system availability during engine start transients and prevents latch-up during load-dump events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX705EUA+ | Provides active-low RESET (not RESET), same 4.65V threshold and 1.6s watchdog, but lacks dedicated RESET output | Suitable where µP accepts active-low reset; requires level-shifting or inverter if active-high required | Select MAX705EUA+ only if board design accommodates active-low reset and no RESET signal is needed for external logic |
| TPS3808G18DBVR | TI part with 1.8V reset threshold, adjustable watchdog (0.5–10s), and higher supply current (1.2µA typ); no PFI/PFO function | Designed for low-voltage µPs (1.8V/3.3V); lacks power-fail comparator for battery monitoring | Choose TPS3808G18DBVR for 1.8V systems needing programmable watchdog, but not for 5V brownout or battery-low detection |
Compared with MAX705EUA+, MAX813LEUA+ delivers essential active-high reset for Intel 80C51-class µPs and integrated PFI/PFO for battery supervision-features absent in the alternative. Against TPS3808G18DBVR, MAX813LEUA+ offers fixed 4.65V monitoring optimized for 5V rails and built-in low-battery detection, making it superior for industrial 5V applications requiring comprehensive power supervision.
Availability
MAX813LEUA+ is available at Aetrix Electronics and suitable for industrial PLC controllers, smart energy meters, medical handheld diagnostics, and automotive body control modules requiring stable component supply across extended temperature ranges.
Supply support for MAX813LEUA+ 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, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.
The MAX813L family targets cost-sensitive microprocessor supervision needs, delivering integrated reset, watchdog, power-fail detection, and manual reset in compact packages for space-constrained embedded systems.
FAQ
What is the reset threshold voltage of the MAX813LEUA+ and how tightly is it specified?
The MAX813LEUA+ has a nominal reset threshold of 4.65V, with a guaranteed tolerance of ±15mV (4.635V to 4.665V) over temperature and supply variations. This tight specification ensures consistent brownout detection across −40°C to +85°C and eliminates false resets caused by minor rail fluctuations, directly supporting reliable operation in industrial 5V systems where the MAX813LEUA+ is deployed.
Does the MAX813LEUA+ provide both active-high and active-low reset outputs?
No, the MAX813LEUA+ provides only an active-high RESET output on Pin 7. It does not include the active-low RESET output found on MAX707/MAX708 variants. This design choice simplifies PCB layout for µPs requiring active-high reset (e.g., Intel 80C51), and the MAX813LEUA+ datasheet confirms RESET is the sole reset signal-making it distinct from dual-output members of the same family.
How does the MAX813LEUA+ handle power-fail detection and what external components are needed?
The MAX813LEUA+ uses its PFI pin with an internal 1.25V reference to detect power failure. To monitor a 5V rail, connect PFI to a resistor divider (e.g., 100kΩ top, 30.1kΩ bottom) so PFI drops below 1.25V before VCC reaches critical levels. PFO then asserts low, enabling µP interrupt-driven shutdown. No additional op-amps or references are required-the MAX813LEUA+ implements full power-fail detection with just two resistors.
Can the MAX813LEUA+ operate reliably during severe brownout conditions?
Yes, the MAX813LEUA+ guarantees valid RESET output down to VCC = 1.2V with ISOURCE = 4µA, enabling continued supervision during deep brownouts where other supervisors fail. Its internal bandgap reference and comparator remain functional below 2V, and the 200ms reset pulse ensures µP reset completion even as VCC recovers-critical behavior confirmed in the MAX813LEUA+ datasheet's Electrical Characteristics table.
What is the watchdog timeout period of the MAX813LEUA+ and how is it cleared?
The MAX813LEUA+ watchdog timer has a nominal timeout period of 1.6 seconds, with a guaranteed range of 1.00s to 2.25s. It is cleared by any rising or falling edge on the WDI pin, by assertion of RESET, or by placing WDI in high-impedance (three-state). This edge-triggered clearing mechanism allows flexible firmware integration-unlike timeout-based alternatives-and is explicitly documented in the MAX813LEUA+ datasheet's Watchdog Timer section.
MAX813LEUA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- -
- Number of Voltages Monitored:
- -
- Voltage - Threshold:
- -
- Output:
- -
- Reset:
- -
- Reset Timeout:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
MAX813LEUA+ FAQ
1.How can I place an order for MAX813LEUA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX813LEUA+ 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 MAX813LEUA+ reliable?
The price and inventory of MAX813LEUA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX813LEUA+ is usually 5 days.
3.What payment methods are accepted for MAX813LEUA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX813LEUA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX813LEUA+?
MAX813LEUA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX813LEUA+ 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 MAX813LEUA+?
For technical support, including MAX813LEUA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX813LEUA+ requirements.
6.How does Aetrix verify that MAX813LEUA+ is sourced from the original manufacturer or authorized distributors?
All MAX813LEUA+ 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 MAX813LEUA+ meets industry standards.
7.What is the process for return or replacement of MAX813LEUA+?
All MAX813LEUA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX813LEUA+, 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 MAX813LEUA+ part is unused and in its original packaging.
Return procedure for MAX813LEUA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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