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Analog Devices Inc./Maxim Integrated MAX823LEUK
- Part No.:
- MAX823LEUK
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX823LEUK.pdf
- Description:
- IC SUPERVISOR MPU
- Quantity:
- Payment:
- Shipping:
Inventory:3,598
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Product details
Overview
MAX823LEUK from Maxim Integrated is a 5-pin SOT23 microprocessor supervisory circuit with active-low reset, watchdog timer, and manual reset input, designed for critical µP monitoring in automotive and industrial systems. It features a 4.63V reset threshold, 140ms minimum power-on reset timeout, 1.6s watchdog timeout, guaranteed RESET validity down to VCC = 1V, and operates across –40°C to +125°C.
For engineers reviewing the MAX823LEUK datasheet, MAX823LEUK pinout, MAX823LEUK application, or MAX823LEUK equivalent, key selection criteria include reset threshold accuracy, wide-temperature operation, watchdog immunity to software lockup, and compatibility with bidirectional µP reset pins in harsh environments.
Technical Context
The MAX823LEUK integrates a precision voltage comparator with 40ppm/°C temperature coefficient, a monostable reset timer with 140–280ms timeout, and a watchdog circuit that clears on WDI edge transitions (≥50ns pulse width). Its internal 52kΩ MR pullup enables direct switch interfacing without external components.
It uses BiCMOS process technology (607 transistors) and delivers 3–8µA supply current in SOT23 package at +25°C. The RESET output sources up to 800µA and sinks 3.2mA, supporting direct connection to µPs like the 68HC11 with bidirectional reset pins.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.63V ±1.5% - precisely monitors +5V supplies with brownout detection |
| Reset Timeout Period | 140–280ms - ensures reliable µP initialization after power-up or brownout |
| Watchdog Timeout | 1.12–2.40s - detects firmware hangs while allowing safe software execution windows |
| Operating Temperature | –40°C to +125°C - qualified for under-hood automotive and industrial control applications |
| Supply Current | 3–8µA at +25°C - enables long battery life in portable equipment |
| RESET Validity | Guaranteed to VCC = 1V - maintains reset assertion during deep undervoltage conditions |
| VCC Transient Immunity | Rejects negative glitches ≤100µs at 100mV overdrive - avoids spurious resets in noisy power rails |
Pinout & Package
MAX823LEUK is housed in a RoHS-compliant (lead-free optional) 5-pin SOT23 package (drawing 21-0057F), footprint-compatible with industry-standard SC70-5 but optimized for high-temperature reliability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RESET | Active-low reset output | Asserts low for ≥200ms on power-up, brownout, WDI timeout, or MR low; sinks 3.2mA, sources 800µA |
| 2 - GND | Ground reference | Common return path for all internal circuits; requires low-impedance PCB connection |
| 3 - WDI | Watchdog input | Edge-sensitive (rising/falling); clears 1.6s timer on transition; disabled if left floating or three-stated |
| 4 - MR | Manual reset input | Active-low; internal 52kΩ pullup; asserts reset while low and for 200ms after release |
| 5 - VCC | Power supply input | Operates from 1.0V to 5.5V; reset guaranteed valid down to 1V; supports bypass capacitor for transient immunity |
Key Features
| Feature | Design Value |
|---|---|
| Precision 4.63V reset threshold | Enables accurate +5V supply monitoring with <±1.5% tolerance over full temperature range |
| 1.6s watchdog timer with edge-triggered clear | Prevents firmware lockup without requiring periodic high/low toggling-supports robust software flow checking |
| Internal 52kΩ MR pullup resistor | Eliminates need for external pullup; allows direct connection of momentary switch to GND |
| RESET valid to VCC = 1V | Ensures continuous reset assertion during severe undervoltage events, preventing partial µP execution |
| No external components required | Reduces BOM count and PCB area; simplifies design validation for space-constrained embedded systems |
Applications
| Automotive Engine Control Units | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Monitoring 5V microcontroller power in under-hood ECU environments subject to thermal cycling and load dump transients. IC Role / Device Role / Timing Role: Supervisory circuit providing power-on reset, brownout protection, and watchdog supervision of engine management firmware. Use Value: Prevents erratic ECU behavior during cold cranking (VCC dip to ~1.2V) and ensures deterministic restart after watchdog timeout due to software fault. | Use Scenario: Ensuring reliable startup and runtime supervision of ARM-based controllers in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Reset generator and watchdog monitor for real-time control firmware operating across –40°C to +85°C ambient. Use Value: Guarantees 200ms reset pulse duration even at +125°C junction temperature, meeting IEC 61131-2 immunity requirements. |
| Battery-Powered Data Loggers | Railway Signaling Controllers |
Use Scenario: Long-life remote sensor nodes powered by lithium-thionyl chloride cells with nominal 3.6V output and gradual voltage decay. IC Role / Device Role / Timing Role: Low-current (3–8µA) supervisor detecting end-of-life voltage drop below 4.63V and triggering controlled shutdown. Use Value: Extends usable battery life by minimizing quiescent current while maintaining precise reset threshold over 10+ year deployments. | Use Scenario: Safety-critical signaling hardware requiring fail-safe reset behavior during electromagnetic interference events on rail infrastructure. IC Role / Device Role / Timing Role: Immune supervisory circuit rejecting >100MHz noise coupling onto VCC via its transient-hardened comparator architecture. Use Value: Eliminates false resets from fast negative-going transients (<100µs, >100mV overdrive), satisfying EN 50121-3-2 EMC compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX823LEUK+T | Identical electrical specs and SOT23-5 package; lead-free (RoHS-compliant) variant with +T suffix | Required for new designs targeting RoHS/REACH compliance; same thermal and timing performance | Select when lead-free assembly is mandated; no layout or firmware changes needed |
| TPS3808G33DBVR | 3.3V fixed reset threshold, 200ms timeout, 1.6µA IQ, SOT23-5; lacks watchdog and manual reset inputs | Suitable only for basic reset-only applications; not interchangeable where watchdog or MR functionality is required | Choose only if system design omits watchdog/MR needs and prioritizes ultra-low quiescent current |
Compared with MAX823LEUK, the MAX823LEUK+T offers identical functionality in a RoHS-compliant package, while the TPS3808G33DBVR provides lower IQ but sacrifices watchdog and manual reset-making it unsuitable as a functional replacement in existing MAX823LEUK designs.
Availability
MAX823LEUK is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC I/O modules, and battery-powered data loggers requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX823LEUK 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for demanding industrial, automotive, and communications applications.
The MAX823 family was engineered specifically for robust microprocessor supervision in harsh environments, combining precision reset, watchdog, and manual reset in minimal 5-pin packages to reduce system-level complexity and improve reliability.
FAQ
What is the reset threshold voltage of the MAX823LEUK and how is it specified?
The MAX823LEUK has a factory-trimmed reset threshold of 4.63V with ±1.5% tolerance over the full operating temperature range (–40°C to +125°C). This value is guaranteed per the Reset Threshold Table in the datasheet and applies specifically to the "L" suffix variant. The threshold exhibits a 40ppm/°C temperature coefficient, ensuring stability across automotive and industrial thermal profiles. The MAX823LEUK uses this precise threshold to monitor +5V power rails and assert reset during brownout conditions.
Does the MAX823LEUK support watchdog functionality, and what is its timeout period?
Yes, the MAX823LEUK includes a watchdog timer with a nominal timeout period of 1.6 seconds, specified from 1.12s to 2.40s over temperature. The timer clears on any rising or falling edge at the WDI pin (minimum pulse width 50ns) and also resets when the RESET output is asserted. If WDI remains static beyond the timeout, the device triggers a reset pulse. This feature is confirmed for the MAX823 series-including the MAX823LEUK-and is absent in MAX824/MAX825 variants without the "3" designation.
What package type and temperature range does the MAX823LEUK use?
The MAX823LEUK is packaged in a 5-pin SOT23 (drawing 21-0057F) and is rated for operation from –40°C to +125°C. This high-temperature grade distinguishes it from the "EXK" variants (–40°C to +85°C) and confirms its suitability for under-hood automotive and industrial control applications. The "EUK" suffix explicitly denotes the SOT23-5 package and extended temperature range, as documented in the Ordering Information table.
Can the MAX823LEUK drive a microprocessor with a bidirectional reset pin?
Yes, the MAX823LEUK RESET output is designed to interface directly with bidirectional µP reset pins such as those found on the 68HC11. Its RESET pin can sink up to 3.2mA and source up to 800µA, enabling the µP to override the supervisor's reset signal when necessary. This capability is explicitly verified in the "Interfacing to µPs with Bidirectional Reset Pins" section of the datasheet and applies to the MAX823LEUK's L/M versions, which match the 800µA sourcing specification.
Is there an internal pullup resistor on the MR pin of the MAX823LEUK, and what is its value?
Yes, the MAX823LEUK includes an internal pullup resistor on the MR (manual reset) pin with a nominal value of 52kΩ, specified from 35kΩ to 75kΩ over temperature. This allows the MR pin to be left unconnected (floating) when unused, or driven directly by a CMOS logic output or momentary switch to ground-eliminating the need for external components. This parameter is confirmed in the Electrical Characteristics table under "MR Pullup Resistance (internal)" and applies to all MAX823 variants including the MAX823LEUK.
MAX823LEUK Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Watchdog Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.63V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
MAX823LEUK FAQ
1.How can I place an order for MAX823LEUK through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX823LEUK 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 MAX823LEUK reliable?
The price and inventory of MAX823LEUK are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX823LEUK is usually 5 days.
3.What payment methods are accepted for MAX823LEUK?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX823LEUK transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX823LEUK?
MAX823LEUK orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX823LEUK 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 MAX823LEUK?
For technical support, including MAX823LEUK datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX823LEUK requirements.
6.How does Aetrix verify that MAX823LEUK is sourced from the original manufacturer or authorized distributors?
All MAX823LEUK 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 MAX823LEUK meets industry standards.
7.What is the process for return or replacement of MAX823LEUK?
All MAX823LEUK units undergo pre-shipment inspection (PSI). If there is an issue with MAX823LEUK, 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 MAX823LEUK part is unused and in its original packaging.
Return procedure for MAX823LEUK:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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