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Analog Devices Inc./Maxim Integrated MAX820SESE+
- Part No.:
- MAX820SESE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX820SESE+.pdf
- Description:
- IC SUPERVISOR MPU 16-SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,171
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Product details
Overview
MAX820SESE+ from Maxim Integrated is a microprocessor supervisory circuit with ±2% reset and low-line threshold accuracy, 200ms power-up reset delay, independent watchdog timer (1.6s nominal timeout), on-board chip-enable gating, and overvoltage detection. It monitors VCC for brownout, powers up µP systems reliably, and protects nonvolatile memory during supply faults in industrial controllers and embedded instrumentation.
For engineers reviewing the MAX820SESE+ datasheet, MAX820SESE+ pinout, MAX820SESE+ application, or MAX820SESE+ equivalent, this page delivers verified functional identity, exact pin roles, confirmed reset/low-line thresholds (e.g., 2.91V internal mode), watchdog timing behavior, CE gating propagation delay (≤10ns), and real-world substitution guidance - all traceable to Maxim's official MAX792/MAX820 datasheet Rev. 4.
Technical Context
The MAX820SESE+ implements dual-voltage monitoring via separate reset and low-line comparators, each with 15mV hysteresis and factory-trimmed ±2% threshold accuracy. Its watchdog function uses an external capacitor on SWT to set timeout (k×CnFms, k=16.2 at 5V), while WDPO provides a 1.7ms advance pulse preceding WDO assertion by 70ns.
Chip-enable gating employs a transmission gate with ≤10ns propagation delay (CE IN → CE OUT), disabled during reset to prevent memory corruption; CE OUT remains low for 15µs after reset assertion if CE IN is low, ensuring write-cycle completion. The device supports both internal threshold mode (RESET IN/INT = GND) and external resistor-programmed thresholds (RESET IN/INT ≥600mV).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold Voltage | 2.91V (nominal, S-suffix), ±2% accuracy ensures precise brownout detection without calibration. |
| Power-Up Reset Delay | 200ms typical - guarantees µP initialization completes before release from reset. |
| Watchdog Timeout Period | 1.6s nominal (SWT = VCC); adjustable via capacitor (e.g., 4.7nF → ~76ms at 5V) for flexible firmware supervision. |
| Chip-Enable Propagation Delay | ≤10ns - enables use with high-speed µPs without timing violation in memory access paths. |
| Supply Current | 70µA typical at +25°C - supports low-power embedded systems with minimal quiescent load. |
| Operating Voltage Range | 2.75V to 5.5V - compatible with 3.3V and 5V logic rails; RESET valid down to VCC = 1V. |
| Low-Line Threshold Offset | 120mV above reset threshold - provides early NMI warning before reset assertion during VCC sag. |
Pinout & Package
MAX820SESE+ is housed in a 16-pin narrow SOIC (SO) package, 3.9mm width, RoHS-compliant with + symbol suffix indicating lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 | RESET / RESET | Active-low and active-high reset outputs; RESET guaranteed valid down to VCC = 1V for fail-safe boot. |
| 3 | VCC | Main supply input (2.75–5.5V); powers all internal comparators, timers, and output drivers. |
| 4 | RESET IN/INT | Mode select: GND = internal threshold; ≥600mV = external resistor programming of reset/low-line thresholds. |
| 5 | LLIN/REFOUT | In external mode: low-line comparator input; in internal mode: buffered 1.30V reference output. |
| 6 | OVO | Open-drain overvoltage comparator output - asserts low when OVI > 1.30V; uncommitted, no internal effect. |
| 7 | OVI | Inverting input for overvoltage comparator; connect to voltage divider for custom overvoltage trip point. |
| 8 | SWT | Watchdog timeout capacitor node; sets timeout period (k×CnFms); must not float or tie to GND. |
| 9 | MR | Manual-reset input with 1.30V threshold; 25µs minimum pulse width; internally pulled up to VCC. |
| 10 | LOW LINE | Active-low NMI output; asserts 120mV above reset threshold to warn µP before reset activation. |
| 11 | WDI | Watchdog input; transition resets timer; no activity > timeout causes WDPO/WDO assertion. |
| 12 | GND | Ground reference for all analog comparators and digital outputs; common return path. |
| 13 | CE OUT | Chip-enable output; gated by CE IN and reset state; holds low 15µs after reset if CE IN was low. |
| 14 | CE IN | Chip-enable input; transmission gate control; high-impedance during reset to isolate memory bus. |
| 15 | WDO | Watchdog fault output; latched low until next WDI transition; used for hardware shutdown or MR forcing. |
| 16 | WDPO | Watchdog-pulse output; 1.7ms low pulse preceding WDO by 70ns - enables two-fault latching via D flip-flop. |
Key Features
| Feature | Design Value |
|---|---|
| ±2% reset/low-line threshold accuracy | Enables reliable brownout detection without external trimming or calibration in critical industrial systems. |
| Independent watchdog with pulsed advance warning (WDPO) | Allows system-level recovery (e.g., interrupt service) before full hardware shutdown via WDO assertion. |
| On-board chip-enable gating with ≤10ns propagation | Prevents spurious writes to CMOS RAM/EEPROM during power transitions without adding external logic. |
| Memory write-cycle completion hold (15µs) | Ensures data integrity by maintaining CE OUT low long enough for slow memory devices to complete writes. |
| Two-stage power-fail warning (LOW LINE + RESET) | Provides hierarchical response: NMI alert at 120mV above reset threshold, then hard reset if sag continues. |
Applications
| Industrial PLC Controller | Medical Diagnostic Instrument |
|---|---|
|
Use Scenario: Power supply monitoring in programmable logic controller with isolated I/O and real-time deterministic execution. IC Role / Device Role / Timing Role: Supervises 3.3V core rail, asserts LOW LINE to trigger µP NMI for graceful I/O freeze, then RESET for full restart if voltage drops below 2.91V. Use Value: Prevents corrupted ladder logic execution and unsafe actuator states during brownout, meeting IEC 61000-4-11 immunity requirements. |
Use Scenario: Embedded µP subsystem in portable ultrasound unit requiring fail-safe boot and memory protection during battery switchover. IC Role / Device Role / Timing Role: Monitors 5V analog front-end supply; gates CE signals to flash memory during undervoltage; uses WDPO to log fault before WDO forces reboot. Use Value: Guarantees image buffer integrity and prevents loss of patient calibration data during transient power dips. |
| Telecom Remote Terminal Unit | Automotive Body Control Module |
|
Use Scenario: Outdoor RTU powered by PoE with wide temperature range (-40°C to +85°C) and ESD-prone environment. IC Role / Device Role / Timing Role: Provides manual reset via front-panel switch (MR), watchdog supervision of communication stack, and overvoltage detection (OVI/OVO) on 48V DC input. Use Value: Eliminates need for discrete comparators and RC timers, reducing BOM count while meeting EN 61000-4-5 surge immunity. |
Use Scenario: Low-voltage 12V-to-3.3V domain in BCM managing door locks, lighting, and CAN transceivers. IC Role / Device Role / Timing Role: Supervises 3.3V MCU rail; uses internal 2.91V threshold to detect alternator dropout; asserts RESET only after 200ms delay to avoid nuisance trips. Use Value: Meets ISO 7637-2 pulse 4 immunity by holding reset active through load-dump transients, preventing MCU lockup. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX792SESE+ | Same pinout and functionality, but ±2.5% reset threshold accuracy (vs. ±2% for MAX820SESE+); no guaranteed low-line accuracy spec. | Suitable where tighter threshold tolerance is not required; lower cost in high-volume production. | Select MAX792SESE+ only if design tolerates wider threshold variation and does not require certified low-line accuracy. |
| TPS3808G33DBVR | Single-channel supervisor (reset only), no watchdog, no CE gating, no low-line output; 3.3V fixed threshold, ±0.5% accuracy. | Limited to basic reset generation; cannot replace dual-warning or memory-protection functions of MAX820SESE+. | Use only as partial substitute where only reset assertion is needed and watchdog/CE features are handled externally. |
Compared with MAX792SESE+, MAX820SESE+ delivers tighter ±2% threshold accuracy essential for precision brownout response, while TPS3808G33DBVR lacks integrated watchdog, low-line warning, and chip-enable gating - making it unsuitable for memory-critical or multi-level fault-response designs.
Availability
MAX820SESE+ is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic instruments, telecom remote terminal units, and automotive body control modules requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for MAX820SESE+ 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 and mixed-signal ICs for industrial, medical, and communications applications, emphasizing reliability, integration, and performance under harsh conditions.
The MAX820SESE+ belongs to Maxim's microprocessor supervisory product line, engineered specifically for fail-safe µP power monitoring, nonvolatile memory protection, and multi-level fault response in mission-critical embedded systems.
FAQ
What is the exact reset threshold voltage for MAX820SESE+?
The MAX820SESE+ has a nominal reset threshold voltage of 2.91V in internal threshold mode, with guaranteed ±2% accuracy across temperature and supply variations. This value corresponds to the 'S' suffix in the part number and is factory-trimmed - confirmed in Maxim's MAX792/MAX820 datasheet Rev. 4, Electrical Characteristics table. The MAX820SESE+ maintains this accuracy without external components or calibration.
Does MAX820SESE+ support external reset threshold programming?
Yes, MAX820SESE+ supports external reset threshold programming via the RESET IN/INT pin. When pulled to ≥600mV (e.g., using a resistor divider), it enters external mode, disconnecting internal references and allowing user-defined reset and low-line thresholds. The MAX820SESE+ retains its ±2% accuracy advantage over MAX792 in this mode when external resistors are selected per Maxim's recommended equations in the datasheet.
How does the watchdog function behave on MAX820SESE+ during power-down?
The watchdog function on MAX820SESE+ is automatically disabled when VCC falls below the reset threshold - preventing false timeouts during brownout. WDPO and WDO remain high while VCC is below threshold, and the watchdog timer resets upon VCC recovery. This behavior ensures robust operation during power sequencing, as documented in the "Watchdog Function" section of the MAX792/MAX820 datasheet.
What is the purpose of the LOW LINE output on MAX820SESE+?
The LOW LINE output on MAX820SESE+ is an active-low signal that asserts 120mV above the reset threshold, providing early warning of impending supply failure. It connects directly to a µP's NMI pin to trigger firmware-level mitigation (e.g., save state, disable outputs) before RESET activates. This two-stage alert is a key differentiator of MAX820SESE+ versus basic supervisors and is explicitly specified in the datasheet's "Low-Line Output" section.
Can MAX820SESE+ be used with 3.3V-only systems?
Yes, MAX820SESE+ operates from 2.75V to 5.5V and is fully specified for 3.3V systems. Its 2.91V reset threshold is ideal for monitoring 3.3V rails, and all outputs (RESET, WDO, CE OUT) are compatible with 3.3V logic levels. The watchdog timeout scales with VCC (k=16.2 at 5V, k=27 at 3V), and supply current remains low (70µA typ), making MAX820SESE+ well-suited for 3.3V embedded applications.
MAX820SESE+ 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:
- -
MAX820SESE+ FAQ
1.How can I place an order for MAX820SESE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX820SESE+ 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 MAX820SESE+ reliable?
The price and inventory of MAX820SESE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX820SESE+ is usually 5 days.
3.What payment methods are accepted for MAX820SESE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX820SESE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX820SESE+?
MAX820SESE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX820SESE+ 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 MAX820SESE+?
For technical support, including MAX820SESE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX820SESE+ requirements.
6.How does Aetrix verify that MAX820SESE+ is sourced from the original manufacturer or authorized distributors?
All MAX820SESE+ 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 MAX820SESE+ meets industry standards.
7.What is the process for return or replacement of MAX820SESE+?
All MAX820SESE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX820SESE+, 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 MAX820SESE+ part is unused and in its original packaging.
Return procedure for MAX820SESE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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