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Analog Devices Inc./Maxim Integrated MAX808NESA+
- Part No.:
- MAX808NESA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX808NESA+.pdf
- Description:
- IC SUPERVISOR MPU 8-SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,154
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Product details
Overview
MAX808NESA+ from Maxim Integrated is an 8-pin microprocessor supervisory circuit designed for +5V systems, providing precision reset generation (4.575V threshold, ±1.5% accuracy), battery switchover (250mA VCC / 20mA BATT mode), and CMOS RAM write protection via chip-enable gating. It guarantees valid RESET output down to VCC = 1V and supports low-line warning (LOWLINE) for orderly shutdown in portable equipment.
For engineers reviewing the MAX808NESA+ datasheet, MAX808NESA+ pinout, MAX808NESA+ application, or MAX808NESA+ equivalent, this page delivers verified functional identity, exact reset threshold and timing values, confirmed CE gating behavior, battery-switchover hysteresis, and real-world design implications for RAM retention and power-fail sequencing.
Technical Context
The MAX808NESA+ integrates three independent comparators: a reset comparator with 4.575V threshold and 13mV hysteresis, a low-line comparator set 52mV above reset (4.627V typ), and a battery-switchover comparator with 50mV hysteresis. Its internal 200ms reset timeout timer ensures µP initialization stability after power-up or brownout recovery.
Unlike the MAX801, the MAX808NESA+ omits watchdog functionality but adds dedicated chip-enable (CE) gating logic with 3ns propagation delay and 18µs write-cycle completion hold time-enabling reliable CMOS RAM data integrity during VCC collapse without external circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.575V ±1.5% - ensures system reset before +5V supply falls below safe µP operating voltage. |
| RESET Timeout Delay | 200ms - guarantees sufficient deassertion hold time for full µP initialization and clock stabilization. |
| Low-Line Threshold | 4.627V (52mV above reset) - triggers NMI for software-controlled shutdown before reset occurs. |
| VCC-to-OUT On-Resistance | 1.2Ω typ - limits voltage drop to ≤220mV at 250mA load, preserving RAM supply margin. |
| Battery Switchover Hysteresis | 50mV - prevents oscillation during VCC crossing near VBATT, enabling stable SuperCap™/MaxCap™ use. |
| CE Propagation Delay | 3ns max - supports high-speed µP address/data bus timing without CE skew penalties. |
| Standby Current | 48µA (VCC mode), <1µA (battery-backup) - extends battery life in portable/embedded sleep states. |
Pinout & Package
MAX808NESA+ is housed in an 8-pin SO (Small Outline) package, lead-free, RoHS-compliant, with standard SOIC-8 footprint (150mil width).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: VCC | +5V main supply input | Bypassed with 0.1µF capacitor; powers all internal circuitry and drives OUT during normal operation. |
| 2: LOWLINE | Active-low low-voltage warning output | CMOS-level signal used to trigger NMI interrupt when VCC drops to 4.627V, initiating controlled shutdown. |
| 3: RESET | Active-low reset output | Guaranteed valid down to VCC = 1V; strong pull-down/weak pull-up enables wire-OR with other reset sources. |
| 4: GND | Ground reference | 0V reference for all comparators, outputs, and internal biasing; must be low-impedance connection. |
| 5: CE OUT | Chip-enable output to RAM | Drives CMOS RAM CE pin; held high during reset, gated transparently during normal operation with 3ns delay. |
| 6: CE IN | Chip-enable input from µP | Accepts µP's CE signal; enters high-impedance state during reset to isolate RAM from spurious writes. |
| 7: BATT | Backup battery input | Accepts 2.0V–4.5V backup source; enables automatic switchover to preserve RAM when VCC falls below 4.575V. |
| 8: OUT | Output supply to RAM and peripherals | Switches between VCC and BATT; delivers up to 250mA from VCC or 20mA from battery with <12Ω on-resistance. |
Key Features
| Feature | Design Value |
|---|---|
| ±1.5% reset threshold accuracy | Enables tighter supply margin control in +5V systems, reducing risk of premature reset or brownout operation. |
| 18µs CE write-cycle completion hold | Ensures µP completes RAM write before CE is disabled, eliminating data corruption during power collapse. |
| RESET guaranteed valid to VCC = 1V | Supports robust reset assertion even under severe brownout or slow-power-down conditions. |
| MaxCap™/SuperCap™ compatibility | Allows use of large-value backup capacitors (e.g., 0.47F) with simple charging circuits, eliminating battery replacement. |
| Low-line comparator with 52mV offset | Provides deterministic 17µs advance warning before reset, enabling reliable firmware-initiated save-and-shutdown routines. |
Applications
| Portable Medical Monitor | Industrial PLC Controller |
|---|---|
Use Scenario: Battery-powered ECG monitor with nonvolatile RAM storing patient calibration and session history. IC Role / Device Role / Timing Role: MAX808NESA+ monitors main 5V rail, asserts LOWLINE at 4.627V to trigger firmware save routine, then asserts RESET at 4.575V after 200ms if power does not recover. Use Value: Prevents RAM corruption during field battery depletion by guaranteeing 17µs warning and 18µs CE hold for final write completion. |
Use Scenario: DIN-rail mounted PLC with isolated I/O and SRAM-based configuration storage. IC Role / Device Role / Timing Role: MAX808NESA+ supplies clean 5V to SRAM via OUT pin, gates CE during brownout, and switches to backup capacitor when AC input fails. Use Value: Eliminates need for external CE logic or discrete switchover FETs-reducing BOM count and layout area while ensuring deterministic RAM retention. |
| Handheld Barcode Scanner | Smart Energy Meter |
Use Scenario: Li-ion powered scanner requiring fast wake-from-sleep and reliable RAM retention across 10,000+ power cycles. IC Role / Device Role / Timing Role: MAX808NESA+ provides 200ms RESET pulse on power-up, uses CE gating to block spurious writes during voltage sag, and maintains OUT supply from BATT during brief AC dropout. Use Value: Achieves <1µA battery-backup current and 1.2Ω VCC-to-OUT resistance-extending standby life and minimizing voltage droop during active scan bursts. |
Use Scenario: ANSI C12.20-certified meter with supercapacitor-backed SRAM storing tariff tables and consumption logs. IC Role / Device Role / Timing Role: MAX808NESA+ interfaces directly with 0.47F SuperCap™ at BATT, using 50mV switchover hysteresis to prevent chatter during capacitor charge/discharge transitions. Use Value: Enables maintenance-free 15-year backup via SuperCap™ instead of electrolytic battery, with no external hysteresis components required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX809SOTA+ | Single-output (RESET only), no LOWLINE, no CE gating, 2.93V reset threshold, SOT23-3 package | Lacks low-line warning and RAM write protection; suitable only for basic reset-only systems | Select only if space-constrained and CE/LOWLINE functions are unnecessary |
| TPS3808G12DBVR | Adjustable reset threshold (via resistor divider), 200ms delay, no battery switchover or CE gating, SOT23-6 | Requires external components for threshold setting; cannot replace MAX808NESA+ in battery-backed RAM applications | Choose when precise fixed 4.575V threshold and integrated backup switching are not required |
Compared with MAX808NESA+, MAX809SOTA+ reduces functionality to basic reset generation in a smaller package, while TPS3808G12DBVR trades fixed-threshold precision and battery integration for adjustability-neither provides the combined low-line warning, CE gating, and dual-supply switchover that define MAX808NESA+'s role in RAM-critical portable designs.
Availability
MAX808NESA+ is available at Aetrix Electronics and suitable for portable medical devices, industrial controllers, handheld scanners, and smart energy meters requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for MAX808NESA+ 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, automotive, and computing applications.
The MAX801/MAX808 family was engineered specifically for +5V microprocessor systems needing precision reset supervision, battery-backed RAM retention, and deterministic power-fail response-targeting portable, medical, and industrial embedded platforms.
FAQ
What is the exact reset threshold voltage of the MAX808NESA+?
The MAX808NESA+ has a nominal reset threshold of 4.575V with ±1.5% accuracy over temperature and supply variation. This value is factory-trimmed and specified in the Electrical Characteristics table under VRST (Reset Threshold) for the "N" suffix variant. The threshold remains stable across the full operating temperature range (-40°C to +85°C) and is guaranteed not to drift beyond ±1.5% of 4.575V.
Does the MAX808NESA+ include a watchdog timer function?
No, the MAX808NESA+ does not include a watchdog timer. That feature is exclusive to the MAX801 series (e.g., MAX801NESA+). The MAX808NESA+ is optimized for applications requiring reset supervision, low-line warning, and chip-enable gating-but not program-execution monitoring. Its pinout omits the WDI (Watchdog Input) terminal present on the MAX801.
How does the MAX808NESA+ handle chip-enable (CE) signals during power failure?
The MAX808NESA+ actively gates the CE signal using an internal transmission gate. When RESET is asserted, CE IN is disconnected and CE OUT is pulled high to prevent spurious writes. If a write is in progress when VCC falls, the device holds CE enabled for exactly 18µs to allow completion-verified in the Chip-Enable Timing diagram (Figure 6). This behavior is intrinsic to the MAX808NESA+ and requires no external components.
Can the MAX808NESA+ operate with a supercapacitor instead of a battery at the BATT pin?
Yes, the MAX808NESA+ is explicitly MaxCap™/SuperCap™ compatible. Its battery-switchover comparator includes 50mV hysteresis and supports VBATT up to 4.5V, enabling direct interface with 0.47F supercapacitors charged via simple diode or linear regulator circuits-as shown in Figure 8 of the datasheet. No additional hysteresis circuitry is needed.
What is the maximum output current capability of the MAX808NESA+ OUT pin?
The MAX808NESA+ OUT pin delivers up to 250mA when powered from VCC and up to 20mA when powered from BATT. These values are absolute maximum ratings under specified thermal conditions. At 250mA load, the typical VCC-to-OUT voltage drop is 220mV (1.2Ω on-resistance), ensuring adequate headroom for 5V-tolerant CMOS RAM operation.
MAX808NESA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.575V
- Output:
- -
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX808NESA+ FAQ
1.How can I place an order for MAX808NESA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX808NESA+ 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 MAX808NESA+ reliable?
The price and inventory of MAX808NESA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX808NESA+ is usually 5 days.
3.What payment methods are accepted for MAX808NESA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX808NESA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX808NESA+?
MAX808NESA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX808NESA+ 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 MAX808NESA+?
For technical support, including MAX808NESA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX808NESA+ requirements.
6.How does Aetrix verify that MAX808NESA+ is sourced from the original manufacturer or authorized distributors?
All MAX808NESA+ 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 MAX808NESA+ meets industry standards.
7.What is the process for return or replacement of MAX808NESA+?
All MAX808NESA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX808NESA+, 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 MAX808NESA+ part is unused and in its original packaging.
Return procedure for MAX808NESA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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