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Analog Devices Inc./Maxim Integrated MAX802LESA+T
- Part No.:
- MAX802LESA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX802LESA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,440
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Product details
Overview
MAX802LESA+T from Maxim Integrated is a microprocessor supervisory IC providing precision reset generation, battery-backup switchover, watchdog timer, and power-fail detection for +5V systems. It asserts active-low RESET during power-up, brownout (4.65V threshold), and watchdog timeout (1.6s), while switching VOUT between VCC and VBATT with 40mV hysteresis. Used in battery-powered controllers and intelligent instruments requiring reliable μP startup and data retention.
For engineers reviewing the MAX802LESA+T datasheet, MAX802LESA+T pinout, MAX802LESA+T application, or MAX802LESA+T equivalent, this page delivers verified specifications, validated pin functions, confirmed operating conditions (–40°C to +85°C), and real-world design implications for reset timing, battery switchover behavior, and power-fail comparator accuracy (±2%).
Technical Context
The MAX802LESA+T integrates four core functions on a single die: a precision voltage monitor with 4.65V ±2% reset threshold, a 200ms reset pulse generator, a 1.6s watchdog timer cleared by WDI edges, and a 1.25V reference-based power-fail comparator (PFI/PFO). Its internal PMOS battery switch connects VOUT to VBATT only when VCC falls below the reset threshold *and* VBATT exceeds VCC by ≥20mV - preventing spurious switchover during slow VCC decay.
Unlike legacy MAX690/MAX692, the MAX802L family guarantees power-fail accuracy to ±2% and supports operation down to VCC = 1.0V for RESET assertion. The device operates in 8-pin SO package with 5Ω VOUT-to-VCC switch impedance and 80Ω VOUT-to-VBATT switch impedance, enabling low-dropout RAM backup with <1μA quiescent current in full battery mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±2% (guaranteed over temperature; triggers RESET when VCC falls below this level) |
| Reset Pulse Width | 200ms (ensures μP completes full initialization before release) |
| Watchdog Timeout | 1.6s (requires WDI edge every 1.6s to prevent unintended reset) |
| Supply Current (Active) | 200–500µA (enables long battery life in always-on monitoring applications) |
| Battery-Backup Current | ≤5.0µA (TA = TMIN to TMAX; preserves lithium cell life for years) |
| VOUT Switch Impedance | 5Ω (VCC→VOUT), 80Ω (VBATT→VOUT) (minimizes voltage drop during RAM backup) |
| Power-Fail Comparator Accuracy | ±2% (supports precise early-warning detection of supply degradation) |
Pinout & Package
MAX802LESA+T is housed in an 8-pin SOIC package (SO) with standard 1.27mm pitch, RoHS-compliant lead-free finish (+ suffix), and moisture sensitivity level (MSL) 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (via 5Ω PMOS) and VBATT (via 80Ω PMOS) based on reset threshold crossing and hysteresis |
| 2 - VCC | +5V main supply input | Primary power source; must be ≥1.0V for guaranteed RESET assertion; powers internal circuitry |
| 3 - GND | Ground reference | Common return path for all analog and digital functions; substrate connection point |
| 4 - PFI | Power-fail comparator input | Monitors external voltage divider; asserts PFO low when input falls below 1.25V reference |
| 5 - PFO | Power-fail output | Open-drain active-low signal used to trigger μP interrupt or initiate graceful shutdown |
| 6 - WDI | Watchdog timer input | Edge-sensitive; floating or high-impedance state disables watchdog; requires toggling every 1.6s |
| 7 - RESET | Active-low reset output | Pulses low for 200ms on power-up/brownout/watchdog timeout; asserted down to VCC = 1.0V |
| 8 - VBATT | Backup battery input | Accepts 2.8–4.8V lithium cells; enables automatic switchover when VCC fails and VBATT > VCC +20mV |
Key Features
| Feature | Design Value |
|---|---|
| Precision Reset Threshold | 4.65V with ±2% tolerance over –40°C to +85°C ensures consistent μP reset across industrial temperature range |
| Guaranteed RESET Assertion at Low VCC | RESET remains valid down to VCC = 1.0V, enabling robust reset signaling even during deep brownout |
| Low Battery-Backup Quiescent Current | ≤5.0µA over full temperature range extends lithium battery life beyond 10 years in standby |
| Controlled Battery Switchover Hysteresis | 40mV hysteresis prevents oscillation during slow VCC decay, eliminating RAM corruption risk |
| Integrated Power-Fail Warning | Dedicated 1.25V reference and comparator enable accurate early detection of supply collapse without external components |
Applications
| Industrial Data Loggers | Medical Diagnostic Handhelds |
|---|---|
|
Use Scenario: Continuous sensor sampling with nonvolatile RAM storage during mains failure. IC Role / Device Role / Timing Role: Supervisory controller asserting RESET to halt μP execution, switching VOUT to VBATT to retain RAM contents, and triggering PFO to save critical data pre-shutdown. Use Value: Prevents data loss during unexpected AC dropout using guaranteed 200ms reset hold time and <1μA battery drain in backup mode. |
Use Scenario: Portable ultrasound or ECG unit operating on rechargeable Li-ion with firmware update capability. IC Role / Device Role / Timing Role: Ensures safe boot sequence via 4.65V reset threshold aligned with +5V regulator dropout, while WDI monitors firmware execution integrity. Use Value: Eliminates corrupted updates by forcing hard reset on watchdog timeout, with ±2% PFI accuracy enabling precise low-battery warning before clinical session interruption. |
| Smart Energy Meters | Ruggedized PLC Controllers |
|
Use Scenario: Tamper-resistant meter retaining tariff tables and consumption history during grid instability. IC Role / Device Role / Timing Role: Provides dual-voltage supervision: RESET for μP reset and PFO for initiating secure flash write operations prior to power collapse. Use Value: Achieves IEC 62053-21 compliance via 40mV switchover hysteresis and ±2% power-fail accuracy, ensuring no metering data loss during 100ms dips. |
Use Scenario: Factory-floor controller exposed to wide ambient temperature swings and noisy 24VDC supplies. IC Role / Device Role / Timing Role: Delivers industrial-grade reliability with –40°C to +85°C operation, 200ms reset pulse, and battery-backed RAM retention during brownouts. Use Value: Guarantees deterministic μP restart after voltage sag with RESET asserted down to VCC = 1.0V, avoiding lockup in harsh electrical environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX802MESA+ | 4.40V reset threshold (vs. 4.65V); identical pinout, package, and features | Suitable for systems with tighter +5V tolerance (±10%) or lower dropout regulators | Select MAX802MESA+ only if system VCC nominal is 5.0V ±10% and brownout must trigger at 4.40V |
| MAX706RESA+ | Same 4.65V threshold and 200ms reset, but lacks battery switchover and PFI/PFO comparator | Applicable where only reset supervision is needed, not RAM backup or power-fail warning | Choose MAX706RESA+ to reduce BOM cost when battery backup and power-fail detection are unnecessary |
Compared with MAX802MESA+, the MAX802LESA+ provides higher reset threshold margin for stable +5V systems; compared with MAX706RESA+, it adds essential battery switchover and power-fail warning - critical for data-retentive embedded designs.
Availability
MAX802LESA+T is available at Aetrix Electronics and suitable for industrial data loggers, medical handhelds, smart energy meters, ruggedized PLC controllers, and battery-powered instrumentation requiring stable component supply across extended temperature ranges.
Supply support for MAX802LESA+T 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, automotive, and communications applications, with emphasis on reliability and integration.
The MAX802L product line targets microprocessor-based systems needing guaranteed reset, battery-backed memory retention, and early power-fail warning - optimized for cost-sensitive, high-reliability embedded control.
FAQ
What is the guaranteed reset threshold voltage for MAX802LESA+T?
The MAX802LESA+T has a guaranteed reset threshold of 4.65V ±2% over the full operating temperature range (–40°C to +85°C). This means RESET is asserted when VCC falls below 4.55V (min) and released only after VCC rises above 4.75V (max), with hysteresis ensuring clean transition. This specification is validated per Maxim's Electrical Characteristics table and applies directly to the MAX802LESA+T device.
Does MAX802LESA+T support battery backup for CMOS RAM, and how does switchover work?
Yes, MAX802LESA+T supports automatic battery backup for CMOS RAM via its VOUT pin. When VCC drops below the 4.65V reset threshold *and* VBATT exceeds VCC by ≥20mV, the internal 80Ω PMOS switch connects VBATT to VOUT. Switchover includes 40mV hysteresis to prevent oscillation during slow VCC decay. In backup mode, quiescent current is ≤5.0µA, preserving lithium battery life. This behavior is confirmed in the Pin Description and Detailed Description sections of the MAX802LESA+T datasheet.
What is the watchdog timeout period for MAX802LESA+T, and how is it cleared?
The MAX802LESA+T features a fixed 1.6s watchdog timeout period. The internal timer is cleared by any rising or falling edge on the WDI pin, by assertion of RESET, or by placing WDI in a high-impedance (three-state) condition. If WDI remains static (high or low) for ≥1.6s, RESET pulses low for 200ms. The timer resumes counting immediately upon RESET deassertion unless WDI is again toggled or tri-stated. This timing and clearing mechanism is explicitly defined in the MAX802LESA+T Electrical Characteristics and Detailed Description.
Can MAX802LESA+T monitor a power supply other than +5V, and how is that implemented?
Yes, MAX802LESA+T can monitor non-+5V supplies using its PFI input and internal 1.25V reference. An external resistor divider scales the target supply voltage so that PFI reaches 1.25V at the desired trip point (e.g., 12V supply → 1.25V at PFI when supply drops to 11.4V). PFO then goes low to signal undervoltage. The MAX802LESA+T datasheet confirms this use case in the Applications Information section, including hysteresis implementation guidance and noise rejection techniques.
What package type and temperature range does MAX802LESA+T specify?
MAX802LESA+T is specified in an 8-pin SOIC (SO) package with lead-free finish (+ suffix), rated for operation from –40°C to +85°C. This is confirmed in the Ordering Information table, where "MAX802LESA" denotes the –40°C to +85°C grade in 8-pin SO. The "+T" suffix indicates tape-and-reel packaging. The device meets industrial temperature requirements and is RoHS-compliant per Maxim's Package Information documentation.
MAX802LESA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Push-Pull, Totem Pole
- 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
MAX802LESA+T FAQ
1.How can I place an order for MAX802LESA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX802LESA+T 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 MAX802LESA+T reliable?
The price and inventory of MAX802LESA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX802LESA+T is usually 5 days.
3.What payment methods are accepted for MAX802LESA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX802LESA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX802LESA+T?
MAX802LESA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX802LESA+T 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 MAX802LESA+T?
For technical support, including MAX802LESA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX802LESA+T requirements.
6.How does Aetrix verify that MAX802LESA+T is sourced from the original manufacturer or authorized distributors?
All MAX802LESA+T 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 MAX802LESA+T meets industry standards.
7.What is the process for return or replacement of MAX802LESA+T?
All MAX802LESA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX802LESA+T, 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 MAX802LESA+T part is unused and in its original packaging.
Return procedure for MAX802LESA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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