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Analog Devices Inc./Maxim Integrated MAX802TEPA+
- Part No.:
- MAX802TEPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX802TEPA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:539
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Product details
Overview
MAX802TEPA+ from Maxim Integrated is a 3.3V microprocessor supervisory circuit with precision reset threshold (3.075V ±2%), 200ms reset timeout, watchdog timer (1.6s), battery-backup switchover, and power-fail monitoring. It monitors VCC supply integrity, asserts active-low RESET during brownout or watchdog timeout, and switches VOUT to VBATT when VCC drops below 2.40V - used in embedded controllers and battery-powered instrumentation.
For engineers reviewing the MAX802TEPA+ datasheet, MAX802TEPA+ pinout, MAX802TEPA+ application, or MAX802TEPA+ equivalent, key selection criteria include reset threshold tolerance (±2%), guaranteed RESET assertion down to VCC = 1V, 40µA VCC supply current, battery-switching hysteresis, and compatibility with lithium backup cells exceeding VCC.
Technical Context
The MAX802TEPA+ integrates a precision reset comparator with 10mV hysteresis, a 1.6s watchdog timer that clears on WDI edge transitions, and a dual-path battery switchover circuit using PMOS switches (3Ω VCC-to-VOUT, 140Ω VBATT-to-VOUT). Its PFI input accepts external voltage dividers for multi-rail monitoring, while PFO provides open-drain power-fail signaling.
It operates across –40°C to +85°C (E-grade), supports VCC from 2.72V to 5.5V (T-suffix), and guarantees RESET assertion even when VCC falls to 1V - critical for safe CMOS RAM retention during brownout. The device lacks internal short-circuit protection and requires 0.1µF local decoupling on VCC and VBATT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V ±2% (VCC falling); ensures reliable reset before 3.3V supply drops below system stability margin |
| Reset Timeout Period | 200ms (typical); holds µP in reset long enough for power stabilization after brownout recovery |
| Watchdog Timeout | 1.6s ±40%; detects µP lockup without requiring software intervention or external timing components |
| VCC Supply Current | 40µA (typ, VCC < 3.6V); enables ultra-low-power operation in battery-backed portable systems |
| Battery Leakage Current | 0.01–0.5µA (max); preserves lithium cell life over years of standby operation |
| Power-Fail Threshold | 1.237V ±20mV (PFI input); supports accurate undervoltage detection of auxiliary rails via resistor divider |
| Operating Temp Range | –40°C to +85°C; qualified for industrial embedded environments without derating |
Pinout & Package
MAX802TEPA+ is housed in an 8-pin plastic DIP (PDIP) package with 0.300" wide body and through-hole mounting. Pin spacing is 0.100", lead finish is lead-free (RoHS-compliant), and thermal resistance is 9.09mW/°C above +70°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT | Supply output for CMOS RAM | Switches between VCC (via 3Ω p-MOS) and VBATT (via 140Ω p-MOS) based on VCC/VBATT comparison; must be decoupled with 0.1µF |
| VCC | Main supply input | Primary 3.0V/3.3V system rail; powers internal circuitry and sources VOUT when active; absolute max = +6.0V |
| GND | Ground reference | Common return for all analog and digital functions; substrate tied to higher of VCC/VBATT |
| PFI | Power-fail input | Monitors external voltage (e.g., via divider); asserts PFO low when input falls below 1.237V; input leakage < ±25nA |
| PFO | Power-fail output | Open-drain signal indicating PFI undervoltage or VCC drop below 2.40V; sinks up to 18mA |
| WDI | Watchdog input | Edge-sensitive (rising/falling); resets watchdog timer; no disable function; input current < ±1µA |
| RESET | Active-low reset output | Push-pull, not open-drain; drives µP reset pin low for 200ms minimum; valid down to VCC = 1V |
| VBATT | Backup-battery input | Accepts lithium cell up to 6.0V; enables seamless switchover without diode drop; connects to VOUT when VCC < 2.40V |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset threshold | ±2% tolerance (vs. ±4% in MAX690/MAX704) enables tighter 3.3V system margin control |
| Guaranteed RESET at low VCC | Asserts valid logic low down to VCC = 1V - ensures µP remains held during deep brownout |
| Battery switchover hysteresis | 25mV typical hysteresis prevents oscillation during VCC near-VSW transitions |
| Low quiescent current | 40µA VCC supply current extends battery life in always-on portable instruments |
| Integrated watchdog timer | 1.6s timeout with automatic clearing on WDI edges eliminates need for external RC timing |
| Power-fail comparator independence | Operates separately from reset circuitry - allows concurrent monitoring of secondary supplies |
Applications
| Battery-Powered Portable Instrumentation | Industrial Embedded Controller Monitoring |
|---|---|
Use Scenario: Handheld multimeter with nonvolatile RAM storing calibration data and user settings. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, battery switchover to lithium cell, and watchdog supervision of ARM Cortex-M0 firmware. Use Value: Ensures RAM retention during battery replacement and prevents corrupted calibration due to µP lockup or supply sag. |
Use Scenario: Programmable logic controller (PLC) I/O module operating in factory automation with 3.3V FPGA and SRAM. IC Role / Device Role / Timing Role: Power supervisor asserting RESET on 3.3V rail dropout and generating PFO interrupt for early warning of auxiliary 5V supply failure. Use Value: Enables graceful shutdown and state preservation before main µP crashes, reducing downtime and data loss. |
| Critical µP Power Monitoring in Medical Devices | Intelligent Sensor Node with Backup Power |
Use Scenario: Portable ECG monitor with flash memory and real-time DSP processing. IC Role / Device Role / Timing Role: Dual-role supervisor: monitors 3.3V supply for safe boot/reset and switches VOUT to backup coin cell during AC adapter disconnection. Use Value: Guarantees uninterrupted patient data logging and prevents firmware corruption during transient power loss. |
Use Scenario: Wireless temperature sensor node powered by Li-SOCl₂ battery with 10-year shelf life. IC Role / Device Role / Timing Role: Low-leakage (0.01µA) supervisor enabling decade-long standby; uses PFI to monitor supercapacitor voltage for wake-up trigger. Use Value: Eliminates external reset IC and discrete battery switch, reducing BOM count and PCB area by 30%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX802SEPA+ | Reset threshold 2.925V ±2%, lower trip point optimized for 3.3V ±10% supplies | Better suited for systems where brownout occurs closer to 2.9V; less margin against 3.3V nominal sag | Select when system VCC tolerance is wider and reset must trigger earlier than 3.075V |
| MAX802REPA+ | Reset threshold 2.625V ±2%, designed for 3.0V ±10% systems | Used in 3.0V rail monitoring; incompatible with 3.3V-only designs due to premature reset assertion | Choose only for dedicated 3.0V applications - not a drop-in replacement for 3.3V systems |
Compared with MAX802SEPA+ and MAX802REPA+, the MAX802TEPA+ offers the highest reset threshold (3.075V) and tightest tolerance (±2%), making it optimal for 3.3V systems requiring robust immunity to nominal supply ripple while maintaining fail-safe reset behavior.
Availability
MAX802TEPA+ is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, and intelligent instrumentation requiring stable component supply across industrial temperature ranges.
Supply support for MAX802TEPA+ 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 high-performance analog and mixed-signal ICs for power, sensing, and interface applications in industrial, automotive, and communications markets.
The MAX802 series belongs to Maxim's microprocessor supervisory product line, engineered specifically for reliable power monitoring and reset generation in 3.0V/3.3V embedded systems with battery backup requirements.
FAQ
What is the exact reset threshold voltage for MAX802TEPA+ and how tightly is it specified?
The MAX802TEPA+ has a nominal reset threshold of 3.075V with a tolerance of ±2% over temperature and supply variations. This means the actual threshold falls between 3.00V and 3.15V when VCC is falling, and between 3.00V and 3.17V when rising - tighter than the ±4% spec of older MAX690 devices. This precision ensures predictable reset behavior in 3.3V systems with narrow supply margins.
Does MAX802TEPA+ support battery voltages higher than VCC, and what is the maximum allowed VBATT?
Yes, MAX802TEPA+ explicitly supports VBATT exceeding VCC - a core feature for lithium coin-cell backup (e.g., 3.6V) in 3.3V systems. The absolute maximum rating for VBATT is +6.0V, and the internal switchover circuit activates when VCC drops below 2.40V (VSW), connecting VBATT to VOUT through a 140Ω p-channel MOSFET. No external diode is needed.
Can the watchdog timer in MAX802TEPA+ be disabled, and how is it cleared?
No, the watchdog timer in MAX802TEPA+ cannot be disabled - it is always active. It is cleared automatically on any edge (rising or falling) at the WDI pin, or while RESET is asserted. If WDI remains static for 1.6 seconds (±40%), the timer times out and triggers a reset pulse. This design prevents accidental watchdog deactivation in safety-critical firmware.
What is the minimum VCC voltage at which MAX802TEPA+ guarantees valid RESET assertion?
MAX802TEPA+ guarantees RESET remains a valid logic low down to VCC = 1.0V, provided VBATT > 1V. This is confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables. Without a backup battery, RESET is still guaranteed functional for VCC > 1V - a critical capability for brownout recovery in low-voltage portable systems.
How does the power-fail comparator (PFI/PFO) interact with the reset function in MAX802TEPA+?
The PFI/PFO circuit in MAX802TEPA+ operates independently from the reset comparator - it has its own 1.237V reference and 10mV hysteresis. PFO goes low when PFI < 1.237V *or* when VCC falls below 2.40V (VSW), but this does not directly assert RESET. To link PFO to reset, external connection to MR (on compatible variants like MAX704) is required; MAX802TEPA+ does not support this direct linkage internally.
MAX802TEPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 3.075V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX802TEPA+ FAQ
1.How can I place an order for MAX802TEPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX802TEPA+ 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 MAX802TEPA+ reliable?
The price and inventory of MAX802TEPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX802TEPA+ is usually 5 days.
3.What payment methods are accepted for MAX802TEPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX802TEPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX802TEPA+?
MAX802TEPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX802TEPA+ 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 MAX802TEPA+?
For technical support, including MAX802TEPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX802TEPA+ requirements.
6.How does Aetrix verify that MAX802TEPA+ is sourced from the original manufacturer or authorized distributors?
All MAX802TEPA+ 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 MAX802TEPA+ meets industry standards.
7.What is the process for return or replacement of MAX802TEPA+?
All MAX802TEPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX802TEPA+, 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 MAX802TEPA+ part is unused and in its original packaging.
Return procedure for MAX802TEPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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