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Analog Devices Inc./Maxim Integrated MAX805TEPA
- Part No.:
- MAX805TEPA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX805TEPA.pdf
- Description:
- IC SUPERVISOR MAX805 MPU
- Quantity:
- Payment:
- Shipping:
Inventory:4,713
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Product details
Overview
MAX805TEPA from Maxim Integrated is a 3.3V microprocessor supervisory circuit with active-high open-drain RESET output, 3.075V reset threshold, 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover-designed for reliable power monitoring in battery-powered embedded controllers and portable instrumentation.
For engineers reviewing the MAX805TEPA datasheet, MAX805TEPA pinout, MAX805TEPA application, or MAX805TEPA equivalent, this page delivers verified technical context, exact pin functions, real-world use cases, and validated alternative options for 3.0V/3.3V µP supervision with battery backup and power-fail warning.
Technical Context
The MAX805TEPA integrates a precision reset comparator with ±4% threshold tolerance (3.075V nominal), a 1.6s watchdog timer that clears on WDI edge transitions, and a dual-path power switch enabling VOUT to seamlessly transition between VCC and VBATT when VCC falls below 2.40V (VSW) - all while supporting battery voltage exceeding VCC during normal operation.
It features an active-high open-drain RESET output (inverse of MAX690/MAX704), a dedicated PFI/PFO power-fail comparator (1.237V threshold, ±20mV hysteresis), manual reset input with internal 70µA pull-up, and guaranteed RESET assertion down to VCC = 1V - making it suitable for brownout detection and CMOS RAM retention in low-voltage systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V (±4%) - ensures reset assertion before 3.3V supply drops below system stability margin. |
| Reset Timeout Period | 200ms (140–280ms over temp) - provides sufficient deassertion delay for µP power stabilization. |
| Watchdog Timeout | 1.6s (1.12–2.24s over temp) - detects µP lockup without requiring software intervention. |
| VCC Supply Current | 40–50µA (VCC < 3.6V) - enables long battery life in always-on supervision mode. |
| Battery Supply Current | 0.4–1µA - minimizes drain on lithium backup cells during extended standby. |
| Power-Fail Threshold | 1.237V (±20mV hysteresis) - supports accurate undervoltage detection on auxiliary rails via external divider. |
| Operating Voltage Range | VCC = 3.17V to 5.5V; VBATT = up to 6.0V - allows use with 3.3V main rail and 3.6V Li coin cell. |
Pinout & Package
MAX805TEPA is housed in an 8-pin plastic DIP (PDIP) package with 0.300" wide body and through-hole mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Supply output for CMOS RAM | Switches between VCC and VBATT; connects to VCC if no battery used. |
| 2 - VCC | Main supply input | Primary 3.0V/3.3V power source; powers internal circuitry and drives VOUT when active. |
| 3 - GND | Ground reference | Common return path for all analog and digital functions; must be low-impedance. |
| 4 - PFI | Power-fail input | Monitors auxiliary voltage via external divider; triggers PFO low when below 1.237V. |
| 5 - PFO | Power-fail output | Active-low open-drain signal indicating power failure or VCC drop below VSW. |
| 6 - WDI | Watchdog input | Edge-sensitive (rising/falling); resets watchdog timer; cannot be disabled. |
| 7 - RESET | Active-high open-drain reset output | Inverse of MAX690 RESET; requires external pull-up to VCC for logic-high assertion. |
| 8 - VBATT | Backup-battery input | Accepts up to 6.0V; enables automatic switchover to preserve RAM during main supply loss. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout, critical for data integrity in low-VCC conditions. |
| Battery-backup switchover with VSW = 2.40V | Triggers at 2.40V to preserve CMOS RAM before VOUT drops below 2.0V retention threshold. |
| 40µA VCC supply current (typ) | Extends operational lifetime in battery-backed portable equipment without compromising supervision reliability. |
| 1µA battery supply current (max) | Minimizes self-discharge of lithium backup cells, supporting multi-year shelf life in storage. |
| 200ms reset timeout with restart-on-brownout | Prevents premature µP release during transient dips; guarantees full reset hold time after each fault. |
Applications
| Battery-Powered Embedded Controller | Portable Medical Instrument |
|---|---|
Use Scenario: Standalone glucose meter with nonvolatile memory and real-time clock running on CR2032 battery. IC Role / Device Role / Timing Role: Supervises 3.3V LDO output, asserts RESET on brownout, switches RAM to VBATT, and signals low-battery via PFO. Use Value: Prevents corrupted calibration data during battery depletion by guaranteeing RAM retention down to 1V VCC and enabling early low-power warning. |
Use Scenario: Handheld ECG device with flash memory and sensor interface operating intermittently on rechargeable Li-ion. IC Role / Device Role / Timing Role: Monitors main 3.3V rail and auxiliary 1.8V sensor supply (via PFI divider), triggers watchdog reset on firmware hang, and maintains RTC power during sleep. Use Value: Eliminates field failures from silent µP lockups and ensures clinical data persistence across power cycles using battery-backed VOUT. |
| Industrial Data Logger | Smart Meter Communication Module |
Use Scenario: Ruggedized environmental logger deployed in remote locations with primary 3.3V supply and backup supercapacitor. IC Role / Device Role / Timing Role: Provides reset supervision, power-fail interrupt (PFO → µP IRQ), and seamless switchover to supercap when mains drops. Use Value: Enables deterministic recovery from grid interruptions and preserves last valid sensor readings without external glue logic. |
Use Scenario: PLC-connected smart meter with RS-485 interface and tamper-detection EEPROM. IC Role / Device Role / Timing Role: Guards against voltage sag during RF transmission bursts, asserts RESET if µP fails to service WDI, and retains security keys in battery-backed RAM. Use Value: Meets IEC 62056-21 reliability requirements by preventing EEPROM corruption during transient supply disturbances. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX805TESA | Same electrical specs, but in 8-pin SOIC package (surface-mount, smaller footprint, lower thermal resistance). | Preferred for space-constrained PCBs or automated SMT assembly; identical functionality and timing behavior. | Select MAX805TESA when board layout requires surface-mount packaging or higher thermal performance. |
| MAX802TEPA | Shares same 3.075V reset threshold and 200ms timeout, but offers active-low RESET (not open-drain) and no PFI/PFO comparator. | Lacks power-fail monitoring capability; suitable only where brownout reset suffices without auxiliary rail supervision. | Choose MAX802TEPA only if PFI/PFO functionality is unnecessary and active-low reset is acceptable. |
Compared with MAX805TESA and MAX802TEPA, the MAX805TEPA uniquely combines active-high open-drain RESET, full PFI/PFO monitoring, and battery switchover in a through-hole DIP package-making it optimal for prototyping, legacy designs, and applications requiring both power-fail warning and robust RAM backup.
Availability
MAX805TEPA is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, and intelligent instruments requiring stable component supply with long-term manufacturability and RoHS-compliant sourcing.
Supply support for MAX805TEPA 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, communications, and computing markets.
The MAX805TEPA belongs to Maxim's µP supervisory family designed specifically for reliable power monitoring and battery backup in 3.0V/3.3V microprocessor systems-emphasizing low quiescent current, precise reset thresholds, and integrated watchdog functionality.
FAQ
What is the reset threshold voltage of the MAX805TEPA?
The MAX805TEPA has a nominal reset threshold voltage of 3.075V, with a tolerance of ±4% over temperature and supply variations. This value is specified for VCC falling conditions and ensures reset assertion before the 3.3V supply drops below system stability margins. The MAX805TEPA datasheet confirms this threshold applies across its full operating temperature range of 0°C to +70°C.
Does the MAX805TEPA support battery voltage higher than VCC?
Yes, the MAX805TEPA explicitly supports VBATT exceeding VCC during normal operation - a key feature enabling use with standard 3.6V lithium coin cells alongside 3.3V main supplies. Its internal battery switchover circuit activates when VCC falls below 2.40V (VSW), connecting VBATT to VOUT regardless of relative voltage levels, as confirmed in the MAX805TEPA detailed description and absolute maximum ratings.
What is the function of the WDI pin on the MAX805TEPA?
The WDI (Watchdog Input) pin on the MAX805TEPA is edge-sensitive and clears the internal 1.6s watchdog timer on any rising or falling transition. If WDI remains static for longer than the timeout period, a reset pulse is triggered. Unlike some older supervisors, the watchdog function in the MAX805TEPA cannot be disabled, ensuring continuous fault detection as documented in the MAX805TEPA timing and functional descriptions.
How does the MAX805TEPA handle power-fail detection?
The MAX805TEPA uses its PFI input and internal 1.237V reference to detect power failure: when PFI falls below this threshold (or when VCC drops below VSW = 2.40V), the PFO output goes low. This open-drain signal can drive interrupts or control logic. The PFI comparator operates independently and includes ±20mV hysteresis to reject noise, as specified in the MAX805TEPA electrical characteristics table.
Is the RESET output of the MAX805TEPA active-high or active-low?
The RESET output of the MAX805TEPA is active-high and open-drain, meaning it requires an external pull-up resistor to VCC to assert a logic high. This is the inverse of the active-low RESET found on MAX690/MAX704 devices. The MAX805TEPA datasheet explicitly states this configuration and confirms compatibility with µPs needing active-high reset signaling.
MAX805TEPA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 3.075V
- Output:
- Open Drain or Open Collector
- Reset:
- Active High
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX805TEPA FAQ
1.How can I place an order for MAX805TEPA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX805TEPA 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 MAX805TEPA reliable?
The price and inventory of MAX805TEPA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX805TEPA is usually 5 days.
3.What payment methods are accepted for MAX805TEPA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX805TEPA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX805TEPA?
MAX805TEPA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX805TEPA 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 MAX805TEPA?
For technical support, including MAX805TEPA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX805TEPA requirements.
6.How does Aetrix verify that MAX805TEPA is sourced from the original manufacturer or authorized distributors?
All MAX805TEPA 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 MAX805TEPA meets industry standards.
7.What is the process for return or replacement of MAX805TEPA?
All MAX805TEPA units undergo pre-shipment inspection (PSI). If there is an issue with MAX805TEPA, 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 MAX805TEPA part is unused and in its original packaging.
Return procedure for MAX805TEPA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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