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Analog Devices Inc./Maxim Integrated MAX804TEPA+
- Part No.:
- MAX804TEPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX804TEPA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:182
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Product details
Overview
MAX804TEPA+ from Maxim Integrated is a 3.3V microprocessor supervisory circuit with active-high open-drain RESET output, 3.075V reset threshold (T-suffix), 200ms reset timeout, 1.6s watchdog timer, and battery-backup switchover capability. It monitors VCC supply integrity, asserts reset during brownout or watchdog timeout, and switches CMOS RAM to VBATT when VCC drops below 2.40V-used in portable embedded controllers requiring reliable power-fail detection and nonvolatile memory retention.
For engineers reviewing the MAX804TEPA+ datasheet, MAX804TEPA+ pinout, MAX804TEPA+ application, or MAX804TEPA+ equivalent, key selection criteria include its ±2% reset threshold accuracy, guaranteed RESET assertion down to VCC = 1V, 40µA VCC supply current, and compatibility with lithium coin-cell backup sources exceeding VCC voltage.
Technical Context
The MAX804TEPA+ integrates a precision reset comparator with 10mV hysteresis, a 1.6s watchdog timer cleared by WDI transitions, and a dual-path power-switching circuit that connects VOUT to VCC above the reset threshold and to VBATT below the 2.40V switchover threshold. Its PFI input supports external undervoltage monitoring with 1.237V threshold and 10mV hysteresis.
Unlike the MAX690/MAX704 families, the MAX804 series features tightened ±2% reset and power-fail threshold tolerances and an active-high open-drain RESET output requiring external pull-up. The device operates across –40°C to +85°C and supports battery voltages up to 6.0V while maintaining 0.4–1.0µA VBATT supply current in backup mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V (±2%) - ensures reset assertion before 3.3V supply falls below system stability margin |
| Reset Timeout Period | 200ms (140–280ms) - guarantees sufficient processor initialization time after power recovery |
| Watchdog Timeout | 1.6s (1.12–2.24s) - provides robust firmware hang detection without false triggers from brief glitches |
| VCC Supply Current | 40–50µA at VCC < 3.6V - enables long-term operation in battery-backed portable systems |
| Battery Supply Current | 0.4–1.0µA - minimizes drain on 3.6V lithium cells during extended backup periods |
| VBATT-to-VOUT On-Resistance | 140Ω typical - limits voltage drop during RAM backup, preserving data retention above 2.0V |
| Power-Fail Input Threshold | 1.237V ±20mV - allows accurate monitoring of auxiliary rails via resistor divider |
Pinout & Package
MAX804TEPA+ is housed in an 8-pin plastic DIP (PDIP) package with lead-free finish (+ suffix), RoHS-compliant, 0.300" wide body, and through-hole mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC and VBATT; connects to RAM VDD; requires 0.1µF local decoupling |
| 2 - VCC | Main system supply input | Accepts 3.02V–5.5V; powers internal circuitry; monitored for reset assertion |
| 3 - GND | Ground reference | Common return for all analog/digital functions; must be low-impedance |
| 4 - PFI | Power-fail input | Monitors auxiliary rail via resistor divider; trips PFO low when < 1.237V |
| 5 - PFO | Power-fail output | Active-low open-drain signal indicating undervoltage condition on PFI or VCC |
| 6 - WDI | Watchdog input | Edge-sensitive; clears 1.6s timer on rising/falling transition; cannot be disabled |
| 7 - RESET | Active-high reset output | Open-drain; requires external pull-up to VCC; asserts high during reset conditions |
| 8 - VBATT | Backup battery input | Accepts 3.6V lithium cell; may exceed VCC; enables seamless RAM switchover |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset comparator | ±2% threshold tolerance ensures consistent reset behavior across temperature and supply variation |
| Guaranteed RESET assertion to VCC = 1V | Enables reliable reset hold-down during deep brownout, preventing partial execution |
| Battery switchover at 2.40V | Triggers before VOUT drops below 2.0V RAM retention limit, maximizing backup duration |
| 1.6s watchdog timer with edge-clearing | Eliminates need for dedicated timer peripherals; immune to static WDI states |
| 40µA VCC supply current | Extends battery life in always-on portable instrumentation and controller applications |
| VBATT > VCC support | Allows use of standard 3.6V lithium coin cells without level-shifting or regulation |
Applications
| Battery-Powered Embedded Controller | Intelligent Portable Instrument |
|---|---|
Use Scenario: A handheld multimeter powered by AA batteries uses MAX804TEPA+ to monitor main 3.3V rail and switch internal SRAM to backup supercapacitor during battery swap. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, watchdog supervision, and seamless RAM power switchover. Use Value: Prevents firmware corruption during hot battery replacement and maintains measurement calibration data in SRAM. |
Use Scenario: An industrial handheld gas detector employs MAX804TEPA+ to supervise its 3.3V MCU supply and trigger immediate shutdown upon power-fail detection. IC Role / Device Role / Timing Role: Power-monitoring and safety-critical reset generator with 200ms timeout and 1.237V PFI threshold. Use Value: Ensures deterministic safe state entry within 200ms of supply collapse, meeting IEC 61508 functional safety requirements. |
| Critical µP Power Monitoring | Portable Medical Sensor Node |
Use Scenario: A remote telemetry module in a patient-worn ECG sensor relies on MAX804TEPA+ to detect 3.3V rail droop and assert reset before ADC sampling errors occur. IC Role / Device Role / Timing Role: Precision supply-voltage monitor with ±2% reset threshold and 10mV hysteresis. Use Value: Eliminates false resets from transient noise while guaranteeing reset before 3.3V supply falls below 3.075V critical margin. |
Use Scenario: A Bluetooth-enabled pulse oximeter uses MAX804TEPA+ to manage lithium coin-cell backup for real-time clock and configuration storage during main battery depletion. IC Role / Device Role / Timing Role: Battery switchover controller with 0.4–1.0µA VBATT leakage and 140Ω on-resistance. Use Value: Extends backup runtime beyond 10 years by minimizing quiescent drain and limiting VOUT voltage sag under load. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX804TESA+ | Same electrical specs but in 8-pin SOIC package (surface-mount); 471mW max power dissipation vs. 727mW for PDIP | Suitable for space-constrained PCBs; requires reflow soldering instead of through-hole assembly | Select MAX804TESA+ for automated SMT production; MAX804TEPA+ preferred for prototyping or high-reliability through-hole designs |
| MAX802TEPA+ | Identical pinout and package, but with active-low RESET output (not open-drain) and same 3.075V threshold | Requires no external pull-up resistor; incompatible with µPs needing active-high reset assertion | Choose MAX802TEPA+ only if target MCU accepts active-low reset; MAX804TEPA+ required for active-high or open-drain interface needs |
Compared with MAX804TESA+, the MAX804TEPA+ offers higher thermal margin and easier manual assembly; compared with MAX802TEPA+, it provides flexible active-high reset signaling essential for interfacing with modern low-voltage MCUs requiring externally pulled-up reset lines.
Availability
MAX804TEPA+ is available at Aetrix Electronics and suitable for battery-powered computers and controllers, intelligent instruments, and critical µP power monitoring requiring stable component supply across industrial temperature ranges.
Supply support for MAX804TEPA+ 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 power management, sensing, and connectivity in industrial, medical, and communications systems.
The MAX804TEPA+ belongs to Maxim's 3.0V/3.3V microprocessor supervisory circuit family, engineered specifically for reliable power monitoring, watchdog supervision, and battery-backed memory retention in portable and embedded applications.
FAQ
What is the reset threshold voltage of the MAX804TEPA+?
The MAX804TEPA+ has a nominal reset threshold voltage of 3.075V with ±2% tolerance over temperature and supply variation. This value is specified for VCC falling and ensures reset assertion before the 3.3V system supply drops below 3.00V, providing a robust margin against brownout-induced firmware errors. The threshold is factory-trimmed and does not require external calibration.
Does the MAX804TEPA+ support battery voltages higher than VCC?
Yes, the MAX804TEPA+ explicitly supports VBATT exceeding VCC - a key design feature enabling direct connection of standard 3.6V lithium coin cells. When VCC falls below the 2.40V switchover threshold, the internal 140Ω PMOS switch connects VBATT to VOUT, preserving CMOS RAM data without level-shifting circuitry. The device guarantees safe operation with VBATT up to +6.0V.
How does the watchdog timer function in the MAX804TEPA+?
The MAX804TEPA+ incorporates a 1.6s watchdog timer (1.12–2.24s range) that triggers reset if the WDI pin remains static - either high or low - for longer than the timeout period. The timer clears on any edge (rising or falling) at WDI and cannot be disabled. Unlike some predecessors, this watchdog remains fully functional even during battery-backup mode, ensuring continuous firmware supervision.
What is the purpose of the PFI and PFO pins on the MAX804TEPA+?
The PFI (Power-Fail Input) pin accepts an external voltage divider to monitor auxiliary power rails, comparing it to a precise 1.237V internal reference. When PFI falls below this threshold, the open-drain PFO (Power-Fail Output) pulls low, signaling undervoltage. PFO can drive interrupts or be connected to MR on compatible devices, extending the MAX804TEPA+'s role beyond primary supply monitoring into multi-rail system supervision.
Can the MAX804TEPA+ operate without a backup battery?
Yes, the MAX804TEPA+ can operate without a backup battery: connect both VBATT and VOUT pins directly to VCC. However, doing so disables battery switchover and backup RAM functionality. For applications requiring only reset supervision and watchdog, this configuration is valid and draws only 40–50µA from VCC. Note that the MAX804TEPA+ is optimized for battery-backed use; alternatives like MAX706T/S/R may be preferable for battery-less designs.
MAX804TEPA+ 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:
- Open Drain, Open Drain
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX804TEPA+ FAQ
1.How can I place an order for MAX804TEPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX804TEPA+ 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 MAX804TEPA+ reliable?
The price and inventory of MAX804TEPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX804TEPA+ is usually 5 days.
3.What payment methods are accepted for MAX804TEPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX804TEPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX804TEPA+?
MAX804TEPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX804TEPA+ 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 MAX804TEPA+?
For technical support, including MAX804TEPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX804TEPA+ requirements.
6.How does Aetrix verify that MAX804TEPA+ is sourced from the original manufacturer or authorized distributors?
All MAX804TEPA+ 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 MAX804TEPA+ meets industry standards.
7.What is the process for return or replacement of MAX804TEPA+?
All MAX804TEPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX804TEPA+, 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 MAX804TEPA+ part is unused and in its original packaging.
Return procedure for MAX804TEPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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