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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 MPU
- Quantity:
- Payment:
- Shipping:
Inventory:752
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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, watchdog timer (1.6s), 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 embedded controllers and portable equipment requiring reliable power sequencing.
For engineers reviewing the MAX804TEPA datasheet, MAX804TEPA pinout, MAX804TEPA application, or MAX804TEPA equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in battery-backed systems, and validated alternative parts for 3.3V µP supervision with precision reset thresholds and integrated watchdog timing.
Technical Context
The MAX804TEPA integrates a precision reset comparator with ±2% tolerance on the 3.075V threshold, a 1.6s watchdog timer that clears on WDI edge transitions, and a dual-path power-switching circuit: VCC-to-VOUT via a 3Ω PMOS switch and VBATT-to-VOUT via a 140Ω switch activated when VCC falls below VSW = 2.40V. Its PFI input accepts 1.237V threshold monitoring with 10mV hysteresis.
It operates across –40°C to +85°C (E-grade), draws only 40µA from VCC at VCC < 3.6V, and guarantees RESET assertion down to VCC = 1V. The active-high RESET output is open-drain, requiring external pull-up, and the device supports manual reset with 200ms delay after MR release.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V (±2%) - ensures reset triggers before 3.3V supply drops below system minimum operating voltage. |
| Reset Timeout Period | 200ms (140–280ms range) - provides sufficient hold time for µP initialization after power stabilization. |
| Watchdog Timeout | 1.6s (1.12–2.24s) - 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 Supply Current | 0.4–1µA - minimizes drain on lithium backup cells during extended standby. |
| VBATT Switch Threshold | 2.40V (2.30–2.50V) - initiates battery switchover early enough to preserve CMOS RAM data above 2.0V. |
| PFI Threshold Voltage | 1.237V (±25mV) - allows accurate monitoring of auxiliary supplies via resistor divider without external reference. |
Pinout & Package
MAX804TEPA is housed in an 8-pin plastic DIP (PDIP) package with 0.300" wide body, RoHS-compliant lead finish, and standard through-hole mounting. Pin spacing follows JEDEC MS-001.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω switch); must be decoupled with 0.1µF capacitor. |
| 2 - VCC | Main supply input | Accepts 3.02V–5.5V; powers internal circuitry and enables VOUT connection to VCC above reset threshold. |
| 3 - GND | Ground reference | Common return path for VCC, VBATT, and all logic inputs/outputs; requires low-inductance PCB connection. |
| 4 - PFI | Power-fail input | Monitors auxiliary supply via resistor divider; trips PFO low when voltage falls below 1.237V. |
| 5 - PFO | Power-fail output | Active-low open-drain signal indicating undervoltage condition on PFI or VCC falling below 2.40V. |
| 6 - WDI | Watchdog input | Edge-sensitive (rising/falling); resets watchdog timer; tied high/low triggers 1.6s timeout and reset. |
| 7 - RESET | Active-high reset output | Open-drain output - requires external pull-up to VCC; asserts high during reset conditions. |
| 8 - VBATT | Backup battery input | Accepts up to 6.0V; connects to VOUT when VCC < 2.40V; may exceed VCC without damage. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout, critical for data retention in volatile memory systems. |
| 200ms reset timeout with restart-on-brownout | Prevents premature µP release during transient dips; internal timer resets each time VCC falls below threshold. |
| Battery switchover with 2.40V VSW threshold | Activates backup power before VOUT drops below 2.0V, preserving SRAM contents without external control logic. |
| 1.6s watchdog timer with edge-clearing | Eliminates need for dedicated watchdog IC; toggling WDI by firmware prevents spurious resets. |
| 40µA VCC supply current (typ) | Extends battery life in always-on portable devices where supervisory circuit remains active indefinitely. |
| ±2% reset and power-fail threshold accuracy | Reduces design margin requirements versus looser-tolerance alternatives like MAX690 (±4%). |
Applications
| Battery-Powered Embedded Controller | Portable Medical Instrument |
|---|---|
Use Scenario: A handheld glucose meter uses lithium coin cell backup to retain calibration data and usage logs during main power removal. IC Role / Device Role / Timing Role: MAX804TEPA monitors 3.3V main rail, asserts RESET on brownout, and switches VOUT to VBATT at 2.40V to sustain SRAM. Use Value: Guarantees data integrity over >10-year shelf life with <1µA battery leakage and no external switchover FET required. |
Use Scenario: An ultrasound probe with internal flash storage and real-time DSP requires deterministic boot sequence after battery insertion or AC reconnection. IC Role / Device Role / Timing Role: MAX804TEPA provides 200ms power-on reset pulse, monitors 3.3V supply stability, and feeds WDI with periodic firmware pulses to prevent lockup-induced misdiagnosis. Use Value: Eliminates risk of corrupted firmware execution due to marginal VCC ramp or processor hang, meeting IEC 62304 Class B safety requirements. |
| Industrial Data Logger | Smart Meter with Tamper Detection |
Use Scenario: A remote environmental sensor node logs temperature/humidity every 15 minutes using supercapacitor backup during grid outages. IC Role / Device Role / Timing Role: MAX804TEPA interfaces PFI to a scaled-down 5V auxiliary rail, triggering PFO interrupt on supply sag, while managing VOUT switchover to supercap. Use Value: Enables precise undervoltage detection independent of main rail, allowing graceful shutdown and timestamped event logging before backup depletion. |
Use Scenario: A utility meter detects physical tampering via sudden 3.3V rail collapse and initiates secure erase of billing history stored in protected EEPROM. IC Role / Device Role / Timing Role: MAX804TEPA's guaranteed RESET assertion down to VCC = 1V ensures erase command executes fully even during rapid power loss. Use Value: Meets ANSI C12.1 and DLMS/COSEM anti-tamper mandates by preventing partial writes or inconsistent state during power interruption. |
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 and pinout, but in 8-pin SOIC package (surface-mount, 150°C max solder temp). | Required for automated PCB assembly; lacks through-hole mounting; thermal performance differs slightly. | Select MAX804TESA for space-constrained or high-volume SMT designs where board area and reflow compatibility are priorities. |
| MAX805TEPA | Identical package and temperature grade, but features active-low RESET (complementary output polarity). | Direct replacement only if host µP accepts active-low reset; requires redesign of pull-up/pull-down network. | Choose MAX805TEPA when interfacing with legacy µPs requiring active-low reset assertion or when sharing RESET net with other active-low supervisors. |
Compared with MAX804TESA and MAX805TEPA, the MAX804TEPA uniquely combines through-hole DIP packaging, active-high open-drain RESET, and ±2% threshold accuracy - making it optimal for prototyping, field-replaceable modules, and mixed-technology boards where mechanical robustness and interface flexibility are essential.
Availability
MAX804TEPA is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, intelligent instruments, critical µP power monitoring, and portable equipment 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 interface applications in industrial, medical, and communications systems.
The MAX804TEPA belongs to Maxim's 3.0V/3.3V microprocessor supervisory family, engineered specifically for reliable power monitoring, battery switchover, and watchdog protection in resource-constrained embedded systems.
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. This value is specified for VCC falling conditions and ensures reset assertion before the 3.3V supply drops below 3.0V, supporting systems with tight voltage margins. The threshold is factory-trimmed and does not require external calibration.
Does the MAX804TEPA support battery backup switchover, and what is the switching threshold?
Yes, the MAX804TEPA supports automatic battery backup switchover. When VCC falls below the battery switch threshold (VSW) of 2.40V (2.30V to 2.50V), VOUT disconnects from VCC and connects to VBATT through a 140Ω internal switch. This ensures CMOS RAM remains powered above 2.0V during main supply failure.
How does the watchdog timer function in the MAX804TEPA?
The MAX804TEPA includes a non-disableable watchdog timer with a nominal timeout of 1.6 seconds. It clears on any rising or falling edge at the WDI pin and triggers RESET if WDI remains static beyond timeout. The timer restarts immediately upon reset deassertion, providing continuous lockup detection without firmware overhead.
What is the function of the PFI and PFO pins on the MAX804TEPA?
The PFI pin accepts an external voltage for power-fail monitoring, comparing it to a 1.237V internal reference. When PFI falls below this threshold, the open-drain PFO pin pulls low. PFO can be used to generate µP interrupts or drive MR on compatible parts like MAX704TEPA, enabling cascaded fault response without additional logic.
Can the MAX804TEPA operate without a backup battery connected?
Yes, the MAX804TEPA can operate without a backup battery. In that case, both VBATT and VOUT must be connected to VCC. However, battery switchover and low-battery warning functionality will be disabled. For pure power-monitoring applications without backup, alternatives like MAX706TEPA may offer cost-optimized feature sets.
What package type and temperature range does the MAX804TEPA use?
The MAX804TEPA is supplied in an 8-pin plastic DIP (PDIP) package rated for operation from –40°C to +85°C (E-grade). Its 0.300" wide body supports through-hole mounting and manual rework, and the device meets RoHS compliance with lead-free terminations indicated by the "+" suffix in ordering codes.
MAX804TEPA 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, 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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