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Analog Devices Inc./Maxim Integrated MAX804SCPA+
- Part No.:
- MAX804SCPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX804SCPA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:534
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Product details
Overview
MAX804SCPA+ from Maxim Integrated is a 3.3V/3.0V microprocessor supervisory circuit with active-high open-drain RESET output, 2.925V reset threshold (S-suffix), 200ms reset timeout, 1.6s watchdog timer, and battery-backup switchover-designed for reliable power monitoring in embedded controllers and battery-powered systems.
For engineers reviewing the MAX804SCPA+ datasheet, MAX804SCPA+ pinout, MAX804SCPA+ application, or MAX804SCPA+ equivalent, this page delivers verified functional specifications, validated pin roles, confirmed battery-switching behavior, and real-world timing constraints critical for brownout resilience and RAM backup integrity.
Technical Context
The MAX804SCPA+ integrates a precision voltage monitor with ±2% reset threshold tolerance, a non-disableable 1.6s watchdog timer cleared by WDI edges, and a dual-path power switchover circuit that connects VOUT to VBATT when VCC falls below 2.40V (VSW) and VBATT > VCC-or to VCC when VCC rises above the 2.925V reset threshold. It guarantees RESET assertion down to VCC = 1V.
Its PFI input monitors external supplies with 1.237V threshold and 10mV hysteresis, while PFO asserts low on power-fail or VCC dropout. The device operates across 0°C to +70°C, draws only 40µA from VCC (typ), and supports lithium battery voltages exceeding VCC without damage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V (±2%) - precisely targets 3.3V ±10% supply systems; ensures reset before VCC drops below 2.85V. |
| Reset Timeout Period | 200ms (140–280ms range) - provides sufficient deassertion delay after power recovery to stabilize µP clocks and peripherals. |
| Watchdog Timeout | 1.6s (1.12–2.24s) - detects µP lockup without requiring software intervention; cannot be disabled. |
| VCC Supply Current | 40µA (typ) at VCC < 3.6V - enables ultra-low-power operation in battery-backed portable equipment. |
| Battery Supply Current | 0.4–1µA (max) - minimizes drain on backup lithium cells during extended standby. |
| VBATT-to-VOUT On-Resistance | 140Ω (typ) - limits voltage drop during battery switchover to preserve CMOS RAM retention above 2.0V. |
| Power-Fail Input Threshold | 1.237V ±20mV - enables accurate undervoltage detection of auxiliary rails via external resistor divider. |
Pinout & Package
MAX804SCPA+ is housed in an 8-pin plastic DIP (PDIP) package with 0.300" wide body, RoHS-compliant lead-free finish (+ suffix), and through-hole mounting compatibility.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Backup power output | Switches between VCC and VBATT; connects to CMOS RAM VDD; requires 0.1µF local decoupling. |
| 2 - VCC | Main supply input | Accepts 2.72–5.5V; powers internal circuitry; monitored for reset assertion and switchover control. |
| 3 - GND | Ground reference | Common return for all analog/digital functions; must be low-impedance for noise immunity. |
| 4 - PFI | Power-fail input | Monitors external rail via resistor divider; triggers PFO low when voltage falls below 1.237V. |
| 5 - PFO | Power-fail output | Active-low open-drain signal; can drive MR on compatible supervisors or generate µP interrupt. |
| 6 - WDI | Watchdog input | Edge-sensitive (rising/falling); resets watchdog timer; tied high/low causes 1.6s timeout and reset. |
| 7 - RESET | Active-high reset output | Open-drain; requires external pull-up; asserts high during reset condition (VCC < 2.925V or WDI timeout). |
| 8 - VBATT | Backup battery input | Accepts up to 6.0V; may exceed VCC; enables seamless RAM backup during main supply failure. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout, preventing µP execution from corrupted memory. |
| Battery-backup switchover with 2.40V VSW threshold | Enters battery mode before VOUT drops below 2.0V, preserving data in static RAM without external logic. |
| ±2% reset and power-fail threshold accuracy | Reduces false resets in noisy industrial environments and improves system-level voltage margin allocation. |
| 200ms reset timeout with restart-on-brownout | Reinitiates timing each time VCC dips below threshold, eliminating race conditions during unstable power-up. |
| Non-disableable watchdog timer | Eliminates risk of accidental watchdog disable in firmware, enforcing hardware-level system recovery. |
Applications
| Battery-Powered Embedded Controller | Critical µP Power Monitoring |
|---|---|
Use Scenario: Portable medical sensor node operating on lithium coin cell with intermittent 3.3V main supply. IC Role / Device Role / Timing Role: Supervises VCC for brownout detection, switches RAM to VBATT at 2.40V, asserts RESET if µP hangs. Use Value: Prevents data loss during battery swap and ensures deterministic boot after power interruption. |
Use Scenario: Industrial PLC CPU board requiring guaranteed reset during AC line sags. IC Role / Device Role / Timing Role: Monitors 3.3V rail with ±2% threshold accuracy; generates 200ms reset pulse on every VCC dip below 2.925V. Use Value: Eliminates need for discrete RC reset circuits and reduces BOM count by 4 components. |
| Intelligent Instrument with RAM Backup | Portable Test Equipment |
Use Scenario: Handheld multimeter storing calibration coefficients in CMOS SRAM. IC Role / Device Role / Timing Role: Provides VOUT from VBATT during main power removal; maintains RAM voltage >2.0V via 140Ω switch. Use Value: Enables hot-swap battery replacement without losing calibration data or requiring reinitialization. |
Use Scenario: Battery-operated oscilloscope with µP-based UI and volatile configuration storage. IC Role / Device Role / Timing Role: Uses WDI to detect firmware freeze; triggers active-high RESET to force controlled reboot. Use Value: Recovers unresponsive UI without user intervention, meeting IEC 61000-4-2 immunity requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX804TCSA+ | Reset threshold 3.075V (±2%), same pinout/package, identical timing and watchdog specs. | Suitable for 3.3V ±5% systems where tighter upper voltage margin is required before reset assertion. | Select when system VCC tolerance is tighter and brownout must occur closer to nominal 3.3V. |
| MAX804RCPA+ | Reset threshold 2.625V (±2%), same pinout/package, identical timing and watchdog specs. | Optimized for 3.0V ±10% supplies; asserts reset later than S-version, extending operational window during sag. | Select for 3.0V systems needing deeper brownout tolerance before reset, e.g., automotive accessory modules. |
Compared with MAX804TCSA+ and MAX804RCPA+, the MAX804SCPA+ offers the optimal reset threshold (2.925V) for 3.3V ±10% supplies-balancing early fault detection against unnecessary resets during transient sags-while maintaining identical watchdog, switchover, and leakage performance.
Availability
MAX804SCPA+ is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, and intelligent instruments requiring stable component supply and long-term lifecycle support.
Supply support for MAX804SCPA+ 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 applications.
The MAX804SCPA+ belongs to Maxim's µP supervisory circuit product line, engineered specifically for robust power monitoring and battery-switchover in 3.0V/3.3V embedded systems where reliability under brownout and watchdog recovery are mission-critical.
FAQ
What is the exact reset threshold voltage of the MAX804SCPA+?
The MAX804SCPA+ has a nominal reset threshold voltage of 2.925V, with a tolerance of ±2% over temperature and supply variations. This value applies to both rising and falling VCC transitions, though hysteresis ensures stable operation-reset is guaranteed to assert before VCC falls below 2.85V and release only after VCC rises above 2.935V. The 'S' in the part number explicitly denotes this 2.925V variant.
Does the MAX804SCPA+ support battery voltages higher than VCC?
Yes, the MAX804SCPA+ fully supports VBATT exceeding VCC-up to 6.0V-as confirmed in its Absolute Maximum Ratings and Detailed Description. Its internal battery switchover circuit activates when VCC falls below 2.40V (VSW) and VBATT > VCC, connecting VBATT to VOUT through a 140Ω switch. This design enables use with standard 3.6V lithium cells in 3.3V systems without level-shifting or protection circuitry.
Is the watchdog timer on the MAX804SCPA+ disableable?
No, the watchdog timer on the MAX804SCPA+ cannot be disabled-it is permanently enabled per the datasheet. The timer times out after 1.6 seconds (1.12–2.24s range) if no edge (rising or falling) is detected on the WDI pin. Reset is triggered immediately upon timeout, and the timer clears automatically during reset assertion or on any WDI transition. This hardwired behavior ensures fail-safe recovery even if firmware fails to service the watchdog.
What is the function of the RESET pin on the MAX804SCPA+?
The RESET pin on the MAX804SCPA+ is an active-high, open-drain output-distinct from the active-low RESET found on MAX690/704 families. It remains high-impedance until asserted, then pulls low only when externally pulled up (e.g., to VCC via 10kΩ). During reset conditions (VCC < 2.925V, WDI timeout, or MR low), it sinks current to signal reset to the µP. This architecture avoids contention with bidirectional µP reset pins and simplifies interface design.
Can the MAX804SCPA+ operate down to 1V VCC and still assert RESET?
Yes, the MAX804SCPA+ guarantees RESET assertion for VCC as low as 1V, as explicitly stated in the datasheet's "Guaranteed RESET Assertion to VCC = 1V" feature. This capability is achieved via internal charge-pump and low-voltage comparator design, ensuring the µP remains held in reset even during severe brownout or capacitor discharge phases-critical for preventing erratic execution in safety-critical or data-logging applications.
MAX804SCPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.925V
- Output:
- Open Drain, Open Drain
- Reset:
- Active High/Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX804SCPA+ FAQ
1.How can I place an order for MAX804SCPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX804SCPA+ 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 MAX804SCPA+ reliable?
The price and inventory of MAX804SCPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX804SCPA+ is usually 5 days.
3.What payment methods are accepted for MAX804SCPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX804SCPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX804SCPA+?
MAX804SCPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX804SCPA+ 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 MAX804SCPA+?
For technical support, including MAX804SCPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX804SCPA+ requirements.
6.How does Aetrix verify that MAX804SCPA+ is sourced from the original manufacturer or authorized distributors?
All MAX804SCPA+ 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 MAX804SCPA+ meets industry standards.
7.What is the process for return or replacement of MAX804SCPA+?
All MAX804SCPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX804SCPA+, 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 MAX804SCPA+ part is unused and in its original packaging.
Return procedure for MAX804SCPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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