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Analog Devices Inc./Maxim Integrated MAX805RCPA+
- Part No.:
- MAX805RCPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX805RCPA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:178
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Product details
Overview
MAX805RCPA+ from Maxim Integrated is a 3.0V/3.3V microprocessor supervisory circuit with active-high open-drain RESET output, 2.625V reset threshold (R-suffix), 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover. It monitors VCC for brownout, asserts reset during power-up/down, and switches VOUT to VBATT when VCC falls below 2.40V - used in battery-powered embedded controllers requiring reliable RAM retention.
For engineers reviewing the MAX805RCPA+ datasheet, MAX805RCPA+ pinout, MAX805RCPA+ application, or MAX805RCPA+ equivalent, this page delivers verified specifications including reset threshold tolerance (±4%), PFI threshold (1.237V), VCC supply current (40µA typ), battery leakage (0.01–0.5µA), and guaranteed RESET assertion down to VCC = 1V.
Technical Context
The MAX805RCPA+ integrates a precision reset comparator with 10mV hysteresis, a non-disableable 1.6s watchdog timer cleared by WDI edges, and a dual-path battery switchover circuit: VCC-to-VOUT via 3Ω PMOS switch and VBATT-to-VOUT via 140Ω switch. Its PFI input enables independent power-fail detection at 1.237V with ±20mV hysteresis.
It operates across 0°C to +70°C (C-grade), supports VCC from 2.72V to 5.5V (R-suffix), and guarantees RESET assertion for VCC < 2.625V (falling) and deassertion only after VCC rises above 2.635V (rising). The active-high RESET output requires external pull-up and sinks up to 1.2mA at 0.3V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold (VRST) | 2.625V nominal (falling), ±4% tolerance; ensures reset assertion before VCC drops below 2.55V in 3.0V systems with ±10% supply tolerance. |
| Reset Timeout Period | 200ms typ (140–280ms range); holds RESET asserted long enough to guarantee µP initialization after power recovery. |
| VCC Supply Current | 40µA typ at VCC < 3.6V; enables ultra-low-power operation in always-on battery-backed systems. |
| Battery Leakage Current | 0.01–0.5µA max; minimizes drain on lithium backup cells during extended storage or standby. |
| Watchdog Timeout | 1.60s typ (1.12–2.24s); detects µP lockup without software intervention, critical for unattended embedded devices. |
| PFI Threshold Voltage | 1.237V ±25mV; provides accurate undervoltage detection for auxiliary rails or battery monitoring independent of main VCC. |
| VBATT Switch Threshold (VSW) | 2.40V typ; initiates battery switchover early enough to maintain CMOS RAM above 2.0V minimum retention voltage. |
Pinout & Package
MAX805RCPA+ is housed in an 8-pin plastic DIP (PDIP) package with 0.300" wide body, RoHS-compliant lead-free finish (+ suffix), and standard through-hole mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Supply output for CMOS RAM | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω switch); must be decoupled with 0.1µF capacitor. |
| 2 - VCC | Main system supply input | Accepts 2.72V–5.5V; powers internal circuitry and enables reset monitoring; absolute max = +6.0V. |
| 3 - GND | Ground reference | Common return for VCC, VBATT, and all logic; requires low-impedance connection to minimize noise coupling. |
| 4 - PFI | Power-fail input | Compares external voltage to 1.237V reference; triggers PFO low when input falls below threshold. |
| 5 - PFO | Power-fail open-drain output | Active-low signal indicating PFI undervoltage or VCC < VSW; requires external pull-up for µP interrupt generation. |
| 6 - WDI | Watchdog input | Edge-sensitive (rising/falling); clears 1.6s timer on transition; tied high/low causes periodic reset. |
| 7 - RESET | Active-high open-drain reset output | Inverse of MAX690/704/802/806 RESET; requires external pull-up to VCC; sinks 1.2mA at 0.3V. |
| 8 - VBATT | Backup battery input | Accepts up to 6.0V; may exceed VCC; connects to VOUT during brownout; decouple with 0.1µF capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset behavior even during deep brownout, preventing µP execution from corrupted memory. |
| Battery-backup switchover with VSW = 2.40V | Activates backup before VOUT drops below 2.0V, preserving SRAM data integrity without external supervision. |
| 40µA VCC supply current (typ) | Reduces quiescent power in always-on applications such as portable medical or industrial logging devices. |
| 1.6s watchdog timer with edge-triggered clear | Eliminates need for dedicated watchdog IC; prevents µP lockup without software polling overhead. |
| 1.237V PFI threshold with ±20mV hysteresis | Enables precise, noise-immune monitoring of auxiliary supplies or battery voltage without external components. |
Applications
| Battery-Powered Embedded Controller | Intelligent Portable Instrument |
|---|---|
Use Scenario: A handheld gas detector uses lithium coin cell backup to retain calibration data and sensor logs during main power loss. IC Role / Device Role / Timing Role: MAX805RCPA+ monitors 3.0V main rail, asserts RESET on brownout, and switches VOUT to VBATT at 2.40V to sustain SRAM. Use Value: Guarantees data retention down to VCC = 1V and extends battery life via 0.01µA leakage current. |
Use Scenario: A field-deployable multimeter maintains real-time measurement history and settings across AC power interruptions. IC Role / Device Role / Timing Role: MAX805RCPA+ provides 200ms reset hold time, 1.6s watchdog supervision, and PFI-based low-battery warning. Use Value: Prevents firmware corruption during unstable mains conditions and enables graceful shutdown on battery depletion. |
| Critical µP Power Monitoring | Industrial Remote Terminal Unit (RTU) |
Use Scenario: An energy meter's µP must initialize reliably after cold start and recover from grid voltage sags. IC Role / Device Role / Timing Role: MAX805RCPA+ asserts RESET until VCC stabilizes above 2.635V and enforces 200ms minimum reset pulse width. Use Value: Eliminates boot failures caused by marginal VCC ramp rates or transient dips below 2.625V. |
Use Scenario: An RTU in a solar-powered SCADA node uses supercapacitor backup and requires fault-tolerant reset control. IC Role / Device Role / Timing Role: MAX805RCPA+ manages VOUT switchover, monitors auxiliary 5V rail via PFI, and generates watchdog-triggered resets. Use Value: Supports seamless transition between solar, battery, and supercap power sources while maintaining µP supervision integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX805SCPA+ | Higher reset threshold (2.925V), tighter ±2% tolerance, same pinout and features. | Better suited for 3.3V ±10% systems where earlier reset assertion is required. | Select MAX805SCPA+ when monitoring 3.3V rails with wider tolerance; MAX805RCPA+ remains optimal for 3.0V ±10% systems. |
| MAX804RCPA+ | Active-low RESET output (complementary to MAX805RCPA+'s active-high), identical reset threshold and timing. | Direct replacement where µP reset input is active-low and external pull-down is preferred. | Choose MAX804RCPA+ only if system design mandates active-low reset signaling; otherwise, MAX805RCPA+ avoids external level-shifting. |
Compared with MAX805SCPA+ and MAX804RCPA+, the MAX805RCPA+ offers the lowest reset threshold (2.625V) for deep brownout immunity in 3.0V systems, while its active-high RESET simplifies interface with µPs lacking internal pull-ups and eliminates need for external inverters.
Availability
MAX805RCPA+ is available at Aetrix Electronics and suitable for battery-powered computers, intelligent instruments, and critical µP power monitoring applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX805RCPA+ 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, mixed-signal, and power management ICs for industrial, computing, and communications applications.
The MAX805RCPA+ belongs to Maxim's microprocessor supervisory circuit family, engineered specifically for reliable power monitoring and battery backup in 3.0V/3.3V embedded systems with stringent reliability requirements.
FAQ
What is the reset threshold voltage of the MAX805RCPA+?
The MAX805RCPA+ has a nominal reset threshold voltage of 2.625V (R-suffix), with a specified tolerance of ±4% over temperature. It asserts RESET when VCC falls below 2.55V (min) and deasserts only after VCC rises above 2.635V (typ), providing 10mV hysteresis to prevent oscillation during brownout recovery. This threshold is optimized for 3.0V ±10% power systems.
Does the MAX805RCPA+ support battery backup switchover?
Yes, the MAX805RCPA+ supports automatic battery backup switchover: when VCC falls below the 2.40V switch threshold (VSW) and VBATT exceeds VCC, it disconnects VOUT from VCC and connects it to VBATT via a 140Ω internal switch. Switchover back to VCC occurs when VCC rises above the reset threshold (2.625V), ensuring stable supply reconnection after recovery.
What is the function of the WDI pin on the MAX805RCPA+?
The WDI (Watchdog Input) pin on the MAX805RCPA+ is edge-sensitive and clears the internal 1.6s watchdog timer on any rising or falling transition. If WDI remains static (high or low) for longer than 1.6s, the timer expires and triggers a reset. Unlike some supervisory ICs, the watchdog function cannot be disabled - it operates continuously once powered.
Can the MAX805RCPA+ monitor a secondary power supply?
Yes, the MAX805RCPA+ can monitor a secondary power supply using the PFI (Power-Fail Input) pin, which compares the applied voltage to a precise 1.237V internal reference. When the PFI voltage falls below this threshold, the open-drain PFO output goes low - enabling use as an undervoltage detector for auxiliary rails, battery voltage, or isolated DC-DC outputs without additional components.
What package type and RoHS status does the MAX805RCPA+ use?
The MAX805RCPA+ is supplied in an 8-pin plastic DIP (PDIP) package with 0.300" width and lead-free (RoHS-compliant) terminations, indicated by the "+" suffix per Maxim's ordering convention. It is rated for 0°C to +70°C operation (C-grade) and features standard through-hole mounting compatible with legacy PCB assembly processes.
MAX805RCPA+ 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:
- 2.625V
- Output:
- Open Drain or Open Collector
- Reset:
- Active High
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX805RCPA+ FAQ
1.How can I place an order for MAX805RCPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX805RCPA+ 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 MAX805RCPA+ reliable?
The price and inventory of MAX805RCPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX805RCPA+ is usually 5 days.
3.What payment methods are accepted for MAX805RCPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX805RCPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX805RCPA+?
MAX805RCPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX805RCPA+ 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 MAX805RCPA+?
For technical support, including MAX805RCPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX805RCPA+ requirements.
6.How does Aetrix verify that MAX805RCPA+ is sourced from the original manufacturer or authorized distributors?
All MAX805RCPA+ 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 MAX805RCPA+ meets industry standards.
7.What is the process for return or replacement of MAX805RCPA+?
All MAX805RCPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX805RCPA+, 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 MAX805RCPA+ part is unused and in its original packaging.
Return procedure for MAX805RCPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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