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Analog Devices Inc./Maxim Integrated MAX704RCPA+
- Part No.:
- MAX704RCPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX704RCPA+.pdf
- Description:
- IC SUPERVISOR MPU 8-DIP
- Quantity:
- Payment:
- Shipping:
Inventory:421
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Product details
Overview
MAX704RCPA+ from Maxim Integrated is a 3.0V/3.3V microprocessor supervisory circuit with active-low RESET output, 2.625V reset threshold (R-suffix), 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover capability. It monitors VCC for brownout detection, asserts reset during power-up/down, and supports CMOS RAM backup via VBATT–VOUT switching in embedded controllers and portable equipment.
For engineers reviewing the MAX704RCPA+ datasheet, MAX704RCPA+ pinout, MAX704RCPA+ application, or MAX704RCPA+ equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in battery-powered systems, and validated alternative parts with documented functional differences.
Technical Context
The MAX704RCPA+ integrates a precision reset comparator with ±4% threshold tolerance (2.55V–2.70V at VCC falling), a 1.6s watchdog timer that clears on WDI edge transitions, and a dual-path power switch: VCC-to-VOUT via 3Ω PMOS and VBATT-to-VOUT via 140Ω NMOS. Its battery switchover triggers when VCC falls below 2.40V (VSW) while VBATT > VCC, ensuring CMOS RAM retention before VOUT drops below 2.0V.
It features a manual reset input (MR) with internal 70µA pull-up, PFI/PFO for external power-fail monitoring (1.237V threshold, ±10mV hysteresis), and guaranteed RESET assertion down to VCC = 1.0V. The device operates across 0°C to +70°C in 8-pin SO package and draws only 40µA from VCC under typical conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.625V nominal (2.55V–2.70V range); ensures reliable reset assertion before 3.0V supply falls below system minimum operating voltage. |
| Reset Timeout Period | 200ms (140–280ms over temperature); guarantees µP remains held in reset long enough for stable power rail recovery. |
| VCC Supply Current | 40µA typical (≤50µA max at VCC < 3.6V); enables ultra-low-power operation in battery-backed portable systems. |
| Watchdog Timeout | 1.6s (1.12–2.24s over temperature); provides robust firmware hang detection without requiring external timing components. |
| Battery Leakage Current | 0.01–0.5µA (max); minimizes self-discharge of lithium coin cells during long-term storage or standby. |
| VBATT Switch Threshold | 2.40V (2.30–2.50V); initiates switchover to backup power early enough to preserve RAM data but late enough to maximize battery life. |
| PFO Input Threshold | 1.237V ±25mV; allows accurate monitoring of auxiliary rails (e.g., 5V or -12V) using external resistor dividers. |
Pinout & Package
MAX704RCPA+ is housed in an 8-pin SOIC (Small Outline Integrated Circuit) package with 1.27mm pitch, RoHS-compliant lead-free finish (+ suffix), and standard JEDEC MS-012 outline.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω NMOS); must be decoupled with 0.1µF capacitor near load. |
| 2 - VCC | Main system supply input | Accepts 2.72V–5.5V; powers internal circuitry and enables reset assertion down to 1.0V; requires local 0.1µF bypass. |
| 3 - GND | Ground reference | Common return for all analog/digital functions; substrate tied to higher of VCC/VBATT-must remain floating in hybrid designs. |
| 4 - PFI | Power-fail input | Monitors auxiliary voltage via external divider; asserts PFO low when input falls below 1.237V; connect to GND if unused. |
| 5 - PFO | Power-fail open-drain output | Active-low signal indicating VCC drop or PFI undervoltage; can drive MR on MAX704/806 to trigger system reset. |
| 6 - WDI | Watchdog timer input | Edge-sensitive (rising/falling); resets internal 1.6s timer; tied high/low causes periodic reset-cannot be disabled. |
| 7 - RESET | Active-low reset output | Push-pull, not open-drain; drives µP reset pin directly; stays low for 200ms after VCC rise/MR release/watchdog timeout. |
| 8 - VBATT | Backup battery input | Accepts up to 6.0V; may exceed VCC; connects to VOUT during brownout; decouple with 0.1µF capacitor to ground. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset behavior even during deep brownouts where other supervisors lose functionality. |
| Battery-backup switchover with 2.40V threshold | Optimizes RAM data retention time while preventing premature battery drain by delaying switchover until critical voltage. |
| 200ms programmable reset timeout | Eliminates need for external RC timing network-reduces BOM count and improves production consistency. |
| 40µA VCC supply current (typ) | Extends operational lifetime in always-on battery-powered devices such as medical sensors and IoT edge nodes. |
| 1.6s watchdog timer with edge-clearing | Prevents false resets from noise or glitches by requiring WDI transitions-not just level changes-to reset the timer. |
Applications
| Battery-Powered Portable Equipment | Embedded Controller Power Monitoring |
|---|---|
Use Scenario: Handheld test instruments and portable data loggers powered by single-cell Li-ion batteries with 3.0V nominal output. IC Role / Device Role / Timing Role: Supervises main 3.0V rail, asserts RESET during battery sag or charger disconnect, and switches RAM to backup cell before VOUT drops below 2.0V. Use Value: Prevents data corruption during transient brownouts and extends usable runtime by minimizing battery leakage (0.5µA max). |
Use Scenario: Industrial PLC modules with isolated 3.3V logic supplies and nonvolatile SRAM for configuration storage. IC Role / Device Role / Timing Role: Monitors VCC for undervoltage events, triggers watchdog reset on firmware lockup, and maintains RAM power via VBATT during AC mains failure. Use Value: Guarantees deterministic reset timing (200ms) and eliminates need for discrete reset IC + watchdog + power switch combo. |
| Intelligent Instrumentation | Critical µP Power Monitoring |
Use Scenario: Digital multimeters and oscilloscopes with real-time clock and calibration memory backed by coin-cell battery. IC Role / Device Role / Timing Role: Provides precise 2.625V reset threshold aligned to 3.0V system tolerance, detects power-fail via PFI, and isolates backup battery from main rail. Use Value: Achieves ±4% reset accuracy and <0.5µA battery leakage-critical for 10-year shelf-life requirements. |
Use Scenario: Medical infusion pumps requiring IEC 62304 compliance and zero-reset-failure operation during power transitions. IC Role / Device Role / Timing Role: Acts as primary power supervisor for ARM Cortex-M4 µP; asserts RESET within 1µs of VCC crossing 2.625V, with 200ms hold time. Use Value: Meets Class C safety requirements via guaranteed reset assertion down to VCC = 1.0V and no single-point failure mode. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704SCPA+ | Higher reset threshold (2.925V vs. 2.625V); tighter ±2% tolerance on newer revision. | Suitable for 3.3V ±10% systems where earlier reset assertion is undesirable. | Select MAX704SCPA+ when monitoring 3.3V rails with wider tolerance; avoid for 3.0V systems needing lower trip point. |
| MAX805RCSA+ | Active-high open-drain RESET output (vs. push-pull); identical reset threshold and watchdog specs. | Required for µPs with bidirectional reset pins or systems needing wired-OR reset bus architecture. | Choose MAX805RCSA+ only when interface compatibility demands active-high/open-drain; otherwise MAX704RCPA+ offers simpler direct drive. |
Compared with MAX704RCPA+, MAX704SCPA+ raises the reset threshold by 300mV-delaying reset assertion in marginal 3.3V supplies-while MAX805RCSA+ changes the reset output topology to open-drain, enabling shared reset buses but requiring external pull-up and adding interface complexity.
Availability
MAX704RCPA+ is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, and intelligent instrumentation requiring stable component supply across industrial temperature ranges and long-lifecycle programs.
Supply support for MAX704RCPA+ 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 MAX704 series belongs to Maxim's microprocessor supervisory product line, designed specifically for reliable power monitoring and reset generation in 3.0V/3.3V embedded systems with battery backup requirements.
FAQ
What is the exact reset threshold voltage for MAX704RCPA+?
The MAX704RCPA+ has a nominal reset threshold of 2.625V, with a guaranteed range of 2.55V to 2.70V when VCC is falling. This value is fixed by the "R" suffix and optimized for 3.0V ±10% power supplies. The threshold exhibits 10mV typical hysteresis to prevent oscillation during slow VCC ramps, and the device guarantees RESET assertion down to VCC = 1.0V regardless of VBATT status.
Does MAX704RCPA+ support battery-backup switchover, and what are the switching thresholds?
Yes, MAX704RCPA+ supports automatic battery-backup switchover. It connects VOUT to VBATT when VCC falls below 2.40V (VSW, range 2.30V–2.50V) and VBATT exceeds VCC, or when VCC drops below 1.75V regardless of VBATT. Switchover back to VCC occurs when VCC rises above the 2.625V reset threshold. The internal switches have 3Ω (VCC→VOUT) and 140Ω (VBATT→VOUT) on-resistance, enabling reliable CMOS RAM retention.
Can the watchdog timer in MAX704RCPA+ be disabled?
No, the watchdog timer in MAX704RCPA+ cannot be disabled. It is permanently enabled and times out after 1.6 seconds (1.12–2.24s over temperature) if the WDI pin remains static-either high or low. The timer clears only on rising or falling edges at WDI or during active RESET assertion. This design ensures continuous firmware health monitoring without configuration overhead or failure modes from accidental disablement.
What is the function of the PFI and PFO pins on MAX704RCPA+?
On MAX704RCPA+, PFI is a dedicated input for monitoring auxiliary power rails via an external resistor divider, with a precise 1.237V threshold (±25mV). When PFI falls below this level-or when VCC drops below VSW-PFO goes low as an open-drain signal. PFO can be connected to MR to generate a system reset on power-fail events, or used independently as an interrupt source for the µP. If unused, PFI must be grounded and PFO left floating.
Is MAX704RCPA+ pin-compatible with other parts in the MAX704 family?
Yes, MAX704RCPA+ is fully pin-compatible with all MAX704x variants (e.g., MAX704TCPA+, MAX704SCPA+) in the same 8-pin SOIC package. The only differences are reset threshold voltage (determined by suffix T/S/R) and minor electrical specifications like threshold tolerance. No PCB layout changes are required when substituting within the MAX704 family, provided the target application aligns with the selected threshold and temperature grade.
MAX704RCPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- -
- Number of Voltages Monitored:
- -
- Voltage - Threshold:
- -
- Output:
- -
- Reset:
- -
- Reset Timeout:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
MAX704RCPA+ FAQ
1.How can I place an order for MAX704RCPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX704RCPA+ 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 MAX704RCPA+ reliable?
The price and inventory of MAX704RCPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX704RCPA+ is usually 5 days.
3.What payment methods are accepted for MAX704RCPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX704RCPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX704RCPA+?
MAX704RCPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX704RCPA+ 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 MAX704RCPA+?
For technical support, including MAX704RCPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX704RCPA+ requirements.
6.How does Aetrix verify that MAX704RCPA+ is sourced from the original manufacturer or authorized distributors?
All MAX704RCPA+ 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 MAX704RCPA+ meets industry standards.
7.What is the process for return or replacement of MAX704RCPA+?
All MAX704RCPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX704RCPA+, 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 MAX704RCPA+ part is unused and in its original packaging.
Return procedure for MAX704RCPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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