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Analog Devices Inc./Maxim Integrated MAX802RCSA+
- Part No.:
- MAX802RCSA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX802RCSA+.pdf
- Description:
- IC SUPERVISOR MPU 8-SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,986
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Product details
Overview
MAX802RCSA+ from Maxim Integrated is a 3.0V/3.3V microprocessor supervisory circuit with precision reset threshold (2.625V ±2%), 200ms reset timeout, watchdog timer (1.6s), battery-backup switchover, and power-fail detection. It monitors VCC supply integrity, asserts active-low RESET during brownout or watchdog timeout, and switches VOUT to VBATT when VCC falls below 2.40V-enabling reliable CMOS RAM retention in portable controllers and embedded systems.
For engineers reviewing the MAX802RCSA+ datasheet, MAX802RCSA+ pinout, MAX802RCSA+ application, or MAX802RCSA+ equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in battery-backed µP systems, and two validated alternative parts with documented functional and tolerance differences.
Technical Context
The MAX802RCSA+ integrates a precision reset comparator with 2.625V nominal threshold (±2% tolerance on VCC falling), a 1.6s watchdog timer cleared by WDI edges, and a dual-path power switch: VCC-to-VOUT via 3Ω PMOS and VBATT-to-VOUT via 140Ω NMOS. Its PFI input accepts external voltage dividers for auxiliary supply monitoring, while PFO provides open-drain power-fail signaling.
Battery switchover activates when VCC drops below VSW = 2.40V (typ) and VBATT > VCC, ensuring VOUT remains ≥2.0V for CMOS RAM retention. The device guarantees RESET assertion down to VCC = 1.0V and supports manual reset via MR with internal 70µA pull-up and 200ms deassertion delay.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.625V ±2% (VCC falling); ensures reliable reset before 3.0V system drops below 2.59V minimum operating voltage. |
| Reset Timeout Period | 200ms (typ); holds µP in reset long enough for stable power recovery and clock stabilization. |
| Watchdog Timeout | 1.6s (typ); 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 equipment. |
| Battery Supply Current | 0.4–1µA (max, TA = –40°C to +85°C); minimizes backup battery drain during extended standby. |
| Power-Fail Threshold | 1.237V ±20mV (PFI input); allows accurate monitoring of auxiliary supplies via resistor divider. |
| VCC-to-VOUT On-Resistance | 3Ω (typ, VCC = 3.3V); limits voltage drop under 50mA load, preserving VOUT regulation for RAM. |
Pinout & Package
MAX802RCSA+ is housed in an 8-pin SOIC package (SO, 150mil width), RoHS-compliant with lead-free finish (+ suffix). Pin spacing is 1.27mm, body dimensions 4.9 × 3.9 × 1.75mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Supply output for CMOS RAM | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω NMOS) based on VCC/VBATT comparison; must be decoupled with 0.1µF capacitor. |
| 2 - VCC | Main supply input | Accepts 2.72V–5.5V; powers internal circuitry and sources VOUT when above reset threshold; absolute max = +6.0V. |
| 3 - GND | Ground reference | Common return for all analog/digital functions; substrate tied to higher of VCC or VBATT-must be floated in hybrid designs. |
| 4 - PFI | Power-fail input | Compares external voltage to 1.237V reference; triggers PFO low when input falls below threshold or VCC drops below 2.40V. |
| 5 - PFO | Power-fail output | Open-drain, active-low signal indicating power failure or low-battery condition; can drive MR on MAX704/MAX806. |
| 6 - WDI | Watchdog input | Edge-sensitive (rising/falling); clears 1.6s timer on transition; tied high/low causes periodic reset; cannot be disabled. |
| 7 - RESET | Active-low reset output | Push-pull, asserted low during power-up, brownout, or watchdog timeout; guaranteed valid down to VCC = 1.0V. |
| 8 - VBATT | Backup-battery input | Accepts up to 6.0V; connects to VOUT when VCC < 2.40V; lithium cell (e.g., 3.6V) may exceed VCC without damage. |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset threshold | ±2% tolerance (vs. ±4% in MAX690/MAX704) enables tighter margin control in 3.0V ±10% systems. |
| Guaranteed RESET assertion to VCC = 1V | Ensures deterministic µP reset even during deep brownout, critical for fail-safe embedded controllers. |
| Battery switchover at 2.40V | Activates before VOUT reaches 2.0V RAM retention limit, maximizing backup time without premature switching. |
| 40µA VCC supply current | Reduces quiescent power in always-on monitoring circuits, extending battery life in portable instrumentation. |
| 1µA battery leakage current | Minimizes self-discharge of backup cells over years of storage, supporting long-term data retention in industrial loggers. |
Applications
| Battery-Powered Portable Controllers | Embedded µP Power Monitoring |
|---|---|
Use Scenario: Handheld test equipment powered by Li-ion battery with 3.3V regulator, requiring RAM retention during battery swap. IC Role / Device Role / Timing Role: Supervisory IC providing VCC monitoring, 200ms reset hold, and automatic VBATT switchover to VOUT at 2.40V. Use Value: Prevents RAM corruption during hot-swap by maintaining VOUT ≥2.0V for >10 seconds using 3.6V lithium cell. |
Use Scenario: Industrial PLC module with 3.0V core supply, needing immunity to 100mV/40µs VCC transients. IC Role / Device Role / Timing Role: Precision reset generator with glitch-immune comparator and 200ms timeout. Use Value: Avoids spurious resets from switching noise while asserting reset within 200ms of true brownout. |
| Intelligent Sensor Nodes | Critical µP Systems with Watchdog |
Use Scenario: Wireless environmental sensor node sleeping for hours, waking periodically to sample and transmit. IC Role / Device Role / Timing Role: Low-current (40µA) supervisor enabling battery life extension and PFI-based low-battery warning. Use Value: Detects battery depletion via PFI divider and signals host µP through PFO before capacity falls below operational threshold. |
Use Scenario: Medical infusion pump controller where µP lockup could cause hazardous delivery errors. IC Role / Device Role / Timing Role: Independent hardware watchdog with 1.6s timeout, cleared only by WDI edge transitions. Use Value: Forces hard reset if firmware hangs, eliminating need for user intervention and meeting IEC 62304 safety requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX802TCSA+ | Higher reset threshold (3.075V ±2%) for 3.3V ±5% systems; identical pinout, package, and feature set. | Suitable for 3.3V rails with tighter supply tolerance; not interchangeable where 2.625V threshold is required for brownout detection. | Select MAX802TCSA+ when system VCC nominal is 3.3V and brownout must occur above 3.0V. |
| MAX802SCSA+ | Mid-range reset threshold (2.925V ±2%) optimized for 3.3V ±10% supplies; same SOIC-8 package and electrical specs. | Used where supply variation spans 2.98V–3.63V; provides earlier reset than T-version but later than R-version. | Choose MAX802SCSA+ for general-purpose 3.3V systems needing balanced margin between noise immunity and early fault detection. |
Compared with MAX802TCSA+ and MAX802SCSA+, the MAX802RCSA+ offers the lowest reset threshold in the family, enabling earliest brownout response in 3.0V systems or noisy 3.3V environments-critical for preserving state in low-voltage battery operation.
Availability
MAX802RCSA+ 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 (–40°C to +85°C).
Supply support for MAX802RCSA+ 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, automotive, and computing markets.
The MAX802RCSA+ belongs to Maxim's microprocessor supervisory product line, engineered specifically for robust power-monitoring and fail-safe reset generation in 3.0V/3.3V battery-backed embedded systems.
FAQ
What is the exact reset threshold voltage for MAX802RCSA+?
The MAX802RCSA+ has a nominal reset threshold of 2.625V with ±2% tolerance on VCC falling. This means reset is guaranteed to assert before VCC falls below 2.59V and will not assert until VCC drops below 2.67V under typical conditions-optimized for 3.0V ±10% power supplies.
Does MAX802RCSA+ support battery switchover when VBATT exceeds VCC?
Yes, the MAX802RCSA+ explicitly supports VBATT > VCC operation. Its internal battery switchover circuit activates when VCC falls below 2.40V (VSW) and VBATT > VCC, connecting VBATT to VOUT through a 140Ω switch-enabling use of standard 3.6V lithium backup cells without level-shifting.
Can the watchdog timer in MAX802RCSA+ be disabled?
No, the watchdog timer in MAX802RCSA+ cannot be disabled. It is permanently enabled and triggers a reset if the WDI pin remains static (high or low) for longer than 1.6s. The timer clears only on rising or falling edges at WDI or during active RESET assertion.
What is the function of the PFI and PFO pins on MAX802RCSA+?
The PFI pin on MAX802RCSA+ accepts an external voltage (e.g., from a resistor divider) for auxiliary supply monitoring; it compares against a 1.237V internal reference. When PFI falls below that threshold-or when VCC drops below 2.40V-the open-drain PFO pin pulls low to signal power failure or low-battery condition.
Is MAX802RCSA+ compatible with 5V systems?
No, MAX802RCSA+ is designed exclusively for 3.0V/3.3V systems. Its operating voltage range is 2.72V to 5.5V, but its reset threshold (2.625V), PFI reference (1.237V), and internal comparators are calibrated for 3.0V/3.3V rails. For 5V systems, use the MAX690 or MAX704 families instead.
MAX802RCSA+ 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:
- -
MAX802RCSA+ FAQ
1.How can I place an order for MAX802RCSA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX802RCSA+ 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 MAX802RCSA+ reliable?
The price and inventory of MAX802RCSA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX802RCSA+ is usually 5 days.
3.What payment methods are accepted for MAX802RCSA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX802RCSA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX802RCSA+?
MAX802RCSA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX802RCSA+ 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 MAX802RCSA+?
For technical support, including MAX802RCSA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX802RCSA+ requirements.
6.How does Aetrix verify that MAX802RCSA+ is sourced from the original manufacturer or authorized distributors?
All MAX802RCSA+ 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 MAX802RCSA+ meets industry standards.
7.What is the process for return or replacement of MAX802RCSA+?
All MAX802RCSA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX802RCSA+, 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 MAX802RCSA+ part is unused and in its original packaging.
Return procedure for MAX802RCSA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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