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Analog Devices Inc./Maxim Integrated MAX802MCSA
- Part No.:
- MAX802MCSA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX802MCSA.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,466
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Product details
Overview
MAX802MCSA from Maxim Integrated is a microprocessor supervisory IC providing reset generation, battery-backup switching, watchdog timer, and power-fail detection for +5V systems. It asserts active-low RESET during power-up, brownout (VCC < 4.40V), and watchdog timeout (1.6s), delivers VOUT from VCC or VBATT with 40mV switchover hysteresis, and features ±2% power-fail accuracy-used in battery-powered controllers requiring reliable μP startup and data retention.
For engineers reviewing the MAX802MCSA datasheet, MAX802MCSA pinout, MAX802MCSA application, or MAX802MCSA equivalent, key selection criteria include its 4.40V reset threshold, 200ms reset pulse width, 50nA battery-backup quiescent current, and compatibility with lithium backup batteries up to 4.55V.
Technical Context
The MAX802MCSA integrates a precision voltage monitor with 4.40V reset threshold (±2% over temperature), a 1.6s watchdog timer cleared by WDI edges or RESET assertion, and a dual-path power switch: a 5Ω PMOS connects VCC to VOUT during normal operation, while an 80Ω PMOS enables VBATT-to-VOUT switchover only when VCC falls below the reset threshold and VBATT exceeds VCC by >20mV.
Its power-fail comparator uses a 1.25V internal reference to drive PFO low when PFI drops below threshold; PFI input leakage is ≤25nA, enabling high-impedance voltage-divider sensing of unregulated rails. The device guarantees RESET assertion down to VCC = 1V and operates across 4.5V–5.5V supply range with 200μA typical supply current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.40V (guaranteed 4.25V–4.50V); triggers RESET on brownout and ensures μP remains held until stable +5V rail is restored |
| Reset Pulse Width | 200ms (140–280ms); provides sufficient hold time for μP initialization and peripheral settling |
| Watchdog Timeout | 1.6s (1.00–2.25s); detects software lockup without requiring external timing components |
| Battery-Backup Current | 50nA (max 1.0μA over temp); minimizes lithium battery drain during extended power loss |
| Power-Fail Accuracy | ±2% (guaranteed); enables precise early-warning detection of +5V regulator dropout before system failure |
| VOUT Switch Resistance | 5Ω (VCC→VOUT), 80Ω (VBATT→VOUT); limits voltage drop under 5mA load while isolating backup source during normal operation |
| Operating Supply Range | 4.5V to 5.5V; compatible with standard +5V ±10% supplies and supports robust brownout margin |
Pinout & Package
MAX802MCSA is housed in an 8-pin SOIC package (SO) with 1.27mm pitch, JEDEC MS-012AC compliant, and rated for 0°C to +70°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (via 5Ω PMOS) and VBATT (via 80Ω PMOS) based on reset threshold crossing and 40mV hysteresis |
| 2 - VCC | +5V main supply input | Primary power source; powers internal circuitry and drives VOUT unless brownout occurs |
| 3 - GND | Ground reference | Common return path for all analog and digital functions; must be low-impedance for accurate voltage monitoring |
| 4 - PFI | Power-fail comparator input | High-impedance (≤25nA leakage) node comparing external voltage divider to 1.25V reference for undervoltage warning |
| 5 - PFO | Power-fail output | Open-drain active-low signal indicating PFI < 1.25V; used to trigger μP interrupt or initiate graceful shutdown |
| 6 - WDI | Watchdog timer input | Edge-sensitive input; toggling within 1.6s prevents RESET assertion; floating or static state disables watchdog |
| 7 - RESET | Active-low reset output | Guaranteed logic-low from VCC ≥1V until 200ms after VCC rises above 4.40V; drives μP reset pin directly |
| 8 - VBATT | Backup battery input | Accepts 2.8V–4.55V lithium cells; enables automatic switchover to preserve RAM contents during main supply failure |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset threshold | 4.40V ±2% over full temperature range ensures consistent brownout response across industrial environments |
| Low-power backup mode | 50nA quiescent current at +25°C enables >10-year lithium battery life in standby applications |
| Controlled switchover hysteresis | 40mV hysteresis prevents oscillation during slow VCC droop, eliminating repeated RAM supply toggling |
| Guaranteed RESET at low VCC | RESET asserted down to VCC = 1V allows reliable reset initiation even during severe brownout conditions |
| Integrated power-fail comparator | 1.25V internal reference with 400ns response time enables fast detection of failing +5V regulators |
Applications
| Battery-Powered Controllers | Critical μP Power Monitoring |
|---|---|
Use Scenario: Industrial programmable logic controllers (PLCs) operating on primary AC/DC supply with lithium coin-cell backup. IC Role / Device Role / Timing Role: Supervisory IC asserting RESET during mains interruption and switching RAM to VBATT to retain configuration and I/O states. Use Value: Prevents data corruption and ensures deterministic restart after power recovery with no firmware intervention required. |
Use Scenario: Medical infusion pumps requiring fail-safe behavior during transient line sags or battery depletion. IC Role / Device Role / Timing Role: Monitors +5V rail with ±2% accuracy and triggers immediate shutdown sequence via PFO before critical voltage collapse. Use Value: Enables compliance with IEC 62304 safety requirements by guaranteeing controlled power-down prior to functional failure. |
| Intelligent Instruments | Embedded Data Loggers |
Use Scenario: Portable gas analyzers powered by rechargeable Li-ion with nonvolatile memory retention needs. IC Role / Device Role / Timing Role: Generates 200ms RESET pulse on power-up and monitors VCC to prevent μP execution during unstable boot. Use Value: Eliminates erratic sensor readings and flash write errors caused by marginal supply voltage during cold start. |
Use Scenario: Remote environmental sensors deployed in unattended locations with seasonal power constraints. IC Role / Device Role / Timing Role: Uses WDI to verify firmware liveness and asserts RESET if telemetry loop stalls, forcing watchdog-initiated reboot. Use Value: Ensures continuous data capture integrity without field maintenance, reducing operational downtime by >99.5%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX802LCSA | 4.60V reset threshold (vs. 4.40V); identical pinout, timing, and feature set | Suitable for +5V ±5% systems where higher trip point avoids nuisance resets during nominal ripple | Select MAX802LCSA when main supply regulation is tighter and brownout margin can be reduced |
| MAX706RCSA | 2.93V reset threshold; no battery switchover; includes manual reset input and watchdog output | Designed for lower-voltage systems (e.g., 3.3V μPs) without backup power requirements | Choose MAX706RCSA only if battery backup is unnecessary and 3.3V-compatible reset threshold is required |
Compared with MAX802LCSA, MAX802MCSA offers lower reset threshold for earlier brownout response in noisy +5V environments; versus MAX706RCSA, it provides integrated battery switchover but lacks manual reset-making it optimal for sealed, battery-backed embedded controllers.
Availability
MAX802MCSA is available at Aetrix Electronics and suitable for battery-powered controllers, intelligent instruments, critical μP power monitoring, and embedded data loggers requiring stable component supply across industrial temperature ranges.
Supply support for MAX802MCSA 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 industrial, medical, and communications applications, with expertise in power management and reliability-critical circuits.
The MAX802MCSA belongs to Maxim's microprocessor supervisory product line, engineered specifically for robust power-up sequencing, brownout protection, and nonvolatile memory retention in battery-backed embedded systems.
FAQ
What is the guaranteed reset threshold voltage for MAX802MCSA?
The MAX802MCSA has a guaranteed reset threshold of 4.40V, specified from 4.25V (min) to 4.50V (max) over the full operating temperature range. This value is confirmed in the Electrical Characteristics table of the official datasheet and applies specifically to the MAX802M variant. The threshold is factory-trimmed and tested, ensuring consistent brownout detection across production units.
Does MAX802MCSA support lithium battery backup, and what is the maximum allowable VBATT voltage?
Yes, MAX802MCSA supports lithium battery backup with a maximum allowable VBATT voltage of 4.55V, as documented in Table 2 of the datasheet. This limit prevents substrate diode conduction when VCC approaches the reset threshold. Typical use cases employ 3.0V–3.6V lithium cells, which operate safely within this constraint and deliver ultra-low 50nA backup current.
How does the watchdog timer in MAX802MCSA function, and what is its timeout period?
The MAX802MCSA watchdog timer times out after 1.6 seconds (1.00–2.25s range) if the WDI pin remains static-either high, low, or floating. It clears on any rising or falling edge at WDI, on RESET assertion, or when WDI is three-stated. The timer resumes counting immediately after RESET deassertion, requiring continuous firmware servicing to prevent unintended reset pulses.
What is the purpose of the 40mV hysteresis in MAX802MCSA's battery switchover circuit?
The 40mV hysteresis in MAX802MCSA's battery switchover prevents rapid toggling between VCC and VBATT during slow or noisy VCC droop. Switchover occurs at VCC = VBATT − 20mV on power-down and reverts at VCC = VBATT + 20mV on recovery-ensuring stable VOUT delivery to CMOS RAM without supply glitches that could corrupt memory contents.
Can MAX802MCSA be used without a backup battery, and how should VBATT be handled in that case?
Yes, MAX802MCSA can operate without a backup battery: ground the VBATT pin and connect VOUT directly to VCC. This bypasses the internal switchover circuitry, eliminating voltage drop across the 5Ω PMOS switch and ensuring VOUT matches VCC exactly-ideal for cost-sensitive designs where data retention during power loss is not required.
MAX802MCSA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.4V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX802MCSA FAQ
1.How can I place an order for MAX802MCSA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX802MCSA 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 MAX802MCSA reliable?
The price and inventory of MAX802MCSA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX802MCSA is usually 5 days.
3.What payment methods are accepted for MAX802MCSA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX802MCSA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX802MCSA?
MAX802MCSA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX802MCSA 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 MAX802MCSA?
For technical support, including MAX802MCSA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX802MCSA requirements.
6.How does Aetrix verify that MAX802MCSA is sourced from the original manufacturer or authorized distributors?
All MAX802MCSA 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 MAX802MCSA meets industry standards.
7.What is the process for return or replacement of MAX802MCSA?
All MAX802MCSA units undergo pre-shipment inspection (PSI). If there is an issue with MAX802MCSA, 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 MAX802MCSA part is unused and in its original packaging.
Return procedure for MAX802MCSA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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