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Analog Devices Inc./Maxim Integrated MAX802SCSA+T
- Part No.:
- MAX802SCSA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX802SCSA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,871
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Product details
Overview
MAX802SCSA+T from Maxim Integrated is a 3.3V/3.0V microprocessor supervisory circuit with active-low RESET output, 2.925V reset threshold (S suffix), 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover-designed for reliable power monitoring in embedded controllers and battery-powered systems.
For engineers reviewing the MAX802SCSA+T datasheet, MAX802SCSA+T pinout, MAX802SCSA+T application, or MAX802SCSA+T equivalent, this page delivers verified specifications, package mapping, functional alternatives, and design-critical timing behavior-including VCC-to-VBATT switchover at 2.40V, guaranteed RESET assertion down to VCC = 1V, and ±2% reset threshold accuracy.
Technical Context
The MAX802SCSA+T integrates a precision voltage monitor, 1.6s watchdog timer with edge-triggered reset clearing, manual reset input (MR) with internal 70µA pull-up, and dual-path power-fail detection via PFI/PFO. Its battery switchover circuit uses a 140Ω VBATT-to-VOUT switch activated when VCC falls below 2.40V (VSW) and VBATT > VCC-or below 1.75V regardless of VBATT.
It features an open-drain active-high RESET output (inverse of RESET), 1.237V power-fail comparator threshold (±20mV hysteresis), and operates across –40°C to +85°C in SO-8 package. The device guarantees valid reset assertion for VCC ≥ 1V and supports CMOS RAM backup without external diodes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V (VCC falling), ±2% tolerance - ensures reliable brownout detection before system instability in 3.3V ±10% supplies. |
| Reset Timeout Period | 200ms (typical), 140–280ms over temperature - provides sufficient hold time for µP initialization after power recovery. |
| Watchdog Timeout | 1.6s (typical), 1.12–2.24s over temperature - enables robust firmware hang detection without false triggers from transient noise. |
| VCC Supply Current | 40–50µA (VCC < 3.6V), 50–65µA (VCC < 5.5V) - minimizes quiescent load on primary supply during normal operation. |
| VBATT Supply Current | 0.4–1µA (C/E grade) - preserves lithium battery life for multi-year backup in portable equipment. |
| Battery Switchover Threshold | VSW = 2.40V (typical), 65mV hysteresis - initiates backup before VOUT drops below 2.0V, ensuring CMOS RAM data retention. |
| Power-Fail Input Threshold | VPFT = 1.237V ±25mV - supports accurate undervoltage monitoring of auxiliary rails via external resistor divider. |
Pinout & Package
MAX802SCSA+T is housed in an 8-pin SOIC (SO-8) package with standard 1.27mm pitch, RoHS-compliant lead-free finish (+ suffix), and moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω NMOS) based on VSW; must be decoupled with 0.1µF capacitor. |
| 2 - VCC | Main supply input | Accepts 2.72V–5.5V (for S version); powers internal circuitry and asserts RESET when below 2.925V. |
| 3 - GND | Ground reference | Common return for all analog/digital functions; requires low-inductance connection to minimize noise coupling. |
| 4 - PFI | Power-fail input | Compares against 1.237V reference; drives PFO low when input falls below threshold-used for auxiliary rail monitoring. |
| 5 - PFO | Power-fail output | Open-drain active-low signal; can be tied to MR on compatible devices (e.g., MAX704) to trigger reset on secondary supply failure. |
| 6 - WDI | Watchdog input | Edge-sensitive (rising/falling); clears 1.6s timer on transition; cannot be disabled-ensures continuous firmware health check. |
| 7 - RESET | Active-high open-drain reset | Inverse of RESET; requires external pull-up to VCC; asserts high for 200ms after brownout, watchdog timeout, or MR release. |
| 8 - VBATT | Battery backup input | Accepts up to 6.0V; may exceed VCC during normal operation; connects to VOUT when VCC < VSW or <1.75V. |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset threshold | ±2% accuracy (vs. ±4% in MAX690/MAX704) - reduces false resets and improves margin for 3.3V ±10% systems. |
| Battery switchover control | VSW = 2.40V with 25mV hysteresis - prevents oscillation during VCC decay and extends battery life by delaying switchover. |
| Guaranteed low-VCC reset | RESET asserted down to VCC = 1V - ensures safe µP halt even during deep brownout conditions where other supervisors fail. |
| Low-power operation | 40µA VCC current (VCC < 3.6V), 0.4µA VBATT leakage - enables multi-year operation on coin-cell batteries in portable instruments. |
| Integrated watchdog timer | 1.6s timeout with edge-triggered clear - eliminates need for external RC timing components and improves reliability vs. discrete solutions. |
Applications
| Battery-Powered Embedded Controllers | Intelligent Portable Instruments |
|---|---|
Use Scenario: Industrial handheld meter with lithium backup maintaining SRAM during main power loss. IC Role / Device Role / Timing Role: Supervisory IC providing VCC brownout detection, automatic VBATT switchover at 2.40V, and 200ms RESET hold for µP safe shutdown. Use Value: Prevents data corruption in nonvolatile memory by guaranteeing RESET assertion before VOUT drops below 2.0V. |
Use Scenario: Portable medical diagnostic device requiring long-term battery-backed configuration storage. IC Role / Device Role / Timing Role: Dual-role supervisor: monitors main 3.3V rail and provides 1.237V PFI threshold for auxiliary sensor supply monitoring. Use Value: Enables single-chip detection of both primary supply failure and secondary rail collapse-reducing BOM count by one comparator IC. |
| Critical µP Power Monitoring | Portable Computing Systems |
Use Scenario: Ruggedized edge controller operating in automotive-grade temperature range (–40°C to +85°C). IC Role / Device Role / Timing Role: Precision reset generator with ±2% threshold and 1.6s watchdog - detects firmware hangs and supply sags beyond 10% tolerance. Use Value: Eliminates need for external voltage reference or timing capacitor, improving layout density and thermal stability. |
Use Scenario: Fanless tablet with 3.0V SoC and coin-cell backup for real-time clock and BIOS settings. IC Role / Device Role / Timing Role: Battery switchover manager connecting VBATT to VOUT only when VCC falls below 2.40V - avoids premature battery drain. Use Value: Extends coin-cell life by >3× vs. fixed-diode solutions due to low 0.4µA VBATT leakage and controlled switchover point. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX802TCSA+T | Reset threshold = 3.075V (T suffix), same SO-8 package and pinout. | Designed for 3.3V ±5% systems; less tolerant of supply sag than S version. | Select when system nominal VCC is stable at 3.3V with tight regulation and minimal ripple. |
| MAX802RCSA+T | Reset threshold = 2.625V (R suffix), same SO-8 package and pinout. | Optimized for 3.0V ±10% supplies; asserts reset later than S version during brownout. | Choose for battery-powered systems where extended runtime before reset is critical, e.g., energy-harvesting nodes. |
Compared with MAX802SCSA+T, the T-suffix variant offers higher reset voltage for tighter 3.3V rails, while the R-suffix variant delays reset assertion to maximize uptime in low-voltage battery systems-both share identical watchdog, switchover, and PFI functionality but differ only in reset threshold calibration.
Availability
MAX802SCSA+T is available at Aetrix Electronics and suitable for battery-powered computers and controllers, intelligent instruments, and critical µP power monitoring requiring stable component supply across industrial temperature ranges.
Supply support for MAX802SCSA+T 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, communications, and computing applications.
The MAX802 series belongs to Maxim's microprocessor supervisory product line, engineered specifically for robust power monitoring and battery backup in 3.0V/3.3V embedded systems with stringent reliability requirements.
FAQ
What is the exact reset threshold voltage for MAX802SCSA+T?
The MAX802SCSA+T has a nominal reset threshold voltage of 2.925V (VCC falling), with ±2% tolerance over temperature and supply variation. This value is factory-trimmed and specified in the Electrical Characteristics table under VRST for MAX802S variants. It ensures reliable reset assertion before VCC drops below 2.85V in 3.3V ±10% systems.
Does MAX802SCSA+T support battery voltage higher than VCC?
Yes, MAX802SCSA+T explicitly supports VBATT exceeding VCC during normal operation-up to 6.0V per Absolute Maximum Ratings. Its internal switchover circuit activates when VCC falls below 2.40V (VSW) and VBATT > VCC, enabling use with standard 3.6V lithium cells without external diodes or level-shifting.
How does the watchdog timer in MAX802SCSA+T function?
The MAX802SCSA+T watchdog timer has a 1.6s timeout (1.12–2.24s over temperature) and is cleared only by rising or falling edges on WDI-not by static logic levels. If WDI remains high or low for >1.6s, RESET is asserted. Unlike older families, the watchdog cannot be disabled, ensuring continuous firmware supervision.
Can MAX802SCSA+T operate without a backup battery?
Yes, MAX802SCSA+T can operate without a backup battery: connect VBATT and VOUT pins directly to VCC. However, battery-switchover and RAM backup functions are then inactive. For pure reset-only applications without backup, alternatives like MAX706SCSA+T may offer lower cost and reduced feature set.
What is the purpose of the PFI and PFO pins on MAX802SCSA+T?
PFI is a dedicated input compared to a 1.237V internal reference; when PFI falls below this threshold, PFO (an open-drain output) pulls low. This allows monitoring of auxiliary power rails (e.g., 5V or analog supplies) using an external resistor divider. PFO can also drive MR on compatible devices like MAX704 to generate cascaded resets.
MAX802SCSA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.925V
- 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
MAX802SCSA+T FAQ
1.How can I place an order for MAX802SCSA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX802SCSA+T 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 MAX802SCSA+T reliable?
The price and inventory of MAX802SCSA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX802SCSA+T is usually 5 days.
3.What payment methods are accepted for MAX802SCSA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX802SCSA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX802SCSA+T?
MAX802SCSA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX802SCSA+T 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 MAX802SCSA+T?
For technical support, including MAX802SCSA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX802SCSA+T requirements.
6.How does Aetrix verify that MAX802SCSA+T is sourced from the original manufacturer or authorized distributors?
All MAX802SCSA+T 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 MAX802SCSA+T meets industry standards.
7.What is the process for return or replacement of MAX802SCSA+T?
All MAX802SCSA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX802SCSA+T, 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 MAX802SCSA+T part is unused and in its original packaging.
Return procedure for MAX802SCSA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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