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Analog Devices Inc./Maxim Integrated MAX690SESA+T
- Part No.:
- MAX690SESA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX690SESA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,127
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Product details
Overview
MAX690SESA+T from Maxim Integrated is a 3.3V microprocessor supervisory circuit with active-low RESET output, 2.925V reset threshold, 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover. It monitors VCC supply integrity, asserts reset during brownout or watchdog timeout, and switches CMOS RAM to VBATT when VCC drops below 2.40V-used in embedded controllers and portable equipment requiring reliable power sequencing.
For engineers reviewing the MAX690SESA+T datasheet, MAX690SESA+T pinout, MAX690SESA+T application, or MAX690SESA+T equivalent, this page delivers verified specifications, validated pin functions, confirmed operating conditions (–40°C to +85°C), and real-world design implications for battery-backed µP systems.
Technical Context
The MAX690SESA+T integrates a precision reset comparator with ±4% threshold tolerance, 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 reset assertion is guaranteed down to VCC = 1V, and it supports manual reset with internal 70µA pull-up.
It features independent power-fail detection (PFI/PFO) with 1.237V threshold and 10mV hysteresis, and operates across VCC = 3.02V–5.5V (for S-version). Battery leakage is limited to ≤1µA, and VCC supply current is 40µA typical at VCC < 3.6V-enabling low-power retention in critical embedded applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V (VCC falling), ±4% tolerance - ensures reset triggers before 3.3V supply drops below 2.85V system margin |
| Reset Timeout Period | 200ms (typical) - guarantees µP remains held in reset long enough for stable power recovery |
| Watchdog Timeout | 1.6s - detects µP lockup without requiring software intervention or external timing components |
| VCC Supply Current | 40µA (typ, VCC < 3.6V) - enables multi-year operation from coin-cell backup in standby mode |
| Battery Supply Current | 0.4–1µA - minimizes drain on lithium backup cells during extended power-loss events |
| VBATT Switch Threshold | 2.40V (VCC rising) - initiates switchover to battery before VOUT falls below 2.0V RAM retention limit |
| Operating Temp Range | –40°C to +85°C - qualified for industrial-grade embedded controller deployment |
Pinout & Package
MAX690SESA+T is housed in an 8-pin SO (Small Outline) package, RoHS-compliant (indicated by '+' suffix), with 1.27mm pitch and surface-mount footprint per land pattern 90-0096.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT | Supply output for CMOS RAM | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω NMOS); must be decoupled with 0.1µF capacitor |
| VCC | Main supply input | Accepts 3.02V–5.5V; powers internal circuitry and drives VOUT when above reset threshold |
| GND | Ground reference | Common return for all analog/digital functions; requires low-inductance connection to system ground plane |
| PFI | Power-fail input | Monitors external supply via voltage divider; trips PFO low when input falls below 1.237V |
| PFO | Power-fail output | Open-drain active-low signal indicating undervoltage condition on PFI or VCC drop below 2.40V |
| WDI | Watchdog input | Edge-sensitive (rising/falling); resets watchdog timer; tied high/low causes 1.6s timeout and reset assertion |
| RESET | Active-low reset output | Push-pull, asserted low during power-up/brownout/watchdog fault; guaranteed valid down to VCC = 1V |
| VBATT | Backup-battery input | Accepts up to 6.0V; connects to VOUT when VCC falls below 2.40V; may exceed VCC in normal operation |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures deterministic reset behavior even during deep brownout, preventing µP execution from corrupted memory |
| Battery-backup switchover with 2.40V threshold | Activates backup power before VOUT drops below 2.0V RAM retention voltage, preserving data integrity |
| 200ms reset timeout with restart-on-brownout | Prevents premature µP release during transient dips; each VCC dip below threshold restarts the timer |
| 1.6s watchdog timer with edge-clearing | Eliminates need for dedicated watchdog IC; toggling WDI resets timer, enabling simple firmware heartbeat |
| 40µA VCC supply current (typ) | Reduces primary supply loading in always-on monitoring applications, extending battery life in portable designs |
Applications
| Battery-Powered Embedded Controller | Intelligent Instrument with Data Retention |
|---|---|
Use Scenario: Industrial sensor node powered by Li-ion battery with intermittent 3.3V main supply. IC Role / Device Role / Timing Role: Supervises VCC rail, asserts RESET during brownout, and switches RAM to VBATT when VCC falls below 2.40V. Use Value: Prevents firmware corruption and preserves calibration data across power interruptions without external logic. |
Use Scenario: Portable multimeter storing measurement history in static RAM during battery swaps. IC Role / Device Role / Timing Role: Provides 200ms reset hold time and seamless VBATT switchover to maintain RAM contents. Use Value: Enables hot-swap of main battery while retaining user settings and last-measurement buffer. |
| Critical µP Power Monitoring | Portable Medical Device with Watchdog Safety |
Use Scenario: Patient monitor with ARM Cortex-M µP requiring guaranteed boot integrity after AC loss. IC Role / Device Role / Timing Role: Monitors 3.3V supply, asserts RESET if VCC drops below 2.925V, and validates power stability before release. Use Value: Meets IEC 60601-1 requirements for fail-safe startup by eliminating marginal-voltage boot attempts. |
Use Scenario: Wearable ECG recorder where µP must recover from lockup without user intervention. IC Role / Device Role / Timing Role: Uses WDI pin to detect firmware hang; triggers 200ms RESET pulse every 1.6s if no heartbeat. Use Value: Achieves Class B functional safety compliance by autonomously recovering from software faults. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704SESA+ | Same 2.925V reset threshold, identical pinout, but adds MR input (manual reset) and removes PFI/PFO functionality | Lacks power-fail monitoring; suited for simpler reset-only systems without auxiliary supply monitoring | Select MAX704SESA+ when manual reset is required and PFI/PFO signals are unused |
| MAX802SESA+ | Same 2.925V reset threshold, tighter ±2% reset tolerance, and same 200ms timeout-but includes PFI/PFO and lacks WDI/watchdog | Provides enhanced reset accuracy but no watchdog capability; used where supply monitoring is critical but µP lockup risk is low | Select MAX802SESA+ when higher reset threshold precision is needed and watchdog function is unnecessary |
Compared with MAX704SESA+, MAX690SESA+ adds watchdog and PFI/PFO but omits MR; compared with MAX802SESA+, it trades ±2% reset accuracy for integrated 1.6s watchdog-making it optimal for systems requiring both supply monitoring and autonomous µP recovery.
Availability
MAX690SESA+T is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, intelligent instruments, and critical µP power monitoring applications requiring stable component supply across industrial temperature ranges.
Supply support for MAX690SESA+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, with emphasis on power management and reliability.
The MAX690 family targets 3.0V/3.3V microprocessor systems needing integrated reset supervision, battery switchover, watchdog, and power-fail warning-designed to replace discrete supervisory circuits in space-constrained embedded designs.
FAQ
What is the exact reset threshold voltage for MAX690SESA+T?
The MAX690SESA+T has a nominal reset threshold of 2.925V (VCC falling), with ±4% tolerance (2.85V to 3.00V min/max). This value is factory-trimmed and specified over –40°C to +85°C. The threshold rises slightly during VCC ramp-up due to 10mV hysteresis, ensuring noise immunity during power recovery. MAX690SESA+T uses this precise trip point to prevent spurious resets in 3.3V systems with ±10% supply tolerance.
Does MAX690SESA+T support manual reset functionality?
No, MAX690SESA+T does not include a manual reset (MR) input. Unlike the MAX704SESA+ or MAX806SESA+, the MAX690SESA+T pinout omits MR-its reset is triggered only by VCC brownout, watchdog timeout, or external assertion via the WDI pin. If manual reset is required, MAX704SESA+ is the direct alternative with identical reset threshold and SO package.
How does the battery switchover work in MAX690SESA+T?
MAX690SESA+T switches VOUT from VCC to VBATT when VCC falls below 2.40V (VSW) and VBATT > VCC, using a 140Ω internal NMOS switch. Switchover back to VCC occurs only after VCC rises above the 2.925V reset threshold-not at VSW-to ensure stable supply before reconnecting RAM. This prevents oscillation and extends battery life by delaying switchover until absolutely necessary.
Can MAX690SESA+T monitor a second power supply?
Yes, MAX690SESA+T can monitor an additional supply using the PFI input. By connecting a resistor divider from the secondary supply to PFI, the device compares the divided voltage against its internal 1.237V reference. When the secondary supply drops below the trip point, PFO goes low-enabling interrupt generation or cascaded reset triggering. This function operates independently of VCC monitoring and remains active as long as VCC > 2.40V.
What is the maximum allowable VCC transient duration before MAX690SESA+T asserts reset?
For a 100mV VCC dip below the 2.925V reset threshold, MAX690SESA+T tolerates transients up to 40µs without asserting reset-per Figure 7 in the datasheet. This immunity is achieved through internal filtering and comparator hysteresis. Adding a 100nF ceramic capacitor close to the VCC pin further suppresses high-frequency glitches, making MAX690SESA+T robust in electrically noisy environments.
MAX690SESA+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:
- Active
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX690SESA+T FAQ
1.How can I place an order for MAX690SESA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690SESA+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 MAX690SESA+T reliable?
The price and inventory of MAX690SESA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690SESA+T is usually 5 days.
3.What payment methods are accepted for MAX690SESA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690SESA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690SESA+T?
MAX690SESA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690SESA+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 MAX690SESA+T?
For technical support, including MAX690SESA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690SESA+T requirements.
6.How does Aetrix verify that MAX690SESA+T is sourced from the original manufacturer or authorized distributors?
All MAX690SESA+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 MAX690SESA+T meets industry standards.
7.What is the process for return or replacement of MAX690SESA+T?
All MAX690SESA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX690SESA+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 MAX690SESA+T part is unused and in its original packaging.
Return procedure for MAX690SESA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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