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Analog Devices Inc./Maxim Integrated MAX690SESA+
- Part No.:
- MAX690SESA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX690SESA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:129
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Product details
Overview
MAX690SESA+ 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 powers CMOS RAM via VOUT during main supply failure-used in embedded controllers and portable equipment requiring reliable power sequencing.
For engineers reviewing the MAX690SESA+ datasheet, MAX690SESA+ pinout, MAX690SESA+ application, or MAX690SESA+ equivalent, this page delivers verified technical context, exact pin functions, real-world use cases, and validated alternative parts for 3.0V/3.3V µP monitoring systems where guaranteed reset assertion down to VCC = 1V and sub-1µA battery current are critical design requirements.
Technical Context
The MAX690SESA+ 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 generator guarantees low-state assertion for VCC < 2.925V and holds RESET low for 200ms after recovery or MR release.
It features independent power-fail detection (PFI/PFO) with 1.237V threshold and 10mV hysteresis, manual reset input (MR) with internal 70µA pull-up, and battery switchover logic that engages when VCC falls below 2.40V (VSW) while VBATT > VCC-enabling seamless RAM backup without external circuitry.
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 system minimum operating voltage. |
| Reset Timeout Period | 200ms (typical) - provides sufficient hold time for µP initialization and peripheral stabilization after power recovery. |
| Watchdog Timeout | 1.6s - detects µP lockup by requiring periodic WDI toggling; prevents uncontrolled system operation. |
| VCC Supply Current | 40µA (typ, VCC < 3.6V) - enables ultra-low-power operation in battery-backed systems over full temperature range. |
| Battery Supply Current | 1µA (max, -40°C to +85°C) - minimizes battery drain during extended backup mode, extending lithium cell life. |
| VBATT Switch Threshold (VSW) | 2.40V - initiates switchover to battery before VOUT drops below 2.0V, preserving CMOS RAM data integrity. |
| Power-Fail Threshold (VPFT) | 1.237V - allows accurate monitoring of auxiliary supplies via external resistor divider without loading error. |
Pinout & Package
MAX690SESA+ is housed in an 8-pin SOIC package (SO) with gull-wing leads, RoHS-compliant (indicated by '+' suffix), and rated for -40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VOUT) | Supply output for CMOS RAM | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω NMOS); maintains RAM voltage during main supply failure. |
| 2 (VCC) | Main supply input | Primary 3.0V/3.3V power source; powers internal circuitry and enables VOUT connection to VCC above reset threshold. |
| 3 (GND) | Ground reference | Common return path for all analog and digital functions; substrate tied to higher of VCC or VBATT. |
| 4 (PFI) | Power-fail input | Monitors auxiliary supply via external divider; asserts PFO low when input falls below 1.237V. |
| 5 (PFO) | Power-fail output | Open-drain active-low signal indicating undervoltage condition on PFI or VCC drop below VSW. |
| 6 (WDI) | Watchdog input | Edge-sensitive input; clears 1.6s timer on rising/falling transition; ties high/low to force periodic reset. |
| 7 (RESET) | Active-low reset output | Guaranteed low for VCC < 2.925V; held low 200ms after VCC rise, MR release, or watchdog timeout. |
| 8 (VBATT) | Backup-battery input | Accepts up to 6.0V; connects to VOUT when VCC < 2.40V; enables lithium cells (e.g., 3.6V) exceeding VCC. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout, preventing µP execution from corrupted memory states. |
| Battery-backup switchover with VBATT > VCC support | Allows use of standard 3.6V lithium coin cells without level-shifting, simplifying backup power architecture. |
| 200ms reset timeout with restart-on-brownout | Prevents premature µP release during transient dips; internal timer resets each time VCC falls below threshold. |
| 1.6s watchdog timer with edge-triggered clear | Eliminates need for dedicated timer peripherals; robust against noise-induced false clears due to edge sensitivity. |
| 40µA VCC supply current (typ) | Reduces quiescent load on primary supply, critical for long-life battery-powered applications like handheld instruments. |
| 1µA max battery leakage current | Extends shelf life of backup batteries beyond 10 years in typical embedded deployments at room temperature. |
Applications
| Battery-Powered Portable Equipment | Embedded Industrial Controller |
|---|---|
|
Use Scenario: Handheld test meters and portable data loggers operate on single-cell lithium batteries with intermittent charging cycles. IC Role / Device Role / Timing Role: MAX690SESA+ monitors main 3.3V rail, asserts RESET during battery sag, switches VOUT to VBATT to retain SRAM contents, and triggers watchdog if firmware hangs. Use Value: Enables 10+ year battery life with zero data loss during power interruption, eliminating need for external backup regulators or supercapacitor management. |
Use Scenario: Programmable logic controllers (PLCs) deployed in factory automation require deterministic boot sequences and fault recovery under noisy 24VDC-derived 3.3V supplies. IC Role / Device Role / Timing Role: MAX690SESA+ provides precise 2.925V reset threshold, 200ms timeout, and PFI-based monitoring of auxiliary 5V I/O rails to generate early warning interrupts. Use Value: Prevents spurious reboots from line transients while enabling predictive maintenance alerts via PFO, improving system uptime and diagnostics. |
| Critical µP Power Monitoring | Intelligent Instrumentation |
|
Use Scenario: Medical diagnostic devices must guarantee safe shutdown and state preservation during AC mains dropout or battery depletion. IC Role / Device Role / Timing Role: MAX690SESA+ asserts RESET before VCC falls below 2.925V, holds it for 200ms, and activates VBATT switchover at 2.40V to sustain SRAM and real-time clock. Use Value: Meets IEC 60601-1 power integrity requirements with no additional components, reducing BOM count and validation effort. |
Use Scenario: Benchtop oscilloscopes and spectrum analyzers use µPs to manage high-speed ADCs and display subsystems powered from tightly regulated 3.3V rails. IC Role / Device Role / Timing Role: MAX690SESA+ monitors VCC stability, uses WDI to verify µP health, and employs PFO to flag undervoltage on analog front-end supplies. Use Value: Eliminates firmware-level power monitoring overhead, freeing CPU cycles for signal processing while ensuring deterministic fault response. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704SESA+ | Identical pinout, same 2.925V reset threshold and 200ms timeout, but adds manual reset (MR) input with internal pull-up. | Required when system needs hardware-initiated reset via pushbutton or logic signal; MAX690SESA+ lacks MR functionality. | Select MAX704SESA+ only if manual reset capability is mandatory; otherwise MAX690SESA+ offers lower cost and simpler layout. |
| MAX802SESA+ | Tighter reset threshold tolerance (±2% vs. ±4%) and improved PFI accuracy (±2% vs. ±75mV), same 2.925V nominal threshold. | Suitable for high-precision systems where supply margin is constrained, e.g., automotive-grade 3.3V domains with strict voltage budgets. | Choose MAX802SESA+ when ±2% reset accuracy is required; MAX690SESA+ suffices for industrial and consumer applications with wider tolerances. |
Compared with MAX704SESA+, MAX690SESA+ omits manual reset but reduces component count and cost; versus MAX802SESA+, it trades tighter thresholds for broader compatibility and lower price-making it optimal for cost-sensitive, non-automotive 3.3V µP systems needing proven reliability.
Availability
MAX690SESA+ is available at Aetrix Electronics and suitable for battery-powered computers, embedded controllers, and intelligent instrumentation requiring stable component supply across industrial temperature ranges (-40°C to +85°C).
Supply support for MAX690SESA+ 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 connectivity in demanding industrial and computing environments.
The MAX690 family targets 3.0V/3.3V microprocessor systems needing integrated reset supervision, watchdog monitoring, and battery-backed RAM retention-optimized for reliability in portable and embedded applications.
FAQ
What is the reset threshold voltage for MAX690SESA+?
The MAX690SESA+ has a nominal reset threshold of 2.925V (VCC falling), with ±4% tolerance over temperature. This value is confirmed in the Electrical Characteristics table for MAX690S variants, and ensures reset assertion before the 3.3V supply drops below 2.85V-critical for maintaining µP stability in systems with ±10% supply tolerance.
Does MAX690SESA+ include a manual reset input?
No, MAX690SESA+ does not include a manual reset (MR) input. Unlike the MAX704SESA+ or MAX806SESA+, the MAX690SESA+ pinout omits MR functionality. Its reset is triggered solely by VCC brownout, watchdog timeout, or power-fail conditions-verified in the Pin Description table where MR is marked "-" for MAX690.
What is the maximum allowable VBATT voltage for MAX690SESA+?
The absolute maximum rating for VBATT is +6.0V, as specified in the Absolute Maximum Ratings table. In normal operation, VBATT may exceed VCC (e.g., 3.6V lithium cell with 3.3V VCC), and the device automatically switches VOUT to VBATT when VCC falls below 2.40V-ensuring safe, seamless backup without external protection.
How does the watchdog timer function in MAX690SESA+?
The MAX690SESA+ watchdog timer has a 1.6s timeout period and clears only on rising or falling edges at the WDI pin-not on static high/low states. If WDI remains unchanged for 1.6s, RESET is asserted. The timer remains cleared while RESET is active, and resumes counting only after RESET deasserts-preventing false timeouts during reset hold.
Can MAX690SESA+ be used without a backup battery?
Yes, MAX690SESA+ can operate without a backup battery: connect both VBATT and VOUT pins directly to VCC. However, battery-switchover functionality is disabled, and the device still provides full reset supervision, watchdog, and power-fail monitoring-confirmed in the Applications Information section under "Operation without a Backup Power Source."
MAX690SESA+ 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:
- 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+ FAQ
1.How can I place an order for MAX690SESA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690SESA+ 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+ reliable?
The price and inventory of MAX690SESA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690SESA+ is usually 5 days.
3.What payment methods are accepted for MAX690SESA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690SESA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690SESA+?
MAX690SESA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690SESA+ 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+?
For technical support, including MAX690SESA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690SESA+ requirements.
6.How does Aetrix verify that MAX690SESA+ is sourced from the original manufacturer or authorized distributors?
All MAX690SESA+ 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+ meets industry standards.
7.What is the process for return or replacement of MAX690SESA+?
All MAX690SESA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX690SESA+, 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+ part is unused and in its original packaging.
Return procedure for MAX690SESA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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