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Analog Devices Inc./Maxim Integrated MAX690SEPA
- Part No.:
- MAX690SEPA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX690SEPA.pdf
- Description:
- IC SUPERVISOR MAX690 MPU
- Quantity:
- Payment:
- Shipping:
Inventory:611
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Product details
Overview
MAX690SEPA from Maxim Integrated is a 3.0V/3.3V 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. It monitors VCC for brownout detection, asserts RESET below threshold, and switches VOUT to VBATT during power failure - used in embedded controllers and battery-powered instrumentation.
For engineers reviewing the MAX690SEPA datasheet, MAX690SEPA pinout, MAX690SEPA application, or MAX690SEPA equivalent, this page delivers verified specifications, validated pin functions, real-world use cases in RAM backup and power-fail warning, and confirmed alternative parts for 3V/3.3V µP supervision with manual reset and watchdog functionality.
Technical Context
The MAX690SEPA integrates a precision reset comparator with ±4% threshold accuracy (2.925V nominal), 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 switch activated when VCC falls below 2.40V (VSW) and VBATT > VCC. It guarantees RESET assertion down to VCC = 1V.
Its PFI/PFO power-fail comparator operates independently with 1.237V threshold and 10mV hysteresis, while MR input features internal 70µA pull-up and 200ms deassertion delay. Battery leakage is limited to ≤1µA (C/E grade), and VCC supply current is 40µA typical at VCC < 3.6V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V (VCC falling), ±4% tolerance - ensures reliable reset before system logic fails at 3.3V ±10% supply |
| Reset Timeout Period | 200ms (typical) - provides sufficient hold time for µP initialization after power stabilization |
| Watchdog Timeout | 1.6s - detects µP lockup without requiring software intervention or external timing components |
| VCC Supply Current | 40µA (typ, VCC < 3.6V) - enables long battery life in portable systems with continuous supervision |
| Battery Supply Current | 1µA max (C/E grade) - minimizes drain on lithium backup cells during extended standby |
| VBATT Switch Threshold | 2.40V (VSW) - triggers switchover early enough to preserve CMOS RAM data above 2.0V minimum |
| PFO Threshold Accuracy | ±75mV - supports accurate power-fail detection for secondary supply monitoring |
Pinout & Package
MAX690SEPA is housed in an 8-pin plastic DIP (PDIP) package with 0.300" wide body, RoHS-compliant lead finish. Pin spacing follows JEDEC MS-001 standard.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Supply output for CMOS RAM | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω switch) based on VCC/VBATT comparison; connects to RAM VDD |
| 2 - VCC | Main supply input | Primary 3.0V/3.3V system rail; powers internal circuitry and defines reset comparator reference |
| 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 external voltage divider; asserts PFO low when input drops below 1.237V ±75mV |
| 5 - PFO | Power-fail output | Open-drain active-low signal indicating VCC drop below VSW or PFI < 1.237V; usable as µP interrupt |
| 6 - WDI | Watchdog input | Edge-sensitive (rising/falling) input; resets 1.6s timer on transition; no disable function |
| 7 - RESET | Active-low reset output | Push-pull output asserted low during brownout, watchdog timeout, or MR activation; guaranteed valid to VCC = 1V |
| 8 - VBATT | Backup-battery input | Accepts up to 6.0V; enables seamless RAM backup when VCC fails; may exceed VCC in normal operation |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout, critical for nonvolatile memory retention |
| Battery-backup switchover with 2.40V VSW threshold | Activates backup before VOUT drops below 2.0V RAM retention limit, extending data hold time |
| 200ms reset timeout with restart-on-brownout | Prevents premature µP release during transient dips; internal timer resets each time VCC falls below VRST |
| 1.6s watchdog timer with edge-triggered clear | Eliminates need for external timing components and prevents false timeouts due to noise on WDI |
| Independent PFI/PFO power-fail comparator | Enables monitoring of auxiliary supplies (e.g., analog rails) without affecting primary reset behavior |
| 40µA VCC supply current (typ) | Reduces quiescent load on main supply, supporting multi-year battery operation in low-power embedded systems |
Applications
| Battery-Powered Embedded Controller | Intelligent Instrumentation |
|---|---|
Use Scenario: Portable data logger with SRAM buffer and lithium coin cell backup. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, RAM backup switchover, and watchdog safety for ARM Cortex-M0 host. Use Value: Prevents corrupted firmware execution during battery depletion and preserves sensor history across power cycles. |
Use Scenario: Handheld multimeter with real-time display and calibration memory. IC Role / Device Role / Timing Role: Dual-role supervisor: resets MCU on supply sag and switches VOUT to VBATT to retain calibration coefficients in CMOS RAM. Use Value: Guarantees measurement integrity by maintaining RAM voltage above 2.0V during AC adapter disconnection. |
| Critical µP Power Monitoring | Portable Medical Device |
Use Scenario: Industrial PLC module operating from unregulated 3.3V DC-DC converter. IC Role / Device Role / Timing Role: Primary power monitor asserting RESET within 200ms of VCC dropping below 2.925V; also feeds PFO to FPGA interrupt line. Use Value: Meets IEC 61000-4-29 immunity requirements by eliminating race conditions during fast transients. |
Use Scenario: Wearable ECG monitor with flash memory and SRAM-based waveform buffer. IC Role / Device Role / Timing Role: Manages power sequencing: asserts RESET on startup, enables watchdog for firmware crash recovery, and activates VBATT switchover during USB disconnect. Use Value: Achieves >99.9% data capture reliability by preventing RAM loss during battery swap or charging interruption. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704SEPA | Same 2.925V reset threshold, identical pinout, but adds manual reset (MR) input with internal pull-up; lacks PFI/PFO comparator | Preferred where manual reset button is required but secondary supply monitoring is unnecessary | Select MAX704SEPA if MR functionality is needed and PFI/PFO is unused; otherwise MAX690SEPA retains full feature set |
| MAX802SEPA | Tighter reset threshold tolerance (±2% vs. ±4%), same 2.925V nominal, identical package and pinout; includes PFI/PFO but no WDI/watchdog | Suitable for high-precision 3.3V systems where watchdog is redundant but reset accuracy is critical (e.g., telecom line cards) | Choose MAX802SEPA when ±2% reset accuracy is mandated and watchdog capability is not required |
Compared with MAX704SEPA and MAX802SEPA, the MAX690SEPA uniquely combines watchdog timer, PFI/PFO comparator, and battery switchover in a single 8-pin DIP - making it the only option among the three that satisfies full-featured µP supervision for portable, battery-backed systems requiring both fault detection and data retention.
Availability
MAX690SEPA is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, and intelligent instrumentation requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for MAX690SEPA 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, communications, and computing applications.
The MAX690 family targets 3.0V/3.3V microprocessor systems needing integrated reset, watchdog, power-fail warning, and battery backup - optimized for reliability in portable and mission-critical embedded environments.
FAQ
What is the exact reset threshold voltage for MAX690SEPA?
The MAX690SEPA has a nominal reset threshold of 2.925V (S-suffix), specified as 2.85V (min) to 3.00V (max) for VCC falling, with ±4% tolerance. This value is guaranteed over the full operating temperature range (-40°C to +85°C) and ensures reliable reset before 3.3V system logic becomes unstable under ±10% supply variation.
Does MAX690SEPA support battery voltage higher than VCC?
Yes, MAX690SEPA explicitly supports VBATT exceeding VCC during normal operation - a key design feature enabling use with 3.6V lithium batteries on 3.3V systems. The internal switchover circuit activates when VCC falls below 2.40V (VSW) and VBATT > VCC, connecting VBATT to VOUT through a 140Ω switch while isolating VCC.
Can the watchdog timer in MAX690SEPA be disabled?
No, the watchdog timer in MAX690SEPA cannot be disabled. It is permanently enabled and triggers a reset if the WDI input remains static (high or low) for longer than 1.6 seconds. The timer clears only on rising or falling edges of WDI or during active RESET assertion - ensuring continuous supervision without configuration overhead.
What is the maximum allowable VCC transient duration that will not trigger RESET on MAX690SEPA?
At 100mV overdrive (i.e., VCC dipping 100mV below the 2.925V threshold), MAX690SEPA tolerates negative-going transients up to 40µs without issuing a reset pulse. This immunity is characterized per Figure 7 in the datasheet and applies at TA = +25°C with VCC = 3.3V; shorter durations are allowed for larger overdrive magnitudes.
How does MAX690SEPA handle power-fail detection without a backup battery?
MAX690SEPA's PFI/PFO power-fail comparator operates independently of VBATT - it functions fully even with VBATT tied to VCC or left unconnected. When PFI drops below 1.237V (±75mV), PFO goes low regardless of battery presence, enabling use as a standalone undervoltage detector for auxiliary rails or system-level power monitoring.
MAX690SEPA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- 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:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX690SEPA FAQ
1.How can I place an order for MAX690SEPA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690SEPA 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 MAX690SEPA reliable?
The price and inventory of MAX690SEPA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690SEPA is usually 5 days.
3.What payment methods are accepted for MAX690SEPA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690SEPA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690SEPA?
MAX690SEPA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690SEPA 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 MAX690SEPA?
For technical support, including MAX690SEPA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690SEPA requirements.
6.How does Aetrix verify that MAX690SEPA is sourced from the original manufacturer or authorized distributors?
All MAX690SEPA 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 MAX690SEPA meets industry standards.
7.What is the process for return or replacement of MAX690SEPA?
All MAX690SEPA units undergo pre-shipment inspection (PSI). If there is an issue with MAX690SEPA, 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 MAX690SEPA part is unused and in its original packaging.
Return procedure for MAX690SEPA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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