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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 MAX690 MPU
- Quantity:
- Payment:
- Shipping:
Inventory:1,420
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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 (S-suffix), 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover capability. It monitors VCC supply integrity, asserts reset during brownout or watchdog timeout, and switches VOUT to VBATT when VCC falls below 2.40V-enabling reliable CMOS RAM retention in portable controllers.
For engineers reviewing the MAX690SESA datasheet, MAX690SESA pinout, MAX690SESA application, or MAX690SESA equivalent, this page delivers verified specifications, validated pin functions, confirmed use cases in battery-powered embedded systems, and two technically documented alternative parts for 3.0V/3.3V µP supervision.
Technical Context
The MAX690SESA integrates a precision reset comparator with ±4% threshold tolerance (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 NMOS. Its PFI/PFO comparator operates independently with 1.237V reference and 10mV hysteresis.
Battery switchover occurs at VSW = 2.40V (VBATT > VCC) on power-down and defers to VRST = 2.925V on power-up, ensuring stable reconnection. RESET assertion is guaranteed down to VCC = 1V, and MR input features internal 70µA pull-up-supporting direct TTL/CMOS or momentary switch interfacing without external components.
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 minimum. |
| Reset Timeout Period | 200ms (typical) - provides sufficient deassertion delay for µP power stabilization after VCC recovery. |
| Watchdog Timeout | 1.6s - detects µP lockup by requiring WDI toggling within this window; non-disableable. |
| VCC Supply Current | 40µA (typ, VCC < 3.6V) - enables ultra-low-power operation in always-on battery-backed systems. |
| Battery Supply Current | 0.4–1µA (max) - minimizes drain on lithium backup cells during extended standby. |
| Battery Switch Threshold | VSW = 2.40V (VBATT > VCC) - initiates switchover before VOUT drops below 2.0V RAM retention limit. |
| Power-Fail Input Threshold | VPFT = 1.237V - supports external voltage divider monitoring of auxiliary supplies (e.g., 5V rail). |
Pinout & Package
MAX690SESA is housed in an 8-pin SO (Small Outline) package, RoHS-compliant, with gull-wing leads and standard SOIC-8 footprint (package code S8+4, outline 21-0041).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Supply output for CMOS RAM | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω NMOS); connects to RAM VDD. |
| 2 - VCC | Main supply input | Primary 3.0V/3.3V power source; powers internal circuitry and drives VOUT when active. |
| 3 - GND | Ground reference | Common return path for all analog/digital functions; substrate tied to higher of VCC/VBATT. |
| 4 - PFI | Power-fail input | Monitors external supply via voltage divider; trips PFO low when input < 1.237V. |
| 5 - PFO | Power-fail output | Open-drain active-low signal indicating undervoltage condition on PFI or VCC < VSW. |
| 6 - WDI | Watchdog input | Edge-sensitive input (rising/falling) that resets 1.6s timer; no pull-up/pull-down required. |
| 7 - RESET | Active-low reset output | Push-pull output asserted low during reset; guaranteed valid down to VCC = 1V. |
| 8 - VBATT | Backup-battery input | Accepts 3.6V lithium cell; may exceed VCC; enables seamless RAM backup during main supply loss. |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset comparator | 2.925V threshold with ±4% tolerance over -40°C to +85°C - eliminates need for external resistor network calibration. |
| Guaranteed RESET assertion to VCC = 1V | Ensures deterministic reset behavior during deep brownout, critical for fail-safe embedded firmware recovery. |
| Battery switchover with hysteresis | VSW = 2.40V (falling), 2.925V (rising) - prevents oscillation during VCC recovery and extends battery life. |
| Low-quiescent-current operation | 40µA VCC supply current (typ) - reduces system standby power by >90% vs. discrete supervisor solutions. |
| Integrated watchdog timer | 1.6s timeout with edge-triggered clear - detects µP hang without software overhead or external timing components. |
Applications
| Battery-Powered Portable Controllers | Embedded Industrial Data Loggers |
|---|---|
|
Use Scenario: Handheld meter with lithium coin cell backup maintaining SRAM during main power removal. IC Role / Device Role / Timing Role: MAX690SESA monitors 3.3V rail, asserts RESET on brownout, and switches VOUT to VBATT at 2.40V to preserve RAM contents. Use Value: Enables 10+ year battery life with <1µA leakage and eliminates need for external diode-or power path. |
Use Scenario: Remote sensor node logging temperature data to static RAM while operating on intermittent solar charge. IC Role / Device Role / Timing Role: MAX690SESA uses PFI to monitor auxiliary 5V sensor supply and triggers PFO interrupt on undervoltage. Use Value: Provides independent power-fail detection without loading µP ADC resources or consuming GPIO pins. |
| Critical µP Power Monitoring | Intelligent Medical Instruments |
|
Use Scenario: Patient monitor requiring guaranteed reset during AC adapter dropout or battery swap. IC Role / Device Role / Timing Role: MAX690SESA asserts RESET for 200ms upon VCC dip below 2.925V and restarts watchdog on WDI edges. Use Value: Prevents corrupted memory writes and ensures deterministic boot sequence after transient supply faults. |
Use Scenario: Portable ultrasound device using SRAM for waveform buffering during battery-only operation. IC Role / Device Role / Timing Role: MAX690SESA provides manual reset via MR switch and guarantees RESET assertion even if VCC drops to 1.0V. Use Value: Supports safe field servicing with hardware-initiated reset and failsafe RAM retention under worst-case supply conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX690TESA | Reset threshold = 3.075V (T-suffix), otherwise identical pinout, timing, and features. | Suitable for 3.3V ±5% systems where tighter supply margin requires earlier reset assertion. | Select MAX690TESA when system VCC tolerance is ±5% and brownout must trigger above 2.925V. |
| MAX706SESA | No watchdog timer, no battery switchover; only RESET, PFI/PFO, and MR; 2.93V reset threshold. | Targeted at cost-sensitive, non-battery-backed applications requiring basic reset and power-fail warning only. | Choose MAX706SESA when watchdog and backup switching are unnecessary and BOM cost reduction is prioritized. |
Compared with MAX690SESA, MAX690TESA offers higher reset threshold for tighter 3.3V supply margins, while MAX706SESA removes watchdog and battery switching to reduce complexity and cost-making it suitable only for simpler, non-backup applications.
Availability
MAX690SESA is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded industrial data loggers, and intelligent medical instruments requiring stable component supply across extended 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 high-performance analog and mixed-signal ICs for power, interface, sensing, and timing applications.
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 industrial environments.
FAQ
What is the exact reset threshold voltage for MAX690SESA?
The MAX690SESA has a nominal reset threshold of 2.925V for VCC falling, with ±4% tolerance over temperature and supply variations. This value is factory-trimmed and specified in the Electrical Characteristics table under VRST for MAX690S variants. The threshold rises to 2.935V on VCC rising due to 10mV hysteresis, preventing oscillation during marginal supply conditions.
Does MAX690SESA support battery voltage higher than VCC?
Yes, MAX690SESA explicitly supports VBATT exceeding VCC-such as a 3.6V lithium cell on a 3.3V system. Its internal battery switchover circuit activates when VCC falls below VSW = 2.40V (with VBATT > VCC), connecting VBATT to VOUT through a 140Ω switch. This design allows safe, automatic backup without external diodes or level-shifting components.
Can the watchdog timer in MAX690SESA be disabled?
No, the watchdog timer in MAX690SESA cannot be disabled. It is a fixed-function block with a 1.6s timeout period that clears only on rising or falling edges at the WDI pin. If WDI is held static (high or low), the timer expires every ~1.8s (tWD + tRS), asserting RESET. This hardwired behavior ensures fail-safe µP supervision without software dependency.
What is the function of the PFI and PFO pins on MAX690SESA?
PFI is a dedicated input for monitoring auxiliary power rails via an external voltage divider; it compares against a 1.237V internal reference. PFO is an open-drain output that goes low when PFI < 1.237V or when VCC falls below VSW = 2.40V. Together, they provide independent power-fail detection-enabling interrupts or secondary reset generation without involving the main µP reset line.
Is MAX690SESA pin-compatible with other devices in the MAX690 family?
Yes, MAX690SESA is fully pin-compatible with all MAX690T/S/R variants (e.g., MAX690TESA, MAX690RESA) in the same SO-8 package. Pin functions, electrical characteristics, and timing parameters are identical across suffixes-only the reset threshold voltage differs. This allows drop-in replacement within the same temperature grade (E-grade, -40°C to +85°C) without PCB changes.
MAX690SESA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- 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:
- 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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