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Analog Devices Inc./Maxim Integrated MAX690SCSA
- Part No.:
- MAX690SCSA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX690SCSA.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,458
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Product details
Overview
MAX690SCSA 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-designed for reliable power monitoring in embedded controllers and battery-powered systems.
For engineers reviewing the MAX690SCSA datasheet, MAX690SCSA pinout, MAX690SCSA application, or MAX690SCSA equivalent, key selection criteria include reset threshold accuracy (±4%), VCC supply current (40µA typ), battery leakage (0.4–1µA), guaranteed RESET assertion down to VCC = 1V, and compatibility with lithium backup batteries exceeding VCC.
Technical Context
The MAX690SCSA integrates a precision voltage monitor, 1.6s watchdog timer with edge-triggered reset clearing, manual reset input with internal 70µA pull-up, and dual-path power switchover logic that connects VOUT to VBATT only when VCC falls below 2.40V (VSW) and VBATT > VCC-or below 1.75V regardless of VBATT.
Its reset comparator features 10mV typical hysteresis to prevent oscillation during brownout recovery, and the PFI/PFO power-fail comparator operates independently with 1.237V threshold and ±20mV hysteresis, enabling external supply monitoring without affecting core reset functionality.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V (nominal), ±4% tolerance-ensures reset assertion before VCC drops below 2.85V in 3.3V ±10% systems |
| Reset Timeout Period | 200ms (typical)-guarantees µP initialization stability after power-up or brownout recovery |
| VCC Supply Current | 40µA (typ, VCC < 3.6V)-enables ultra-low-power operation in always-on battery-backed applications |
| Battery Leakage Current | 0.4–1µA (max)-minimizes drain on lithium coin cells during long-term backup mode |
| Watchdog Timeout | 1.6s (typ)-detects µP lockup while allowing sufficient time for normal firmware execution cycles |
| VBATT-to-VOUT On-Resistance | 140Ω (typ)-limits voltage drop during RAM backup, supporting CMOS RAM retention down to ~2.0V |
| Power-Fail Threshold | 1.237V (PFI input)-enables accurate monitoring of auxiliary supplies via external resistor divider |
Pinout & Package
MAX690SCSA is housed in an 8-pin SO (Small Outline) package with gull-wing leads, RoHS-compliant, 150°C max reflow profile, and 2.032mm body width.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω switch) based on VCC/VBATT comparison and reset state |
| 2 - VCC | Main system supply input | Accepts 1.0V–5.5V; powers internal circuitry and enables battery switchover logic above VSW = 2.40V |
| 3 - GND | Ground reference | Common return for all analog and digital functions; substrate tied to higher of VCC or VBATT |
| 4 - PFI | Power-fail input | Monitors external supply via resistor divider; asserts PFO low when voltage falls below 1.237V |
| 5 - PFO | Power-fail open-drain output | Active-low signal indicating undervoltage condition on PFI or VCC falling below VSW |
| 6 - WDI | Watchdog input | Edge-sensitive (rising/falling); clears 1.6s timer on transition; no disable option |
| 7 - RESET | Active-low reset output | Push-pull, asserted low during power-up, brownout, watchdog timeout, or MR assertion; guaranteed to VCC = 1V |
| 8 - VBATT | Backup battery input | Supports VBATT > VCC (e.g., 3.6V Li cell); enables seamless RAM backup without diode loss |
Key Features
| Feature | Design Value |
|---|---|
| Battery-Backup Switchover | Automatic VOUT connection to VBATT when VCC < 2.40V and VBATT > VCC-preserves CMOS RAM data without external diodes |
| Guaranteed Reset Assertion | RESET remains valid down to VCC = 1V-ensures fail-safe behavior even during deep brownout |
| Watchdog Timer with Edge Clearing | 1.6s timeout cleared by any WDI edge-not just toggles-reducing firmware overhead for periodic servicing |
| Independent Power-Fail Comparator | Dedicated PFI/PFO path with 1.237V threshold and 10mV hysteresis-allows monitoring of secondary rails without interfering with reset timing |
| Manual Reset with Debounce | MR input includes 70µA internal pull-up and 200ms post-release delay-eliminates need for external RC debounce |
Applications
| Battery-Powered Embedded Controller | Intelligent Instrument with RAM Backup |
|---|---|
Use Scenario: Portable gas detector operating on 3.3V Li-ion with 32kB SRAM storing calibration data and event logs. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, watchdog supervision, and automatic RAM backup switchover to 3.6V coin cell during main supply failure. Use Value: Prevents data corruption during transient brownouts and ensures 10+ year data retention in storage mode using <1µA battery leakage. |
Use Scenario: Handheld multimeter with real-time clock and nonvolatile memory requiring continuous power during battery replacement. IC Role / Device Role / Timing Role: Provides seamless VOUT switchover from 3.3V main rail to 3.6V backup battery within 1µs, maintaining RTC and RAM integrity. Use Value: Eliminates need for external backup diodes or supercapacitor charging circuits-reducing BOM count and PCB area by 3 components. |
| Critical µP Power Monitoring | Portable Medical Sensor Node |
Use Scenario: Industrial PLC I/O module powered by 3.3V DC-DC converter with strict uptime requirements. IC Role / Device Role / Timing Role: Monitors VCC for dips below 2.925V, asserts RESET for 200ms, and triggers watchdog reset if µP fails to service WDI every 1.6s. Use Value: Achieves SIL-2 functional safety compliance through deterministic reset timing and independent fault detection paths. |
Use Scenario: Wearable ECG sensor with Bluetooth LE MCU, powered by rechargeable 3.3V LiPo, requiring zero-data-loss during charge interruption. IC Role / Device Role / Timing Role: Detects VCC sag during USB charger disconnect, asserts RESET to halt BLE transmission, and switches VOUT to backup capacitor bank. Use Value: Enables graceful shutdown and RAM preservation using integrated 200ms timeout-no external timing components required. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX690TCSA | 3.075V reset threshold (vs. 2.925V); identical pinout, timing, and feature set | Suitable for 3.3V ±5% systems where tighter supply tolerance requires earlier reset assertion | Select MAX690TCSA when system VCC must remain ≥3.075V for reliable operation; otherwise MAX690SCSA matches 3.3V ±10% designs. |
| MAX706SCSA | No watchdog timer; no battery switchover; PFI/PFO only; 200ms reset timeout; 2.93V threshold | Lower-cost option for basic reset-only applications without RAM backup or watchdog needs | Choose MAX706SCSA only if battery backup and watchdog supervision are unnecessary-saves cost but removes two critical reliability features. |
Compared with MAX690TCSA and MAX706SCSA, the MAX690SCSA uniquely balances precise 2.925V reset threshold, integrated watchdog, and zero-loss battery switchover-making it optimal for portable systems requiring both data integrity and fault resilience.
Availability
MAX690SCSA 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 (0°C to +70°C).
Supply support for MAX690SCSA 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, computing, and communications markets.
The MAX690 family was designed specifically for 3.0V/3.3V microprocessor systems needing integrated reset supervision, watchdog protection, and seamless battery-backed RAM retention-targeting portable and mission-critical embedded applications.
FAQ
What is the exact reset threshold voltage for MAX690SCSA?
The MAX690SCSA has a nominal reset threshold voltage of 2.925V, with ±4% tolerance over temperature and supply variations. This value is specified for VCC falling conditions and ensures reset assertion before VCC drops below 2.85V in 3.3V ±10% systems. The rising threshold is 2.935V, providing 10mV hysteresis to prevent chatter during recovery.
Does MAX690SCSA support battery voltages higher than VCC?
Yes, MAX690SCSA explicitly supports VBATT exceeding VCC-such as a 3.6V lithium coin cell with a 3.3V main supply. Its internal battery switchover circuit activates when VCC falls below 2.40V (VSW) and VBATT > VCC, connecting VOUT directly to VBATT through a 140Ω switch without diode voltage drop, preserving RAM data integrity.
Can the watchdog timer in MAX690SCSA be disabled?
No, the watchdog timer in MAX690SCSA cannot be disabled. It is permanently enabled and times out after 1.6 seconds (typical) if the WDI input remains static. The timer resets on any edge (rising or falling) at WDI, ensuring robust detection of µP lockup without requiring dedicated firmware configuration.
What is the maximum allowable VCC transient duration that will not trigger a reset on MAX690SCSA?
For a 100mV overdrive (i.e., VCC dipping 100mV below the 2.925V reset threshold), MAX690SCSA tolerates negative-going transients up to 40µs without asserting RESET. This immunity is achieved via internal filtering and comparator hysteresis, and is further enhanced by placing a 100nF bypass capacitor close to the VCC pin.
How does MAX690SCSA handle manual reset (MR) deassertion?
When MR is pulled low, MAX690SCSA asserts RESET immediately. Upon MR returning high, RESET remains asserted for a guaranteed 200ms timeout period-providing clean, debounced reset release without external components. The MR pin includes a 70µA internal pull-up, allowing direct connection to a momentary switch to ground.
MAX690SCSA 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:
- 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
MAX690SCSA FAQ
1.How can I place an order for MAX690SCSA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690SCSA 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 MAX690SCSA reliable?
The price and inventory of MAX690SCSA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690SCSA is usually 5 days.
3.What payment methods are accepted for MAX690SCSA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690SCSA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690SCSA?
MAX690SCSA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690SCSA 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 MAX690SCSA?
For technical support, including MAX690SCSA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690SCSA requirements.
6.How does Aetrix verify that MAX690SCSA is sourced from the original manufacturer or authorized distributors?
All MAX690SCSA 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 MAX690SCSA meets industry standards.
7.What is the process for return or replacement of MAX690SCSA?
All MAX690SCSA units undergo pre-shipment inspection (PSI). If there is an issue with MAX690SCSA, 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 MAX690SCSA part is unused and in its original packaging.
Return procedure for MAX690SCSA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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