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Analog Devices Inc./Maxim Integrated MAX690RCSA+T
- Part No.:
- MAX690RCSA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX690RCSA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,506
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Product details
Overview
MAX690RCSA+T from Maxim Integrated is a 3.0V/3.3V microprocessor supervisory circuit with active-low RESET output, 2.625V 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 MAX690RCSA+T datasheet, MAX690RCSA+T pinout, MAX690RCSA+T application, or MAX690RCSA+T equivalent, key selection criteria include reset threshold accuracy (±75mV), VCC supply current (40µA typ), guaranteed RESET assertion down to VCC = 1V, and dual-supply switchover behavior between VCC and VBATT.
Technical Context
The MAX690RCSA+T integrates a precision reset comparator with 2.625V nominal threshold (VCC rising: 2.55V–2.72V), a 1.6s watchdog timer cleared by WDI edges, and a bidirectional battery switchover circuit that connects VOUT to VBATT when VCC falls below 2.40V (VSW) and VBATT > VCC. It features separate PFI/PFO for independent power-fail detection at 1.237V ±10mV.
Its internal architecture includes a PMOS VCC-to-VOUT switch (3Ω typical on-resistance), a 140Ω VBATT-to-VOUT switch, and logic-level MR input with 70µA internal pull-up. RESET remains asserted during brownout, watchdog timeout, or manual reset, with 200ms minimum pulse width after recovery.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.625V nominal (VCC falling), ±75mV tolerance - ensures reset triggers before 3.0V system drops below 2.55V, preventing unreliable µP operation. |
| Reset Timeout Period | 200ms typ (140–280ms range) - guarantees sufficient hold time for µP initialization after power-up or brownout recovery. |
| VCC Supply Current | 40µA typ at VCC < 3.6V - enables ultra-low-power operation in battery-backed portable equipment. |
| Watchdog Timeout | 1.6s typ (1.12–2.24s range) - provides robust software hang detection without requiring external timing components. |
| Battery Leakage Current | 0.01–0.5µA - minimizes drain on lithium backup cells during long-term storage or standby. |
| VBATT Switch Threshold (VSW) | 2.40V typ - initiates switchover to battery before VOUT drops below 2.0V, preserving CMOS RAM data integrity. |
| PFO Threshold Accuracy | ±75mV - supports precise undervoltage warning for auxiliary supplies via external resistor divider on PFI. |
Pinout & Package
MAX690RCSA+T is housed in an 8-pin SOIC package (SO, 150mil width), RoHS-compliant (indicated by '+' suffix), with standard JEDEC MS-012AC outline and 90-0096 land pattern.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT | Supply output for CMOS RAM | Switches automatically between VCC and VBATT; connected to VCC via 3Ω PMOS when active, to VBATT via 140Ω switch during backup. |
| VCC | Main supply input | Primary 3.0V/3.3V system rail; powers internal circuitry and defines reset comparator reference. |
| GND | Ground reference | Common return path for all analog and digital functions; substrate tied to higher of VCC/VBATT. |
| PFI | Power-fail input | Monitors auxiliary voltage via external divider; triggers PFO low when input falls below 1.237V ±10mV. |
| PFO | Power-fail output | Open-drain active-low signal indicating PFI undervoltage or VCC < VSW; can drive MR on compatible parts. |
| WDI | Watchdog input | Edge-sensitive input (rising/falling clears 1.6s timer); no disable function - requires periodic toggling in firmware. |
| RESET | Active-low reset output | Push-pull output asserted low during reset conditions; guaranteed valid down to VCC = 1V. |
| VBATT | Backup-battery input | Accepts up to 6.0V; may exceed VCC; enables seamless RAM retention during main supply failure. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout, critical for systems with wide input voltage ranges. |
| Battery can exceed VCC in normal operation | Supports standard 3.6V lithium coin cells without level-shifting, simplifying backup power design. |
| 200ms reset time delay with hysteresis | Prevents chatter during marginal VCC transitions; 10mV typical hysteresis avoids oscillation near threshold. |
| 40µA VCC supply current (typ) | Reduces quiescent load on primary supply, extending battery life in always-on portable applications. |
| VCC-to-VOUT on-resistance ≤3Ω | Minimizes voltage drop under load (e.g., 50mA → <150mV drop), maintaining stable RAM supply. |
Applications
| Battery-Powered Computers and Controllers | Embedded Controllers |
|---|---|
Use Scenario: Portable data loggers powered by single-cell Li-ion with onboard SRAM requiring uninterrupted memory retention during AC loss. IC Role / Device Role / Timing Role: Supervisory IC providing VCC brownout detection, manual reset, and automatic VBATT switchover to VOUT. Use Value: Guarantees RAM data retention down to VCC = 1V and enables 200ms reset hold time for clean µP restart after power recovery. | Use Scenario: Industrial PLC modules operating from 3.3V rails with watchdog supervision for firmware crash recovery. IC Role / Device Role / Timing Role: System-level reset generator with 1.6s watchdog timeout and edge-triggered WDI interface. Use Value: Eliminates need for discrete RC reset circuits and external watchdog timers, reducing BOM count and layout area. |
| Intelligent Instruments | Critical µP Power Monitoring |
Use Scenario: Handheld multimeters with real-time clock and configuration EEPROM backed by CR2032 battery. IC Role / Device Role / Timing Role: Dual-supply supervisor managing VCC/VBATT switchover and generating power-fail interrupt via PFO. Use Value: Provides accurate 1.237V PFI threshold (±75mV) for early warning of main supply degradation before system shutdown. | Use Scenario: Medical diagnostic devices where µP must never execute corrupted code due to undervoltage. IC Role / Device Role / Timing Role: Precision reset monitor with 2.625V threshold and guaranteed assertion to VCC = 1V. Use Value: Meets IEC 60601 safety requirements by ensuring deterministic reset behavior across full temperature range (–40°C to +85°C). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704RCSA+ | Same 2.625V reset threshold, but adds manual reset (MR) input; lacks watchdog timer. | Suitable where manual reset is required but watchdog supervision is unnecessary. | Select MAX704RCSA+ if system design mandates hardware-initiated reset without software watchdog dependency. |
| MAX802RCSA+ | Tighter reset threshold tolerance (±2% vs. ±75mV) and improved PFI accuracy (±2% vs. ±75mV). | Better suited for high-precision 3.0V systems with strict supply tolerance budgets. | Choose MAX802RCSA+ when reset threshold stability over temperature and voltage is prioritized over integrated watchdog functionality. |
Compared with MAX704RCSA+, MAX690RCSA+ provides essential watchdog supervision at the cost of MR input; versus MAX802RCSA+, it trades tighter threshold accuracy for integrated 1.6s watchdog - making it optimal for cost-sensitive, firmware-reliant embedded systems needing both reset and watchdog in one device.
Availability
MAX690RCSA+T is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, intelligent instruments, and critical µP power monitoring requiring stable component supply across industrial temperature ranges.
Supply support for MAX690RCSA+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, computing, and consumer applications.
The MAX690 family targets 3.0V/3.3V microprocessor systems requiring integrated reset, watchdog, and battery-backup switchover - eliminating discrete solutions in space-constrained portable and embedded designs.
FAQ
What is the exact reset threshold voltage for MAX690RCSA+T?
The MAX690RCSA+T has a nominal reset threshold of 2.625V for VCC falling, with a guaranteed range of 2.55V to 2.70V. On VCC rising, the threshold is 2.55V to 2.72V, incorporating 10mV typical hysteresis to prevent oscillation. This matches the 'R' suffix designation per Maxim's ordering guide and is validated in the Electrical Characteristics table.
Does MAX690RCSA+T support battery voltage higher than VCC?
Yes, MAX690RCSA+T explicitly supports VBATT exceeding VCC - a core feature enabling direct connection of standard 3.6V lithium batteries. 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.
What is the watchdog timeout period for MAX690RCSA+T?
The watchdog timeout period for MAX690RCSA+T is 1.6 seconds typical, with a specified range of 1.12s to 2.24s over temperature and supply voltage. The timer resets on any edge (rising or falling) at the WDI pin and cannot be disabled - a fixed behavior confirmed in the Detailed Description section.
Can MAX690RCSA+T operate without a backup battery?
Yes, MAX690RCSA+T can operate without a backup battery: connect both VBATT and VOUT pins to VCC. However, battery-backup functionality (RAM retention during power loss) is disabled. For non-battery applications, Maxim recommends alternatives like MAX706RCSA+ or MAX708RCSA+ optimized for single-supply use.
What package type and RoHS status does MAX690RCSA+T use?
MAX690RCSA+T uses an 8-pin SOIC package (S8+4 code, JEDEC MS-012AC outline) with 150mil width and RoHS-compliant lead-free construction - indicated by the '+' suffix in the part number per Maxim's ordering information and Package Drawing documentation.
MAX690RCSA+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:
- 2.625V
- 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
MAX690RCSA+T FAQ
1.How can I place an order for MAX690RCSA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690RCSA+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 MAX690RCSA+T reliable?
The price and inventory of MAX690RCSA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690RCSA+T is usually 5 days.
3.What payment methods are accepted for MAX690RCSA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690RCSA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690RCSA+T?
MAX690RCSA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690RCSA+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 MAX690RCSA+T?
For technical support, including MAX690RCSA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690RCSA+T requirements.
6.How does Aetrix verify that MAX690RCSA+T is sourced from the original manufacturer or authorized distributors?
All MAX690RCSA+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 MAX690RCSA+T meets industry standards.
7.What is the process for return or replacement of MAX690RCSA+T?
All MAX690RCSA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX690RCSA+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 MAX690RCSA+T part is unused and in its original packaging.
Return procedure for MAX690RCSA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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