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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:215
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Product details
Overview
MAX690SCSA+ from Maxim Integrated is a 3.3V/3.0V 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-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, this page delivers verified specifications, exact pin functions, real-world use cases in RAM backup and brownout protection, and validated alternative parts for 3V/3.3V µP supervision.
Technical Context
The MAX690SCSA+ integrates a precision reset comparator with ±4% threshold accuracy, a dedicated power-fail comparator (VPFT = 1.237V, ±20mV hysteresis), and a non-disableable watchdog timer that triggers reset on WDI inactivity exceeding 1.6s. Its dual-supply architecture enables seamless VCC-to-VBATT switchover at VSW = 2.40V (typ) with 140Ω on-resistance.
It features guaranteed RESET assertion down to VCC = 1V, supports manual reset via MR input (70µA internal pull-up), and maintains 40µA VCC supply current (VCC < 3.6V) and only 1µA VBATT leakage-enabling long-term battery-backed CMOS RAM retention without compromising system uptime.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V (VCC falling), ±4% tolerance - ensures reset activation before 3.3V supply drops below 2.85V system minimum |
| Reset Timeout Period | 200ms (typ) - provides sufficient hold time for µP initialization after power stabilization |
| Watchdog Timeout | 1.6s (typ) - detects µP lockup while allowing normal firmware execution windows |
| VCC Supply Current | 40µA (typ, VCC < 3.6V) - minimizes quiescent load on primary supply during active operation |
| Battery Supply Current | 1µA (max, VBATT mode) - extends lithium battery life beyond 10 years in standby |
| Power-Fail Threshold | 1.237V (VPFT), ±20mV hysteresis - enables accurate undervoltage detection on auxiliary rails |
| VBATT-to-VOUT On-Resistance | 140Ω (typ, TA = +25°C) - limits voltage drop during battery switchover to preserve RAM data integrity |
Pinout & Package
MAX690SCSA+ is housed in an 8-pin SOIC package (SO) with gull-wing leads, RoHS-compliant (indicated by '+' suffix), and rated for 0°C to +70°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC and VBATT based on switchover threshold; connects to RAM VDD for seamless backup |
| 2 - VCC | Main system supply input | Primary 3.0V/3.3V power source; powers internal circuitry and enables VOUT sourcing when above VRST |
| 3 - GND | Ground reference | Common return path for all analog and digital functions; substrate tied to higher of VCC/VBATT |
| 4 - PFI | Power-fail comparator input | Monitors external rail via resistor divider; asserts PFO low when input falls below 1.237V |
| 5 - PFO | Power-fail open-drain output | Signals undervoltage condition to µP interrupt or MR input; requires external pull-up for logic-high state |
| 6 - WDI | Watchdog timer input | Edge-sensitive (rising/falling); resets watchdog timer on transition; ties high/low to force periodic reset |
| 7 - RESET | Active-low reset output | Drives µP reset pin low for 200ms on power-up, brownout, or watchdog timeout; guaranteed valid to VCC = 1V |
| 8 - VBATT | Backup battery input | Accepts 3.6V lithium cell; exceeds VCC in normal operation; enables VOUT switchover when VCC falls below 2.40V |
Key Features
| Feature | Design Value |
|---|---|
| Battery-backup switchover | Automatic VCC-to-VBATT transition at 2.40V with 140Ω switch resistance preserves RAM data during brownouts |
| Guaranteed reset assertion | RESET remains valid down to VCC = 1V - ensures µP stays held in reset even during deep undervoltage events |
| Low-power operation | 40µA VCC supply current and 1µA VBATT leakage enable >10-year battery life in always-on backup applications |
| Integrated watchdog timer | 1.6s timeout with edge-triggered clear - detects firmware hangs without requiring external timing components |
| Manual reset support | MR input with 70µA internal pull-up allows momentary switch interface without external biasing components |
Applications
| Battery-Backed RAM Preservation | Critical µP Power Monitoring |
|---|---|
|
Use Scenario: Maintaining SRAM contents during AC power loss in industrial controllers using a 3.6V lithium coin cell. IC Role / Device Role / Timing Role: Supervisory IC providing automatic VCC-to-VBATT switchover at 2.40V and holding RESET until stable VCC recovery. Use Value: Eliminates need for external diode-or circuitry and guarantees RAM data retention with <1µA battery drain. |
Use Scenario: Preventing erratic µP behavior during 3.3V supply brownouts in portable medical devices. IC Role / Device Role / Timing Role: Precision reset supervisor asserting active-low RESET for 200ms whenever VCC dips below 2.925V. Use Value: Ensures deterministic µP restart with ±4% reset threshold accuracy and immunity to sub-40µs VCC glitches. |
| Embedded Controller Watchdog Protection | Multi-Rail Power-Fail Detection |
|
Use Scenario: Detecting firmware lockups in automotive body control modules running on 3.3V supplies. IC Role / Device Role / Timing Role: Watchdog timer monitoring WDI transitions; triggering RESET if no edge occurs within 1.6s. Use Value: Provides fail-safe recovery without software intervention, with guaranteed timer clear on any WDI edge. |
Use Scenario: Monitoring a 5V auxiliary rail in telecom base stations using resistor-divider scaling to PFI input. IC Role / Device Role / Timing Role: Independent power-fail comparator generating PFO low signal when scaled input falls below 1.237V. Use Value: Enables early warning of secondary supply failure with 20mV hysteresis to reject noise on divided rail. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704SCSA+ | Identical pinout, same 2.925V reset threshold and 200ms timeout, but adds manual reset (MR) input functionality not present in MAX690S | Required where hardware-initiated reset via pushbutton is needed; MR input pulls up internally at 70µA | Select MAX704SCSA+ when manual reset capability is mandatory; otherwise MAX690SCSA+ offers lower BOM count |
| MAX802SCSA+ | Tighter reset threshold tolerance (±2% vs. ±4%) and improved power-fail comparator accuracy (±2% vs. ±75mV) | Suitable for high-precision systems where supply margin is constrained; requires tighter layout control for noise immunity | Choose MAX802SCSA+ for designs demanding enhanced voltage-monitoring accuracy; MAX690SCSA+ suffices for standard industrial tolerance |
Compared with MAX704SCSA+, MAX690SCSA+ omits MR input to reduce complexity and cost in fixed-reset applications; versus MAX802SCSA+, it trades tighter thresholds for broader compatibility with legacy 3.3V systems where ±4% is sufficient.
Availability
MAX690SCSA+ is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, and intelligent instruments requiring stable component supply across industrial temperature ranges.
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, communications, and computing markets.
The MAX690 series belongs to Maxim's microprocessor supervisory product line, engineered specifically for robust power monitoring and battery switchover in 3.0V/3.3V µP systems with minimal external components.
FAQ
What is the exact reset threshold voltage for MAX690SCSA+?
The MAX690SCSA+ 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 0°C to +70°C operating range and ensures reset assertion before the 3.3V supply falls below 2.85V, aligning with typical system-level undervoltage margins.
Does MAX690SCSA+ support manual reset functionality?
No, the MAX690SCSA+ does not include a manual reset (MR) input. That function is provided in the pin-compatible MAX704SCSA+ variant. The MAX690SCSA+ relies solely on power-on reset, brownout detection, and watchdog timeout for reset generation-making it ideal for applications where hardware reset buttons are unnecessary and BOM simplification is prioritized.
Can MAX690SCSA+ be used without a backup battery?
Yes, MAX690SCSA+ can operate without a backup battery: connect both VBATT and VOUT pins directly to VCC. However, doing so disables battery switchover and power-fail monitoring via PFI/PFO. For pure reset supervision without backup, alternatives like MAX706SCSA+ may offer better optimization, but MAX690SCSA+ remains functional with VBATT tied to VCC.
What is the maximum allowable VCC transient duration before MAX690SCSA+ asserts reset?
At 100mV overdrive (i.e., VCC falling 100mV below the 2.925V threshold), the MAX690SCSA+ tolerates negative-going transients up to 40µs without issuing a reset pulse. This immunity is confirmed in Figure 7 of the datasheet and ensures robust operation against brief supply glitches common in noisy industrial environments.
Is MAX690SCSA+ pin-compatible with other members of the MAX690T/S/R family?
Yes, all MAX690T/S/R variants-including MAX690SCSA+-share identical 8-pin SOIC pinout, electrical interface, and functional block diagram. Only the reset threshold voltage differs (3.075V for T, 2.925V for S, 2.625V for R). This allows direct substitution within the same package footprint when adjusting for different supply tolerances or system voltage margins.
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:
- 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:
- 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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