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Analog Devices Inc./Maxim Integrated MAX690SCPA+
- Part No.:
- MAX690SCPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX690SCPA+.pdf
- Description:
- IC SUPERVISOR
- Quantity:
- Payment:
- Shipping:
Inventory:509
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Product details
Overview
MAX690SCPA+ from Maxim Integrated is an 8-pin microprocessor supervisory IC providing reset generation, battery backup switchover, watchdog timer, and power-fail warning for +5V systems. It delivers a 4.65V reset threshold, 50ms reset timeout, fixed 1.6s watchdog timeout, 1.3V PFI comparator, and VOUT switching between VCC and VBATT - used in embedded controllers and industrial instrumentation requiring reliable power monitoring.
For engineers reviewing the MAX690SCPA+ datasheet, MAX690SCPA+ pinout, MAX690SCPA+ application, or MAX690SCPA+ equivalent, key selection criteria include its fixed-reset timing, lack of CE gating or adjustable timeouts (distinguishing it from 16-pin MAX691/693 variants), battery switchover hysteresis (50mV/70mV), and compatibility with 2.0–4.25V backup batteries in space-constrained designs.
Technical Context
The MAX690SCPA+ integrates four core supervisory functions in a single 8-pin package: precision reset generation with 4.65V threshold and 40mV hysteresis; automatic battery switchover using internal PNP and MOSFET paths; a fixed 1.6s watchdog timer triggered by WDI transitions; and a 1.3V reference-based power-fail comparator feeding PFO. All logic operates from VCC or VBATT, with VOUT sourcing up to 50mA.
No external timing components are required: reset delay is internally set to 50ms (non-adjustable), watchdog timeout is fixed at 1.6s nominal, and oscillator configuration is disabled - OSC SEL and OSC IN pins are unused. The device lacks CE IN/CE OUT, BATT ON, LOW LINE, and WDO outputs present in 16-pin family members, confirming its role as a minimal-feature, cost-optimized variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V (min 4.5V, max 4.75V) - ensures reliable reset assertion before +5V supply drops below microprocessor VCC operating minimum. |
| Reset Timeout Delay | 50ms - holds RESET low after VCC recovery to accommodate microprocessor clock startup and initialization. |
| Watchdog Timeout Period | 1.6s (nominal) - detects software hangs without requiring external timing elements or configuration pins. |
| Battery Switchover Threshold | VCC − VBATT = 70mV (rising), 50mV (falling) - prevents oscillation during slow VCC decay while enabling seamless RAM backup transition. |
| VOUT Output Capability | 50mA continuous - powers CMOS RAM directly; bypass capacitor ≥0.1µF required for stability and transient current delivery. |
| Supply Current (Battery Mode) | 1µA max (VCC = 0V, VBATT = 2.8V) - extends lithium or coin-cell backup life for years in standby applications. |
| PFI Comparator Threshold | 1.3V (±0.1V) - enables early power-fail warning via external resistor divider, allowing data save before reset triggers. |
Pinout & Package
MAX690SCPA+ is housed in an 8-pin plastic DIP (Dual In-line Package) with 0.3-inch body width and through-hole mounting. Pin 1 is marked with a notch or dot; pin numbering follows standard counter-clockwise layout from top-left corner.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VBATT | Backup battery input; connects to VOUT when VCC falls below VBATT − 50mV; tie to GND if unused. |
| 2 | VCC | +5V main supply input; monitored for reset and watchdog; absolute max 6.0V. |
| 3 | GND | Ground reference for all analog and digital circuitry; must be low-impedance connection. |
| 4 | VOUT | Switched output - higher of VCC or VBATT; powers CMOS RAM; requires ≥0.1µF bypass capacitor. |
| 5 | PFI | Power-fail input; noninverting comparator input referenced to 1.3V; connect to voltage divider for early warning. |
| 6 | PFO | Power-fail output; open-drain active-low signal asserted when PFI < 1.3V; sinks up to 3.2mA. |
| 7 | WDI | Watchdog input; three-level (low/mid/high); toggling required every ≤1.6s; floating disables watchdog. |
| 8 | RESET | Active-low reset output; asserted when VCC < 4.65V or WDI unattended; internal 3µA pullup; drives CMOS directly. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Power Supervision | Combines reset, battery switchover, watchdog, and power-fail detection in one 8-pin IC - eliminates 4–6 discrete components and saves PCB area. |
| Precision Reset Threshold | 4.65V ±150mV over full temperature range - matches standard +5V ±5% supply tolerance and ensures deterministic reset behavior. |
| Ultra-Low Battery Current | 1µA max in backup mode - enables >10-year coin-cell lifetime for real-time clocks and SRAM retention. |
| Robust VOUT Switching | Internal PNP + 200Ω MOSFET path - provides <0.5V dropout at 50mA and <0.1V dropout at 250µA, minimizing backup voltage loss. |
| Glitch-Immune Monitoring | 100µs reset comparator response + internal filtering - rejects short transients on VCC without false resets. |
Applications
| Industrial Controllers | Embedded Data Loggers |
|---|---|
|
Use Scenario: Programmable logic controller (PLC) maintaining volatile register states during AC mains interruption. IC Role / Device Role / Timing Role: MAX690SCPA+ asserts RESET to halt CPU execution and switches VOUT to VBATT to sustain RAM and RTC power. Use Value: Guarantees 50ms reset hold time and seamless switchover at 50mV hysteresis - prevents corrupted I/O state during brownout recovery. |
Use Scenario: Remote environmental sensor node logging temperature/humidity to battery-backed SRAM between transmissions. IC Role / Device Role / Timing Role: MAX690SCPA+ monitors main supply and triggers PFO interrupt for last-chance data save before VCC collapse. Use Value: 1.3V PFI threshold enables configurable early-warning window (e.g., 4.85V detection) - preserves integrity of multi-second measurement buffers. |
| Medical Instrumentation | Automotive Body Control Modules |
|
Use Scenario: Portable ECG monitor storing waveform snapshots in SRAM during brief battery swap. IC Role / Device Role / Timing Role: MAX690SCPA+ maintains VOUT from VBATT while main battery is disconnected, holding RAM contents and RTC time. Use Value: 1µA battery standby current extends CR2032 life beyond 5 years - meets IEC 62304 Class B reliability requirements. |
Use Scenario: Door module retaining window position and mirror settings after ignition-off battery drain. IC Role / Device Role / Timing Role: MAX690SCPA+ detects VCC sag below 4.65V and asserts RESET to freeze MCU state before power loss. Use Value: 40mV reset hysteresis prevents chatter during alternator ripple - avoids spurious reboots in 12V automotive electrical environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX692SCPA+ | 4.4V reset threshold (vs. 4.65V); same 8-pin DIP, 50ms reset, 1.6s watchdog, but supports 4.5–5.5V VCC range. | Suitable for +5V ±10% supplies (e.g., unregulated wall adapters), whereas MAX690SCPA+ targets tighter +5V ±5% systems. | Select MAX692SCPA+ when system VCC tolerance exceeds ±5%; otherwise MAX690SCPA+ provides better noise margin at nominal 5V. |
| TPS3823-50DBVR | Single-function 4.63V reset IC (no battery switchover, no watchdog, no PFI); SOT-23-5 package; 2.5–5.5V operation; 200ms reset delay. | Only replaces MAX690SCPA+'s reset function - requires separate circuits for battery backup, watchdog, and power fail. | Choose TPS3823-50DBVR only if supervisory features beyond reset are handled elsewhere; MAX690SCPA+ remains superior for integrated protection. |
Compared with MAX692SCPA+, MAX690SCPA+ offers higher reset threshold for improved noise immunity in clean 5V rails; compared with TPS3823-50DBVR, it delivers four integrated functions in one package - reducing BOM count, board area, and qualification effort for full-system supervision.
Availability
MAX690SCPA+ is available at Aetrix Electronics and suitable for industrial controllers, embedded data loggers, medical instrumentation, and automotive body control modules requiring stable component supply across extended temperature ranges (0°C to +70°C).
Supply support for MAX690SCPA+ 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 semiconductors for power, sensing, and interface applications - emphasizing integration, reliability, and low-power operation.
The MAX690 family was engineered specifically for microprocessor-based systems needing compact, single-chip supervision - delivering reset, battery backup, watchdog, and power-fail functions without external timing components.
FAQ
What is the reset threshold voltage of the MAX690SCPA+ and how does it behave during power-up?
The MAX690SCPA+ has a guaranteed reset threshold of 4.65V (min 4.5V, max 4.75V). During power-up, RESET remains low until VCC rises above 4.75V, then stays asserted for a fixed 50ms timeout - ensuring the microprocessor completes clock stabilization and initialization before release. This behavior is fully internal and requires no external components.
Does the MAX690SCPA+ support adjustable watchdog timeout or reset delay?
No. The MAX690SCPA+ implements fixed timing: 1.6s watchdog timeout and 50ms reset delay. Unlike 16-pin variants (e.g., MAX691), it lacks OSC SEL and OSC IN pins for adjustment. The watchdog is disabled if WDI is left floating, and enabled only when actively toggled within the 1.6s window.
Can the MAX690SCPA+ be used with a 3.3V microprocessor system?
No. The MAX690SCPA+ is specified for +5V systems only: its reset threshold is 4.65V, VCC operating range is 4.75–5.5V, and VOUT switching assumes a 5V primary rail. For 3.3V systems, consider the MAX6326 or MAX6369 families - not the MAX690SCPA+.
What is the maximum load current supported by VOUT on the MAX690SCPA+?
VOUT on the MAX690SCPA+ delivers up to 50mA continuously when powered from VCC. In battery backup mode (VCC = 0V), it sustains 250µA at <0.1V dropout. Exceeding 50mA requires an external PNP transistor - which the MAX690SCPA+ does not support via a BATT ON output (unlike MAX691).
How does the MAX690SCPA+ handle power-fail detection without a dedicated PFO pull-up resistor?
The MAX690SCPA+ PFO is an open-drain output with no internal pull-up. A pull-up resistor (typically 10kΩ to VCC or VOUT) is mandatory to generate a valid logic-high level when PFO is inactive. Without it, PFO floats high and cannot drive interrupts reliably - this requirement is explicitly documented in the MAX690SCPA+ datasheet.
MAX690SCPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- -
- Number of Voltages Monitored:
- -
- Voltage - Threshold:
- -
- Output:
- -
- Reset:
- -
- Reset Timeout:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
MAX690SCPA+ FAQ
1.How can I place an order for MAX690SCPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690SCPA+ 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 MAX690SCPA+ reliable?
The price and inventory of MAX690SCPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690SCPA+ is usually 5 days.
3.What payment methods are accepted for MAX690SCPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690SCPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690SCPA+?
MAX690SCPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690SCPA+ 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 MAX690SCPA+?
For technical support, including MAX690SCPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690SCPA+ requirements.
6.How does Aetrix verify that MAX690SCPA+ is sourced from the original manufacturer or authorized distributors?
All MAX690SCPA+ 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 MAX690SCPA+ meets industry standards.
7.What is the process for return or replacement of MAX690SCPA+?
All MAX690SCPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX690SCPA+, 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 MAX690SCPA+ part is unused and in its original packaging.
Return procedure for MAX690SCPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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