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Analog Devices Inc./Maxim Integrated MAX690AEPA+
- Part No.:
- MAX690AEPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX690AEPA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:210
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Product details
Overview
The MAX690AEPA+ from Maxim Integrated is a microprocessor supervisory circuit providing precision reset generation, battery-backup switchover, watchdog timer, and power-fail detection for +5V systems. It asserts an active-low RESET pulse during power-up (VCC ≥ 1V), brownout (VCC < 4.65V), and watchdog timeout (1.6s), while switching VOUT to VBATT when VCC drops below threshold-enabling reliable CMOS RAM retention in battery-powered controllers.
For engineers reviewing the MAX690AEPA+ datasheet, MAX690AEPA+ pinout, MAX690AEPA+ application, or MAX690AEPA+ equivalent, this page delivers verified functional identity, confirmed −40°C to +85°C industrial temperature operation, exact 8-pin PDIP package mapping, validated 200ms reset pulse width, and two rigorously cross-referenced alternative parts with documented technical and application differences.
Technical Context
The MAX690AEPA+ integrates four independent monitoring functions on a single die: a precision 4.65V ±2% reset threshold detector with 200ms delay, a 1.6s watchdog timer cleared by WDI edge transitions, a 1.25V reference-based power-fail comparator (PFI/PFO), and a bidirectional battery switchover circuit that connects VOUT to VBATT only when VCC falls below 4.65V and VBATT exceeds VCC by >20mV.
Its internal architecture uses a P-channel MOSFET for VOUT-to-VCC switching (5Ω typical on-resistance) and an 80Ω PMOS switch for VOUT-to-VBATT backup mode, with guaranteed RESET assertion down to VCC = 1.2V and quiescent supply current of 200µA (active) / 50nA (battery-backup). All logic thresholds are referenced to VCC, and WDI features internal 35% VCC biasing for floating-state immunity.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±2% - guarantees deterministic reset assertion at nominal +5V supply dropout, compatible with TTL/CMOS µP reset inputs. |
| Reset Pulse Width | 200ms - ensures sufficient duration to fully initialize microprocessors including 80C51-family and Motorola 68HC11. |
| Watchdog Timeout | 1.6s - provides robust software hang detection without requiring external timing components. |
| Battery-Backup Current | 50nA - enables multi-year lithium battery life in standby, critical for uninterruptible memory retention. |
| Operating Temperature | −40°C to +85°C - qualified for industrial environments including factory automation and remote telemetry nodes. |
| Supply Current (Active) | 200µA - minimizes loading on primary +5V rail during normal operation. |
| Power-Fail Threshold | 1.25V - allows flexible external resistor-divider configuration to monitor unregulated DC inputs or negative rails. |
Pinout & Package
MAX690AEPA+ is housed in an 8-pin plastic DIP (PDIP) package with 0.300" wide body, lead-free finish (indicated by '+' suffix), and standard through-hole mounting. Pin spacing conforms to JEDEC MS-001.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Switched Output Supply | Delivers regulated +5V from VCC or backup battery VBATT; connects to CMOS RAM VDD with <5Ω drop in active mode. |
| 2 - VCC | Main Power Input | +5V system supply input; powers internal circuitry and enables VOUT-to-VCC connection above reset threshold. |
| 3 - GND | Analog/Digital Ground | Common reference for all internal comparators, reset generator, and battery switchover logic. |
| 4 - PFI | Power-Fail Input | High-impedance (±25nA) comparator input referenced to 1.25V; used to monitor auxiliary supplies or unregulated rails. |
| 5 - PFO | Power-Fail Output | Open-drain active-low output signaling undervoltage condition; drives µP interrupt or external latch. |
| 6 - WDI | Watchdog Input | Edge-sensitive input (50ns min pulse width); toggling resets 1.6s timer; floating state disables watchdog. |
| 7 - RESET | Reset Output | Active-low open-drain output; pulses low for 200ms on power-up/brownout/watchdog timeout; asserted down to VCC = 1.2V. |
| 8 - VBATT | Battery Backup Input | Accepts 2.8V–4.8V lithium cell; activates switchover only when VCC < 4.65V and VBATT > VCC + 20mV (40mV hysteresis). |
Key Features
| Feature | Design Value |
|---|---|
| Precision Reset Threshold | 4.65V ±2% over full temperature range ensures consistent µP initialization across −40°C to +85°C without external calibration. |
| Guaranteed Low-VCC Reset Assertion | RESET remains valid down to VCC = 1.2V, enabling safe shutdown sequencing even during deep brownout conditions. |
| Ultra-Low Battery-Backup Current | 50nA quiescent draw extends CR2032 lithium battery life beyond 10 years in memory-retention applications. |
| Intelligent Battery Switchover | VBATT engages only when VCC drops below 4.65V *and* VBATT exceeds VCC by 20mV-prevents false switching during slow VCC decay. |
| Integrated Power-Fail Comparator | Dedicated 1.25V reference and PFI/PFO pair enables accurate early-warning detection of supply degradation before µP reset triggers. |
Applications
| Battery-Powered Computers and Controllers | Intelligent Instruments |
|---|---|
Use Scenario: Portable data loggers powered by coin-cell batteries require nonvolatile RAM retention during AC power loss or battery replacement. IC Role / Device Role / Timing Role: MAX690AEPA+ monitors main +5V rail and automatically switches VOUT to VBATT when VCC drops below 4.65V, preserving SRAM contents. Use Value: Enables hot-swap battery replacement without system reset or data loss, leveraging 40mV switchover hysteresis to prevent oscillation during marginal VCC conditions. | Use Scenario: Handheld multimeters with real-time clock and calibration memory must retain settings during brief power interruptions. IC Role / Device Role / Timing Role: MAX690AEPA+ provides 200ms RESET pulse on power-up and brownout, while its 1.25V PFI comparator detects pre-failure voltage sag on the analog front-end supply. Use Value: Prevents corrupted calibration data writes by halting µP execution before supply collapse, using guaranteed RESET assertion down to VCC = 1.2V. |
| Critical μP Power Monitoring | Industrial Remote Telemetry Nodes |
Use Scenario: PLC I/O modules must guarantee deterministic startup and fault recovery in noisy factory environments with fluctuating 5V rails. IC Role / Device Role / Timing Role: MAX690AEPA+ combines 4.65V reset threshold, 1.6s watchdog, and PFO interrupt to detect both supply faults and firmware hangs. Use Value: Eliminates need for discrete reset IC + watchdog + supervisor, reducing BOM count and PCB area while improving MTBF via integrated hysteresis and noise-immune WDI biasing. | Use Scenario: Wireless sensor nodes deployed in unattended locations rely on lithium thionyl chloride batteries for 10+ year operation. IC Role / Device Role / Timing Role: MAX690AEPA+ operates in ultra-low-current battery-backup mode (50nA), powering only essential SRAM and RTC during extended sleep cycles. Use Value: Achieves decade-long field life by minimizing leakage paths-VBATT current drops to <1µA when VCC is >1V below VBATT, per internal switchover comparator shutdown. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX802LEPA+ | Identical reset threshold (4.65V), same 200ms reset width and 1.6s watchdog, but guarantees ±2% power-fail accuracy vs. MAX690AEPA+'s unspecified PFI tolerance. | Preferred where precise early-warning voltage monitoring is required (e.g., predictive maintenance systems), not just reset generation. | Select MAX802LEPA+ when PFI comparator accuracy is critical; otherwise MAX690AEPA+ offers identical core supervision at lower cost. |
| MAX706PEPA+ | Same 4.65V reset threshold and 200ms pulse, but adds manual reset input (MR) and active-high RESET output-lacks battery switchover and PFI/PFO functionality. | Suitable for simpler systems needing only reset and watchdog, without RAM backup or power-fail warning capability. | Choose MAX706PEPA+ if battery backup and power-fail detection are unnecessary; MAX690AEPA+ is mandatory when VOUT switchover is required. |
Compared with MAX802LEPA+, MAX690AEPA+ trades guaranteed PFI accuracy for broader feature integration (battery switchover + PFO), while MAX706PEPA+ sacrifices switchover and PFI to add manual reset-making MAX690AEPA+ the optimal choice for complete +5V system supervision with memory retention.
Availability
MAX690AEPA+ is available at Aetrix Electronics and suitable for battery-powered computers and controllers, intelligent instruments, critical μP power monitoring, industrial remote telemetry nodes, and portable medical devices requiring stable component supply across extended temperature ranges.
Supply support for MAX690AEPA+ 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, automotive, and communications applications, with expertise in power management and supervisory circuits.
The MAX690A family targets microprocessor-based systems requiring coordinated reset, watchdog, battery backup, and power-fail monitoring in a single compact package-optimized for reliability in harsh industrial environments.
FAQ
What is the operating temperature range of the MAX690AEPA+?
The MAX690AEPA+ is rated for operation from −40°C to +85°C, making it suitable for industrial applications such as factory automation, remote sensors, and outdoor telemetry equipment. This extended temperature grade distinguishes it from the commercial-grade MAX690ACPA (0°C to +70°C) and ensures reliable reset assertion, watchdog timing, and battery switchover performance across the full range.
Does the MAX690AEPA+ support active-high reset output?
No, the MAX690AEPA+ provides only an active-low RESET output. The active-high variant is the MAX805L series (e.g., MAX805LEPA+), which outputs RESET instead of RESET. The MAX690AEPA+ RESET pin is open-drain and requires an external pull-up; it asserts low for 200ms during power-up, brownout, or watchdog timeout, and remains low while VCC is below 4.65V.
What is the maximum allowable backup battery voltage for the MAX690AEPA+?
The MAX690AEPA+ supports a maximum VBATT voltage of 4.80V, as specified in Maxim's application notes for lithium battery compatibility. Exceeding this voltage risks forward-biasing the internal substrate diode (D1) when VCC approaches the reset threshold, potentially causing unintended current flow from VBATT to VCC and compromising reliability.
How does the watchdog timer on the MAX690AEPA+ get reset?
The MAX690AEPA+ watchdog timer resets on any rising or falling edge applied to the WDI pin, or when RESET is asserted, or when WDI is left floating (due to internal 35% VCC biasing). A continuous high or low on WDI for 1.6s triggers reset; the timer restarts immediately after each qualifying edge, enabling robust software supervision without dedicated timer peripherals.
Can the MAX690AEPA+ monitor negative supply voltages?
Yes, the MAX690AEPA+ power-fail comparator can monitor negative rails using an external resistor network (Figure 7 in the datasheet). By referencing PFI to ground and applying the negative rail through a voltage divider, PFO asserts low when the negative supply magnitude degrades-enabling detection of −5V or −12V rail failures in mixed-supply systems.
MAX690AEPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX690AEPA+ FAQ
1.How can I place an order for MAX690AEPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690AEPA+ 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 MAX690AEPA+ reliable?
The price and inventory of MAX690AEPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690AEPA+ is usually 5 days.
3.What payment methods are accepted for MAX690AEPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690AEPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690AEPA+?
MAX690AEPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690AEPA+ 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 MAX690AEPA+?
For technical support, including MAX690AEPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690AEPA+ requirements.
6.How does Aetrix verify that MAX690AEPA+ is sourced from the original manufacturer or authorized distributors?
All MAX690AEPA+ 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 MAX690AEPA+ meets industry standards.
7.What is the process for return or replacement of MAX690AEPA+?
All MAX690AEPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX690AEPA+, 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 MAX690AEPA+ part is unused and in its original packaging.
Return procedure for MAX690AEPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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