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Analog Devices Inc./Maxim Integrated MAX690TEPA+
- Part No.:
- MAX690TEPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX690TEPA+.pdf
- Description:
- IC SUPERVISOR MPU 8-DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,509
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Product details
Overview
MAX690TEPA+ from Maxim Integrated is a 3.3V microprocessor supervisory circuit with precision reset threshold (3.075V ±4%), 200ms reset timeout, integrated watchdog timer (1.6s), battery-backup switchover, and power-fail monitoring. It monitors VCC supply integrity, asserts active-low RESET during brownout or watchdog timeout, and switches VOUT to VBATT when VCC drops below 2.40V - used in embedded controllers and battery-powered instrumentation requiring reliable power-up/power-down sequencing.
For engineers reviewing the MAX690TEPA+ datasheet, MAX690TEPA+ pinout, MAX690TEPA+ application, or MAX690TEPA+ equivalent, this page delivers verified technical context, exact pin functions, real-world use cases, and validated alternative parts for 3.0V/3.3V µP supervision in industrial and portable systems.
Technical Context
The MAX690TEPA+ integrates a precision reset comparator with 10mV hysteresis, a 1.6s watchdog timer that clears on WDI edge transitions, and a dual-path power-switching architecture: a 3Ω PMOS switch connects VCC to VOUT during normal operation, while a 140Ω switch engages VBATT-to-VOUT when VCC falls below VSW (2.40V). Its PFI/PFO comparator operates independently with 1.237V threshold and ±10mV hysteresis.
It supports battery-backed CMOS RAM retention via automatic switchover, guarantees RESET assertion down to VCC = 1V, and features manual reset input (MR) with internal 70µA pull-up and 200ms deassertion delay. The device operates across –40°C to +85°C and draws only 40µA typical VCC supply current at VCC < 3.6V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V ±4% (VCC falling); ensures reliable reset assertion before 3.3V system drops below 3.0V operating margin |
| Reset Timeout Period | 200ms (typical); provides sufficient hold time for µP initialization and peripheral stabilization |
| Watchdog Timeout | 1.6s (typical); detects µP lockup without requiring software intervention or external timing components |
| VCC Supply Current | 40µA (typ, VCC < 3.6V); enables long battery life in always-on supervision applications |
| Battery Supply Current | 0.4–1µA (max); minimizes drain on lithium backup cells during extended standby |
| VBATT-to-VOUT On-Resistance | 140Ω (typ); limits voltage drop and power loss during battery-backup mode |
| Power-Fail Threshold | 1.237V ±10mV; enables accurate undervoltage detection of auxiliary rails via external resistor divider |
Pinout & Package
MAX690TEPA+ is housed in an 8-pin plastic DIP (PDIP) package with 0.300" wide body, RoHS-compliant lead finish indicated by the '+' suffix.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | Supply output for CMOS RAM | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω switch) based on VCC level; must be decoupled with 0.1µF capacitor |
| 2 - VCC | Main supply input | Accepts 1.0V to 5.5V; powers internal circuitry and enables reset assertion when below 3.075V |
| 3 - GND | Ground reference | Common return path for VCC, VBATT, and all logic signals; requires low-inductance connection |
| 4 - PFI | Power-fail input | Monitors auxiliary rail via external divider; triggers PFO low when voltage falls below 1.237V |
| 5 - PFO | Power-fail output | Open-drain active-low signal; can drive MR on compatible devices (e.g., MAX704) to initiate reset |
| 6 - WDI | Watchdog input | Edge-sensitive; clearing pulse resets 1.6s timer; tied high/low causes periodic reset (every ~1.8s) |
| 7 - RESET | Active-low reset output | Pulled low for 200ms after power-up, brownout, or watchdog timeout; guaranteed valid down to VCC = 1V |
| 8 - VBATT | Backup-battery input | Accepts up to 6.0V; may exceed VCC; connects to VOUT during brownout to preserve RAM data |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout conditions where other supervisors lose functionality |
| Battery-backup switchover with 2.40V threshold | Enters battery mode before VOUT drops below 2.0V RAM retention limit, maximizing data integrity |
| 200ms reset timeout with restart-on-brownout | Prevents premature µP release during transient dips; timer resets each time VCC falls below threshold |
| 1.6s watchdog timer with edge-triggered clear | Eliminates need for dedicated watchdog IC; immune to static WDI states (no disable option) |
| Independent power-fail comparator (1.237V) | Enables monitoring of secondary supplies (e.g., analog rails) without affecting primary reset behavior |
| 40µA VCC supply current (typ) | Reduces system quiescent power by >5× versus discrete supervision solutions |
Applications
| Battery-Powered Embedded Controller | Intelligent Portable Instrument |
|---|---|
Use Scenario: Handheld multimeter with nonvolatile RAM storing calibration coefficients and user settings. IC Role / Device Role / Timing Role: Supervises 3.3V main supply and switches RAM to 3.6V lithium coin cell during battery swap or main power removal. Use Value: Prevents RAM corruption during hot-swap events; 0.4–1µA battery leakage preserves 10+ year shelf life. |
Use Scenario: Portable gas detector with µP-based sensor interface and alarm logic. IC Role / Device Role / Timing Role: Monitors 3.3V rail for brownout, asserts RESET to halt unsafe operation, and triggers PFO-driven interrupt on auxiliary 5V sensor supply failure. Use Value: Dual-supply fault detection avoids false alarms; 200ms reset hold ensures clean µP reboot before sensor reinitialization. |
| Critical µP Power Monitoring | Industrial Data Logger |
Use Scenario: Remote telemetry node powered by solar-charged Li-ion with intermittent 3.3V regulation. IC Role / Device Role / Timing Role: Detects VCC droop below 3.075V, initiates watchdog reset if µP hangs, and maintains RAM via VBATT during dusk/dawn transitions. Use Value: 1.6s watchdog prevents firmware lockup-induced data loss; switchover hysteresis avoids oscillation near 2.40V threshold. |
Use Scenario: Ruggedized environmental logger recording temperature/humidity every 10 seconds using EEPROM and RTC. IC Role / Device Role / Timing Role: Provides precise power-on reset timing (200ms), monitors backup supercap voltage via PFI, and asserts RESET if VCC falls during write cycle. Use Value: Guarantees EEPROM write completion before reset; 10mV PFI hysteresis rejects line noise during field deployment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704TEPA+ | Identical pinout and reset threshold (3.075V), but adds manual reset input (MR) with 70µA internal pull-up; same 200ms timeout and 1.6s watchdog. | Preferred when system requires hardware-initiated reset via pushbutton or logic signal; MR enables field service recovery without power cycle. | Select MAX704TEPA+ if manual reset functionality is required; otherwise MAX690TEPA+ offers identical core supervision at lower cost. |
| MAX802TEPA+ | Tighter reset threshold tolerance (±2% vs. ±4%) and improved PFI accuracy (±2% vs. ±75mV); same 8-pin PDIP package and functional block diagram. | Suitable for high-precision 3.3V systems where supply tolerance margins are constrained; no change to PCB layout or firmware. | Choose MAX802TEPA+ for designs demanding tighter voltage monitoring specs; MAX690TEPA+ remains optimal for cost-sensitive industrial applications. |
Compared with MAX704TEPA+, MAX690TEPA+ omits MR functionality but retains identical reset, watchdog, and battery switchover performance; versus MAX802TEPA+, it trades tighter tolerances for broader availability and lower unit cost in standard industrial temperature grade.
Availability
MAX690TEPA+ 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.
Supply support for MAX690TEPA+ 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 emphasis on power management and reliability-critical functions.
The MAX690 series targets 3.0V/3.3V microprocessor systems needing integrated reset, watchdog, and battery-backup control in a single 8-pin package - optimized for embedded controllers and portable instrumentation.
FAQ
What is the reset threshold voltage of the MAX690TEPA+ and how tightly is it specified?
The MAX690TEPA+ has a nominal reset threshold of 3.075V with a tolerance of ±4% over temperature and supply variations. This specification ensures reliable reset assertion before the 3.3V system supply falls below 3.0V, and is guaranteed across the full –40°C to +85°C operating range. The MAX690TEPA+ datasheet confirms this value applies specifically to the 'T' variant, distinguishing it from the 'S' (2.925V) and 'R' (2.625V) versions.
Does the MAX690TEPA+ include a manual reset input (MR) function?
No, the MAX690TEPA+ does not include a manual reset input. That function is present in the pin-compatible MAX704TEPA+ and MAX806TEPA+ variants. The MAX690TEPA+ relies solely on power-on reset, brownout detection, and watchdog timeout for reset generation. If hardware-initiated reset is required, MAX704TEPA+ is the direct alternative with identical reset threshold and package.
How does the MAX690TEPA+ handle battery-backup switchover, and what is the switchover voltage?
The MAX690TEPA+ switches VOUT from VCC to VBATT when VCC falls below 2.40V (VSW), ensuring CMOS RAM remains powered above its 2.0V data retention minimum. Switchover uses a 140Ω internal switch, and reconnection to VCC occurs only after VCC rises above the 3.075V reset threshold - not at VSW - to guarantee supply stability. This behavior is explicitly documented for the MAX690T/S/R family in the datasheet's Backup-Battery Switchover section.
Can the MAX690TEPA+ monitor a second power supply, and how is that implemented?
Yes, the MAX690TEPA+ can monitor a second supply using the PFI (power-fail input) pin, which compares an external voltage (scaled via resistor divider) against a 1.237V internal reference. When PFI falls below this threshold, PFO goes low - an open-drain signal usable for interrupts or cascaded reset triggering. This function operates independently of the main reset comparator and is confirmed in the MAX690TEPA+ datasheet's Power-Fail Comparator section.
What is the watchdog timeout period of the MAX690TEPA+, and can it be disabled?
The MAX690TEPA+ features a fixed 1.6s watchdog timeout period (typical), with a specified range of 1.12s to 2.24s over temperature and supply. Unlike some earlier Maxim supervisors, the watchdog function cannot be disabled - it clears only on WDI edge transitions or during RESET assertion. This behavior is explicitly stated in the Watchdog Input section of the MAX690TEPA+ datasheet and applies to all MAX690T/S/R variants.
MAX690TEPA+ 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:
- -
MAX690TEPA+ FAQ
1.How can I place an order for MAX690TEPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690TEPA+ 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 MAX690TEPA+ reliable?
The price and inventory of MAX690TEPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690TEPA+ is usually 5 days.
3.What payment methods are accepted for MAX690TEPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690TEPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690TEPA+?
MAX690TEPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690TEPA+ 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 MAX690TEPA+?
For technical support, including MAX690TEPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690TEPA+ requirements.
6.How does Aetrix verify that MAX690TEPA+ is sourced from the original manufacturer or authorized distributors?
All MAX690TEPA+ 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 MAX690TEPA+ meets industry standards.
7.What is the process for return or replacement of MAX690TEPA+?
All MAX690TEPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX690TEPA+, 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 MAX690TEPA+ part is unused and in its original packaging.
Return procedure for MAX690TEPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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