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Analog Devices Inc./Maxim Integrated MAX690TESA+T
- Part No.:
- MAX690TESA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX690TESA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,029
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Product details
Overview
MAX690TESA+T from Maxim Integrated is a 3.3V microprocessor supervisory circuit with active-low RESET output, 3.075V reset threshold (T-suffix), 200ms reset timeout, watchdog timer (1.6s), and battery-backup switchover capability. It monitors VCC supply integrity, asserts reset during brownout or watchdog timeout, and switches CMOS RAM to VBATT when VCC drops below 2.40V - used in battery-powered embedded controllers requiring reliable power-fail detection and nonvolatile memory retention.
For engineers reviewing the MAX690TESA+T datasheet, MAX690TESA+T pinout, MAX690TESA+T application, or MAX690TESA+T equivalent, this page delivers verified specifications including reset threshold tolerance (±4%), PFO comparator accuracy (±75mV), VCC supply current (40µA typical), battery leakage (0.4–1µA), and SO-8 package compatibility - all confirmed from Maxim's official datasheet Rev 3 (4/15).
Technical Context
The MAX690TESA+T integrates five core functions: precision voltage monitoring (3.075V ±4% falling threshold), 200ms reset timeout generator, 1.6s watchdog timer with edge-triggered clear, bidirectional battery switchover (VBATT > VCC supported), and independent power-fail comparator (1.237V threshold, ±75mV accuracy). Its internal PMOS VCC-to-VOUT switch (3Ω typical) and NMOS VBATT-to-VOUT switch (140Ω typical) enable seamless RAM backup without external FETs.
It operates across –40°C to +85°C (E-grade), supports VCC from 3.17V to 5.5V and VBATT up to 6.0V, guarantees RESET assertion down to VCC = 1.0V, and features guaranteed low-power operation: 40µA VCC supply current at VCC < 3.6V and ≤1µA battery supply current - making it suitable for long-life portable systems with lithium coin-cell backup.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold (VCC falling) | 3.075V ±4% - ensures reset triggers before 3.3V supply falls below system minimum operating voltage (3.15V at ±5% tolerance) |
| Reset Timeout Period | 200ms typical - provides sufficient hold time for µP initialization after power-up or brownout recovery |
| Watchdog Timeout | 1.6s ±40% - detects µP lockup with margin for software servicing intervals |
| VCC Supply Current | 40µA typical at VCC < 3.6V - enables multi-year operation on coin-cell backup without significant drain |
| Battery Leakage Current | 0.4–1µA - preserves lithium battery shelf life in standby mode |
| Power-Fail Threshold | 1.237V ±75mV - supports accurate undervoltage detection of auxiliary rails via external resistor divider |
| VCC-to-VOUT On-Resistance | 3Ω typical - minimizes voltage drop feeding CMOS RAM from main supply |
Pinout & Package
MAX690TESA+T is housed in an 8-pin SOIC (SO-8) package with standard 1.27mm pitch, RoHS-compliant lead-free finish (+ suffix), and moisture sensitivity level MSL-1. Pin 1 is marked by a beveled corner or dot.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT (Pin 1) | Supply output for CMOS RAM | Switches between VCC (via 3Ω PMOS) and VBATT (via 140Ω NMOS) based on VCC/VBATT comparison; connects directly to RAM VDD |
| VCC (Pin 2) | Main supply input | Primary 3.0V/3.3V system rail; powers internal circuitry and sources VOUT when above VSW (2.40V) |
| GND (Pin 3) | Ground reference | Common return for VCC, VBATT, and logic signals; substrate tied to higher of VCC/VBATT |
| PFI (Pin 4) | Power-fail input | Monitors auxiliary voltage via external divider; asserts PFO low when input falls below 1.237V |
| PFO (Pin 5) | Power-fail open-drain output | Active-low flag indicating PFI undervoltage or VCC < VSW; can drive MR on MAX704/MAX806 |
| WDI (Pin 6) | Watchdog input | Edge-sensitive (rising/falling) trigger; resets watchdog timer; cannot be disabled |
| RESET (Pin 7) | Active-low reset output | Push-pull, asserted low during reset condition; guaranteed valid down to VCC = 1.0V |
| VBATT (Pin 8) | Backup-battery input | Accepts 3.6V lithium cell; may exceed VCC; supplies VOUT when VCC drops below VSW |
Key Features
| Feature | Design Value |
|---|---|
| Battery switchover with VCC < VBATT support | Enables use of 3.6V lithium cells without diode drop or external regulators; switchover at 2.40V prevents premature RAM data loss |
| Guaranteed RESET assertion to VCC = 1V | Ensures µP remains held in reset even during deep brownout, preventing erratic execution at marginal supply |
| 200ms reset timeout with restart-on-brownout | Internal timer resets on every VCC dip below threshold, eliminating need for external RC timing components |
| 1.6s watchdog with edge-triggered clear | Eliminates false timeouts caused by noise; requires only one µP I/O toggle per service interval |
| Independent power-fail comparator | Allows monitoring of secondary rails (e.g., analog supply) without affecting reset behavior or requiring shared thresholds |
Applications
| Battery-Powered Embedded Controller | Critical µP Power Monitoring |
|---|---|
Use Scenario: Industrial sensor node powered by CR2032 coin cell with 3.3V MCU and SRAM, operating unattended for 5+ years. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, watchdog supervision, and automatic RAM backup switchover. Use Value: 40µA VCC supply current and ≤1µA battery leakage extend battery life; 3.075V reset threshold matches 3.3V ±5% system tolerance. |
Use Scenario: Medical infusion pump with safety-critical µP requiring guaranteed reset during AC power interruption and DC rail collapse. IC Role / Device Role / Timing Role: Primary power supervisor asserting RESET within 10µs of VCC falling below 3.075V and holding for 200ms. Use Value: Guaranteed RESET assertion down to VCC = 1.0V prevents unsafe state transitions; 200ms timeout exceeds µP reset requirement. |
| Intelligent Instrumentation | Portable Data Logger |
Use Scenario: Handheld multimeter with EEPROM and real-time clock, using lithium backup to retain calibration and time during main battery replacement. IC Role / Device Role / Timing Role: Dual-role device managing both µP reset integrity and seamless VOUT switchover to VBATT. Use Value: VBATT > VCC capability allows direct connection of 3.6V LiMnO₂ cell; 140Ω VBATT-to-VOUT switch limits dropout under 1mA RAM load. |
Use Scenario: Environmental logger recording temperature/humidity every 10 seconds, powered by rechargeable Li-ion with periodic USB charging. IC Role / Device Role / Timing Role: Watchdog supervisor detecting firmware hangs and power-fail comparator signaling USB disconnect. Use Value: 1.6s watchdog timeout aligns with 10s sampling interval; PFO output triggers µP interrupt for graceful shutdown before backup depletion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704TESA+ | Same 3.075V reset threshold, but adds active-high RESET output (open-drain) and manual reset input (MR); no watchdog timer | Suitable where manual reset is required and watchdog supervision is unnecessary; MR simplifies field service reset | Select MAX704TESA+ if system requires hardware-initiated reset but does not need watchdog supervision |
| MAX802TESA+ | Tighter reset threshold tolerance (±2% vs. ±4%) and improved PFI accuracy (±2% vs. ±75mV); identical pinout and core functionality | Better suited for high-precision 3.3V systems where supply tolerance must be held to ±2% over temperature | Select MAX802TESA+ when tighter voltage monitoring accuracy is required and cost premium is acceptable |
Compared with MAX704TESA+, MAX690TESA+ provides watchdog supervision but lacks MR; compared with MAX802TESA+, it offers lower cost and adequate accuracy for standard 3.3V ±5% systems, trading precision for broader design margin and legacy compatibility.
Availability
MAX690TESA+T is available at Aetrix Electronics and suitable for battery-powered computers and controllers, intelligent instrumentation, and critical µP power monitoring requiring stable component supply across industrial temperature ranges (–40°C to +85°C).
Supply support for MAX690TESA+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, medical, communications, and consumer applications, emphasizing reliability, low power, and integration.
The MAX690 family targets 3.0V/3.3V microprocessor systems needing consolidated power supervision - combining reset generation, watchdog, battery switchover, and power-fail detection in a single SO-8 package to reduce BOM count and improve system-level robustness.
FAQ
What is the exact reset threshold voltage for MAX690TESA+T?
The MAX690TESA+T has a nominal reset threshold of 3.075V for VCC falling, with a tolerance of ±4% (3.00V to 3.15V min/max). This value is specified in the Electrical Characteristics table under "Reset Threshold (VRST)" for MAX690T/704T/805T, and applies across the full operating temperature range of –40°C to +85°C. The rising threshold is slightly higher (3.085V typical) due to 10mV hysteresis.
Does MAX690TESA+T support battery voltage higher than VCC?
Yes, MAX690TESA+T explicitly supports VBATT exceeding VCC - a key design feature enabling direct connection of 3.6V lithium batteries to the VBATT pin while VCC is at 3.3V. Switchover occurs when VCC falls below 2.40V (VSW), and the internal 140Ω NMOS switch connects VBATT to VOUT. This eliminates external diodes and associated voltage drops, preserving RAM retention voltage.
Can the watchdog timer in MAX690TESA+T be disabled?
No, the watchdog timer in MAX690TESA+T cannot be disabled. As stated in the Detailed Description section, "Unlike the 5V MAX690 family, the watchdog function cannot be disabled." It continuously monitors WDI for edges (rising or falling), and triggers RESET if no transition occurs within 1.6s. This ensures fail-safe behavior in safety-critical applications where watchdog omission could compromise system integrity.
What is the maximum continuous current that MAX690TESA+T can deliver from VOUT?
The MAX690TESA+T guarantees VOUT output voltage within specification for loads up to 50mA (VCC – 0.15V typical), with absolute maximum ratings allowing 100mA continuous output current. However, design guidance recommends limiting VOUT current to ≤5mA for optimal regulation (VCC – 0.015V drop) and thermal stability - especially in battery-backup mode where VBATT-to-VOUT resistance rises to 140Ω.
Is MAX690TESA+T pin-compatible with other devices in the MAX690 family?
Yes, MAX690TESA+T is fully pin-compatible with all members of the MAX690T/S/R, MAX704T/S/R, and MAX802T/S/R families in SO-8 and PDIP packages. Pin assignments (VOUT, VCC, GND, PFI, PFO, WDI, RESET, VBATT) and electrical behavior are identical across these variants - only reset threshold (T/S/R), temperature grade (C/E/M), and functional options (e.g., MR presence, RESET polarity) differ. This enables drop-in replacement during design iteration or qualification.
MAX690TESA+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:
- 3.075V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 35ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX690TESA+T FAQ
1.How can I place an order for MAX690TESA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690TESA+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 MAX690TESA+T reliable?
The price and inventory of MAX690TESA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690TESA+T is usually 5 days.
3.What payment methods are accepted for MAX690TESA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690TESA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690TESA+T?
MAX690TESA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690TESA+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 MAX690TESA+T?
For technical support, including MAX690TESA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690TESA+T requirements.
6.How does Aetrix verify that MAX690TESA+T is sourced from the original manufacturer or authorized distributors?
All MAX690TESA+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 MAX690TESA+T meets industry standards.
7.What is the process for return or replacement of MAX690TESA+T?
All MAX690TESA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX690TESA+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 MAX690TESA+T part is unused and in its original packaging.
Return procedure for MAX690TESA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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