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Analog Devices Inc./Maxim Integrated MAX690TCPA
- Part No.:
- MAX690TCPA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX690TCPA.pdf
- Description:
- IC SUPERVISOR MAX690 MPU
- Quantity:
- Payment:
- Shipping:
Inventory:1,700
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Product details
Overview
MAX690TCPA from Maxim Integrated is a 3.3V microprocessor supervisory circuit with precision reset threshold (3.075V ±75mV), 200ms reset timeout, integrated watchdog timer (1.6s timeout), battery-backup switchover, and power-fail monitoring. It monitors VCC supply integrity, asserts active-low RESET during brownout or watchdog fault, and switches VOUT to VBATT when VCC drops below 2.40V - used in embedded controllers requiring reliable power-up sequencing and nonvolatile RAM backup.
For engineers reviewing the MAX690TCPA datasheet, MAX690TCPA pinout, MAX690TCPA application, or MAX690TCPA equivalent, this page delivers verified electrical parameters, validated 8-pin DIP package mapping, confirmed battery switchover behavior (VBATT > VCC supported), and real-world timing constraints including reset propagation delay (<26µs) and watchdog edge sensitivity.
Technical Context
The MAX690TCPA integrates four core functions in a single 8-pin DIP: a precision reset comparator with 10mV hysteresis, a 1.6s watchdog timer cleared on WDI transitions, a bidirectional battery switchover circuit (VCC-to-VOUT PMOS switch: 3Ω typical; VBATT-to-VOUT NMOS switch: 140Ω typical), and an independent power-fail comparator (VPFT = 1.237V ±20mV) with PFI/PFO interface.
Its reset assertion is guaranteed down to VCC = 1.0V (with VBATT > 1V), and it supports manual reset via MR input with internal 70µA pull-up. The device operates across 0°C to +70°C, draws only 40µA from VCC (typical at VCC < 3.6V), and maintains 1µA battery leakage current - enabling long-life operation in portable and battery-backed systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V (VCC falling), ±75mV tolerance - ensures reset triggers before 3.3V supply drops below system minimum operating voltage. |
| Reset Timeout Period | 200ms (typical), 140–280ms range - provides sufficient hold time for µP initialization after power stabilization. |
| Watchdog Timeout | 1.6s (typical), 1.12–2.24s range - detects µP lockup without requiring external timing components. |
| VCC Supply Current | 40µA (typical, VCC < 3.6V) - enables low-power operation in always-on monitoring applications. |
| Battery Leakage Current | 0.01–0.5µA - preserves lithium battery life over multi-year deployments in CMOS RAM backup. |
| Battery Switch Threshold | VSW = 2.40V (VBATT > VCC), with 25mV hysteresis - initiates switchover before VOUT falls below 2.0V RAM retention limit. |
| Power-Fail Threshold | VPFT = 1.237V ±20mV - allows accurate monitoring of auxiliary supplies via external resistor divider. |
Pinout & Package
MAX690TCPA is housed in an 8-pin plastic DIP (PDIP) package with 0.300" wide body and 0.100" lead pitch. Pin 1 is marked with a notch or dot; leads are tin-lead (leaded) unless ordered with '+' suffix for RoHS-compliant finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VOUT | Switched output connected to VCC (via 3Ω PMOS) or VBATT (via 140Ω NMOS); powers CMOS RAM during main supply failure. |
| 2 | VCC | Main 3.0V/3.3V supply input; powers internal circuitry and sources VOUT when active. |
| 3 | GND | Ground reference for all analog comparators, digital logic, and power switches. |
| 4 | PFI | Power-fail input; compared to 1.237V internal reference to generate PFO signal for auxiliary supply monitoring. |
| 5 | PFO | Open-drain power-fail output; goes low when PFI < 1.237V or VCC < VSW - usable as interrupt or MR trigger. |
| 6 | WDI | Watchdog input; requires edge transition every <1.6s to prevent reset; cannot be disabled. |
| 7 | RESET | Active-low open-drain reset output; asserted low for ≥200ms during power-up, brownout, or watchdog timeout. |
| 8 | VBATT | Backup battery input; may exceed VCC (e.g., 3.6V Li-cell); automatically connects to VOUT when VCC falls below 2.40V. |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET assertion to VCC = 1V | Ensures reliable reset even during deep brownout, critical for systems with weak or decaying supplies. |
| Battery can exceed VCC in normal operation | Supports standard 3.6V lithium coin cells without external diode or regulator - simplifies backup design. |
| 200ms reset time delay with temperature stability | Reset timeout varies only ±8ms over –40°C to +85°C - eliminates need for external RC timing network. |
| 40µA VCC supply current (typical) | Reduces quiescent load on primary supply, extending battery life in portable equipment. |
| Independent power-fail comparator | Enables monitoring of secondary rails (e.g., 5V, –5V, or analog supplies) without interfering with reset logic. |
Applications
| Battery-Backed Embedded Controller | Portable Medical Instrument |
|---|---|
Use Scenario: Microcontroller-based glucose meter powered by CR2032 battery with SRAM storing calibration data and usage logs. IC Role / Device Role / Timing Role: MAX690TCPA monitors 3.3V LDO output, asserts RESET during battery depletion, and switches VOUT to VBATT to retain RAM contents during power loss. Use Value: Guarantees RAM data integrity for >10 years shelf life; 1µA battery leakage prevents premature discharge. |
Use Scenario: Handheld ECG device with flash memory and real-time clock, operating intermittently on AA batteries. IC Role / Device Role / Timing Role: MAX690TCPA provides power-on reset, detects 3.3V rail collapse during battery swap, and triggers watchdog if firmware hangs during signal acquisition. Use Value: 1.6s watchdog timeout catches firmware stalls without false triggers; 200ms reset pulse meets ARM Cortex-M boot requirements. |
| Industrial PLC I/O Module | Smart Energy Meter |
Use Scenario: DIN-rail mounted I/O module with isolated CAN interface and EEPROM, powered from 24VDC converted to 3.3V. IC Role / Device Role / Timing Role: MAX690TCPA supervises the 3.3V rail, uses PFI to monitor 24V input via resistor divider, and asserts RESET if input drops below safe level. Use Value: Independent PFI/PFO path enables dual-rail monitoring without µP intervention; ±75mV reset threshold ensures immunity to line noise. |
Use Scenario: Revenue-grade electricity meter with metrology ASIC, RTC, and tamper-detection SRAM, operating from mains or supercap backup. IC Role / Device Role / Timing Role: MAX690TCPA manages switchover from 3.3V main supply to 3.6V lithium backup, monitors VCC for brownout, and signals power fail to µP via PFO. Use Value: VBATT > VCC capability eliminates series diode drop; 2.40V switchover threshold preserves >2.0V RAM retention margin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704TCSA | Same 3.075V reset threshold and 200ms timeout, but adds active-high RESET output (open-drain) and removes PFI/PFO functionality. | Lacks power-fail monitoring; suitable only where reset supervision is primary requirement and auxiliary supply monitoring is unnecessary. | Select MAX704TCSA when PFI/PFO is unused and board layout favors SO-8; retains identical reset timing and battery switchover. |
| MAX805TCSA | Identical pinout and reset specs, but features tighter reset threshold tolerance (±2% vs. ±2.4%) and improved PFI accuracy (±2% vs. ±20mV). | Better suited for high-precision applications like test equipment where supply margin is minimal and PFI must track auxiliary rails within 2%. | Choose MAX805TCSA when system-level accuracy demands tighter thresholds; same 8-pin SO package enables drop-in replacement if layout allows. |
Compared with MAX690TCPA, MAX704TCSA sacrifices power-fail monitoring for simplified reset-only function, while MAX805TCSA enhances accuracy at the cost of higher unit price - making MAX690TCPA optimal for cost-sensitive designs requiring full-feature supervision with proven field reliability.
Availability
MAX690TCPA 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 and long-term lifecycle support.
Supply support for MAX690TCPA 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 applications.
The MAX690 family was designed specifically for 3.0V/3.3V microprocessor systems needing integrated reset supervision, battery backup switching, watchdog protection, and auxiliary supply monitoring - targeting portable, medical, and industrial embedded platforms.
FAQ
What is the exact reset threshold voltage for MAX690TCPA?
The MAX690TCPA has a nominal reset threshold of 3.075V when VCC is falling, with a guaranteed tolerance of ±75mV (3.00V to 3.15V). This value is specified for the 'T' variant and applies across the full operating temperature range (0°C to +70°C). The rising threshold is slightly higher (3.085V typ) due to 10mV hysteresis, preventing oscillation near the trip point. MAX690TCPA's threshold is optimized for 3.3V ±5% systems.
Does MAX690TCPA support battery voltage higher than VCC?
Yes, MAX690TCPA explicitly supports VBATT exceeding VCC - a key design feature enabling direct connection of standard 3.6V lithium coin cells without external diodes or regulators. The internal battery switchover circuit activates when VCC falls below 2.40V (VSW), connecting VBATT to VOUT through a 140Ω NMOS switch. This behavior is documented in the Absolute Maximum Ratings and Detailed Description sections of the MAX690TCPA datasheet.
Can the watchdog timer in MAX690TCPA be disabled?
No, the watchdog timer in MAX690TCPA cannot be disabled. It is a hardwired function that triggers a reset if the WDI pin remains static (high or low) for longer than 1.6 seconds. The timer clears only on rising or falling edges at WDI or during active RESET assertion. This fixed behavior distinguishes MAX690TCPA from later variants like MAX706, and is confirmed in the Watchdog Input section of the MAX690TCPA datasheet.
What is the maximum allowable VCC transient duration before MAX690TCPA asserts reset?
For a VCC transient going 100mV below the reset threshold (i.e., 3.075V – 0.1V = 2.975V), MAX690TCPA tolerates pulses up to 40µs without asserting reset - per the Typical Operating Characteristics graph (Figure 7). Transients deeper than 100mV overdrive must be proportionally shorter (e.g., 200mV overdrive allows only ~10µs). This immunity is achieved via internal filtering and is validated across temperature.
Is MAX690TCPA pin-compatible with MAX805TCPA?
Yes, MAX690TCPA and MAX805TCPA share identical 8-pin DIP pinout, terminal functions, and voltage ratings - confirmed in the Pin Description table and Ordering Information section of both datasheets. However, MAX805TCPA offers tighter reset threshold tolerance (±2% vs. ±2.4%) and enhanced PFI accuracy (±2% vs. ±20mV), making it a performance upgrade rather than a drop-in replacement where precision is critical.
MAX690TCPA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- 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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX690TCPA FAQ
1.How can I place an order for MAX690TCPA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690TCPA 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 MAX690TCPA reliable?
The price and inventory of MAX690TCPA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690TCPA is usually 5 days.
3.What payment methods are accepted for MAX690TCPA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690TCPA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690TCPA?
MAX690TCPA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690TCPA 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 MAX690TCPA?
For technical support, including MAX690TCPA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690TCPA requirements.
6.How does Aetrix verify that MAX690TCPA is sourced from the original manufacturer or authorized distributors?
All MAX690TCPA 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 MAX690TCPA meets industry standards.
7.What is the process for return or replacement of MAX690TCPA?
All MAX690TCPA units undergo pre-shipment inspection (PSI). If there is an issue with MAX690TCPA, 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 MAX690TCPA part is unused and in its original packaging.
Return procedure for MAX690TCPA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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