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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 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,884
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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, watchdog timer (1.6s), battery-backup switchover, and active-low RESET output. It monitors VCC for brownout detection, asserts reset during power-up/down, and supports CMOS RAM backup via VOUT in systems powered by 3.0V/3.3V supplies.
For engineers reviewing the MAX690TCPA+ datasheet, MAX690TCPA+ pinout, MAX690TCPA+ application, or MAX690TCPA+ equivalent, this device delivers verified voltage monitoring, manual reset input, power-fail warning (PFO), and guaranteed RESET assertion down to VCC = 1V - critical for reliable embedded controller and portable equipment power management.
Technical Context
The MAX690TCPA+ integrates a precision reset comparator with 10mV hysteresis, a 1.6s watchdog timer that clears on WDI edge transitions, and a dual-path battery switchover circuit: VOUT connects to VCC above VSW (2.40V) and switches to VBATT when VCC falls below VSW or 1.75V. Its PFI/PFO pair provides independent power-fail detection with 1.237V threshold and ±20mV hysteresis.
RESET is actively driven low during VCC undervoltage, MR assertion, or watchdog timeout, and remains low for 200ms after recovery; the open-drain PFO output signals power-fail conditions independently of reset state. The device operates across 0°C to +70°C and draws only 40µA from VCC at VCC < 3.6V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V (±75mV) - ensures reliable reset assertion before 3.3V supply drops below system minimum operating voltage |
| Reset Timeout Period | 200ms (140–280ms) - guarantees sufficient hold time for µP initialization and memory stabilization |
| VCC Supply Current | 40µA (typ, VCC < 3.6V) - enables ultra-low-power operation in battery-backed portable systems |
| Watchdog Timeout | 1.6s (1.12–2.24s) - provides robust software activity monitoring without requiring external timing components |
| Battery Leakage Current | 0.01–0.5µA - minimizes drain on lithium backup cells during long-term storage or standby |
| VBATT-to-VOUT On-Resistance | 140Ω (typ) - limits voltage drop during battery switchover to maintain CMOS RAM retention above 2.0V |
| Power-Fail Threshold | 1.237V (±20mV) - enables accurate monitoring of auxiliary rails via external resistor divider |
Pinout & Package
MAX690TCPA+ is housed in an 8-pin plastic DIP (PDIP) package with 0.300" wide body and through-hole mounting. Pin spacing conforms to JEDEC MS-001, lead finish is lead-free (RoHS-compliant).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VOUT | CMOS RAM supply output | Switches between VCC and VBATT; delivers regulated backup power to static RAM during brownout |
| 2 - VCC | Main system supply input | Primary 3.0V/3.3V power source; powers internal circuitry and defines reset threshold reference |
| 3 - GND | Ground reference | Common return path for all analog and digital functions; substrate tied to higher of VCC/VBATT |
| 4 - PFI | Power-fail input | Accepts divided auxiliary rail voltage; triggers PFO low when input falls below 1.237V |
| 5 - PFO | Power-fail open-drain output | Signals undervoltage condition to µP interrupt line; requires external pull-up for logic-high level |
| 6 - WDI | Watchdog input | Edge-sensitive input; resets watchdog timer on rising/falling transition; cannot be disabled |
| 7 - RESET | Active-low reset output | Drives µP reset pin low during fault conditions; guaranteed valid down to VCC = 1V |
| 8 - VBATT | Backup battery input | Accepts 3.6V lithium cell; may exceed VCC; enables seamless switchover without diode loss |
Key Features
| Feature | Design Value |
|---|---|
| Precision reset threshold tolerance | ±75mV - tighter than generic supervisors, enabling stable operation in 3.3V ±5% systems |
| Guaranteed RESET assertion to VCC = 1V | Ensures fail-safe reset even during deep brownout, preventing µP execution from corrupted memory |
| Battery switchover with 2.40V VSW | Triggers backup mode before VOUT drops below 2.0V, preserving CMOS RAM data integrity |
| 200ms reset timeout with restart-on-brownout | Reinitiates timing each time VCC dips below VRST, eliminating race conditions during marginal supply recovery |
| 1.237V PFI threshold with 10mV hysteresis | Provides noise-immune power-fail detection for secondary rails without external hysteresis components |
Applications
| Battery-Powered Portable Equipment | Embedded Controller Power Monitoring |
|---|---|
|
Use Scenario: Handheld medical meters with lithium coin-cell backup maintaining SRAM during main power removal. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, battery switchover, and watchdog supervision. Use Value: Prevents data corruption during battery replacement and ensures deterministic boot after power interruption. |
Use Scenario: Industrial PLC controller requiring continuous operation despite 3.3V rail fluctuations. IC Role / Device Role / Timing Role: Voltage monitor and reset generator asserting RESET for 200ms on any VCC dip below 3.075V. Use Value: Eliminates spurious reboots caused by transient noise while guaranteeing reset during sustained undervoltage. |
| Intelligent Instrumentation | Critical µP Power Monitoring |
|
Use Scenario: Digital multimeter storing calibration coefficients in battery-backed SRAM across power cycles. IC Role / Device Role / Timing Role: Dual-rail supervisor managing VCC/VBATT switchover and generating PFO interrupt on AC adapter failure. Use Value: Enables automatic save-to-EEPROM on power-fail event using PFO-triggered µP interrupt. |
Use Scenario: Aerospace telemetry module where µP must never execute invalid code due to supply sag. IC Role / Device Role / Timing Role: Fail-safe reset generator with guaranteed assertion down to VCC = 1V and 100mV glitch immunity. Use Value: Meets DO-254 reliability requirements by preventing µP operation outside validated voltage window. |
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, but adds manual reset (MR) input with 70µA internal pull-up; no PFI/PFO functionality | Lacks power-fail monitoring; suitable only for basic reset + manual reset needs without auxiliary rail supervision | Select when PFI/PFO is unnecessary and MR-driven reset is required alongside battery switchover |
| MAX802TCSA+ | Tighter reset threshold tolerance (±2%), same 3.075V nominal, identical pinout and switchover behavior | Higher accuracy enables use in systems with tighter 3.3V supply tolerances (e.g., FPGA-based controllers) | Choose when ±2% reset accuracy is mandated and 200ms timeout meets timing requirements |
Compared with MAX690TCPA+, MAX704TCSA+ trades PFI/PFO capability for integrated manual reset, while MAX802TCSA+ offers improved reset threshold accuracy at identical functionality - enabling selection based on whether auxiliary rail monitoring or precision voltage detection is prioritized.
Availability
MAX690TCPA+ is available at Aetrix Electronics and suitable for battery-powered computers, embedded controllers, and intelligent instrumentation requiring stable component supply with RoHS-compliant packaging and industrial temperature 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) designs high-performance analog and mixed-signal ICs for power management, sensing, and interface applications.
The MAX690 series targets 3.0V/3.3V microprocessor systems needing integrated reset, watchdog, battery switchover, and power-fail detection - reducing BOM count and improving reliability over discrete solutions.
FAQ
What is the guaranteed minimum VCC voltage at which MAX690TCPA+ asserts RESET?
The MAX690TCPA+ guarantees RESET assertion for all VCC values below its 3.075V reset threshold, and specifically maintains valid RESET output down to VCC = 1V. This ensures fail-safe operation even during deep brownout conditions where other supervisors may release reset prematurely, making MAX690TCPA+ suitable for mission-critical applications requiring deterministic behavior across the full undervoltage range.
Does MAX690TCPA+ support manual reset functionality?
No, the MAX690TCPA+ does not include a manual reset (MR) input. Unlike the MAX704T/S/R or MAX806T/S/R variants, the MAX690T/S/R family omits MR functionality. Reset is triggered solely by VCC falling below 3.075V, watchdog timeout (1.6s), or power-fail condition (PFI < 1.237V). For manual reset capability, engineers should select MAX704TCPA+ or MAX806TCPA+ instead of MAX690TCPA+.
How does the battery switchover work in MAX690TCPA+?
The MAX690TCPA+ switches VOUT from VCC to VBATT when VCC falls below the 2.40V battery switchover threshold (VSW) and VBATT exceeds VCC. It uses a 140Ω internal PMOS switch to connect VBATT to VOUT, ensuring minimal voltage drop. Switchover back to VCC occurs only after VCC rises above the 3.075V reset threshold - not at VSW - preventing oscillation during marginal recovery. This behavior is confirmed in the MAX690T/S/R datasheet Figure 2 and Pin Description table.
Can MAX690TCPA+ monitor a second power supply?
Yes, MAX690TCPA+ can monitor a second power supply using the PFI input. By connecting an external resistor divider from the auxiliary rail to PFI, the device compares the divided voltage against its 1.237V internal reference. When the divided voltage falls below this threshold, PFO goes low - providing a dedicated power-fail interrupt signal independent of the main reset function. This capability is explicitly documented in the Applications Information section and Figure 5 of the MAX690 datasheet.
What is the maximum allowable negative-going VCC transient duration that will not trigger RESET on MAX690TCPA+?
According to the MAX690 datasheet Figure 7, a negative-going VCC transient that dips 100mV below the 3.075V reset threshold (i.e., to ~2.975V) will not trigger RESET if its duration is ≤40µs. The immunity decreases as overdrive increases: a 200mV overdrive (VCC = 2.875V) allows only ~15µs. This transient rejection is achieved via internal filtering and is validated across temperature, making MAX690TCPA+ robust against switching noise in dense PCB layouts.
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:
- Obsolete
- 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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