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Analog Devices Inc./Maxim Integrated MAX690RCPA+
- Part No.:
- MAX690RCPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX690RCPA+.pdf
- Description:
- IC SUPERVISOR MPU 8-DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,613
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Product details
Overview
MAX690RCPA+ from Maxim Integrated is a 3.0V/3.3V microprocessor supervisory circuit with precision reset threshold (2.625V), 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 - enabling reliable CMOS RAM retention in portable controllers.
For engineers reviewing the MAX690RCPA+ datasheet, MAX690RCPA+ pinout, MAX690RCPA+ application, or MAX690RCPA+ equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in battery-powered embedded systems, and validated alternative parts for design continuity and supply resilience.
Technical Context
The MAX690RCPA+ integrates a precision reset comparator with ±75mV threshold accuracy (2.55V–2.70V), a 1.6s watchdog timer cleared by WDI transitions, and dual-path power management: VCC-to-VOUT via 3Ω PMOS switch and VBATT-to-VOUT via 140Ω switch activated at VSW = 2.40V. Its PFI/PFO comparator operates independently with 1.237V threshold and 10mV hysteresis.
It supports battery-backed operation with <1µA VBATT supply current and guarantees RESET assertion down to VCC = 1V. The device features guaranteed active-low RESET output drive (1.2mA sink), 40µA VCC quiescent current at VCC < 3.6V, and operates across 0°C to +70°C in 8-pin plastic DIP package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.625V nominal (2.55V–2.70V range); ensures reliable reset assertion before 3.0V system enters undervoltage failure zone. |
| Reset Timeout Period | 200ms (140–280ms); provides sufficient hold time for µP initialization after power stabilization. |
| Watchdog Timeout | 1.6s (1.12–2.24s); detects µP lockup without requiring external timing components. |
| VCC Supply Current | 40µA typical (VCC < 3.6V); enables ultra-low-power operation in always-on battery backup mode. |
| Battery Supply Current | 0.4–1µA; minimizes drain on lithium coin cell (e.g., CR2032) during extended backup periods. |
| VBATT-to-VOUT On-Resistance | 140Ω typical; limits voltage drop under 1mA load to ~140mV, preserving RAM data integrity. |
| Power-Fail Input Threshold | 1.237V ±25mV; allows accurate monitoring of auxiliary rails (e.g., 5V or -5V) via external resistor divider. |
Pinout & Package
MAX690RCPA+ 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 dot or notch; pins are numbered counterclockwise from top-left corner.
| 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/VBATT comparison; must be decoupled with 0.1µF capacitor. |
| 2 - VCC | Main supply input | Accepts 2.72V–5.5V; powers internal circuitry and drives VOUT when above reset threshold; absolute max = +6.0V. |
| 3 - GND | Ground reference | Common return for all analog/digital functions; substrate tied to higher of VCC or VBATT - must be floated in hybrid designs. |
| 4 - PFI | Power-fail input | Monitors auxiliary supply via external divider; triggers PFO low when input falls below 1.237V; input leakage < ±25nA. |
| 5 - PFO | Power-fail output | Open-drain active-low signal; asserts when PFI < 1.237V or VCC < 2.40V; can drive MR on MAX704/MAX806 for cascaded reset. |
| 6 - WDI | Watchdog input | Edge-sensitive (rising/falling); clears 1.6s timer on transition; tied high/low causes periodic reset; input current < ±1µA. |
| 7 - RESET | Active-low reset output | Pulsed low for 200ms on power-up/brownout/watchdog; sinks 1.2mA; guaranteed valid down to VCC = 1V. |
| 8 - VBATT | Backup-battery input | Accepts up to 6.0V; may exceed VCC (e.g., 3.6V Li-cell); connects to VOUT when VCC < 2.40V; leakage < 0.5µA. |
Key Features
| Feature | Design Value |
|---|---|
| Battery-backup switchover | Automatic VOUT switching to VBATT at VCC = 2.40V (±25mV), with 140Ω on-resistance - preserves RAM data during main supply interruption. |
| Guaranteed RESET assertion to VCC = 1V | Ensures deterministic µP reset even during deep brownout, critical for fail-safe recovery in industrial controllers. |
| 200ms reset timeout with restart-on-brownout | Internal timer resets on every VCC dip below threshold - prevents spurious release during unstable power conditions. |
| 1.6s watchdog timer with edge-triggered clear | Eliminates need for external RC timing; immune to static WDI states; prevents µP lockup without software intervention. |
| Independent power-fail comparator | Dedicated 1.237V reference with 10mV hysteresis - enables simultaneous monitoring of secondary supplies without affecting reset behavior. |
Applications
| Battery-Powered Portable Controllers | Embedded Industrial Data Loggers |
|---|---|
|
Use Scenario: Handheld meter with SRAM-based configuration storage and lithium coin-cell backup. IC Role / Device Role / Timing Role: Supervisory IC providing brownout reset, battery switchover, and watchdog supervision for ARM Cortex-M0 host MCU. Use Value: Ensures RAM retention during battery replacement and prevents corrupted firmware execution during transient 3.0V rail dips. |
Use Scenario: Remote environmental sensor node operating on 3.3V Li-SOCl₂ primary battery with 10-year field life. IC Role / Device Role / Timing Role: Power integrity monitor asserting RESET if main supply falls below 2.625V, while enabling low-leakage backup mode. Use Value: 0.4–1µA VBATT current extends battery life; 200ms reset pulse guarantees clean µP boot after cold-start. |
| Intelligent Medical Instrumentation | Critical µP Power Monitoring in Test Equipment |
|
Use Scenario: Portable ECG analyzer with nonvolatile SRAM storing calibration coefficients and patient history. IC Role / Device Role / Timing Role: Dual-role supervisor: monitors 3.0V supply for µP reset and uses PFI to detect failure of isolated 5V analog front-end rail. Use Value: PFO-driven interrupt alerts µP to analog rail fault before data corruption occurs; 1.237V PFI threshold enables precise divider design. |
Use Scenario: Benchtop oscilloscope requiring deterministic startup and immunity to AC line sags. IC Role / Device Role / Timing Role: Primary power supervisor asserting RESET during 3.3V rail collapse and generating watchdog timeout if FPGA config fails. Use Value: 100mV overdrive immunity (40µs max glitch rejection) prevents false resets from switching regulator noise. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX704RCPA+ | Same 2.625V reset threshold, but adds manual reset (MR) input with 70µA internal pull-up; lacks PFI/PFO functionality. | Preferred where manual reset button is required but auxiliary supply monitoring is unnecessary. | Select MAX704RCPA+ only if MR functionality is needed and PFI/PFO is unused - footprint-compatible but functionally reduced. |
| MAX802RCPA+ | Tighter reset threshold tolerance (±2% vs. ±75mV), same 2.625V nominal; identical pinout and battery switchover specs. | Suitable for high-precision 3.0V systems where tighter supply margin control is mandated (e.g., MIL-STD-704). | Choose MAX802RCPA+ when ±2% reset accuracy is required; otherwise MAX690RCPA+ offers cost-effective standard performance. |
Compared with MAX704RCPA+, MAX690RCPA+ provides full PFI/PFO monitoring at the expense of MR input; compared with MAX802RCPA+, it trades tighter reset tolerance for broader availability and lower unit cost in standard industrial applications.
Availability
MAX690RCPA+ is available at Aetrix Electronics and suitable for battery-powered computers and controllers, embedded controllers, intelligent instruments, critical µP power monitoring, and portable equipment requiring stable component supply across industrial temperature ranges.
Supply support for MAX690RCPA+ 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 requiring integrated reset supervision, battery backup, watchdog timing, and auxiliary supply monitoring - targeting portable and embedded applications where reliability and low power are essential.
FAQ
What is the exact reset threshold voltage for MAX690RCPA+?
The MAX690RCPA+ has a nominal reset threshold of 2.625V, with a guaranteed range of 2.55V to 2.70V for VCC falling and 2.55V to 2.72V for VCC rising. This threshold is optimized for 3.0V ±10% power supplies, ensuring reset assertion before the supply falls below 2.59V. The value is laser-trimmed at wafer test and specified across the full 0°C to +70°C operating range.
Does MAX690RCPA+ support manual reset functionality?
No, MAX690RCPA+ does not include a manual reset (MR) input. Unlike the MAX704RCPA+ or MAX806RCPA+, the MAX690RCPA+ pinout omits MR - pin 6 is dedicated to WDI (watchdog input). If manual reset is required, MAX704RCPA+ is the functionally closest alternative with identical reset threshold and package.
How does the battery switchover work on MAX690RCPA+?
MAX690RCPA+ switches VOUT from VCC to VBATT when VCC falls below the battery switchover threshold (VSW = 2.40V ±25mV) and VBATT > VCC. It uses a 140Ω internal switch for VBATT-to-VOUT path and a 3Ω PMOS for VCC-to-VOUT. Switchover back to VCC occurs only after VCC rises above the reset threshold (2.625V), ensuring stable supply reconnection.
Can MAX690RCPA+ monitor a 5V auxiliary supply?
Yes, MAX690RCPA+ can monitor a 5V auxiliary supply using the PFI input with an external resistor divider. The PFI threshold is fixed at 1.237V ±25mV, so a 4.06:1 divider (e.g., 39kΩ + 10kΩ) scales 5V to 1.02V - allowing precise trip point setting. PFO asserts low when the divided voltage falls below threshold, enabling µP interrupt or cascaded reset via MR on compatible devices.
What is the maximum allowable VCC transient duration that won't trigger reset on MAX690RCPA+?
At 100mV overdrive (i.e., VCC dipping 100mV below 2.625V), MAX690RCPA+ tolerates negative-going transients up to 40µs without issuing a reset pulse. Immunity decreases with larger overdrive: at 200mV overdrive, max duration drops to ~15µs. A 0.1µF bypass capacitor at VCC improves noise rejection, and the internal comparator hysteresis further enhances glitch immunity.
MAX690RCPA+ 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:
- -
MAX690RCPA+ FAQ
1.How can I place an order for MAX690RCPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690RCPA+ 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 MAX690RCPA+ reliable?
The price and inventory of MAX690RCPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690RCPA+ is usually 5 days.
3.What payment methods are accepted for MAX690RCPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690RCPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690RCPA+?
MAX690RCPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690RCPA+ 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 MAX690RCPA+?
For technical support, including MAX690RCPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690RCPA+ requirements.
6.How does Aetrix verify that MAX690RCPA+ is sourced from the original manufacturer or authorized distributors?
All MAX690RCPA+ 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 MAX690RCPA+ meets industry standards.
7.What is the process for return or replacement of MAX690RCPA+?
All MAX690RCPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX690RCPA+, 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 MAX690RCPA+ part is unused and in its original packaging.
Return procedure for MAX690RCPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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