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Analog Devices Inc./Maxim Integrated MAX694CPA+
- Part No.:
- MAX694CPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX694CPA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:133
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Product details
Overview
MAX694CPA+ from Maxim Integrated is an 8-pin microprocessor supervisory IC providing reset generation, battery backup switchover, watchdog timer, and power-fail detection for +5V systems. It delivers a 4.65V reset threshold, 200ms reset timeout, fixed 1.6s watchdog timeout, 1.3V PFI comparator, and VOUT switching between VCC and VBATT - used in industrial controllers and embedded instrumentation to ensure reliable µP startup, brownout recovery, and RAM data retention during power loss.
For engineers reviewing the MAX694CPA+ datasheet, MAX694CPA+ pinout, MAX694CPA+ application, or MAX694CPA+ equivalent, key selection considerations include its 200ms reset delay (vs. 50ms in MAX690), fixed watchdog timing, absence of CE gating or BATT ON output, and compatibility with 2.0–4.25V backup batteries and 4.75–5.5V VCC supplies.
Technical Context
The MAX694CPA+ integrates four core supervisory functions in a single 8-pin DIP package: a precision voltage monitor with 4.65V ±150mV reset threshold and 40mV hysteresis; a battery switchover circuit that connects VOUT to the higher of VCC or VBATT with 50mV/70mV power-down/power-up thresholds; a 1.6s watchdog timer triggered by WDI transitions; and a 1.3V reference-based power-fail comparator monitoring PFI.
It operates across 0°C to +70°C (C-suffix), draws ≤1µA in battery backup mode (VCC = 0V, VBATT = 2.8V), and supports VOUT sourcing up to 50mA from VCC or VBATT. Unlike 16-pin variants, it lacks CE IN/OUT, BATT ON, LOW LINE, OSC SEL, OSC IN, and WDO - confirming its role as a streamlined, cost-optimized supervisory solution for space-constrained µP systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V (min 4.5V, max 4.75V) - ensures reliable reset assertion before µP logic fails at +5V supply. |
| Reset Timeout Delay | 200ms - holds RESET low long enough for slow-starting crystal oscillators and system stabilization. |
| Watchdog Timeout | 1.6s nominal - detects firmware hangs without requiring external timing components. |
| Battery Voltage Range | 2.0V to 4.25V - supports common lithium and alkaline backup cells while maintaining switchover integrity. |
| VOUT Output Capability | 50mA from VCC or VBATT - powers CMOS RAM directly; no external transistor needed for typical memory loads. |
| Supply Current (Backup) | ≤1µA (VCC = 0V, VBATT = 2.8V) - extends battery life to >10 years in standby memory retention. |
| PFI Comparator Threshold | 1.3V (±0.1V) - enables early power-fail warning via resistor divider on unregulated or regulated rails. |
Pinout & Package
MAX694CPA+ is housed in an 8-pin plastic DIP (Dual In-line Package) with 0.3-inch body width and through-hole mounting. Pin 1 is marked with a notch or dot; pins are numbered counter-clockwise from top-left when viewed from top.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VBATT | Backup battery input; internally compared to VCC to enable automatic switchover to VOUT. |
| 2 | RESET | Active-low open-drain reset output; asserts for 200ms after VCC rises above 4.65V or WDI timeout. |
| 3 | WDI | Three-level watchdog input; toggling required every 1.6s; floating disables watchdog. |
| 4 | PFO | Active-low power-fail output; goes low when PFI < 1.3V - used for NMI or early shutdown signaling. |
| 5 | VOUT | Switched output; delivers higher of VCC or VBATT to CMOS RAM; requires ≥0.1µF bypass capacitor. |
| 6 | VCC | +5V main supply input (4.75–5.5V); powers internal circuitry and sources VOUT during normal operation. |
| 7 | GND | Ground reference for all analog and digital functions; must be low-impedance return path. |
| 8 | PFI | Noninverting input to 1.3V comparator; connected to resistor divider for power-fail or low-battery sensing. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 4-function supervision | Eliminates 4 discrete ICs or 10+ passive components - reduces BOM count and PCB area in µP systems. |
| 200ms reset timeout | Guarantees µP clock stability and register initialization before release - critical for systems using slow-start oscillators. |
| Low-quiescent battery backup | 1µA max current draw extends 3V lithium cell life beyond 10 years - suitable for maintenance-free instrumentation. |
| VOUT switchover with hysteresis | 50mV/70mV power-down/power-up thresholds prevent oscillation near VCC ≈ VBATT - ensures clean RAM power transition. |
| 1.3V precision PFI comparator | Enables configurable power-fail warning at any rail voltage (e.g., 4.8V VCC fail) using two external resistors. |
Applications
| Industrial Controller Power Management | Embedded Data Logger |
|---|---|
|
Use Scenario: PLC or RTU operating in remote locations with intermittent AC power and battery backup. IC Role / Device Role / Timing Role: MAX694CPA+ monitors 5V rail, asserts RESET on brownout, switches RAM to VBATT, and triggers PFO interrupt before VCC drops below µP operational range. Use Value: Prevents corrupted control state during grid dips; retains real-time clock and sensor history for 10+ years on coin cell. |
Use Scenario: Battery-powered environmental sensor node logging temperature/humidity to EEPROM. IC Role / Device Role / Timing Role: MAX694CPA+ holds µP in reset until stable 5V is established, enables RAM backup during sleep cycles, and warns of impending power loss via PFO. Use Value: Guarantees atomic write completion before shutdown; eliminates need for software checksum recovery on power restoration. |
| Medical Diagnostic Instrument | Automotive Infotainment Module |
|
Use Scenario: Portable ultrasound or ECG device with nonvolatile settings storage and safety-critical boot sequence. IC Role / Device Role / Timing Role: MAX694CPA+ enforces 200ms power-on reset window, prevents erroneous RAM writes during undervoltage, and provides early PFI alert for graceful UI shutdown. Use Value: Meets IEC 62304 power sequencing requirements; avoids clinical data loss during battery swap or charger disconnect. |
Use Scenario: Head unit with CAN interface, display, and audio subsystem powered from vehicle 12V via 5V LDO. IC Role / Device Role / Timing Role: MAX694CPA+ detects ignition-off voltage decay, initiates controlled save-to-flash sequence via PFO, and maintains RTC power via VOUT/VBATT switchover. Use Value: Survives load-dump transients and cold-crank events; ensures radio presets and navigation history persist across engine restarts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX690CPA+ | Same 8-pin DIP package; 50ms reset timeout (not 200ms); identical 4.65V threshold and 1.6s watchdog. | Suitable for systems with fast-start oscillators or where shorter reset hold time is acceptable. | Select MAX690CPA+ only if 50ms reset meets µP clock stabilization requirements - not drop-in compatible due to timing difference. |
| MAX694CSA+ | Identical electrical specs and pinout; SOIC-8 package (surface-mount) instead of PDIP-8. | Required for automated SMT assembly; same thermal and electrical performance but smaller footprint. | Choose MAX694CSA+ for new PCB designs targeting reflow assembly; no layout change needed beyond pad conversion. |
Compared with MAX694CPA+, MAX690CPA+ offers faster reset release but risks premature µP release before oscillator stability, while MAX694CSA+ provides identical functionality in a compact surface-mount form - making the latter ideal for high-density boards and the former a timing-sensitive alternative for legacy through-hole designs.
Availability
MAX694CPA+ is available at Aetrix Electronics and suitable for industrial controllers, embedded data loggers, medical diagnostic instruments, and automotive infotainment modules requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for MAX694CPA+ 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing applications.
The MAX690 family - including MAX694CPA+ - was designed specifically to replace discrete reset/battery-switching circuits in microprocessor-based systems, delivering integrated reliability, low power, and precise voltage monitoring in minimal footprint.
FAQ
What is the reset timeout delay of the MAX694CPA+?
The MAX694CPA+ features a fixed 200ms reset timeout delay after VCC rises above the 4.65V threshold. This extended hold time ensures microprocessors with slow-starting crystal oscillators or complex initialization sequences complete boot reliably. Unlike the 50ms delay in MAX690CPA+, this value is factory-trimmed and not adjustable - confirmed in the Electrical Characteristics table under "Reset Timeout Delay (MAX694/MAX695)".
Does the MAX694CPA+ support chip-enable (CE) gating for RAM write protection?
No, the MAX694CPA+ does not include CE gating functionality. This feature is exclusive to the 16-pin MAX691/MAX693/MAX695 variants. The MAX694CPA+ relies on its active-low RESET signal to inhibit µP writes during power-up/down; designers must implement external logic (e.g., AND gate with RESET and CE) if write protection beyond reset assertion is required.
What is the maximum backup battery voltage supported by the MAX694CPA+?
The MAX694CPA+ supports backup battery voltages from 2.0V to 4.25V, as specified in the Electrical Characteristics table under "Operating Voltage Range (MAX690, MAX691, MAX694, MAX695 VBATT)". Voltages above 4.25V risk violating absolute maximum ratings and may damage the VBATT input stage - lithium coin cells (3.0V) and alkaline (up to 3.6V fresh) are fully compatible.
Can the watchdog timer on the MAX694CPA+ be disabled?
Yes, the watchdog timer on the MAX694CPA+ is disabled when the WDI pin is left floating. Internal biasing pulls WDI to ~38% of VCC, placing it in a mid-supply "inactive" state that prevents timeout assertion. Driving WDI continuously high or low will trigger a 1.6s timeout and RESET pulse - so floating is the recommended disable method per the Pin Description and Watchdog Timer sections.
What package type is used for the MAX694CPA+?
The MAX694CPA+ uses an 8-pin plastic DIP (PDIP) package with 0.3-inch body width and through-hole leads. The "CPA+" suffix explicitly denotes this package per Maxim's ordering guide; it is not available in SOIC or TSSOP variants - those use "CSA+" or "CTM+" suffixes. Lead finish is lead-free (RoHS-compliant) and matte tin.
MAX694CPA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Battery Backup Circuit
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.65V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX694CPA+ FAQ
1.How can I place an order for MAX694CPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX694CPA+ 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 MAX694CPA+ reliable?
The price and inventory of MAX694CPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX694CPA+ is usually 5 days.
3.What payment methods are accepted for MAX694CPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX694CPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX694CPA+?
MAX694CPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX694CPA+ 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 MAX694CPA+?
For technical support, including MAX694CPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX694CPA+ requirements.
6.How does Aetrix verify that MAX694CPA+ is sourced from the original manufacturer or authorized distributors?
All MAX694CPA+ 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 MAX694CPA+ meets industry standards.
7.What is the process for return or replacement of MAX694CPA+?
All MAX694CPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX694CPA+, 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 MAX694CPA+ part is unused and in its original packaging.
Return procedure for MAX694CPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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