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Analog Devices Inc./Maxim Integrated MAX690CPA+
- Part No.:
- MAX690CPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX690CPA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:992
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Product details
Overview
The MAX690CPA+ from Maxim Integrated is an 8-pin microprocessor supervisory circuit providing precision reset generation, battery backup switchover, watchdog timer, and power-fail warning for +5V systems. It features a 4.65V reset threshold, 50ms reset timeout, fixed 1.6s watchdog timeout, 1.3V PFI comparator, and VOUT switching between VCC and VBATT - used in embedded controllers and industrial instrumentation requiring reliable µP power monitoring.
For engineers reviewing the MAX690CPA+ datasheet, MAX690CPA+ pinout, MAX690CPA+ application, or MAX690CPA+ equivalent, key selection criteria include its fixed-reset timing, absence of CE gating or adjustable timeouts (unlike 16-pin variants), 8-pin PDIP package compatibility, and suitability for cost-sensitive, space-constrained µP systems needing basic supervision without RAM write protection.
Technical Context
The MAX690CPA+ integrates four core supervision functions in a single 8-pin DIP: 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 50–70mV switchover window and 20mV hysteresis; a fixed 1.6s watchdog timer triggered by WDI transitions; and a 1.3V reference-based power-fail detector with PFO output.
It operates across 0°C to +70°C (C-suffix), supports VCC = 4.75–5.5V and VBATT = 2.0–4.25V, delivers up to 50mA from VOUT, and draws only 1µA in battery-backup mode when VCC = 0V and VBATT = 2.8V. The device lacks CE IN/OUT, BATT ON, LOW LINE, OSC SEL, OSC IN, and WDO pins - distinguishing it from 16-pin MAX691/MAX693 family members.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V typical; holds µP in reset until VCC rises above 4.75V, ensuring stable boot after brownout. |
| Reset Timeout Delay | 50ms nominal; provides sufficient time for 5V regulator and crystal oscillator stabilization before µP release. |
| Watchdog Timeout | 1.6s fixed; detects software lockup if WDI is not toggled, triggering automatic system recovery. |
| Battery Switchover | VCC–VBATT threshold: 70mV on power-up, 50mV on power-down; prevents oscillation during slow VCC decay. |
| PFI Comparator Threshold | 1.3V ±100mV; enables early power-fail warning via external resistor divider before VCC drops below reset level. |
| VOUT Output Capability | 50mA max from VCC; powers CMOS RAM directly; requires ≥0.1µF bypass capacitor for stability. |
| Supply Current (Backup) | 1µA max at VCC = 0V, VBATT = 2.8V; extends lithium or coin-cell battery life for years in standby. |
Pinout & Package
MAX690CPA+ is housed in an 8-pin plastic DIP (PDIP) package with 0.3-inch width, through-hole mounting, and industry-standard pin spacing. Pin functions are validated per Maxim's official MAX690 datasheet (Rev 5, 4/15).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VBATT) | Backup Battery Input | Connects to 2.0–4.25V battery; internally compared to VCC to enable switchover; tie to GND if unused. |
| 2 (VCC) | +5V Power Supply Input | Main system supply; monitored for reset assertion; must be bypassed with ≥0.1µF capacitor. |
| 3 (GND) | Ground Reference | Common 0V return for all analog and digital circuitry; critical for accurate voltage monitoring. |
| 4 (PFI) | Power-Fail Input | Noninverting input to 1.3V comparator; driven by external resistor divider to detect pre-fail condition. |
| 5 (PFO) | Power-Fail Output | Active-low open-drain output; asserts NMI or interrupt when PFI < 1.3V; requires external pullup. |
| 6 (WDI) | Watchdog Input | Three-level input (low/mid/high); toggling resets watchdog; floating disables timer; 200ns min pulse width. |
| 7 (RESET) | Reset Output | Active-low, open-drain output; drives µP reset line low during power-up/down/brownout or watchdog fault. |
| 8 (VOUT) | Switched Output | Internally connected to higher of VCC or VBATT; powers CMOS RAM; requires ≥0.1µF bypass cap. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Supervision | Combines reset, battery switchover, watchdog, and power-fail detection in one 8-pin IC-reducing BOM count and PCB area vs. discrete solutions. |
| Precision Reset Threshold | 4.65V ±150mV with 40mV hysteresis ensures robust immunity to noise and prevents false resets during marginal VCC conditions. |
| Low-Quiescent Backup Mode | 1µA max supply current when VCC = 0V enables multi-year operation on CR2032 or BR2032 batteries without replacement. |
| VOUT Switching Architecture | Internal PNP transistor (VCC→VOUT) and 200Ω MOSFET (VBATT→VOUT) provide low-dropout switchover with <100mV differential loss. |
| Fail-Safe Power Monitoring | 1.3V PFI comparator and dedicated PFO output allow configurable early-warning detection of falling VCC or low battery voltage. |
Applications
| Industrial Controller Supervision | Embedded Data Logger |
|---|---|
Use Scenario: PLC or RTU monitoring 24V DC input converted to +5V, with nonvolatile RAM backup during mains failure. IC Role / Device Role / Timing Role: MAX690CPA+ generates power-on reset, switches RAM supply to battery on AC loss, and triggers watchdog if firmware hangs. Use Value: Ensures deterministic boot, preserves sensor history in RAM during outages, and recovers autonomously from software faults without manual intervention. |
Use Scenario: Battery-powered environmental sensor node logging temperature/humidity to SRAM, operating unattended for months. IC Role / Device Role / Timing Role: MAX690CPA+ supplies regulated VOUT to RAM during main power loss, monitors battery health via PFI, and asserts PFO to initiate graceful shutdown. Use Value: Eliminates need for external diode-OR or LDO in backup path; 1µA standby current extends CR2032 life beyond 5 years; PFI threshold allows configurable low-battery alert. |
| Automotive Body Control Module | Medical Diagnostic Instrument |
Use Scenario: BCM retaining configuration settings and fault logs during ignition cycling or battery disconnect events. IC Role / Device Role / Timing Role: MAX690CPA+ holds µP in reset until 5V rail stabilizes post-ignition, switches RAM to backup cell, and detects brownout on 5V bus. Use Value: Prevents corrupted EEPROM writes during unstable power; guarantees clean boot sequence; meets automotive cold-crank (4.5V) and load-dump immunity requirements. |
Use Scenario: Portable ultrasound or ECG device storing calibration data and last-session parameters in battery-backed CMOS RAM. IC Role / Device Role / Timing Role: MAX690CPA+ provides fail-safe reset signaling, isolates RAM from noisy 5V supply during measurement, and warns of declining backup battery via PFI. Use Value: Maintains data integrity under transient EMI or power sags; eliminates risk of memory corruption during clinical use; supports IEC 60601-1 power interruption compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX692CPA+ | 4.40V reset threshold (vs. 4.65V); same 8-pin PDIP, fixed 50ms/1.6s timing, identical pinout and supervision functions. | Suitable for +5V ±10% systems (e.g., industrial 4.5–5.5V rails) where lower reset threshold avoids nuisance resets during marginal VCC. | Select MAX692CPA+ when system VCC tolerance exceeds ±5% or when interfacing with 4.5V-tolerant µPs. |
| TPS3823-50DBVR | TI device with 4.63V reset threshold, 200ms timeout, push-pull RESET, no battery switchover or watchdog; SOT-23-5 package. | Lacks VOUT switching and WDI functionality; suited for simple reset-only applications where board space is critical and backup power is handled externally. | Choose TPS3823-50DBVR only if battery backup and watchdog are unnecessary and footprint reduction outweighs supervision feature loss. |
Compared with MAX692CPA+, MAX690CPA+ offers tighter reset accuracy for standard +5V ±5% supplies; versus TPS3823-50DBVR, it delivers full supervision integration (switchover + watchdog + PFI) in a legacy-compatible DIP package, enabling drop-in upgrades in existing designs without layout changes.
Availability
MAX690CPA+ is available at Aetrix Electronics and suitable for industrial controllers, embedded data loggers, automotive body modules, and medical diagnostic instruments requiring stable component supply, long-lifecycle support, and RoHS-compliant through-hole packaging.
Supply support for MAX690CPA+ 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, computing, and communications markets.
The MAX690CPA+ belongs to the MAX690–MAX695 microprocessor supervisory family, designed specifically to replace discrete reset generators, battery switches, and watchdog circuits in cost-sensitive, reliability-critical µP systems.
FAQ
What is the reset threshold voltage of the MAX690CPA+ and how does it behave during power-up?
The MAX690CPA+ has a guaranteed reset threshold of 4.65V (min 4.5V, max 4.75V) with 40mV hysteresis. During power-up, RESET remains low until VCC rises above 4.75V, then stays asserted for a nominal 50ms timeout to ensure µP clock stability. This behavior is confirmed in the Electrical Characteristics table and Figure 6 of the official datasheet.
Does the MAX690CPA+ support adjustable watchdog timeout or reset delay?
No, the MAX690CPA+ implements fixed timing: 1.6s watchdog timeout and 50ms reset delay. Unlike the 16-pin MAX691/MAX693 variants, it lacks OSC SEL and OSC IN pins required for adjustment. This is explicitly stated in the "MAX690, MAX692, and MAX694" section of the datasheet (page 6) and confirmed in Table 1.
Can the MAX690CPA+ be used to protect CMOS RAM write operations during power failure?
The MAX690CPA+ does not include CE IN/CE OUT pins or chip-enable gating logic - a feature exclusive to the 16-pin MAX691/MAX693/MAX695. Therefore, it cannot directly control RAM write enable lines. However, its active-low RESET output can be combined with external logic (e.g., NAND gate) to inhibit writes during brownout, as noted on page 7 of the datasheet.
What is the maximum battery voltage supported by the MAX690CPA+ and how is switchover controlled?
The MAX690CPA+ supports VBATT from 2.0V to 4.25V. Switchover occurs when VCC falls below VBATT minus 50mV (power-down) or rises above VBATT plus 70mV (power-up), with 20mV hysteresis to prevent chatter. This behavior is defined in the Battery Switchover section (page 7) and Electrical Characteristics table (page 2).
Is the MAX690CPA+ pin-compatible with other devices in the MAX690 family?
Yes, MAX690CPA+, MAX692CPA+, and MAX694CPA+ share identical 8-pin PDIP pinouts and core supervision functions (reset, switchover, watchdog, PFI/PFO). They differ only in reset threshold (4.65V vs. 4.40V vs. 4.65V with 200ms reset) and watchdog timing (1.6s vs. 1.6s vs. 1.6s), making them direct replacements where timing and threshold align with system requirements.
MAX690CPA+ 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:
- 35ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX690CPA+ FAQ
1.How can I place an order for MAX690CPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX690CPA+ 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 MAX690CPA+ reliable?
The price and inventory of MAX690CPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX690CPA+ is usually 5 days.
3.What payment methods are accepted for MAX690CPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX690CPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX690CPA+?
MAX690CPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX690CPA+ 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 MAX690CPA+?
For technical support, including MAX690CPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX690CPA+ requirements.
6.How does Aetrix verify that MAX690CPA+ is sourced from the original manufacturer or authorized distributors?
All MAX690CPA+ 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 MAX690CPA+ meets industry standards.
7.What is the process for return or replacement of MAX690CPA+?
All MAX690CPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX690CPA+, 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 MAX690CPA+ part is unused and in its original packaging.
Return procedure for MAX690CPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX690CPA+ Tags
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MIC826SYMT-TR
Microchip Technology
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APX803S-31SA-7
Diodes Incorporated
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APX803L20-29SA-7
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