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Analog Devices Inc./Maxim Integrated MAX705CPA+
- Part No.:
- MAX705CPA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX705CPA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:293
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Product details
Overview
MAX705CPA+ from Maxim Integrated is a low-cost microprocessor supervisory circuit in 8-pin plastic DIP package, providing active-low reset output, 1.6s watchdog timer, 1.25V power-fail comparator input, and debounced manual-reset input. It asserts a guaranteed 200ms reset pulse when VCC drops below 4.65V or MR is pulled low, and supports reliable power monitoring in +5V μP systems including industrial controllers and embedded instrumentation.
For engineers reviewing the MAX705CPA+ datasheet, MAX705CPA+ pinout, MAX705CPA+ application, or MAX705CPA+ equivalent, this page delivers verified technical context, exact pin functions, real-world use cases, and validated alternative parts - all grounded in Maxim's official specifications for the C-grade (0°C to +70°C), lead-free, PDIP-packaged device.
Technical Context
The MAX705CPA+ integrates four core supervisory functions on a single die: a precision voltage monitor with 4.65V ±150mV threshold and 40mV hysteresis, a watchdog timer triggered by WDI edge transitions with 1.0–2.25s timeout window, a 1.25V reference-based power-fail comparator (PFI/PFO), and TTL/CMOS-compatible manual-reset input with 250μA internal pull-up. All outputs are push-pull and fully specified down to VCC = 1V.
Its reset generator guarantees valid logic levels at VCC ≥ 1V (RESET ≤ 0.4V at ISINK = 3.2mA), and features 250ns MR-to-RESET delay, 400ns PFI assertion/deassertion response, and watchdog timeout immunity during reset assertion or WDI three-state. The device operates exclusively from a +5V supply (1.0V to 5.5V) and draws only 150–350μA quiescent current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±150mV - triggers reset when +5V rail sags below safe μP operating level |
| Reset Pulse Width | 200ms typical - ensures full μP initialization before release, with ≥140ms minimum guarantee |
| Watchdog Timeout | 1.6s nominal (1.0–2.25s range) - detects μP lockup without requiring external timing components |
| Power-Fail Threshold | 1.25V ±50mV at PFI - enables early warning of +5V regulator dropout via external resistor divider |
| Supply Current | 150–350μA - enables always-on supervision in battery-backed or low-power systems |
| Operating Voltage | 1.0V to 5.5V - ensures RESET remains valid even during deep brownout recovery |
| MR Input Pull-Up | 250μA typical - eliminates need for external pull-up; supports direct switch or logic drive |
Pinout & Package
MAX705CPA+ uses an 8-pin plastic DIP (PDIP) package with 0.3-inch body width and through-hole mounting. Pin spacing is 0.1 inch; lead finish is lead(Pb)-free/RoHS-compliant (indicated by '+' suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (MR) | Manual-Reset Input | Active-low TTL/CMOS-compatible trigger; internally pulled up with 250μA; debounces switch closures via 140ms min pulse width |
| 2 (VCC) | +5V Supply Input | Main power rail connection; device functional from 1.0V to 5.5V; RESET valid at VCC = 1V |
| 3 (GND) | Ground Reference | 0V return for all analog and digital functions; required for accurate voltage monitoring |
| 4 (PFI) | Power-Fail Input | Comparator inverting input referenced to 1.25V; monitors auxiliary voltages (e.g., +12V via divider) or battery level |
| 5 (PFO) | Power-Fail Output | Active-low open-drain compatible output; sinks current when PFI < 1.25V; used for NMI or orderly shutdown signaling |
| 6 (WDI) | Watchdog Input | Edge-sensitive input; toggling within 1.6s prevents timeout; floating or high-Z disables watchdog |
| 7 (RESET) | Active-Low Reset Output | Push-pull output; pulses low for 200ms on power-up/brownout/MR; holds low while VCC < 4.65V |
| 8 (WDO) | Watchdog Output | Push-pull active-low output; goes low on timeout or VCC brownout; no minimum pulse width; clears immediately on VCC rise |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET at VCC = 1V | Ensures fail-safe reset assertion during deep brownout recovery, critical for nonvolatile memory write protection |
| Debounced MR input | Eliminates external RC filtering; 140ms minimum pulse width prevents contact bounce from causing spurious resets |
| Independent PFI/PFO comparator | Enables flexible power-fail detection on any voltage rail (positive or negative) using external resistive networks |
| Watchdog immunity during reset | WDI monitoring pauses while RESET is asserted, preventing false timeouts during controlled system restart |
| Lead-free RoHS-compliant packaging | Meets global environmental regulations; + suffix confirms Pb-free terminations and processing per JEDEC J-STD-020 |
Applications
| Industrial PLC Power Monitoring | Embedded Controller Brownout Protection |
|---|---|
Use Scenario: Programmable logic controller maintains operation during factory line voltage fluctuations. IC Role / Device Role / Timing Role: MAX705CPA+ continuously monitors +5V supply and asserts RESET if voltage dips below 4.65V for >200ms. Use Value: Prevents corrupted ladder logic execution and I/O state mismatches during transient brownouts. |
Use Scenario: Remote sensor node powered by regulated +5V with backup battery; must survive brief AC dropout. IC Role / Device Role / Timing Role: MAX705CPA+ generates 200ms reset pulse on VCC sag and enables PFI-based battery-low warning. Use Value: Ensures clean firmware restart and initiates graceful data save before backup power depletion. |
| Medical Instrumentation Watchdog | Test Equipment Manual Reset Interface |
Use Scenario: Benchtop oscilloscope runs safety-critical firmware; must recover autonomously from processor hang. IC Role / Device Role / Timing Role: MAX705CPA+ watches WDI toggles from CPU heartbeat signal; triggers RESET via MR if missed for 1.6s. Use Value: Eliminates need for operator intervention during unattended long-duration measurements. |
Use Scenario: Automated test fixture requires field-serviceable reset without opening enclosure. IC Role / Device Role / Timing Role: MAX705CPA+ accepts front-panel pushbutton on MR pin; provides noise-immune, debounced reset pulse. Use Value: Reduces service downtime and avoids accidental resets due to mechanical switch bounce. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX706CPA+ | 4.40V reset threshold (vs. 4.65V); otherwise identical pinout, features, and timing | Suitable for systems with tighter +5V tolerance or lower-voltage μPs requiring earlier reset assertion | Select MAX706CPA+ only if design requires reset at 4.40V; otherwise MAX705CPA+ matches standard +5V μP requirements. |
| MAX813LCPA+ | Active-high RESET output (no WDO); same 4.65V threshold, PFI/PFO, and MR functionality | Required for μPs with active-high reset inputs (e.g., Intel 80C51); lacks watchdog capability | Choose MAX813LCPA+ when active-high reset is mandatory and watchdog function is unnecessary. |
Compared with MAX705CPA+, MAX706CPA+ lowers reset threshold by 250mV for earlier fault detection, while MAX813LCPA+ removes watchdog but adds active-high RESET - making each alternative suitable only for specific μP interface or voltage-margin requirements.
Availability
MAX705CPA+ is available at Aetrix Electronics and suitable for industrial PLCs, embedded controllers, medical instrumentation, and automated test equipment requiring stable component supply across extended production lifecycles.
Supply support for MAX705CPA+ 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 precision analog and mixed-signal ICs for industrial, computing, and communications markets, emphasizing reliability, integration, and low-power operation.
The MAX705–MAX708/MAX813L family targets cost-sensitive microprocessor systems needing consolidated power monitoring, reset generation, and watchdog functionality in compact packages - specifically optimized for +5V μP platforms.
FAQ
What is the reset threshold voltage for MAX705CPA+?
The MAX705CPA+ has a nominal reset threshold of 4.65V, with a guaranteed range of 4.50V to 4.75V over temperature and supply variation. This threshold triggers the active-low RESET output whenever VCC falls below that level, ensuring μP reset before logic corruption occurs. The device also provides 40mV hysteresis to prevent chatter near the trip point.
Does MAX705CPA+ support operation below 5V supply?
Yes, MAX705CPA+ operates from 1.0V to 5.5V and guarantees valid RESET output down to VCC = 1V (RESET ≤ 0.4V at ISINK = 3.2mA). This allows robust brownout detection and reset assertion even during deep undervoltage conditions, unlike many supervisory circuits that cease functioning below 2.5V or 3.0V.
How does the watchdog timer in MAX705CPA+ work?
The MAX705CPA+ watchdog timer monitors the WDI pin and times out after 1.6 seconds (1.0–2.25s range) if no rising or falling edge is detected. Upon timeout, WDO goes low. The timer resets automatically when RESET is asserted, WDI is three-stated, or an edge occurs - enabling reliable lockup detection without external components.
Can MAX705CPA+ monitor voltages other than +5V?
Yes, MAX705CPA+ can monitor any DC voltage using the PFI input and its internal 1.25V reference. By connecting PFI to a resistor divider from a +12V rail or battery, the device asserts PFO when the monitored voltage drops below the calculated threshold - enabling power-fail warning, low-battery detection, or multi-rail supervision.
Is MAX705CPA+ pin-compatible with other devices in the family?
Yes, MAX705CPA+ shares identical 8-pin PDIP pinout and footprint with MAX706CPA+, MAX707CPA+, MAX708CPA+, and MAX813LCPA+. All variants maintain consistent pin assignments for VCC, GND, MR, PFI, PFO, RESET, WDI, and WDO (or RESET), enabling drop-in substitution where functional requirements align - subject to threshold, output polarity, and feature differences.
MAX705CPA+ 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:
- Simple Reset/Power-On Reset
- 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
MAX705CPA+ FAQ
1.How can I place an order for MAX705CPA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX705CPA+ 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 MAX705CPA+ reliable?
The price and inventory of MAX705CPA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX705CPA+ is usually 5 days.
3.What payment methods are accepted for MAX705CPA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX705CPA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX705CPA+?
MAX705CPA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX705CPA+ 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 MAX705CPA+?
For technical support, including MAX705CPA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX705CPA+ requirements.
6.How does Aetrix verify that MAX705CPA+ is sourced from the original manufacturer or authorized distributors?
All MAX705CPA+ 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 MAX705CPA+ meets industry standards.
7.What is the process for return or replacement of MAX705CPA+?
All MAX705CPA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX705CPA+, 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 MAX705CPA+ part is unused and in its original packaging.
Return procedure for MAX705CPA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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