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Analog Devices Inc./Maxim Integrated MAX705EPA
- Part No.:
- MAX705EPA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
MAX705EPA.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,324
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Product details
Overview
MAX705EPA from Maxim Integrated is a precision microprocessor supervisory circuit in 8-pin PDIP 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 operation down to VCC = 1V - used in industrial controllers and embedded systems requiring deterministic power-up sequencing and brownout protection.
For engineers reviewing the MAX705EPA datasheet, MAX705EPA pinout, MAX705EPA application, or MAX705EPA equivalent, this page delivers verified functional identity, exact pin roles, temperature-rated electrical behavior (–40°C to +85°C), and real-world design implications for reset timing, watchdog interaction, and power-fail warning implementation.
Technical Context
The MAX705EPA integrates four core supervisory functions on a single die: a precision voltage monitor with 4.65V ±150mV threshold and 40mV hysteresis, a monostable watchdog timer triggered by WDI edge transitions with 1.6s timeout (±0.6s), a high-impedance 1.25V comparator input (PFI) with ±25nA bias current, and a TTL/CMOS-compatible manual-reset input with internal 250µA pull-up and 150ns minimum pulse width rejection.
Its RESET output remains valid and sinks ≥3.2mA at VCC = 1V, while WDO responds within 400ns to VCC droop below threshold - independent of watchdog state - enabling dual-purpose low-line detection. The device operates from 1.0V to 5.5V supply and draws only 150–500µA quiescent current across its full temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V (min 4.50V, max 4.75V) - ensures reset assertion before critical µP supply instability at +5V systems |
| Reset Pulse Width | 200ms (min 140ms, max 280ms) - guarantees sufficient duration to fully initialize most 8-bit and 16-bit microcontrollers |
| Watchdog Timeout | 1.6s (min 1.0s, max 2.25s) - provides robust software hang detection without excessive system interruption latency |
| PFI Threshold | 1.25V (min 1.20V, max 1.30V) - enables accurate early-warning monitoring of +5V, +12V, or negative rails via external divider |
| Supply Current | 150–500µA (TA = –40°C to +85°C) - supports low-power battery-backed operation and minimizes thermal load in dense layouts |
| VCC Operating Range | 1.0V to 5.5V - allows valid RESET assertion during deep brownout and compatibility with wide-input LDOs |
| MR Input Threshold | 0.8V (low), 2.0V (high) - ensures noise-immune manual reset triggering with standard logic-level switches or GPIOs |
Pinout & Package
MAX705EPA is housed in an 8-pin plastic DIP (PDIP) package with 0.3-inch body width and through-hole mounting. Pin spacing is 0.1 inch (2.54 mm), compatible with standard prototyping and production PCB footprints.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 MR | Active-low manual-reset input | Internally pulled up with 250µA; triggers 200ms RESET pulse when driven below 0.8V; debounces pushbutton switches |
| 2 VCC | +5V supply input | Primary power rail; RESET remains valid down to 1.0V; supports 1.0–5.5V operating range |
| 3 GND | Ground reference | Common return for all analog and digital functions; must be low-impedance connection to avoid noise coupling |
| 4 PFI | Power-fail comparator input | High-impedance (±25nA) node referenced to 1.25V internal bandgap; used for early-warning voltage monitoring |
| 5 PFO | Power-fail open-drain output | Sinks current when PFI < 1.25V; can interrupt µP or drive external logic; requires external pull-up |
| 6 WDI | Watchdog input | Edge-sensitive input; clears internal timer on rising/falling edges; floating disables watchdog function |
| 7 RESET | Active-low reset output | Push-pull output; asserts low for ≥140ms during power-up/brownout; sinks ≥3.2mA at VCC ≥ 2.0V |
| 8 WDO | Watchdog open-drain output | Drives low on timeout or VCC droop; no minimum pulse width; requires external pull-up; usable as low-line indicator |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET validity at VCC = 1V | Enables fail-safe reset assertion even during severe brownout - critical for nonvolatile memory write protection |
| Debounced TTL/CMOS-compatible MR input | Eliminates need for external RC debounce network; accepts direct switch or GPIO connection with 150ns noise immunity |
| Independent 1.25V power-fail comparator | Allows monitoring of auxiliary rails (+12V, –5V, etc.) without additional ICs; supports hysteresis via PFO feedback |
| 200ms reset pulse width with 40mV hysteresis | Prevents oscillatory reset during marginal VCC recovery; meets JEDEC JESD8-12A timing requirements for µP initialization |
| 1.6s watchdog timeout with edge-triggered clear | Supports flexible firmware supervision - timer resets on any WDI transition, not just toggles, simplifying software integration |
Applications
| Industrial PLC Controller | Medical Diagnostic Instrument |
|---|---|
Use Scenario: Power sequencing and runtime fault detection in DIN-rail mounted programmable logic controllers exposed to wide ambient temperature swings and EMI-rich factory environments. IC Role / Device Role / Timing Role: Supervisory circuit asserting active-low RESET during AC line sags, initiating watchdog-triggered recovery on firmware lockup, and signaling power-fail to EEPROM before shutdown. Use Value: Prevents corrupted I/O state and invalid control outputs by guaranteeing µP reset integrity down to VCC = 1V and delivering deterministic 200ms pulse width. |
Use Scenario: Ensuring safe boot and continuous operation of portable ultrasound or patient monitor units powered by Li-ion batteries with variable discharge profiles. IC Role / Device Role / Timing Role: Monitoring main +5V rail and backup battery voltage via PFI divider; generating early warning (PFO) before brownout; holding µP in reset until stable VCC > 4.65V. Use Value: Enables graceful data save and hardware shutdown using PFO interrupt, while RESET pulse width exceeds minimum µP requirement by 40%. |
| Automotive Infotainment Head Unit | Telecom Remote Terminal Unit |
Use Scenario: Cold-cranking resilience and ignition-switch transient suppression in automotive-grade infotainment systems operating from 9–16V battery input with LDO-regulated +5V domain. IC Role / Device Role / Timing Role: Detecting VCC droop below 4.65V during engine cranking; asserting RESET to prevent erratic display or audio output; using WDO as low-line flag for UI dimming. Use Value: –40°C to +85°C rating ensures functionality during cold starts; 1.6s watchdog prevents frozen UI without requiring MCU intervention. |
Use Scenario: Maintaining uptime in outdoor telecom RTUs powered by solar-charged batteries and subject to frequent partial discharge cycles and lightning-induced transients. IC Role / Device Role / Timing Role: Supervising primary +5V supply and secondary –12V bias rail; using PFI/PFO to detect failing backup battery; triggering watchdog reset on communication stack freeze. Use Value: Dual-rail monitoring capability eliminates need for second supervisor; low 500µA max supply current extends battery life between charges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX706EPA | 4.40V reset threshold (vs. 4.65V); identical pinout, timing, and feature set | Better suited for systems with tighter +5V tolerance or lower-noise LDOs where earlier reset assertion is required | Select MAX706EPA when VCC margin is constrained below 4.65V; otherwise MAX705EPA provides wider safety margin |
| MAX813LEPA | Active-high RESET output only (no RESET); same 4.65V threshold, 200ms pulse, and watchdog functionality | Required for µPs with active-high reset inputs (e.g., Intel 80C51); lacks active-low RESET output for legacy designs | Choose MAX813LEPA only if target µP mandates active-high reset; MAX705EPA offers greater interface flexibility |
Compared with MAX706EPA and MAX813LEPA, the MAX705EPA uniquely combines 4.65V reset threshold, active-low RESET, and full watchdog capability in a single PDIP package - making it optimal for general-purpose +5V µP systems needing maximum timing margin and dual-reset polarity support.
Availability
MAX705EPA is available at Aetrix Electronics and suitable for industrial controllers, medical diagnostic instruments, automotive infotainment head units, and telecom remote terminal units requiring stable component supply across extended temperature ranges.
Supply support for MAX705EPA 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 MAX705–MAX708/MAX813L family was designed to replace discrete reset generators and watchdog circuits in cost-sensitive microprocessor systems - delivering integrated supervision with guaranteed timing, low quiescent current, and extended voltage operating range.
FAQ
What is the reset threshold voltage for MAX705EPA?
The MAX705EPA has a nominal reset threshold of 4.65V, with guaranteed limits of 4.50V (min) and 4.75V (max) over its full operating temperature range (–40°C to +85°C). This threshold ensures reliable reset assertion before +5V supply instability affects microprocessor operation, and is confirmed in the Electrical Characteristics table of the official datasheet.
Does MAX705EPA support operation at VCC = 1V?
Yes, MAX705EPA guarantees valid RESET output down to VCC = 1V - specifically, RESET remains a logic-low output sinking ≥50µA at VCC = 1V. This capability is explicitly specified in the datasheet's Electrical Characteristics and enables fail-safe behavior during deep brownout conditions where other supervisors may release reset prematurely.
How does the watchdog timer in MAX705EPA work?
The MAX705EPA watchdog timer times out after 1.6 seconds (1.0–2.25s range) if the WDI input remains static; it clears on any rising or falling edge. Unlike toggle-only watchdogs, this edge-sensitive design simplifies firmware integration. WDO goes low on timeout or VCC droop, and the timer also clears automatically during RESET assertion - ensuring coordinated fault response.
Can MAX705EPA monitor voltages other than +5V?
Yes, MAX705EPA can monitor any DC voltage via its PFI pin using an external resistor divider. With a precise 1.25V internal reference, PFI enables accurate early-warning detection for +12V supplies (e.g., ~11V trip point), negative rails, or battery voltages. The datasheet provides design examples including hysteresis and noise filtering techniques for robust implementation.
What is the function of the PFO pin on MAX705EPA?
The PFO (Power-Fail Output) pin on MAX705EPA is an open-drain output that pulls low when the PFI input falls below 1.25V. It serves as an interrupt source for microprocessors to initiate orderly shutdown, trigger data save routines, or activate backup power. PFO requires an external pull-up resistor and is electrically isolated from the reset generator - enabling independent use in multi-rail monitoring schemes.
MAX705EPA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
MAX705EPA FAQ
1.How can I place an order for MAX705EPA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX705EPA 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 MAX705EPA reliable?
The price and inventory of MAX705EPA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX705EPA is usually 5 days.
3.What payment methods are accepted for MAX705EPA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX705EPA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX705EPA?
MAX705EPA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX705EPA 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 MAX705EPA?
For technical support, including MAX705EPA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX705EPA requirements.
6.How does Aetrix verify that MAX705EPA is sourced from the original manufacturer or authorized distributors?
All MAX705EPA 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 MAX705EPA meets industry standards.
7.What is the process for return or replacement of MAX705EPA?
All MAX705EPA units undergo pre-shipment inspection (PSI). If there is an issue with MAX705EPA, 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 MAX705EPA part is unused and in its original packaging.
Return procedure for MAX705EPA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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