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Analog Devices Inc./Maxim Integrated MAX705EUA+
- Part No.:
- MAX705EUA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX705EUA+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:2,027
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Product details
Overview
MAX705EUA+ from Maxim Integrated is a precision microprocessor supervisory circuit in an 8-pin µMAX 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 remains valid down to VCC = 1V - used in embedded controllers and industrial instrumentation for reliable power-up/down and brownout recovery.
For engineers reviewing the MAX705EUA+ datasheet, MAX705EUA+ pinout, MAX705EUA+ application, or MAX705EUA+ equivalent, key selection criteria include its -40°C to +85°C operating range, 4.65V reset threshold, watchdog timeout tolerance, PFI comparator accuracy, and µMAX footprint compatibility with space-constrained PCB layouts.
Technical Context
The MAX705EUA+ integrates four core supervisory functions on a single die: a precision voltage monitor with 40mV hysteresis, a monostable watchdog timer triggered by WDI edge transitions, a high-impedance (±25nA) 1.25V reference-based power-fail comparator, and a TTL/CMOS-compatible MR input with internal 250µA pull-up. All logic outputs drive standard CMOS loads with guaranteed VOL ≤ 0.4V at ISINK = 3.2mA.
Its reset generator uses an internal RC timing network to ensure ≥140ms minimum pulse width after VCC rise or MR release, while the watchdog circuit detects pulses as narrow as 50ns and clears on any WDI transition, RESET assertion, or high-impedance state - enabling robust firmware supervision without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±150mV - triggers reset during brownout when +5V supply dips below safe µP operating level |
| Reset Pulse Width | 200ms typical - ensures full µP initialization and memory stabilization before release |
| Watchdog Timeout | 1.6s ±0.65s - provides sufficient time for firmware main loop execution while detecting hangs |
| PFI Threshold | 1.25V ±50mV - enables accurate early-warning detection of +5V regulator dropout or battery sag |
| Supply Current | 150–350µA - supports low-power operation in battery-backed systems without compromising supervision integrity |
| VCC Operating Range | 1.0V to 5.5V - guarantees RESET validity down to 1V, enabling fail-safe behavior during deep brownout |
| MR Input Pull-Up | 250µA - eliminates need for external pull-up resistor and ensures clean TTL/CMOS-compatible switching |
Pinout & Package
The MAX705EUA+ is housed in an 8-pin µMAX package (outline 21-0036), measuring 3.0mm × 3.0mm × 0.8mm with exposed pad for thermal enhancement and RoHS-compliant lead-free finish (+ suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (WDO) | Watchdog Output | Active-low open-drain output signaling watchdog timeout or VCC brownout; requires external pull-up |
| 2 (RESET) | Active-Low Reset Output | Push-pull output asserting guaranteed low-state reset pulse for µP initialization |
| 3 (WDI) | Watchdog Input | TTL/CMOS-compatible input that resets watchdog timer on rising/falling edges; floating disables timer |
| 4 (PFO) | Power-Fail Output | Active-low open-drain output indicating PFI < 1.25V; used for NMI or orderly shutdown signaling |
| 5 (PFI) | Power-Fail Input | High-impedance comparator input referenced to internal 1.25V bandgap; accepts voltage divider for multi-rail monitoring |
| 6 (GND) | Ground Reference | Common return path for all analog and digital functions; must be low-inductance connection |
| 7 (VCC) | +5V Supply Input | Primary power rail; powers internal circuitry and defines reset threshold reference |
| 8 (MR) | Manual-Reset Input | Active-low input with internal 250µA pull-up; debounced via 200ms reset pulse to prevent contact bounce issues |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET Validity at VCC = 1V | Ensures fail-safe reset assertion even during severe brownout, preventing µP runaway before supply collapse |
| Debounced Manual-Reset Input | Eliminates need for external RC filter or firmware debounce logic, reducing BOM count and layout complexity |
| 1.25V Precision Power-Fail Comparator | Enables accurate early-warning detection of +5V dropout or battery voltage sag without external reference |
| 200ms Minimum Reset Pulse Width | Meets or exceeds most µP reset timing requirements (e.g., Intel 80C51, ARM Cortex-M) without external timing components |
| µMAX 8-Pin Package | Reduces board area by >60% vs. SO-8 and >75% vs. PDIP-8, critical for compact industrial and portable designs |
Applications
| Industrial PLC Controller | Medical Diagnostic Instrument |
|---|---|
Use Scenario: Monitors +5V rail in programmable logic controller during factory floor voltage fluctuations and ESD events. IC Role / Device Role / Timing Role: Supervisory IC asserting active-low RESET to hold CPU in known state during brownout; WDO connected to NMI for watchdog-triggered fault logging. Use Value: Prevents spurious I/O writes and corrupted ladder logic execution by guaranteeing 200ms reset hold time and validating RESET down to VCC = 1V. | Use Scenario: Provides power supervision for FPGA-based imaging subsystem in portable ultrasound equipment with backup battery. IC Role / Device Role / Timing Role: Uses PFI/PFO to detect main supply degradation and trigger controlled data save before switchover to backup battery. Use Value: Achieves 1.25V ±50mV PFI threshold accuracy to initiate shutdown 120ms before +5V regulator dropout, preserving image buffer integrity. |
| Automotive Body Control Module | Smart Energy Meter |
Use Scenario: Supervises microcontroller in body control unit exposed to cold-crank (4.5V) and load-dump (18V) transients. IC Role / Device Role / Timing Role: Active-low RESET output interfaces directly to µP reset pin; MR tied to service-mode switch for field firmware recovery. Use Value: With -40°C to +85°C rating and 4.65V reset threshold, ensures reliable startup after cold cranking and prevents false resets during transient overvoltage. | Use Scenario: Monitors both +5V logic rail and +12V metering front-end supply in ANSI C12.20-certified electricity meters. IC Role / Device Role / Timing Role: Configured with dual voltage dividers on PFI to assert RESET if either rail falls below safe operating margin. Use Value: Leverages single IC to supervise two independent rails, reducing component count while maintaining 140–280ms reset pulse width per IEC 62053-21 timing compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX706EUA+ | 4.40V reset threshold (vs. 4.65V); identical pinout, timing, and feature set | Suitable for systems using lower-tolerance +5V regulators or requiring earlier reset assertion | Select MAX706EUA+ only if design requires reset at 4.40V; otherwise MAX705EUA+ matches standard +5V LDO dropout margins. |
| MAX813LEUA+ | Active-high RESET output (RESET) instead of active-low; same 4.65V threshold and watchdog functionality | Required for µPs with active-high reset inputs (e.g., legacy 80C51 derivatives) | Choose MAX813LEUA+ when interfacing to processors lacking active-low reset capability; no change to supervision logic or PCB layout needed. |
Compared with MAX706EUA+, the MAX705EUA+ provides higher reset threshold margin for standard +5V supplies; compared with MAX813LEUA+, it delivers direct compatibility with modern µPs requiring active-low reset assertion - simplifying interface design and eliminating level-shifting components.
Availability
MAX705EUA+ is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic instruments, automotive body control modules, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX705EUA+ 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 microprocessor-based systems - delivering integrated supervision with guaranteed timing, low quiescent current, and small-footprint packaging.
FAQ
What is the guaranteed minimum reset pulse width for MAX705EUA+?
The MAX705EUA+ guarantees a minimum reset pulse width of 140ms, with a typical value of 200ms and maximum of 280ms. This timing ensures compatibility with most microprocessors' reset setup requirements, including ARM Cortex-M series and legacy 8051 derivatives. The pulse is generated internally and does not require external capacitors or resistors. The MAX705EUA+ maintains this specification across its full -40°C to +85°C operating temperature range and 1.0V to 5.5V supply voltage range.
Does MAX705EUA+ support watchdog functionality with automatic clearing on power-up?
Yes, the MAX705EUA+ watchdog timer automatically clears on power-up when VCC rises above the reset threshold, and also clears whenever the RESET signal is asserted, WDI is placed in high-impedance state, or a rising/falling edge is detected on WDI. This ensures the watchdog does not falsely trigger during startup or after a reset event. The MAX705EUA+ watchdog timeout period is 1.6 seconds ±0.65 seconds, and it detects input pulses as narrow as 50ns - making it suitable for real-time firmware supervision in safety-critical applications.
Can MAX705EUA+ monitor voltages other than +5V, such as +12V or negative rails?
Yes, the MAX705EUA+ can monitor voltages beyond +5V using the PFI input with an external resistor divider. For example, a +12V rail can be scaled to 1.25V at PFI to trigger PFO when the rail drops below ~11V. It can also monitor negative supplies by configuring PFI as the inverting input of a comparator with PFO driving an external transistor stage - as shown in Figure 7 of the datasheet. The MAX705EUA+ PFI input draws only ±25nA, minimizing loading error on precision divider networks.
What is the operating temperature range and package type of MAX705EUA+?
The MAX705EUA+ is rated for operation from -40°C to +85°C and is supplied in an 8-pin µMAX package (package code U8+1, outline 21-0036). This RoHS-compliant, lead-free package measures 3.0mm × 3.0mm × 0.8mm with an exposed thermal pad, offering superior thermal performance and board-space savings versus SO-8 or PDIP-8 alternatives. The "+" suffix explicitly denotes lead-free/RoHS-compliant packaging per Maxim's ordering convention.
How does the manual-reset input (MR) of MAX705EUA+ behave electrically?
The MR input of MAX705EUA+ is an active-low, TTL/CMOS-compatible pin with an internal 250µA pull-up current. Its logic thresholds are VIH ≥ 2.0V and VIL ≤ 0.8V at VCC = 5V, and it features built-in debouncing via the 200ms reset pulse - eliminating need for external RC filters. MR can be driven directly from logic outputs or momentary switches; when shorted to GND, it forces a full reset pulse regardless of VCC level. The MAX705EUA+ guarantees MR-to-RESET delay of ≤250ns, ensuring deterministic response.
MAX705EUA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- 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:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-uMAX/uSOP
MAX705EUA+ FAQ
1.How can I place an order for MAX705EUA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX705EUA+ 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 MAX705EUA+ reliable?
The price and inventory of MAX705EUA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX705EUA+ is usually 5 days.
3.What payment methods are accepted for MAX705EUA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX705EUA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX705EUA+?
MAX705EUA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX705EUA+ 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 MAX705EUA+?
For technical support, including MAX705EUA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX705EUA+ requirements.
6.How does Aetrix verify that MAX705EUA+ is sourced from the original manufacturer or authorized distributors?
All MAX705EUA+ 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 MAX705EUA+ meets industry standards.
7.What is the process for return or replacement of MAX705EUA+?
All MAX705EUA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX705EUA+, 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 MAX705EUA+ part is unused and in its original packaging.
Return procedure for MAX705EUA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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