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Analog Devices Inc./Maxim Integrated MAX705ESA
- Part No.:
- MAX705ESA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX705ESA.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,433
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Product details
Overview
MAX705ESA from Maxim Integrated is a precision microprocessor supervisory circuit in 8-pin SO package, providing active-low reset output (4.65V threshold), 1.6s watchdog timeout, 1.25V power-fail comparator input, and debounced manual-reset input. It ensures reliable power-up/down/brownout reset for +5V µP systems in industrial controllers and embedded instrumentation.
For engineers reviewing the MAX705ESA datasheet, MAX705ESA pinout, MAX705ESA application, or MAX705ESA equivalent, this page delivers verified electrical parameters, thermal range (-40°C to +85°C), SO package footprint details, and validated alternatives for µP reset and watchdog supervision in mission-critical embedded designs.
Technical Context
The MAX705ESA integrates four core supervisory functions on a single die: a precision voltage monitor with 40mV hysteresis triggering a guaranteed 200ms reset pulse; a watchdog timer that detects WDI edge transitions and asserts WDO after 1.6s of inactivity; a 1.25V reference-based power-fail comparator with nanosecond-level response; and a TTL/CMOS-compatible MR input with internal 250µA pull-up and 150ns minimum pulse width tolerance.
Its reset generator remains functional down to VCC = 1V, ensuring deterministic behavior during deep brownout. The PFI/PFO pair operates independently of VCC monitoring, enabling flexible external voltage supervision (e.g., +12V rails or negative supplies) without additional comparators or references.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.65V ±150mV - triggers reset when VCC drops below nominal +5V supply, with 40mV hysteresis to prevent chatter during slow voltage recovery |
| Reset Pulse Width | 200ms typical - guarantees sufficient duration to fully initialize Intel 80C51 and similar µPs requiring >100ms assertion |
| Watchdog Timeout | 1.6s ±0.65s - provides robust software activity monitoring with tolerance for brief interrupt latency or low-power sleep cycles |
| Power-Fail Threshold | 1.25V ±50mV - enables accurate early-warning detection of +5V regulator dropout via external resistor divider |
| Supply Current | 350µA max at +70°C - supports low-power operation in battery-backed systems while maintaining full supervisory functionality |
| Operating Voltage Range | 1.0V to 5.5V - ensures valid RESET output even during severe brownout conditions down to 1V, critical for graceful shutdown |
| MR Input Threshold | 0.8V low / 2.0V high - compatible with standard TTL and CMOS logic families without level-shifting circuitry |
Pinout & Package
MAX705ESA is housed in an 8-pin Small Outline (SO) package, 3.9mm × 4.9mm body size, 1.27mm lead pitch, RoHS-compliant with lead-free option available (suffix '+').
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 MR | Manual-Reset Input | Active-low TTL/CMOS-compatible trigger with 250µA internal pull-up; debounces pushbutton switches via 140ms minimum reset pulse |
| 2 VCC | +5V Supply Input | Primary power rail connection; device monitors this voltage for reset generation and powers all internal circuits |
| 3 GND | Ground Reference | 0V return path for all analog and digital signals; must be low-impedance to ensure accurate threshold detection |
| 4 PFI | Power-Fail Input | Non-inverting input of comparator referenced to 1.25V; used to monitor auxiliary voltages (e.g., +12V, -5V) via external divider |
| 5 PFO | Power-Fail Output | Open-drain active-low output asserting when PFI < 1.25V; sinks current to signal power degradation to µP NMI or interrupt line |
| 6 WDO | Watchdog Output | Open-drain active-low output asserting after 1.6s WDI inactivity; also pulls low during VCC brownout independent of watchdog state |
| 7 RESET | Active-Low Reset Output | Guaranteed logic-low output (≤0.4V @ 3.2mA) during reset; pulses 200ms on power-up and holds low until VCC exceeds 4.65V + hysteresis |
| 8 WDI | Watchdog Input | Edge-sensitive input detecting rising/falling transitions; 50ns minimum pulse width; floating or high-Z disables watchdog function |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed RESET validity at VCC = 1V | Ensures deterministic reset assertion during deep brownout, preventing µP runaway before supply collapse |
| Debounced TTL/CMOS-compatible MR input | Eliminates need for external RC debounce network; 150ns MR pulse width tolerance supports fast mechanical switch bounce |
| Precision 4.65V reset threshold with 40mV hysteresis | Prevents oscillatory reset during marginal VCC recovery; matches standard +5V linear regulator dropout characteristics |
| Independent 1.25V power-fail comparator | Enables early warning of secondary supply failure (e.g., +12V, -5V) without loading main VCC rail or requiring external reference |
| 1.6s watchdog timeout with edge-triggered clear | Supports firmware watchdog servicing within interrupt handlers without tight timing constraints; tolerates brief CPU stalls |
Applications
| Industrial PLC Controller | Medical Diagnostic Instrument |
|---|---|
Use Scenario: Continuous operation in factory-floor PLCs subject to voltage sags, EMI, and thermal cycling. IC Role / Device Role / Timing Role: Supervisory IC generating power-on reset, brownout reset, and watchdog timeout pulses to hold µP in safe state during instability. Use Value: Prevents spurious I/O activation or corrupted memory writes during transient supply faults, meeting IEC 61000-4-11 immunity requirements. |
Use Scenario: Battery-backed portable ultrasound or ECG units requiring fail-safe shutdown before backup power depletion. IC Role / Device Role / Timing Role: Monitors main +5V rail and battery voltage via PFI divider; asserts PFO to initiate controlled data save and power-down sequence. Use Value: Enables ≥200ms of deterministic µP execution time after PFI drop, allowing full RAM dump to nonvolatile storage before VCC collapse. |
| Automotive Body Control Module | Smart Energy Meter |
Use Scenario: Under-hood BCM exposed to load-dump transients and cold-crank brownouts (-1V to +16V VCC excursions). IC Role / Device Role / Timing Role: Provides robust reset assertion during cranking (VCC dips to ~3.5V) and validates µP startup only after stable +5V is restored. Use Value: Guarantees RESET remains asserted until VCC exceeds 4.65V + 40mV hysteresis, eliminating false starts during slow battery recharge. |
Use Scenario: Revenue-grade meter operating 24/7 with tamper detection and secure firmware updates over PLC or RF links. IC Role / Device Role / Timing Role: Uses WDI toggling as heartbeat signal during firmware update; WDO assertion halts update and triggers rollback on communication loss. Use Value: Ensures atomic firmware updates by tying watchdog timeout directly to communication layer liveness, preventing partial flash corruption. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar µP supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX706ESA | 4.40V reset threshold (vs. 4.65V); identical pinout, timing, and feature set | Suitable for systems using +5V regulators with tighter dropout specs (e.g., LDOs with <200mV dropout) | Select MAX706ESA when VCC regulation margin is ≤250mV; otherwise MAX705ESA ensures compatibility with standard 7805-style regulators. |
| MAX813LESA | Active-high RESET output only (no RESET); same 4.65V threshold, 1.6s watchdog, and PFI/PFO functions | Required for µPs with active-high reset inputs (e.g., Intel 80C51, ARM Cortex-M0+ with configurable reset polarity) | Choose MAX813LESA when system design mandates active-high reset assertion without external inverter; note missing active-low RESET pin. |
Compared with MAX706ESA and MAX813LESA, the MAX705ESA uniquely provides both active-low RESET and full watchdog functionality at the industry-standard 4.65V threshold, making it optimal for legacy 8051/8086-based controllers requiring dual-polarity reset signaling and brownout resilience.
Availability
MAX705ESA is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostic instruments, automotive body control modules, smart energy meters, and critical µP power monitoring applications requiring stable component supply across extended temperature ranges.
Supply support for MAX705ESA 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 markets.
The MAX705–MAX708/MAX813L family was designed to replace discrete reset generators and watchdog circuits in cost-sensitive µP systems, delivering integrated supervision with guaranteed timing and voltage accuracy in compact SO and µMAX packages.
FAQ
What is the reset threshold voltage for MAX705ESA and how is it specified?
The MAX705ESA has a nominal reset threshold of 4.65V, with a guaranteed range of 4.50V to 4.75V over its full operating temperature range (-40°C to +85°C). This threshold is referenced to the VCC supply and includes 40mV of built-in hysteresis to prevent oscillation during slow voltage recovery. The specification ensures reliable reset assertion for standard +5V linear regulators with typical dropout characteristics, and the MAX705ESA maintains valid RESET output down to VCC = 1V.
Does MAX705ESA provide both active-low and active-high reset outputs?
No, the MAX705ESA provides only an active-low RESET output. It does not include the active-high RESET output found in the MAX707ESA, MAX708ESA, or MAX813LESA variants. The MAX705ESA pinout includes RESET (pin 7), WDO (pin 6), and WDI (pin 8), but no dedicated active-high reset terminal. For designs requiring active-high reset, MAX813LESA is the direct functional alternative with identical supervision features except output polarity.
How does the watchdog timer in MAX705ESA operate and what is its timeout period?
The MAX705ESA watchdog timer monitors the WDI (pin 8) input and asserts WDO (pin 6) low if no rising or falling edge occurs within 1.6 seconds. The timeout period is specified as 1.00s to 2.25s over temperature, with 1.6s typical. The timer clears automatically on any WDI transition, during RESET assertion, or when WDI is three-stated. This behavior allows robust firmware supervision without requiring precise timing margins, and the MAX705ESA's WDO output can also serve as a low-line indicator during VCC brownout.
Can MAX705ESA monitor voltages other than the main VCC supply?
Yes, the MAX705ESA can monitor auxiliary voltages using its PFI (pin 4) and PFO (pin 5) pins. The PFI input is referenced to an internal 1.25V comparator threshold, so connecting an external resistor divider to PFI enables supervision of +12V, -5V, or other rails. For example, a 10:1 divider on a +12V rail yields 1.2V at PFI, triggering PFO low before the +12V supply collapses. The MAX705ESA's PFI input draws only ±25nA, minimizing loading on the monitored source.
What package type and temperature range does MAX705ESA use?
The MAX705ESA is supplied in an 8-pin Small Outline (SO) package with 1.27mm lead pitch and operates over the extended industrial temperature range of -40°C to +85°C. This SO package (package code S8+2) is RoHS-compliant and available in lead-free form with '+' suffix. Its 3.9mm × 4.9mm footprint provides board space savings versus DIP while maintaining compatibility with standard SO-8 reflow profiles and automated assembly processes.
MAX705ESA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- 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:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX705ESA FAQ
1.How can I place an order for MAX705ESA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX705ESA 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 MAX705ESA reliable?
The price and inventory of MAX705ESA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX705ESA is usually 5 days.
3.What payment methods are accepted for MAX705ESA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX705ESA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX705ESA?
MAX705ESA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX705ESA 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 MAX705ESA?
For technical support, including MAX705ESA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX705ESA requirements.
6.How does Aetrix verify that MAX705ESA is sourced from the original manufacturer or authorized distributors?
All MAX705ESA 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 MAX705ESA meets industry standards.
7.What is the process for return or replacement of MAX705ESA?
All MAX705ESA units undergo pre-shipment inspection (PSI). If there is an issue with MAX705ESA, 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 MAX705ESA part is unused and in its original packaging.
Return procedure for MAX705ESA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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