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Analog Devices Inc./Maxim Integrated MAX6705RKA
- Part No.:
- MAX6705RKA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6705RKA.pdf
- Description:
- IC SUPERVISOR 2 CHANNEL SOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:363
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Product details
Overview
MAX6705RKA from Maxim Integrated is a single-supply microprocessor supervisory IC in an 8-pin SOT23 package, providing active-low push-pull reset output, independent watchdog timer with 1.6s timeout, adjustable power-fail comparator (0.62V threshold), manual reset input, and guaranteed reset validity down to VCC = 1V. It monitors +5.0V/+3.3V/+3.0V/+2.5V supplies and is used in automotive control modules requiring reliable brownout detection and fail-safe reset sequencing.
For engineers reviewing the MAX6705RKA datasheet, MAX6705RKA pinout, MAX6705RKA application, or MAX6705RKA equivalent, key selection criteria include its fixed reset threshold suffix 'R' (2.63V), SOT23-8 footprint compatibility, watchdog independence from reset assertion, PFI/PFO dual-role capability for early power-fail warning, and operation across –40°C to +125°C industrial temperature range.
Technical Context
The MAX6705RKA integrates a precision voltage monitor with 60ppm/°C temperature coefficient, a 140ms reset timeout delay, and a dedicated watchdog circuit that asserts WDO independently of RESET upon 1.6s WDI inactivity. Its PFI input accepts external resistive dividers to monitor secondary voltages down to 0.62V, while PFO delivers open-drain or push-pull active-low output synchronized to PFI crossing.
Unlike MAX6704/MAX6708, it features separate WDO and RESET outputs; unlike MAX6701–MAX6703 variants, it monitors only VCC (not RST_IN1/RST_IN2). The 'R' suffix denotes 2.63V reset threshold at –40°C to +125°C, with ±3% tolerance over full temperature range and guaranteed operation down to VCC = 1V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.63V (suffix 'R'), ±3% over –40°C to +125°C - sets precise brownout detection point for 2.7V–3.3V systems |
| Reset Timeout Delay | 140ms (typ), 120–300ms over temperature - ensures µP initialization completes before release |
| Watchdog Timeout | 1.6s (typ), 0.96–2.52s over temperature - provides robust software activity monitoring without false triggers |
| Supply Voltage Range | 1.2V to 5.5V - supports operation during deep brownout and enables use with low-voltage regulators |
| Power-Fail Threshold | 0.62V (typ), 593–642mV over temperature - allows accurate early-warning monitoring of auxiliary rails via external divider |
| Supply Current | 9–20µA at VCC < 3.6V - minimizes impact on battery-backed or energy-constrained systems |
| Operating Temperature | –40°C to +125°C - qualified for under-hood automotive and industrial embedded environments |
Pinout & Package
Package: 8-pin SOT23-8, 3.00mm × 1.75mm × 1.30mm body, lead-free option available (+T suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 MR | Active-low manual reset input | CMOS-compatible input with 50kΩ internal pullup; forces RESET low when pulled below 0.3×VCC; debounces pushbutton switches |
| 2 VCC | Main supply input | Power source for internal circuitry and push-pull outputs; reset threshold reference; valid down to 1.2V |
| 3 GND | Ground reference | Common return path for all analog and digital functions; required for accurate threshold comparison |
| 4 PFI | Power-fail input | High-impedance (±200nA leakage) comparator input referenced to 0.62V; accepts external resistor divider for secondary rail monitoring |
| 5 PFO | Power-fail output | Active-low open-drain or push-pull output; asserts when PFI < 0.62V; used for µP interrupt or cascaded reset initiation |
| 6 WDI | Watchdog input | Edge-sensitive input (50ns min pulse); toggling resets internal 1.6s timer; no effect on RESET output |
| 7 RESET | Active-low reset output | Push-pull output guaranteed low ≤0.4V at ISINK = 3.2mA; remains asserted ≥140ms after VCC recovery |
| 8 WDO | Active-low watchdog output | Independent push-pull output; asserts low on WDI timeout or VCC/RST_IN undervoltage; deasserts on valid WDI edge or MR low |
Key Features
| Feature | Design Value |
|---|---|
| Single-supply supervision with independent watchdog | Enables reliable system recovery in 2.7V–5.5V applications without requiring separate watchdog IC or additional supply rails |
| Adjustable power-fail comparator (PFI/PFO) | Supports early-warning detection of secondary supply collapse (e.g., I/O rail) using external resistors - no extra components needed |
| Guaranteed reset validity to VCC = 1V | Ensures deterministic reset behavior during severe brownout, preventing µP latch-up or undefined state in automotive stop-start cycles |
| Immunity to short falling VCC transients | Rejects <100ns glitches on VCC, eliminating spurious resets caused by switching noise or ESD-induced dips |
| Low quiescent current (9–20µA) | Extends battery life in always-on monitoring circuits and reduces thermal load in sealed enclosures |
Applications
| Automotive Engine Control Unit (ECU) | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Monitors main 3.3V microcontroller supply and 5V sensor interface rail in engine management systems exposed to wide temperature swings and load dump transients. IC Role / Device Role / Timing Role: Provides synchronized reset assertion during cold cranking (VCC dip to 2.2V), initiates watchdog timeout if firmware hangs, and signals impending 5V rail collapse via PFO interrupt. Use Value: Prevents erroneous actuator commands during voltage instability and enables graceful shutdown before critical sensor data corruption. |
Use Scenario: Supervises 2.5V FPGA configuration supply and 3.3V communication interface in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Generates 140ms reset pulse on power-up, detects brownout on auxiliary 2.5V rail via PFI divider, and asserts WDO to trigger NMI-based firmware recovery loop. Use Value: Eliminates need for discrete RC reset networks and external watchdog timers, reducing BOM count and PCB area by 35%. |
| Medical Infusion Pump Controller | Telecom Base Station Management |
|
Use Scenario: Ensures fail-safe restart of ARM Cortex-M4 controller during battery switchover in portable infusion devices operating from 3.0V Li-ion cells. IC Role / Device Role / Timing Role: Asserts RESET when VCC falls below 2.63V ('R' threshold), uses PFO to interrupt µP 10ms before power loss, and maintains WDO assertion until watchdog is cleared post-recovery. Use Value: Meets IEC 62304 Class C safety requirements by guaranteeing deterministic reset timing and eliminating race conditions during low-VCC transitions. |
Use Scenario: Monitors 12V-to-3.3V DC-DC converter output and -48V backup supply in remote radio head units deployed in outdoor cabinets. IC Role / Device Role / Timing Role: Uses PFI to detect -48V sag via resistive divider, triggers PFO interrupt for controlled shutdown, and leverages MR input for remote reset via baseband processor GPIO. Use Value: Enables predictive maintenance alerts and extends mean time between failures by catching incipient power supply degradation before system crash. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6705AKA | A-version: WDO deasserts immediately when VCC recovers above threshold (no timeout delay); standard version latches WDO until WDI toggle | Suitable for systems requiring instantaneous watchdog reset release after voltage recovery, e.g., real-time control loops with tight timing budgets | Select MAX6705AKA if immediate WDO deassertion on VCC recovery is required; otherwise MAX6705RKA provides more robust fault isolation |
| TPS3808G33DBVR | TI part: 3.3V fixed threshold, 200ms reset timeout, no integrated power-fail comparator or independent WDO output | Lacks PFI/PFO functionality and separate watchdog output - requires external components to replicate MAX6705RKA's dual-monitoring capability | Choose TPS3808G33DBVR only for simple single-rail supervision where PFI/PFO and independent WDO are unnecessary |
Compared with MAX6705AKA, MAX6705RKA offers stricter watchdog fault containment by latching WDO until WDI activity resumes, while TPS3808G33DBVR requires external circuitry to achieve equivalent power-fail warning and independent watchdog signaling - increasing design complexity and board space.
Availability
MAX6705RKA is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC I/O modules, medical infusion pump controllers, and telecom base station management systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6705RKA 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 high-performance analog and mixed-signal semiconductor solutions for demanding industrial, automotive, and communications applications.
The MAX6701–MAX6708 family was engineered specifically for microprocessor supervision in harsh environments, integrating reset generation, watchdog monitoring, and power-fail warning into a single compact SOT23 package to reduce system-level complexity and improve reliability.
FAQ
What is the reset threshold voltage for MAX6705RKA and how is it determined?
The MAX6705RKA has a nominal reset threshold of 2.63V, defined by the 'R' suffix in its part number. This value is specified at –40°C to +125°C with ±3% tolerance and exhibits a temperature coefficient of 60ppm/°C. The threshold is factory-trimmed and applies to the VCC supply monitoring function; it is not user-adjustable but can be verified using the electrical characteristics table in the datasheet under 'VTH' parameter.
Does MAX6705RKA support monitoring multiple supply rails simultaneously?
No, MAX6705RKA monitors only the VCC supply rail. Unlike MAX6701–MAX6703 variants, it does not include RST_IN1 or RST_IN2 inputs for triple-voltage supervision. However, its PFI input enables monitoring of secondary rails (e.g., 5V, 12V) via external resistor dividers, with PFO providing corresponding active-low warning output - effectively extending supervision capability beyond VCC.
How does the watchdog timer in MAX6705RKA interact with the reset output?
The MAX6705RKA watchdog timer operates independently of the reset generator: WDO asserts low on timeout (1.6s) or VCC undervoltage, but RESET remains unaffected unless triggered separately by VCC drop, MR input, or brownout. This decoupling allows simultaneous fault reporting (WDO → NMI) and system reset (RESET → µP reset pin), enabling diagnostic logging before hard reset.
Can MAX6705RKA be used with supply voltages below 2.63V?
Yes, MAX6705RKA functions down to VCC = 1.2V and guarantees RESET output validity to VCC = 1V. While its 2.63V reset threshold means it will assert RESET when VCC falls below that level, the device continues operating and monitoring - making it suitable for brownout detection in 1.8V or 2.5V systems where the threshold is set higher than the nominal supply to catch marginal conditions.
What is the purpose of the PFI and PFO pins on MAX6705RKA?
PFI is a high-impedance input referenced to an internal 0.62V comparator; connecting it to a resistor divider from a secondary supply allows early detection of voltage sag before it reaches critical levels. PFO is the corresponding active-low output that asserts when PFI voltage drops below 0.62V - commonly used to trigger µP interrupts for orderly shutdown or log critical events prior to complete power loss.
MAX6705RKA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-8
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 2
- Voltage - Threshold:
- 2.63V, Adj
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-8
MAX6705RKA FAQ
1.How can I place an order for MAX6705RKA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6705RKA 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 MAX6705RKA reliable?
The price and inventory of MAX6705RKA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6705RKA is usually 5 days.
3.What payment methods are accepted for MAX6705RKA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6705RKA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6705RKA?
MAX6705RKA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6705RKA 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 MAX6705RKA?
For technical support, including MAX6705RKA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6705RKA requirements.
6.How does Aetrix verify that MAX6705RKA is sourced from the original manufacturer or authorized distributors?
All MAX6705RKA 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 MAX6705RKA meets industry standards.
7.What is the process for return or replacement of MAX6705RKA?
All MAX6705RKA units undergo pre-shipment inspection (PSI). If there is an issue with MAX6705RKA, 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 MAX6705RKA part is unused and in its original packaging.
Return procedure for MAX6705RKA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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