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Analog Devices Inc./Maxim Integrated MAX6746KA31
- Part No.:
- MAX6746KA31
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6746KA31.pdf
- Description:
- IC SUPERVISOR UP RESET CIRCUIT
- Quantity:
- Payment:
- Shipping:
Inventory:30,011
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Product details
Overview
MAX6746KA31 from Maxim Integrated is a low-power microprocessor supervisory circuit designed for single-voltage monitoring in automotive and industrial embedded systems. It features a factory-trimmed 3.075V ±2% reset threshold, capacitor-adjustable 0.506–9.487ms reset timeout (via SRT pin), and capacitor-adjustable watchdog timeout (via SWT pin), with push-pull active-low RESET output. It operates across -40°C to +125°C and draws only 3.7µA at VCC ≤ 2.0V.
For engineers reviewing the MAX6746KA31 datasheet, MAX6746KA31 pinout, MAX6746KA31 application, or MAX6746KA31 equivalent, this device supports critical µP reset supervision in battery-powered equipment, intelligent instruments, and automotive ECUs where precise voltage thresholding, transient immunity, and configurable timing are required.
Technical Context
The MAX6746KA31 implements a dual-comparator architecture: one monitors VCC against its fixed 3.075V threshold, while another accepts external resistor-divider input via RESET IN for dual-voltage applications (though MAX6746 variant lacks RESET IN functionality per Selector Guide). Reset assertion is guaranteed for VCC ≥ 1V, with 20µs response to VCC transients.
Its watchdog logic is configurable via WDS pin: normal mode (tWD = 5.06×10⁶ × CSWT) or extended mode (128× tWD), with WDI edge-triggered clearing and MR manual reset support. The device uses internal ramp-current-based timing for high accuracy over temperature and supply voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V ±2% - factory-trimmed for stable brownout detection at nominal 3.3V rails |
| Supply Current | 3.7µA (typ) at VCC ≤ 2.0V - enables multi-year operation in battery-backed systems |
| Reset Timeout Range | 0.506ms to 9.487ms - set by 100pF–1500pF capacitor on SRT pin, supporting diverse µP boot times |
| Watchdog Timeout Range | 0.506ms–9.487ms (normal) or 64.77ms–1214.4ms (extended) - selectable via WDS pin and SWT capacitor |
| Operating Temp | -40°C to +125°C - fully specified for under-hood automotive and industrial control environments |
| RESET Output Type | Push-pull active-low - eliminates external pull-up, simplifies interface to µP reset inputs |
| Power Supply Immunity | Rejects transients ≤50µs at 100mV below VTH - prevents spurious resets during EMI or load-switching events |
Pinout & Package
MAX6746KA31 is housed in an 8-pin SOT23-8 package (2.9mm × 1.6mm × 1.1mm), optimized for space-constrained PCB layouts in automotive and portable equipment.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | MR (Manual Reset Input) | Active-low input; internally pulled up to VCC; asserts reset when held low ≥1µs; rejects 100ns glitches |
| 2 | SWT (Watchdog Timeout Input) | Capacitor connection point to ground; sets basic watchdog timeout period (tWD = 5.06×10⁶ × CSWT) |
| 3 | SRT (Reset Timeout Input) | Capacitor connection point to ground; sets reset timeout period (tRP = 5.06×10⁶ × CSRT) |
| 4 | GND | Ground reference for all analog and digital circuitry; must be low-impedance return path |
| 5 | WDS (Watchdog Select Input) | Logic input: GND = normal mode, VCC = extended mode (128× tWD); state change clears watchdog timer |
| 6 | WDI (Watchdog Input) | Falling-edge sensitive; clears watchdog timer on each valid transition; ignored during RESET assertion |
| 7 | RESET (Active-Low Reset Output) | Push-pull driver; asserts low during VCC drop, MR activation, or watchdog fault; holds for full tRP after recovery |
| 8 | VCC | Supply input (1.2V–5.5V); powers internal circuitry and serves as monitored rail for fixed-threshold detection |
Key Features
| Feature | Design Value |
|---|---|
| Factory-Trimmed Reset Threshold | 3.075V ±2% - eliminates external resistor network, reduces BOM count and layout area |
| Capacitor-Adjustable Timing | Independent SRT/CSRT and SWT/CSWT tuning - enables precise match to µP boot sequence and software watchdog service intervals |
| Watchdog Mode Selection | WDS pin toggles between normal (ms-range) and extended (100ms–1.2s) timeout - accommodates both fast-boot and long-loop firmware |
| Transient Immunity | Valid reset assertion only for VCC dips >100mV lasting >50µs - suppresses noise-induced false resets in electrically noisy environments |
| Low-Voltage Validity | RESET guaranteed functional down to VCC = 1V - ensures reliable reset signaling during deep brownout conditions |
Applications
| Automotive Engine Control Unit (ECU) | Industrial PLC I/O Module |
|---|---|
Use Scenario: Monitors 3.3V microcontroller supply in engine management system exposed to load dump and cold-crank transients. IC Role / Device Role / Timing Role: Primary VCC supervisor asserting reset during brownout and providing watchdog safety net for firmware hang detection. Use Value: Factory-trimmed 3.075V threshold matches 3.3V rail tolerance; 125°C rating ensures reliability under hood; push-pull RESET avoids pull-up loading on noisy 3.3V domain. |
Use Scenario: Supervises dual 24V-to-3.3V DC-DC outputs powering FPGA and ARM Cortex-M7 in modular automation controller. IC Role / Device Role / Timing Role: Single-supply monitor with manual reset override for field service; capacitor-adjustable timeouts align with FPGA configuration time and firmware watchdog window. Use Value: 3.7µA quiescent current extends backup battery life; MR pin allows hardware-initiated reinitialization without host processor involvement. |
| Portable Medical Infusion Pump | Battery-Powered Smart Sensor Node |
Use Scenario: Ensures safe restart of safety-critical ARM-based pump controller after Li-ion battery voltage sag during motor startup. IC Role / Device Role / Timing Role: Voltage supervisor with guaranteed RESET validity down to VCC = 1V, preventing undefined µP state during deep discharge. Use Value: Push-pull output eliminates need for external pull-up, reducing leakage paths; low ICC extends runtime between charges. |
Use Scenario: Supervises ultra-low-power RISC-V SoC in wireless environmental sensor operating from coin cell for 5+ years. IC Role / Device Role / Timing Role: Reset generator with extended watchdog mode (128×) enabling infrequent firmware checks to minimize wake-up current. Use Value: Adjustable tWD up to 1.2s allows long sleep intervals while maintaining fail-safe reset coverage; SOT23-8 footprint fits compact 2-layer PCB. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6747KA31 | Same 3.075V threshold and timing specs, but features open-drain RESET output instead of push-pull | Required when interfacing to mixed-voltage systems (e.g., 3.3V supervisor driving 5V µP reset) or needing wired-OR reset bus | Select MAX6747KA31 if level-shifting or bus-wired reset topology is needed; otherwise MAX6746KA31 simplifies design with integrated drive. |
| TPS3808G33 | 3.3V fixed threshold (±0.5%), 350ms min reset timeout, 2.5µA ICC, no adjustable watchdog, SOT23-6 package | Lacks capacitor-adjustable timing and watchdog - suitable only for basic power-on reset without firmware supervision | Choose TPS3808G33 for cost-sensitive, non-watchdog applications requiring tighter threshold accuracy and lower ICC; not a functional replacement for watchdog-enabled designs. |
Compared with MAX6747KA31, MAX6746KA31 offers simpler µP interface via push-pull output but less flexibility in voltage-level translation; versus TPS3808G33, it trades threshold precision and ultra-low ICC for essential watchdog configurability and timing adaptability in safety-critical firmware.
Availability
MAX6746KA31 is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC modules, and portable medical devices requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6746KA31 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 demanding industrial, automotive, and computing applications.
The MAX6746–MAX6753 family was engineered to deliver configurable, low-power µP supervision with robust transient immunity for automotive-grade and mission-critical embedded systems where deterministic reset behavior is non-negotiable.
FAQ
What is the exact reset threshold voltage of MAX6746KA31?
The MAX6746KA31 has a factory-trimmed reset threshold of 3.075V with ±2% tolerance over -40°C to +125°C. This value is confirmed in Table 2 of the datasheet under suffix "31", and applies specifically to the VCC monitoring function. The device does not support external RESET IN adjustment, as indicated in the Selector Guide for MAX6746.
Does MAX6746KA31 support watchdog functionality, and how is it configured?
Yes, MAX6746KA31 supports a capacitor-adjustable watchdog timer. The timeout period is set by a capacitor on the SWT pin (tWD = 5.06×10⁶ × CSWT), and extended mode (128× multiplier) is enabled by pulling WDS high. WDI provides edge-triggered watchdog clearing, and the timer resets automatically upon any RESET assertion.
What is the function of the MR pin on MAX6746KA31, and what are its electrical requirements?
The MR pin on MAX6746KA31 is an active-low manual reset input with internal 12–28kΩ pull-up to VCC. It requires a minimum pulse width of 1µs to assert RESET and rejects transients shorter than 100ns. No external components are needed; leaving MR unconnected disables manual reset functionality.
Can MAX6746KA31 operate reliably at VCC = 1.2V, and what is its supply current at that voltage?
Yes, MAX6746KA31 is fully operational at VCC = 1.2V, with guaranteed RESET validity and functional timing. According to Electrical Characteristics table, supply current ICC is 4.2–9µA (min–max) at VCC ≤ 3.3V, and typifies 3.7µA at VCC ≤ 2.0V - confirming sub-5µA operation well within the 1.2V–5.5V operating range.
What package type and pin-compatible alternatives exist for MAX6746KA31?
MAX6746KA31 is supplied in an 8-pin SOT23-8 package. While no direct pin-compatible drop-in replacements exist due to unique pin assignments (e.g., dedicated WDS, SWT, SRT), MAX6747KA31 shares identical pinout and timing specs but substitutes open-drain RESET for push-pull - making it a mechanically identical, functionally adjacent alternative requiring only minor schematic revision.
MAX6746KA31 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:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 3.075V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 5.692ms Minimum
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-8
MAX6746KA31 FAQ
1.How can I place an order for MAX6746KA31 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6746KA31 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 MAX6746KA31 reliable?
The price and inventory of MAX6746KA31 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6746KA31 is usually 5 days.
3.What payment methods are accepted for MAX6746KA31?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6746KA31 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6746KA31?
MAX6746KA31 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6746KA31 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 MAX6746KA31?
For technical support, including MAX6746KA31 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6746KA31 requirements.
6.How does Aetrix verify that MAX6746KA31 is sourced from the original manufacturer or authorized distributors?
All MAX6746KA31 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 MAX6746KA31 meets industry standards.
7.What is the process for return or replacement of MAX6746KA31?
All MAX6746KA31 units undergo pre-shipment inspection (PSI). If there is an issue with MAX6746KA31, 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 MAX6746KA31 part is unused and in its original packaging.
Return procedure for MAX6746KA31:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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