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Analog Devices Inc./Maxim Integrated MAX6746KA26
- Part No.:
- MAX6746KA26
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6746KA26.pdf
- Description:
- IC SUPERVISOR UP RESET CIRCUIT
- Quantity:
- Payment:
- Shipping:
Inventory:550
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Product details
Overview
MAX6746KA26 from Maxim Integrated is a low-power microprocessor supervisory circuit with factory-trimmed 2.625V ±2% VCC reset threshold, capacitor-adjustable reset timeout (tRP), and watchdog timeout (tWD), supporting single-supply monitoring in automotive systems. It features push-pull active-low RESET output, manual reset input (MR), and operates across -40°C to +125°C. Used for reliable power-on reset and watchdog supervision in battery-powered controllers.
For engineers reviewing the MAX6746KA26 datasheet, MAX6746KA26 pinout, MAX6746KA26 application, or MAX6746KA26 equivalent, this page delivers verified electrical parameters, automotive-grade timing behavior, SOT23-8 package details, and validated alternative options for µP reset design validation and BOM optimization.
Technical Context
The MAX6746KA26 implements dual-path reset assertion: one triggered by VCC falling below its 2.625V threshold, the other by MR pull-down. Reset remains asserted for a user-defined timeout period (tRP) set via external capacitor on SRT pin, with typical tRP = 7.59 ms at CSRT = 1500 pF.
It includes a selectable watchdog timer with normal mode only (no WDS pin - confirmed by Selector Guide and Pin Configurations), where tWD is set by CSWT and extends 128× when WDS is high (but WDS is not present on MAX6746). Watchdog fault detection occurs on WDI falling edge timing violations relative to tWD.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Reset Threshold | 2.625V ±2% - factory-trimmed voltage at which reset asserts during brownout; enables precise supply monitoring without external resistors. |
| Supply Current | 3.7 µA at VCC ≤ 2.0V - ultra-low quiescent current supports long-life battery operation in portable and automotive modules. |
| Reset Timeout (tRP) | 0.506–9.487 ms - adjustable via 100–1500 pF capacitor on SRT; covers boot-time requirements from fast MCUs to complex SoCs. |
| Watchdog Timeout (tWD) | 0.506–9.487 ms - capacitor-adjustable via SWT pin; matches software service intervals without firmware changes. |
| Operating Temp Range | -40°C to +125°C - fully specified for under-hood automotive and industrial embedded applications. |
| RESET Output Type | Push-pull active-low - drives µP reset pin directly without external pull-up; ensures valid logic down to VCC ≥ 1V. |
| Manual Reset Input | MR pin with 20 kΩ internal pull-up - supports momentary switch interface without external components; rejects 100 ns glitches. |
Pinout & Package
MAX6746KA26 is housed in an 8-pin SOT23-8 package (JEDEC MO-178AA), surface-mount, lead-free compatible (suffix +T), with 1.27 mm pitch and 2.9 mm × 1.6 mm footprint. Thermal resistance θJA = 112°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | MR (Manual Reset Input) | Active-low input with internal 20 kΩ pull-up to VCC; initiates reset when pulled low ≥1 µs; immune to <100 ns transients. |
| 2 | RESET IN | Not connected on MAX6746KA26 - unused pin per Selector Guide; device monitors only VCC, not external voltage. |
| 3 | SWT (Watchdog Timeout Input) | Capacitor connection point (to GND) setting tWD; formula tWD = 5.06×10⁶ × CSWT seconds; disables watchdog if shorted to GND. |
| 4 | SRT (Reset Timeout Input) | Capacitor connection point (to GND) setting tRP; formula tRP = 5.06×10⁶ × CSRT seconds; defines minimum reset pulse width. |
| 5 | GND | Ground reference for all analog comparators, timers, and digital logic; must be low-impedance return path. |
| 6 | WDI (Watchdog Input) | Falling-edge-sensitive input; resets watchdog timer on each valid transition; asserts RESET if no edge occurs within tWD. |
| 7 | RESET | Push-pull active-low output; sinks ≥50 µA at VOL ≤ 0.3V (VCC ≥ 1.0V); drives µP reset pin directly. |
| 8 | VCC | Power supply input (1.2–5.5V); powers internal comparators, timers, and logic; also monitored for VTH = 2.625V reset trigger. |
Key Features
| Feature | Design Value |
|---|---|
| Factory-trimmed reset threshold | 2.625V ±2% - eliminates resistor-divider design effort and drift; guarantees accuracy over full automotive temperature range. |
| Capacitor-adjustable timeouts | tRP and tWD independently set via SRT/SWT pins - enables precise timing alignment with µP boot code and watchdog service routines. |
| Power-supply transient immunity | Rejects VCC glitches ≤50 µs when 100 mV below VTH - prevents spurious resets during ECU load-dump or ignition transients. |
| Guaranteed RESET validity | RESET logic state defined for VCC ≥ 1V - ensures deterministic µP reset behavior during slow power ramp-down in automotive cold-crank conditions. |
| Low supply current | 3.7 µA at VCC ≤ 2.0V - extends battery life in always-on telematics and sensor nodes without compromising supervision integrity. |
Applications
| Automotive Engine Control Unit (ECU) | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Monitors 3.3V microcontroller supply during engine start-stop cycles with high-voltage transients. IC Role / Device Role / Timing Role: Primary VCC supervisor asserting reset during brownout and providing watchdog supervision of main MCU firmware loop. Use Value: Prevents corrupted flash writes and undefined state during 6V–16V battery swings; 125°C rating ensures reliability near exhaust manifolds. |
Use Scenario: Supervises dual-rail 5V/3.3V logic in DIN-rail mounted programmable logic controller with isolated field I/O. IC Role / Device Role / Timing Role: Single-chip solution for VCC reset and watchdog, eliminating discrete RC networks and reducing board area by >40%. Use Value: Factory-trimmed 2.625V threshold matches common 3.3V LDO dropout margin; push-pull RESET drives optocoupler input directly. |
| Medical Infusion Pump Controller | Smart Energy Meter MCU |
|
Use Scenario: Ensures fail-safe restart of ARM Cortex-M4-based pump controller after battery swap or power interruption. IC Role / Device Role / Timing Role: Critical safety monitor asserting hardware reset and verifying firmware liveness via WDI strobing every 100 ms. Use Value: 3.7 µA ICC enables >5-year shelf life on primary lithium battery; MR pin supports nurse-initiated emergency reset without PCB routing. |
Use Scenario: Supervises metrology SoC in ANSI C12.20-compliant electricity meter operating in outdoor enclosures up to 70°C ambient. IC Role / Device Role / Timing Role: Resets metering processor during AC line sags and validates firmware execution via windowed watchdog (not applicable to MAX6746KA26). Use Value: Adjustable tRP (0.5–9.5 ms) accommodates variable boot times across firmware revisions; SOT23-8 footprint simplifies rework and volume assembly. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar µP supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6326UR26-T | Fixed 2.63V reset threshold, no watchdog, 1.6 µA ICC, SOT23-3 package | Lacks watchdog and manual reset; suited only for basic reset-only use cases | Select when watchdog functionality is unnecessary and board space is constrained (3-pin vs 8-pin). |
| TPS3808G125DBVR | 2.625V threshold, 1.8 µA ICC, fixed 200 ms reset delay, no adjustable timeout or watchdog | No capacitor-adjustable timing; requires external RC for custom delays; no WDI support | Choose for cost-sensitive designs where fixed delay suffices and ultra-low ICC (<2 µA) is critical. |
Compared with MAX6746KA26, MAX6326UR26-T reduces component count but forfeits watchdog supervision and timing flexibility, while TPS3808G125DBVR offers lower current but eliminates design adaptability for evolving firmware timing requirements.
Availability
MAX6746KA26 is available at Aetrix Electronics and suitable for automotive ECUs, industrial PLCs, medical infusion pumps, and smart energy meters requiring stable component supply with guaranteed long-term lifecycle support.
Supply support for MAX6746KA26 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 precision analog, mixed-signal, and power management ICs for demanding industrial, automotive, and medical applications.
The MAX6746–MAX6753 family delivers configurable µP supervision with capacitor-adjustable timing, targeting automotive and industrial systems needing robust, low-power, and temperature-stable reset and watchdog functions.
FAQ
What is the exact factory-trimmed reset threshold voltage for MAX6746KA26?
The MAX6746KA26 has a factory-trimmed VCC reset threshold of 2.625V with ±2% tolerance over -40°C to +125°C. This value is confirmed in Table 2 of the datasheet (suffix "26" corresponds to 2.625V nominal), and is independent of external components - no resistor divider is required for VCC monitoring.
Does MAX6746KA26 support dual-voltage monitoring (e.g., VCC and RESET IN)?
No, MAX6746KA26 does not support dual-voltage monitoring. Per the Selector Guide and Pin Configurations, it includes only the MR pin (Pin 1) and lacks RESET IN functionality (Pin 2 is unused). It monitors VCC only - unlike MAX6748–MAX6751, which feature adjustable RESET IN inputs.
Can MAX6746KA26 be used with a windowed watchdog timer?
No, MAX6746KA26 does not implement a windowed watchdog. It belongs to the MAX6746–MAX6751 subgroup, which supports only standard (single-trigger) watchdog operation. Windowed watchdog functionality is exclusive to MAX6752/MAX6753, which have SET0/SET1 pins and dual timeout periods (tWD1/tWD2).
What is the function of the WDS pin on MAX6746KA26?
The WDS pin is not present on MAX6746KA26. According to the Selector Guide and Pin Configurations diagram, WDS is only implemented on MAX6746–MAX6751 variants that include it (e.g., MAX6746KA26 uses Pins 1–8 as MR, RESET IN [NC], SWT, SRT, GND, WDI, RESET, VCC). WDS appears only on later variants like MAX6748–MAX6751.
Is MAX6746KA26 compatible with 1.8V microcontrollers?
Yes, MAX6746KA26 supports VCC as low as 1.2V and guarantees valid RESET output down to VCC ≥ 1V. Its 2.625V reset threshold is appropriate for monitoring 3.3V supplies, but the device itself can operate from 1.2V–5.5V. For 1.8V µPs, ensure the monitored rail (e.g., 1.8V LDO output) matches a supported threshold variant - MAX6746KA18 would be required, not KA26.
MAX6746KA26 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:
- 2.625V
- 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
MAX6746KA26 FAQ
1.How can I place an order for MAX6746KA26 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6746KA26 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 MAX6746KA26 reliable?
The price and inventory of MAX6746KA26 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6746KA26 is usually 5 days.
3.What payment methods are accepted for MAX6746KA26?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6746KA26 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6746KA26?
MAX6746KA26 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6746KA26 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 MAX6746KA26?
For technical support, including MAX6746KA26 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6746KA26 requirements.
6.How does Aetrix verify that MAX6746KA26 is sourced from the original manufacturer or authorized distributors?
All MAX6746KA26 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 MAX6746KA26 meets industry standards.
7.What is the process for return or replacement of MAX6746KA26?
All MAX6746KA26 units undergo pre-shipment inspection (PSI). If there is an issue with MAX6746KA26, 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 MAX6746KA26 part is unused and in its original packaging.
Return procedure for MAX6746KA26:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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