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Analog Devices Inc./Maxim Integrated MAX6751KA26
- Part No.:
- MAX6751KA26
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6751KA26.pdf
- Description:
- IC SUPERVISOR UP RESET CIRCUIT
- Quantity:
- Payment:
- Shipping:
Inventory:3,702
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Product details
Overview
MAX6751KA26 from Maxim Integrated is a capacitor-adjustable microprocessor supervisory circuit with dual-voltage monitoring (VCC and external RESET IN), factory-trimmed 2.625V ±2% reset threshold, watchdog select input (WDS), and push-pull active-low RESET output. It asserts reset during VCC brownout, manual reset, or watchdog timeout, and is specified for automotive operation from −40°C to +125°C. Used in battery-powered embedded controllers requiring reliable power-on reset and software fault detection.
For engineers reviewing the MAX6751KA26 datasheet, MAX6751KA26 pinout, MAX6751KA26 application, or MAX6751KA26 equivalent, this page delivers verified technical context, exact pin functions, capacitor-based timing design guidance, automotive-grade supply transient immunity, and validated alternative options for dual-supply monitoring with adjustable watchdog timeout.
Technical Context
The MAX6751KA26 integrates two independent reset comparators: one monitors VCC against its factory-trimmed 2.625V threshold, the other monitors an externally divided voltage at RESET IN using a fixed 1.235V internal reference. Reset assertion persists for a capacitor-programmable timeout (tRP = 5.06 × 10⁶ × CSRT) after both monitored voltages recover.
It implements a single-mode watchdog timer (normal/extended via WDS) with timeout set by CSWT (tWD = 5.06 × 10⁶ × CSWT), extended 128× when WDS = VCC. Unlike MAX6752/MAX6753, it lacks windowed watchdog logic and uses WDI edge-triggered clearing without fast/slow fault discrimination.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.625V ±2% (factory-trimmed VCC monitor); enables precise brownout detection at 2.6V nominal systems |
| RESET Output Type | Push-pull active-low; drives µP reset pin directly without external pullup, supports 3.2mA sink at VCC ≥4.5V |
| Supply Current | 3.7µA typical at VCC ≤2.0V; enables multi-year battery life in always-on monitoring applications |
| Operating Temp | −40°C to +125°C; fully specified for under-hood automotive and industrial control environments |
| Reset Timeout | Capacitor-adjustable (CSRT): 0.506ms to 9.487ms range; matches diverse µP initialization durations |
| Watchdog Timeout | Capacitor-adjustable (CSWT): 0.506ms–9.487ms (normal), up to 1214ms (extended ×128); aligns with firmware service intervals |
| RESET Valid Down To | VCC ≥1V guaranteed; ensures deterministic reset state during deep brownout recovery |
Pinout & Package
MAX6751KA26 is housed in an 8-pin SOT23-8 package (2.9mm × 1.6mm × 1.1mm), lead-free compatible, rated for automotive temperature range.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RESET IN | Adjustable reset comparator input | Accepts external resistor-divider to monitor secondary supply (e.g., 3.3V rail); threshold referenced to 1.235V internal bandgap |
| 2 - GND | Ground reference | Common return for all analog and digital circuitry; must be low-impedance connection to system ground plane |
| 3 - SWT | Watchdog timeout capacitor node | Connects to ground via CSWT to set basic watchdog period; shorting to GND disables watchdog function |
| 4 - SRT | Reset timeout capacitor node | Connects to ground via CSRT to set reset pulse width; determines minimum hold time for µP initialization |
| 5 - SET1 | Logic input (not used in MAX6751) | No functional connection in MAX6751; tied to GND or left floating per layout best practice; unused in this variant |
| 6 - WDI | Watchdog input | Falling-edge sensitive; must be toggled within tWD to prevent reset; cleared on any transition or RESET assertion |
| 7 - RESET | Active-low reset output | Push-pull driver; asserts low during VCC/RESET IN fault or watchdog timeout; deasserts after tRP expires |
| 8 - VCC | Power supply input | Monitored supply rail (2.625V threshold); powers internal circuitry; valid operation from 1.2V to 5.5V |
Key Features
| Feature | Design Value |
|---|---|
| Dual-voltage supervision | Simultaneously monitors VCC (2.625V) and external rail via RESET IN; triggers reset if either falls below threshold |
| Capacitor-programmable timing | Independent CSRT and CSWT capacitors set reset and watchdog timeouts without trimming resistors or firmware |
| Watchdog select (WDS) | Single pin extends watchdog timeout 128× (e.g., 0.1µF → 65s), enabling flexible firmware service scheduling |
| Automotive-grade reliability | Specified over −40°C to +125°C with ±2% threshold accuracy and 3.7µA quiescent current at low VCC |
| Transient-immune reset | Rejects <50µs VCC transients down to 100mV below threshold, preventing spurious resets in noisy environments |
Applications
| Automotive Engine Control Unit (ECU) | Battery-Powered Telematics Module |
|---|---|
Use Scenario: Monitors 5V microcontroller supply and 3.3V CAN transceiver rail during cold cranking and load dump events. IC Role / Device Role / Timing Role: Dual-supply supervisor asserting reset if either rail dips below specification; provides 10ms reset pulse for full µP reinitialization. Use Value: Prevents ECU lockup during voltage sags; eliminates need for discrete comparators and RC timers in space-constrained under-hood layouts. |
Use Scenario: Ensures reliable boot and runtime watchdog coverage in GPS/GSM modules powered by Li-ion batteries (3.0–4.2V range). IC Role / Device Role / Timing Role: Supervises main processor VCC and backup RTC supply; uses extended watchdog mode (WDS = VCC) for 60s firmware service interval. Use Value: Extends battery life via ultra-low 3.7µA ICC; replaces two discrete supervisors with single 8-pin SOT23 solution. |
| Industrial PLC I/O Controller | Medical Patient Monitor Power Sequencer |
Use Scenario: Validates 24V-to-5V DC/DC output and isolated 3.3V logic rail before enabling fieldbus communication interfaces. IC Role / Device Role / Timing Role: Dual-threshold supervisor with manual reset override (via external switch on RESET IN); reset timeout set to 5ms for deterministic startup. Use Value: Guarantees safe I/O enable only after stable power; avoids bus contention during power-up sequencing. |
Use Scenario: Coordinates power-up of analog front-end, digital processor, and display subsystems in Class II medical devices. IC Role / Device Role / Timing Role: Monitors primary 3.3V processor rail and auxiliary 1.8V sensor supply; asserts reset until both stabilize for ≥2ms. Use Value: Meets IEC 60601-1 power integrity requirements; eliminates risk of corrupted sensor data during partial power-up. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6750KA26 | Same 2.625V VCC threshold and dual-monitor architecture, but includes manual reset input (MR) pin instead of SET1 | Suitable where operator-initiated reset is required; MR pin simplifies switch interface without external divider | Select MAX6750KA26 if hardware reset button is needed; MAX6751KA26 saves board space when MR is unnecessary |
| TPS3808G33DBVR | Fixed 3.3V reset threshold, no adjustable RESET IN input, no WDS pin; offers 200ms min reset timeout and 3.5µA ICC | Limited to single-rail 3.3V systems; lacks dual-supply capability and extended watchdog mode | Choose TPS3808G33DBVR for cost-sensitive 3.3V-only designs where dual monitoring and programmable watchdog are not required |
Compared with MAX6750KA26, MAX6751KA26 trades manual reset functionality for dedicated SET1 (unused) and simplified pinout-ideal for fixed dual-rail monitoring without user intervention. Versus TPS3808G33DBVR, MAX6751KA26 provides broader voltage flexibility, dual-rail supervision, and 128× watchdog extension, at the cost of higher design complexity.
Availability
MAX6751KA26 is available at Aetrix Electronics and suitable for automotive engine control units, battery-powered telematics modules, and industrial PLC I/O controllers requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6751KA26 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 and mixed-signal ICs for demanding industrial, automotive, and medical applications, emphasizing high reliability and low power.
The MAX6746–MAX6753 family delivers capacitor-adjustable µP supervision with dual-voltage monitoring and scalable watchdog functionality, targeting automotive and industrial systems needing robust power-up sequencing and runtime fault detection.
FAQ
What is the factory-trimmed reset threshold voltage for MAX6751KA26?
The MAX6751KA26 has a factory-trimmed VCC reset threshold of 2.625V ±2% over −40°C to +125°C. This value is encoded in the "26" suffix per Table 2 of the datasheet. The device also monitors RESET IN using a separate 1.235V internal reference for external rail supervision. Both thresholds are guaranteed across the full automotive temperature range.
Does MAX6751KA26 support manual reset functionality?
No, MAX6751KA26 does not include a dedicated manual reset (MR) input. Its pin 1 is RESET IN for adjustable external rail monitoring, unlike MAX6746/MAX6747 which use pin 1 as MR. To implement manual reset with MAX6751KA26, connect a momentary switch between RESET IN and GND (as shown in Figure 3 of the datasheet), pulling the monitored voltage to zero to trigger reset.
How do I calculate the capacitor values for reset and watchdog timeout on MAX6751KA26?
For reset timeout (tRP), use CSRT = tRP / 5.06 × 10⁶ (tRP in seconds, CSRT in farads). For watchdog timeout (tWD), use CSWT = tWD / 5.06 × 10⁶. In extended mode (WDS = VCC), multiply tWD by 128 before calculating CSWT. Example: 100ms extended timeout requires CSWT = (0.1 × 128) / 5.06 × 10⁶ ≈ 2.53nF. Use low-leakage ceramic capacitors.
What is the difference between MAX6751KA26 and MAX6752KA26?
MAX6751KA26 implements a standard edge-triggered watchdog with normal/extended modes via WDS. MAX6752KA26 features a windowed watchdog that detects both fast (tWDI < tWD1) and slow (tWDI > tWD2) faults using SET0/SET1 pins. MAX6751KA26 lacks SET0/SET1 and windowed timing; it uses WDS and WDI only. They share the same 2.625V VCC threshold and SOT23-8 package.
Is MAX6751KA26 qualified for automotive applications?
Yes, MAX6751KA26 is fully specified for the automotive temperature range (−40°C to +125°C) and offered in AEC-Q100–compatible packaging. Its ±2% reset threshold accuracy, 3.7µA supply current at low VCC, and immunity to 50µs VCC transients meet critical automotive power-supply monitoring requirements. The "KA" prefix and SOT23-8 package denote automotive-grade qualification.
MAX6751KA26 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:
- 2.625V, Adj
- Output:
- Open Drain or Open Collector
- 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
MAX6751KA26 FAQ
1.How can I place an order for MAX6751KA26 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6751KA26 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 MAX6751KA26 reliable?
The price and inventory of MAX6751KA26 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6751KA26 is usually 5 days.
3.What payment methods are accepted for MAX6751KA26?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6751KA26 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6751KA26?
MAX6751KA26 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6751KA26 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 MAX6751KA26?
For technical support, including MAX6751KA26 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6751KA26 requirements.
6.How does Aetrix verify that MAX6751KA26 is sourced from the original manufacturer or authorized distributors?
All MAX6751KA26 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 MAX6751KA26 meets industry standards.
7.What is the process for return or replacement of MAX6751KA26?
All MAX6751KA26 units undergo pre-shipment inspection (PSI). If there is an issue with MAX6751KA26, 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 MAX6751KA26 part is unused and in its original packaging.
Return procedure for MAX6751KA26:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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