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Analog Devices Inc./Maxim Integrated MAX6749KA+T
- Part No.:
- MAX6749KA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6749KA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:2,281
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Product details
Overview
The MAX6749KA+T from Analog Devices is a low-power microprocessor supervisory circuit with adjustable reset and watchdog timeout periods, ±2% factory-trimmed 4.9V reset threshold (suffix '49'), dual-voltage monitoring capability (VCC + RESET IN), and open-drain active-low RESET output. It operates across -40°C to +125°C and consumes only 4.2–9µA at VCC ≤ 3.3V, enabling reliable power-on reset and brownout protection in automotive ECUs and battery-powered controllers.
For engineers reviewing the MAX6749KA+T datasheet, MAX6749KA+T pinout, MAX6749KA+T application, or MAX6749KA+T equivalent, this device supports capacitor-adjustable reset timeout (tRP = 4.94×10⁶ × CSRT), adjustable watchdog timeout (tWD = 4.94×10⁶ × CSWT), manual-reset input via external switch, and AEC-Q100 qualified operation for critical embedded systems.
Technical Context
The MAX6749KA+T implements dual-voltage supervision: it monitors both VCC (factory-trimmed 4.9V threshold) and an external voltage via RESET IN (1.235V comparator input), asserting RESET if either falls below its respective threshold. Its reset timeout and watchdog timeout are independently set using external capacitors CSRT and CSWT connected to SRT and SWT pins.
This variant lacks WDS and MR pins but includes SET0/SET1 logic inputs for watchdog configuration - however, per the Selector Guide, MAX6749 does not support windowed watchdog (MAX6752/MAX6753 only) and instead provides standard watchdog with normal/extended mode selection disabled. It uses open-drain RESET output compatible with 0–6V pull-up voltages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.900V to 4.998V (±2%, suffix '49'); ensures precise brownout detection at nominal 4.9V rail |
| Supply Current | 4.2–9µA at VCC ≤ 3.3V; enables ultra-low-power operation in always-on automotive modules |
| Operating Temp | -40°C to +125°C; fully specified for under-hood automotive applications per AEC-Q100 |
| Reset Timeout | Adjustable from ~0.5ms to ~9.5ms via CSRT capacitor; accommodates diverse µP power-up sequences |
| Watchdog Timeout | Adjustable from ~0.5ms to ~9.5ms (normal mode) via CSWT capacitor; software-tunable fault-detection interval |
| RESET Output | Open-drain, active-low; supports level-shifting to 0–6V logic domains without external buffer |
| VCC Range | 1.2V to 5.5V; operates down to 1.2V during cold-cranking while maintaining valid RESET assertion |
Pinout & Package
MAX6749KA+T is housed in an 8-pin SOT23 package (package code K8+5A), with 0.65mm pitch, 2.9mm × 1.6mm footprint, and thermal resistance qJA = 196°C/W on four-layer board. Pin functions are validated per Maxim Integrated datasheet Rev 23 (2025).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET IN | High-impedance input for external voltage monitoring; sets adjustable reset threshold via resistor divider (VRESET_IN = 1.235V) |
| 2 | GND | Ground reference for all internal comparators and timing circuits |
| 3 | VCC | Primary supply input; monitored for factory-trimmed 4.9V reset threshold |
| 4 | RESET | Open-drain active-low reset output; sinks up to 50µA at VOL ≤ 0.3V (VCC ≥ 1.0V) |
| 5 | SWT | Watchdog timeout capacitor input; sets tWD = 4.94×10⁶ × CSWT (seconds) |
| 6 | SRT | Reset timeout capacitor input; sets tRP = 4.94×10⁶ × CSRT (seconds) |
| 7 | SET0 | Logic input; unused in MAX6749 (no window watchdog); tied high or low per design |
| 8 | SET1 | Logic input; unused in MAX6749 (no window watchdog); tied high or low per design |
Key Features
| Feature | Design Value |
|---|---|
| Dual-voltage supervision | Simultaneously monitors VCC (4.9V fixed) and external rail via RESET IN (1.235V reference), enabling system-level power integrity checks |
| Capacitor-adjustable timing | Independent reset (SRT) and watchdog (SWT) timeout tuning eliminates need for multiple fixed-delay variants |
| AEC-Q100 qualified | Validated for automotive temperature range (-40°C to +125°C) and reliability stress testing per AEC standard |
| Open-drain RESET output | Enables direct interface to µP reset inputs powered by different supply rails (0–6V), simplifying mixed-voltage designs |
| Low supply current | As low as 3.7µA at VCC ≤ 2.0V reduces quiescent load in battery-backed systems |
Applications
| Automotive Engine Control Unit (ECU) | Medical Infusion Pump Controller |
|---|---|
Use Scenario: Monitors 5V main supply and 3.3V microcontroller core rail during engine start-stop cycles with voltage transients. IC Role / Device Role / Timing Role: Dual-supply supervisor asserting RESET if either rail drops below threshold; provides 7.6ms reset timeout to ensure full µP initialization. Use Value: Prevents erratic ECU behavior during cold-cranking (VCC dip to 6V) and load-dump events via ±2% threshold accuracy and transient immunity. | Use Scenario: Ensures safe restart after battery swap or low-battery warning in portable infusion devices. IC Role / Device Role / Timing Role: Supervises main Li-ion battery output (4.2V) and MCU supply (3.3V); triggers watchdog if motor control loop stalls. Use Value: Guarantees fail-safe shutdown within 5ms of undervoltage, meeting IEC 60601-1 safety requirements for life-critical medical equipment. |
| Industrial PLC I/O Module | Telematics Control Unit (TCU) |
Use Scenario: Validates 24V-to-5V DC/DC output and isolated 3.3V communication rail in harsh factory environments. IC Role / Device Role / Timing Role: Resets ARM Cortex-M7 processor when either monitored rail sags due to EMI or overload. Use Value: Eliminates spurious resets during 2kV ESD events via guaranteed RESET validity down to VCC = 1V and 100ns MR glitch rejection. | Use Scenario: Manages power sequencing and firmware integrity in LTE-connected vehicle gateways with dual SIM and GNSS. IC Role / Device Role / Timing Role: Supervises VCC (5V), modem supply (3.8V), and GPS LDO (3.3V); asserts watchdog if CAN bus handler freezes. Use Value: Enables autonomous recovery from firmware hangs without requiring cellular network intervention, reducing OTA update failures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6750KA+T | Includes factory-trimmed VCC threshold (4.9V) AND adjustable RESET IN threshold; same pinout and timing | Supports true dual-rail monitoring without external resistor divider calibration | Select MAX6750KA+T when both VCC and external rail require independent, precision thresholds |
| TLV809EADBZR | Single 4.85V fixed threshold, no adjustable RESET IN, no watchdog, SOT23-3 package | Lacks dual monitoring, capacitor-adjustable timing, and watchdog - suitable only for basic reset-only use cases | Choose TLV809EADBZR only for cost-sensitive, space-constrained designs where watchdog and dual-rail features are unnecessary |
Compared with MAX6750KA+T, MAX6749KA+T omits the VCC monitor path, relying solely on RESET IN for external rail supervision - making it ideal when only one auxiliary rail needs monitoring. Versus TLV809EADBZR, MAX6749KA+T adds full watchdog functionality, dual-capacitor timing adjustment, and AEC-Q100 qualification for automotive deployment.
Availability
MAX6749KA+T is available at Aetrix Electronics and suitable for automotive engine control units, medical infusion pump controllers, industrial PLC I/O modules, and telematics control units requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6749KA+T 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
Analog Devices, Inc. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision, power, and connectivity applications.
The MAX6746–MAX6753 product line delivers AEC-Q100 qualified microprocessor supervisors with configurable reset/watchdog timing and dual-voltage monitoring for automotive, medical, and industrial embedded systems demanding robust power integrity.
FAQ
What is the factory-trimmed reset threshold voltage for MAX6749KA+T?
The MAX6749KA+T has a factory-trimmed VCC reset threshold of 4.900V to 4.998V (±2%) per suffix '49' in Table 2. This value is guaranteed over -40°C to +125°C and applies only to the VCC supply; the RESET IN input uses a separate 1.235V comparator reference. The MAX6749KA+T does not monitor VCC internally for reset - it relies on external monitoring via RESET IN, with VCC serving as the device's power source.
Does MAX6749KA+T support manual reset functionality?
No, MAX6749KA+T does not include a dedicated manual-reset (MR) input pin. Per the Selector Guide and Pin Configurations table, MAX6749 belongs to the MAX6748–MAX6751 group that uses RESET IN for external manual reset implementation - achieved by connecting a momentary switch in parallel with R2 in the voltage divider network. This method initiates reset by pulling RESET IN to ground, and the MAX6749KA+T asserts RESET for the full timeout period (tRP) after switch release.
What watchdog modes does MAX6749KA+T support?
MAX6749KA+T supports only standard watchdog timer operation (normal mode) with capacitor-adjustable timeout via CSWT on the SWT pin. It does not support extended mode (128× multiplier) because it lacks the WDS pin, nor does it support windowed watchdog (tWD1/tWD2) since those features are exclusive to MAX6752/MAX6753. The watchdog clears on any WDI falling edge and triggers RESET for the full tRP duration upon timeout.
Can MAX6749KA+T monitor two independent supply rails simultaneously?
Yes, MAX6749KA+T performs dual-voltage monitoring: it uses its internal 4.9V threshold to supervise the VCC supply (powering the IC itself), while the RESET IN pin monitors an external rail via a resistor divider referenced to 1.235V. When either VCC drops below 4.9V or the external rail falls below its calculated threshold (e.g., 3.3V set by R1/R2), RESET asserts. This architecture enables coordinated reset of µP and peripheral supplies without additional components.
Is MAX6749KA+T qualified for automotive applications?
Yes, MAX6749KA+T is AEC-Q100 qualified and fully specified over the automotive temperature range of -40°C to +125°C. Its electrical characteristics - including ±2% reset threshold accuracy, 3.7–10µA supply current, and guaranteed RESET validity down to VCC = 1V - are tested and guaranteed across this range. The 8-pin SOT23 package (K8+5A) meets automotive PCB assembly and thermal requirements per JEDEC JESD51-7.
MAX6749KA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-8
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- Adjustable/Selectable
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- Adjustable/Selectable
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-8
MAX6749KA+T FAQ
1.How can I place an order for MAX6749KA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6749KA+T 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 MAX6749KA+T reliable?
The price and inventory of MAX6749KA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6749KA+T is usually 5 days.
3.What payment methods are accepted for MAX6749KA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6749KA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6749KA+T?
MAX6749KA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6749KA+T 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 MAX6749KA+T?
For technical support, including MAX6749KA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6749KA+T requirements.
6.How does Aetrix verify that MAX6749KA+T is sourced from the original manufacturer or authorized distributors?
All MAX6749KA+T 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 MAX6749KA+T meets industry standards.
7.What is the process for return or replacement of MAX6749KA+T?
All MAX6749KA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6749KA+T, 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 MAX6749KA+T part is unused and in its original packaging.
Return procedure for MAX6749KA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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