My Inquiry
My Account
Analog Devices Inc./Maxim Integrated MAX6749KA
- Part No.:
- MAX6749KA
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6749KA.pdf
- Description:
- IC SUPERVISOR UP RESET CIRCUIT
- Quantity:
- Payment:
- Shipping:
Inventory:1,031
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MAX6749KA from Maxim Integrated is a capacitor-adjustable microprocessor supervisory circuit with dual-voltage monitoring capability (RESET IN + VCC), ±2% factory-trimmed reset threshold of 1.575V, 3.7µA supply current at VCC ≤ 2.0V, and open-drain active-low RESET output. It supports automotive-grade operation from −40°C to +125°C and is used in battery-powered portable equipment requiring robust brownout detection and manual reset immunity.
For engineers reviewing the MAX6749KA datasheet, MAX6749KA pinout, MAX6749KA application, or MAX6749KA equivalent, this device delivers precise voltage supervision with adjustable reset/watchdog timeouts, transient-immune reset assertion, and guaranteed RESET validity down to VCC ≥ 1V - critical for low-power embedded controllers and intelligent instrumentation.
Technical Context
The MAX6749KA monitors both VCC and an external voltage via RESET IN using separate comparators: one with fixed 1.575V threshold (VTH), the other with adjustable 1.235V internal reference (VRESET IN) for resistor-divider-based monitoring. It lacks manual reset (MR) and watchdog select (WDS) pins - distinguishing it from MAX6746/MAX6747/MAX6750–MAX6751 variants.
It implements a standard watchdog timer (not windowed) with timeout set by CSWT capacitor on SWT pin, and reset timeout set by CSRT capacitor on SRT pin. Its pinout matches the 8-pin SOT23-8 package shared across the MAX6746–MAX6753 family but omits MR, WDS, and SET0/SET1 pins - confirmed by Pin Description table and MAX6749-specific ordering row.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | Fixed 1.575V ±2% on VCC; 1.235V ±1.5% on RESET IN - enables dual-rail monitoring without external reference |
| Supply Current | 3.7µA typical at VCC ≤ 2.0V - ensures ultra-low power consumption in always-on battery systems |
| Operating Temp | −40°C to +125°C - fully qualified for under-hood automotive and industrial control environments |
| Reset Timeout | Adjustable from 0.506ms to 9.487ms via CSRT capacitor - configurable to match µP power-up timing requirements |
| Watchdog Timeout | Adjustable from 0.506ms to 9.487ms (normal mode) via CSWT capacitor - supports software execution cycle alignment |
| RESET Output | Open-drain active-low - allows level-shifting to logic supplies up to 6V and wired-OR reset bus implementation |
| RESET Validity | Guaranteed valid for VCC ≥ 1V - ensures deterministic reset behavior during deep brownout conditions |
Pinout & Package
MAX6749KA is housed in an 8-pin SOT23-8 package (JEDEC MO-178AA), measuring 2.9mm × 1.6mm × 1.1mm, with gull-wing leads and lead-free (RoHS-compliant) option available as MAX6749KA+T.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET IN | High-impedance input to adjustable reset comparator; connects to center tap of external resistor divider to monitor secondary supply rail |
| 2 | SWT | Watchdog timeout capacitor node; sets tWD = 5.06×10⁶ × CSWT (seconds) - disables watchdog when shorted to GND |
| 3 | SRT | Reset timeout capacitor node; sets tRP = 5.06×10⁶ × CSRT (seconds) - determines minimum reset pulse width after fault clearance |
| 4 | GND | Analog/digital ground reference - must be low-impedance connection to system ground plane |
| 5 | VCC | Main supply input (1.2V–5.5V); powers internal circuitry and provides reference for fixed-threshold VCC monitoring |
| 6 | RESET | Open-drain active-low reset output; sinks ≥50µA at VOL ≤ 0.3V (VCC ≥ 1.0V) - requires external pullup for logic-level translation |
| 7 | WDI | Watchdog input; falling edge clears timer; ignored during RESET assertion - detects pulses ≥300ns wide |
| 8 | NC | No connect - internally unconnected; must remain floating or tied to GND per layout best practice |
Key Features
| Feature | Design Value |
|---|---|
| Dual-voltage monitoring | Simultaneously supervises VCC (1.575V fixed) and external rail via RESET IN (1.235V reference) - eliminates need for second supervisor IC |
| Capacitor-adjustable timing | Independent CSRT and CSWT capacitors set reset and watchdog timeouts - enables precise tuning without firmware changes |
| Power-supply transient immunity | Rejects transients ≤50µs wide when VCC dips 100mV below threshold - prevents spurious resets in noisy automotive environments |
| Ultra-low quiescent current | 3.7µA at VCC ≤ 2.0V - extends battery life in portable medical and sensor devices operating >10 years on coin cell |
| Automotive temperature grade | Specified over −40°C to +125°C - meets AEC-Q100 stress test requirements for engine control and ADAS subsystems |
Applications
| Battery-Powered Portable Equipment | Automotive Body Control Module |
|---|---|
Use Scenario: Handheld diagnostic tool powered by single Li-ion cell with dynamic load switching causing VCC sag. IC Role / Device Role / Timing Role: Monitors both battery voltage (via VCC pin) and regulated 3.3V rail (via RESET IN) to assert RESET if either drops below threshold. Use Value: Prevents corrupted firmware execution during brownout by guaranteeing reset pulse width ≥0.506ms, even at 1.8V VCC. | Use Scenario: Central body controller managing door locks, lighting, and HVAC with multiple supply rails. IC Role / Device Role / Timing Role: Supervises main 5V domain (VCC) and isolated 12V-to-3.3V converter output (RESET IN) to detect dual-rail failure. Use Value: Enables fail-safe shutdown before CAN communication corruption occurs, leveraging −40°C to +125°C operational range. |
| Intelligent Industrial Sensor Node | Medical Point-of-Care Device |
Use Scenario: Wireless temperature sensor node with intermittent RF transmission causing supply ripple. IC Role / Device Role / Timing Role: Uses open-drain RESET to interface with 1.8V µP while powered from 3.3V rail; WDI strobed by firmware every 2s. Use Value: Guarantees watchdog timeout accuracy within ±2% over temperature, preventing false resets during RF burst events. | Use Scenario: Portable blood glucose meter using CR2032 coin cell with voltage decay from 3.0V to 2.0V over product lifetime. IC Role / Device Role / Timing Role: Fixed 1.575V VCC threshold ensures reliable reset initiation before µP enters undefined state near end-of-life voltage. Use Value: Achieves >10-year shelf life with 3.7µA ICC - reduces annual battery self-discharge impact by 40% vs. comparable supervisors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6748KA | Same 8-pin SOT23-8 package and dual-monitoring architecture, but features push-pull RESET output instead of open-drain | Requires no external pullup; unsuitable for wired-OR reset buses or level-shifting to higher voltages | Select MAX6748KA when interfacing directly to 3.3V/5V µP reset inputs without voltage translation needs |
| TLV803EB26DBVR | Single-supply monitor only (no RESET IN pin); fixed 2.63V threshold; 0.5µs propagation delay vs. 20µs for MAX6749KA | Lacks dual-rail capability and adjustable timeouts; optimized for fast, simple reset-only functions | Select TLV803EB26DBVR for cost-sensitive, single-rail applications where capacitor adjustment and secondary rail monitoring are unnecessary |
Compared with MAX6748KA and TLV803EB26DBVR, the MAX6749KA uniquely combines open-drain flexibility, dual-voltage supervision, and capacitor-adjustable timing - making it optimal for systems requiring interoperability across mixed-voltage domains and field-programmable timeout calibration.
Availability
MAX6749KA is available at Aetrix Electronics and suitable for battery-powered portable equipment, automotive body control modules, and intelligent industrial sensor nodes requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6749KA 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 product line delivers capacitor-programmable µP supervisors targeting systems needing field-tunable reset/watchdog timing and dual-rail monitoring without firmware dependency.
FAQ
What is the exact reset threshold voltage for MAX6749KA?
The MAX6749KA has a fixed VCC reset threshold of 1.575V ±2% and an adjustable RESET IN threshold based on a 1.235V ±1.5% internal reference. This allows precise dual-rail monitoring: VCC is checked against 1.575V, while external rails connect to RESET IN through a resistor divider scaled to 1.235V. The 1.575V value is factory-trimmed and confirmed in Table 2 of the datasheet under suffix "16".
Does MAX6749KA support manual reset functionality?
No, MAX6749KA does not include a manual reset (MR) input. Per the Selector Guide and Pin Configurations, MR is only present on MAX6746 and MAX6747 variants. The MAX6749KA relies solely on VCC and RESET IN voltage monitoring plus WDI watchdog triggering for reset assertion - making it suitable for systems where operator-initiated reset is handled externally or not required.
What watchdog architecture does MAX6749KA implement?
MAX6749KA implements a standard (non-windowed) watchdog timer, identical to MAX6746–MAX6751. It uses the SWT pin to set timeout via external capacitor (tWD = 5.06×10⁶ × CSWT), and WDI falling edges to clear the timer. Unlike MAX6752/MAX6753, it lacks SET0/SET1 pins and cannot perform min/max windowed fault detection - confirmed by its absence from the MAX6752/MAX6753 pinout and Selector Guide.
Can MAX6749KA monitor two independent supply rails simultaneously?
Yes, MAX6749KA monitors two rails concurrently: VCC (with fixed 1.575V threshold) and an external rail via the RESET IN pin (using 1.235V internal reference with external resistor divider). This dual-monitoring capability is explicitly listed in the Selector Guide and enabled by dedicated comparators - allowing independent fault detection on primary and auxiliary supplies without additional ICs.
What is the minimum VCC voltage required for guaranteed RESET functionality in MAX6749KA?
MAX6749KA guarantees valid RESET output logic state for VCC ≥ 1V, as stated in the Features list and Electrical Characteristics table. Below 1V, RESET current-sinking capability degrades significantly. For applications requiring reset assertion down to 0V, a pulldown resistor is not applicable here since MAX6749KA uses open-drain RESET - unlike push-pull variants such as MAX6748KA.
MAX6749KA 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:
- Adjustable/Selectable
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 5.692ms Minimum
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-8
MAX6749KA FAQ
1.How can I place an order for MAX6749KA through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6749KA 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 reliable?
The price and inventory of MAX6749KA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6749KA is usually 5 days.
3.What payment methods are accepted for MAX6749KA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6749KA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6749KA?
MAX6749KA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6749KA 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?
For technical support, including MAX6749KA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6749KA requirements.
6.How does Aetrix verify that MAX6749KA is sourced from the original manufacturer or authorized distributors?
All MAX6749KA 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 meets industry standards.
7.What is the process for return or replacement of MAX6749KA?
All MAX6749KA units undergo pre-shipment inspection (PSI). If there is an issue with MAX6749KA, 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 part is unused and in its original packaging.
Return procedure for MAX6749KA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX6749KA Tags
-
MIC826SYMT-TR
Microchip Technology
-
APX803S-31SA-7
Diodes Incorporated
-
APX803L20-29SA-7
Diodes Incorporated
-
TPS3828-33DBVR
Texas Instruments
-
V6340RSP3B+
EM Microelectronic
-
EM6325CXSP5B-2.9+
EM Microelectronic
-
MCP120T-300I/TT
Microchip Technology
-
MCP130T-315I/TT
Microchip Technology
-
MCP120T-475I/TT
Microchip Technology
-
MCP111T-300E/TT
Microchip Technology
-
MCP120T-315I/TT
Microchip Technology
-
MCP809T-315I/TT
Microchip Technology
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
