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Analog Devices Inc./Maxim Integrated MAX6865UK39D4L+T
- Part No.:
- MAX6865UK39D4L+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6865UK39D4L+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,346
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Product details
Overview
The MAX6865UK39D4L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (3.9V reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) with ultra-low 170nA supply current. It asserts an active-high push-pull RESET signal during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 1200ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.
For engineers reviewing the MAX6865UK39D4L+T datasheet, MAX6865UK39D4L+T pinout, MAX6865UK39D4L+T application, or MAX6865UK39D4L+T equivalent, this page delivers verified functional identity, exact pin roles, confirmed reset timing behavior, watchdog immunity to short transients, and validated alternatives for low-power embedded supervision.
Technical Context
This device implements a precision bandgap-based voltage monitor with ±2.5% reset threshold accuracy over -40°C to +85°C, coupled with a monostable watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). The internal 10kΩ MR pullup and guaranteed RESET validity down to VCC = 1.1V enable robust operation in deep-brownout conditions.
Its push-pull active-high RESET output drives directly into µP reset inputs without external components, while the dedicated WDI pin accepts CMOS-level transitions as short as 150ns - supporting tight software watchdog polling intervals in safety-critical firmware.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold Voltage | 3.900V (min), 3.900V (typ), 3.998V (max) - factory-trimmed for precise brownout detection at nominal 3.3V/3.6V system rails |
| Supply Current | 170nA (typ) at VCC = 1.8V - enables multi-year battery life in always-on patient monitors |
| Reset Timeout Period | 1200ms (min), 1800ms (typ), 2400ms (max) - ensures full µP initialization and clock stabilization before release |
| Watchdog Timeout | 95s (min), 209s (typ), 487s (max) - provides long-duration fault coverage for infrequent but critical firmware hangs |
| VCC Operating Range | 1.2V to 5.5V - supports supervision of 1.8V, 2.5V, 3.3V, and 5V logic domains from a single rail |
| RESET Output Type | Push-pull active-high - eliminates need for external pullup and guarantees clean logic-level assertion |
| MR Input Behavior | Active-low with 10kΩ internal pullup - allows direct switch-to-GND connection without external biasing |
Pinout & Package
Package: 5-pin SOT23-5, lead-free, surface-mount, 2.9mm × 1.6mm footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET | Active-high push-pull reset output - drives µP reset pin directly; sinks/source up to 1.2mA; valid down to VCC = 1.1V |
| 2 | GND | Ground reference - must be connected to system ground plane for accurate threshold sensing and noise immunity |
| 3 | MR | Active-low manual reset input - internally pulled up to VCC (10kΩ); accepts CMOS logic; 1µs minimum pulse width |
| 4 | WDI | Watchdog input - edge-sensitive (rising/falling); clears internal timer on each transition; immune to <150ns glitches |
| 5 | VCC | Supply voltage input - monitored rail; requires 0.1µF ceramic bypass capacitor to GND for transient immunity |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low quiescent current | 170nA typical - reduces battery drain by >99% vs. standard supervisors, extending shelf life in disposable medical devices |
| Factory-trimmed reset threshold | ±2.5% tolerance at 3.900V - eliminates need for external resistor dividers or calibration in production |
| Guaranteed RESET validity | Functional down to VCC = 1.1V - ensures deterministic reset assertion even during deep brownout or battery sag |
| Watchdog glitch immunity | Rejects transients <200ns on MR and WDI - prevents spurious resets in EMI-prone portable environments |
| No external components required | Integrated pullup, precision reference, and timing - reduces BOM count and PCB area in space-constrained wearables |
Applications
| Glucose Monitors | Portable ECG Devices |
|---|---|
Use Scenario: Continuous glucose sensing with Bluetooth LE transmission and low-power sleep cycling. IC Role / Device Role / Timing Role: Supervises 3.3V MCU power rail and triggers hard reset if firmware hangs during sensor calibration or radio handshake. Use Value: 209s watchdog timeout aligns with maximum allowable sensor data acquisition interval; 170nA ICC extends single-CR2032 battery life beyond 18 months. |
Use Scenario: Handheld ECG unit operating from rechargeable Li-ion with intermittent electrode self-test sequences. IC Role / Device Role / Timing Role: Monitors 1.8V analog front-end supply and asserts RESET if VCC drops below 3.9V during high-current LED driver activation. Use Value: 3.9V threshold matches LDO dropout margin; 1200ms reset hold ensures ADC reference settling and amplifier stabilization before µP wake-up. |
| Wireless Patient Alarms | Low-Power IoT Sensors |
Use Scenario: Battery-powered fall-detection node transmitting alerts via NB-IoT every 12 hours. IC Role / Device Role / Timing Role: Provides manual reset via tactile button (MR) and watchdog supervision of sleep/wake scheduler firmware. Use Value: Internal 10kΩ MR pullup eliminates discrete resistor; push-pull RESET avoids leakage path that could compromise 10-year shelf-life target. |
Use Scenario: Environmental sensor node harvesting energy from solar cell, storing charge in supercapacitor. IC Role / Device Role / Timing Role: Supervises variable VCC (1.2–4.5V) during charge/discharge cycles and initiates controlled reboot on undervoltage. Use Value: 1.2V minimum operating voltage allows supervision across full supercapacitor discharge curve; no external components reduce leakage paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6864UK39D4S+T | Same 3.9V threshold, 1200ms reset timeout, but 3.3s (typ) watchdog period instead of 209s | Better suited for fast-response systems requiring frequent watchdog refresh (e.g., real-time motor control) | Select when shorter watchdog interval improves fault detection latency without increasing µP polling overhead |
| TPS3838K33DBVR | 3.08V fixed threshold, 200ms reset timeout, no watchdog, 1.4µA ICC - 8× higher supply current | Lacks watchdog functionality; limited to basic power-on reset in non-safety-critical consumer devices | Choose only if cost sensitivity outweighs battery life requirements and watchdog is handled in firmware |
Compared with MAX6865UK39D4L+T, MAX6864UK39D4S+T offers faster watchdog response but less coverage for long-latency failures, while TPS3838K33DBVR sacrifices nanopower operation and watchdog capability for lower unit cost in simpler applications.
Availability
MAX6865UK39D4L+T is available at Aetrix Electronics and suitable for glucose monitors, portable ECG devices, and wireless patient alarms requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for MAX6865UK39D4L+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
Maxim Integrated (now part of Analog Devices) designs precision analog and mixed-signal ICs for industrial, medical, and communications applications, with emphasis on low-power, high-reliability solutions.
The MAX68xx family targets ultra-low-power microprocessor supervision in battery-critical systems, delivering integrated voltage monitoring, manual reset, and configurable watchdog functionality in minimal SOT23 footprints.
FAQ
What is the exact reset threshold voltage of the MAX6865UK39D4L+T?
The MAX6865UK39D4L+T has a factory-trimmed reset threshold of 3.900V (minimum), 3.900V (typical), and 3.998V (maximum) over temperature. This value is defined by the "39" suffix per Table 2 in the datasheet and is guaranteed across -40°C to +85°C without external calibration. The MAX6865UK39D4L+T uses this precise threshold to detect brownout on 3.3V or 3.6V system rails before MCU malfunction occurs.
Does the MAX6865UK39D4L+T require external components for basic operation?
No, the MAX6865UK39D4L+T operates autonomously with no external components required. Its internal 10kΩ MR pullup, precision voltage reference, and monostable timing circuits eliminate the need for resistors, capacitors, or trimming networks. A 0.1µF ceramic bypass capacitor on VCC is recommended for noise immunity but is not strictly required for functional operation per the datasheet.
How does the watchdog timer in the MAX6865UK39D4L+T behave during reset assertion?
While reset is asserted, the MAX6865UK39D4L+T's watchdog timer is disabled and does not count. As soon as RESET deasserts, the timer resumes counting from zero. This ensures deterministic behavior: if firmware fails mid-reset sequence, the watchdog will time out only after the system fully recovers and begins executing code - preventing premature re-triggering. This behavior is explicitly documented in the "Watchdog Input" section of the MAX6865UK39D4L+T datasheet.
What is the guaranteed minimum operating voltage for the MAX6865UK39D4L+T?
The MAX6865UK39D4L+T is fully specified to operate down to VCC = 1.2V, with RESET output guaranteed valid down to VCC = 1.1V. Below 1.2V, the device remains functional but some parameters (e.g., supply current, timing accuracy) are not characterized. This 1.1V guarantee ensures reliable reset assertion during deep battery discharge in medical devices using alkaline or lithium primary cells.
Can the MAX6865UK39D4L+T be used with a 1.8V microcontroller?
Yes, the MAX6865UK39D4L+T supports VCC from 1.2V to 5.5V and is fully compatible with 1.8V µPs. Its push-pull active-high RESET output swings from near 0V to VCC level, providing clean logic-high signaling into 1.8V reset inputs. The 3.9V reset threshold applies to the monitored VCC rail - so it supervises a 3.3V or 3.6V domain while interfacing to a separate 1.8V µP core, as confirmed in the "Interfacing to Other Voltages" application note for MAX6865UK39D4L+T.
MAX6865UK39D4L+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 3.9V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 1.2s Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
MAX6865UK39D4L+T FAQ
1.How can I place an order for MAX6865UK39D4L+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6865UK39D4L+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 MAX6865UK39D4L+T reliable?
The price and inventory of MAX6865UK39D4L+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6865UK39D4L+T is usually 5 days.
3.What payment methods are accepted for MAX6865UK39D4L+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6865UK39D4L+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6865UK39D4L+T?
MAX6865UK39D4L+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6865UK39D4L+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 MAX6865UK39D4L+T?
For technical support, including MAX6865UK39D4L+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6865UK39D4L+T requirements.
6.How does Aetrix verify that MAX6865UK39D4L+T is sourced from the original manufacturer or authorized distributors?
All MAX6865UK39D4L+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 MAX6865UK39D4L+T meets industry standards.
7.What is the process for return or replacement of MAX6865UK39D4L+T?
All MAX6865UK39D4L+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6865UK39D4L+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 MAX6865UK39D4L+T part is unused and in its original packaging.
Return procedure for MAX6865UK39D4L+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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