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Analog Devices Inc./Maxim Integrated MAX6865UK39D2L+T
- Part No.:
- MAX6865UK39D2L+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6865UK39D2L+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,011
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Product details
Overview
The MAX6865UK39D2L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 3.9V reset threshold (±2.5%), 40ms minimum reset timeout, and integrated watchdog timer with 209s typical timeout. It monitors VCC, responds to manual reset (MR), and asserts active-high push-pull RESET during brownout, power-up, or watchdog expiration - used in glucose monitors and battery-powered medical devices.
For engineers reviewing the MAX6865UK39D2L+T datasheet, MAX6865UK39D2L+T pinout, MAX6865UK39D2L+T application, or MAX6865UK39D2L+T equivalent, this page delivers verified functional identity, exact pin roles, confirmed timing parameters, real-world use cases, and two validated alternative parts for portable low-power µP reset supervision.
Technical Context
The MAX6865UK39D2L+T implements a precision bandgap-based voltage monitor with 0.5% hysteresis, a digital watchdog timer that clears on any WDI edge (min pulse width 150ns), and an internal 10kΩ MR pullup. Its reset assertion logic combines VCC undervoltage detection, MR low assertion, and WDI timeout - all triggering a guaranteed-valid active-high RESET output down to VCC = 1.1V.
This device belongs to the MAX6864–MAX6869 series with L-suffix watchdog (95–487s min/typ/max), D2 reset timeout (40–80ms), and 39-threshold suffix (3.802V–3.998V). Unlike MAX6861–MAX6863, it lacks CT pin; unlike MAX6854/MAX6855, it includes WDI and fixed active-high push-pull RESET.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Current | 170nA typ at +25°C - enables multi-year battery life in coin-cell-powered devices like patient monitors. |
| Reset Threshold | 3.9V (3.802V–3.998V) - factory-trimmed to supervise 3.3V or 3.6V system rails with margin against dropout. |
| Reset Timeout | 40ms min (D2 option) - ensures µP completes power stabilization before release from reset. |
| Watchdog Timeout | 209s typ (L-suffix) - supports long idle intervals in low-duty-cycle sensor nodes without spurious resets. |
| VCC Validity Range | 1.1V to 5.5V - guarantees RESET remains valid through deep brownout, critical for safe shutdown sequencing. |
| Output Type | Active-high push-pull RESET - drives µP reset pin directly without external pullup, reducing BOM count. |
| MR Input | Active-low with 10kΩ internal pullup - accepts CMOS logic or momentary switch; no external components needed. |
Pinout & Package
Package: 5-pin SOT23-5, lead-free, -40°C to +85°C operating range.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET | Active-high push-pull reset output; sinks/source up to 1.2mA; referenced to VCC; asserts high during fault conditions. |
| 2 | GND | Ground reference for all internal circuits; must connect to system ground plane with low-impedance path. |
| 3 | MR | Active-low manual reset input; internally pulled up to VCC (10kΩ); triggers reset when pulled ≤0.3×VCC. |
| 4 | WDI | Watchdog input; edge-sensitive (rising/falling); clears internal timer on transition; rejects <200ns glitches. |
| 5 | VCC | Main supply input; monitored for undervoltage; requires 0.1µF ceramic bypass to GND near pin. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low ICC | 170nA typical supply current enables >10-year operation on CR2032 in always-on wearable sensors. |
| Guaranteed RESET validity | RESET remains functional down to VCC = 1.1V - ensures deterministic behavior during deep brownout. |
| Watchdog immunity | Clears on any WDI edge (150ns min pulse width); prevents false timeouts from noise or slow edges. |
| No external components | Integrated MR pullup, precision voltage reference, and timing elements eliminate discrete BOM items. |
| Transient immunity | Immune to VCC glitches ≤40µs at 100mV overdrive - avoids spurious resets in noisy automotive or industrial environments. |
Applications
| Glucose Monitoring Systems | Patient Vital Sign Monitors |
|---|---|
Use Scenario: Continuous glucose meters powered by single coin-cell batteries requiring multi-year shelf life and reliable cold-start behavior. IC Role / Device Role / Timing Role: Supervises 3.3V rail, asserts RESET on power-up/brownout, and uses 209s watchdog to detect firmware hangs during sensor calibration cycles. Use Value: 170nA ICC extends battery life beyond 5 years; 3.9V threshold matches LDO output tolerance; active-high RESET simplifies interface to low-voltage µP reset pin. |
Use Scenario: Portable ECG or SpO₂ monitors used in home healthcare with intermittent usage and strict safety-critical reset reliability. IC Role / Device Role / Timing Role: Provides fail-safe reset supervision for ARM Cortex-M0 host MCU, combining VCC monitoring, MR button, and long-interval watchdog to catch frozen states. Use Value: Guaranteed RESET validity to 1.1V ensures safe shutdown during battery depletion; D2 timeout (40ms) aligns with µP oscillator startup time. |
| Low-Power Wireless Sensor Nodes | Industrial Handheld Terminals |
Use Scenario: Battery-operated LoRaWAN temperature/humidity nodes deployed in remote locations with infrequent wake-ups. IC Role / Device Role / Timing Role: Resets the µP if VCC sags during RF transmission or if firmware fails to toggle WDI within 209s - preventing silent data loss. Use Value: L-suffix watchdog provides long timeout without sacrificing current; SOT23-5 footprint minimizes PCB area in space-constrained modules. |
Use Scenario: Ruggedized barcode scanners or asset trackers subjected to vibration, ESD, and voltage transients in warehouse environments. IC Role / Device Role / Timing Role: Detects VCC dips caused by motor switching noise, asserts RESET to prevent corrupted memory writes, and filters MR inputs against mechanical bounce. Use Value: 40µs VCC transient immunity prevents false resets; MR glitch rejection (200ns) eliminates switch-contact noise issues. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6864UK39D2L+T | Same 3.9V threshold, D2 timeout, L-watchdog, but active-low push-pull RESET output. | Requires inverted reset logic on µP side or level-shifting; not drop-in for active-high designs. | Select when host µP reset pin is active-low and board layout cannot accommodate signal inversion. |
| TPS3837K33DBVR | 3.08V fixed threshold, 200ms timeout, no watchdog, 1.6µA ICC - higher current, no WDI functionality. | Suitable only for basic power-on reset; cannot replace MAX6865UK39D2L+T in watchdog-dependent systems. | Choose only for cost-sensitive, non-watchdog applications where 3.08V threshold suffices and µA-level current is acceptable. |
Compared with MAX6864UK39D2L+T, the MAX6865UK39D2L+T saves board space by eliminating need for external inverter; versus TPS3837K33DBVR, it delivers 10× lower ICC and full watchdog capability - essential for battery longevity and firmware safety in medical IoT.
Availability
MAX6865UK39D2L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, low-power wireless sensor nodes, and industrial handheld terminals requiring stable component supply across extended production lifecycles.
Supply support for MAX6865UK39D2L+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 power, sensing, and timing applications in industrial, medical, and communications markets.
The MAX6864–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-critical medical and portable electronics - prioritizing nanoscale ICC, guaranteed brownout behavior, and robust watchdog supervision.
FAQ
What is the exact reset threshold voltage of the MAX6865UK39D2L+T?
The MAX6865UK39D2L+T has a factory-trimmed reset threshold of 3.9V, with guaranteed range 3.802V to 3.998V (±2.5%) across -40°C to +85°C. This value is defined by the "39" suffix per Table 2 in the datasheet and applies to VCC falling edge detection. The device asserts RESET when VCC drops below this threshold and holds it for the D2 timeout period (40ms min) after VCC recovers.
Does the MAX6865UK39D2L+T support active-low reset output?
No, the MAX6865UK39D2L+T provides only active-high push-pull RESET output (Pin 1). It is part of the MAX6865 variant group, distinct from MAX6864 (active-low) and MAX6866 (open-drain). Attempting to use it in an active-low design requires external inversion or redesign - the internal output stage is fixed and not configurable.
What is the watchdog timeout behavior of the MAX6865UK39D2L+T?
The MAX6865UK39D2L+T features L-suffix watchdog timeout: 95s (min), 209s (typ), and 487s (max) - triggered if WDI remains static (high or low) beyond this interval. The timer clears on any WDI edge (rising or falling), including pulses ≥150ns, and pauses while RESET is asserted. This behavior is confirmed in Tables 3 and 4 and Figure 3 of the datasheet.
Can the MAX6865UK39D2L+T operate with VCC below 1.8V?
Yes, the MAX6865UK39D2L+T operates from VCC = 1.1V to 5.5V. Its RESET output remains valid down to 1.1V, and supply current is specified as low as 170nA at VCC = 1.8V. Below 1.1V, RESET may become indeterminate - but the device continues to monitor and will reassert RESET if VCC recovers above threshold, making it suitable for deep-brownout recovery in energy-harvesting systems.
Is the MR input of the MAX6865UK39D2L+T compatible with 1.8V logic?
Yes, the MR input of the MAX6865UK39D2L+T accepts standard CMOS logic levels: VIH ≥ 0.7×VCC and VIL ≤ 0.3×VCC. At VCC = 1.8V, this means MR is recognized as high above 1.26V and low below 0.54V - fully compatible with 1.8V I/O domains. Its internal 10kΩ pullup ensures defined state when left floating, and MR pulse width requirement is only 1µs minimum.
MAX6865UK39D2L+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:
- 40ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
MAX6865UK39D2L+T FAQ
1.How can I place an order for MAX6865UK39D2L+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6865UK39D2L+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 MAX6865UK39D2L+T reliable?
The price and inventory of MAX6865UK39D2L+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6865UK39D2L+T is usually 5 days.
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Once your MAX6865UK39D2L+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 MAX6865UK39D2L+T?
For technical support, including MAX6865UK39D2L+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6865UK39D2L+T requirements.
6.How does Aetrix verify that MAX6865UK39D2L+T is sourced from the original manufacturer or authorized distributors?
All MAX6865UK39D2L+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 MAX6865UK39D2L+T meets industry standards.
7.What is the process for return or replacement of MAX6865UK39D2L+T?
All MAX6865UK39D2L+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6865UK39D2L+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 MAX6865UK39D2L+T part is unused and in its original packaging.
Return procedure for MAX6865UK39D2L+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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