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Analog Devices Inc./Maxim Integrated MAX6865UK39D3L+T
- Part No.:
- MAX6865UK39D3L+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6865UK39D3L+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,073
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Product details
Overview
The MAX6865UK39D3L+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%), 300ms 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 battery-powered glucose monitors and portable medical devices.
For engineers reviewing the MAX6865UK39D3L+T datasheet, MAX6865UK39D3L+T pinout, MAX6865UK39D3L+T application, or MAX6865UK39D3L+T equivalent, this page delivers verified specifications, validated pin functions, confirmed reset timing behavior, and real-world design context for low-power embedded systems requiring guaranteed reset validity down to VCC = +1.1V.
Technical Context
The MAX6865UK39D3L+T implements a precision voltage monitor with hysteresis (0.5% of VTH), a digital watchdog timer that clears on any WDI edge and expires if WDI remains static >209s (typ), and a fixed 300ms reset timeout after VCC recovery or MR deassertion. Its internal 10kΩ MR pullup and glitch rejection (200ns) enable direct switch interfacing without external components.
This device belongs to the MAX6864–MAX6869 series with active-high push-pull RESET output, manual reset input (MR), and watchdog input (WDI). It operates across -40°C to +85°C, guarantees RESET validity down to VCC = +1.1V, and is immune to VCC transients ≤40µs at 100mV overdrive - critical for noisy battery-supplied environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Current | 170nA typ at VCC = 1.8V; enables multi-year operation on coin-cell batteries. |
| Reset Threshold | 3.900V ±2.5% (VTH = 3.802V to 3.998V); factory-trimmed for precise brownout detection. |
| Reset Timeout | 300ms min (D3 option); ensures µP initialization completes before release. |
| Watchdog Timeout | 209s typ (L suffix); supports long-loop firmware without spurious resets. |
| VCC Range | 1.2V to 5.5V; valid reset assertion guaranteed down to VCC = +1.1V. |
| Output Type | Active-high push-pull RESET; drives directly into µP reset pin without pullup. |
| MR Input | Active-low with 10kΩ internal pullup; accepts CMOS logic or momentary switch to GND. |
Pinout & Package
Package: 5-pin SOT23-5, lead-free, surface-mount. Pin 1 is RESET (active-high push-pull), Pin 2 is GND, Pin 3 is MR (active-low manual reset), Pin 4 is WDI (watchdog input), Pin 5 is VCC (supply voltage input).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET | Active-high push-pull output; asserts high during fault conditions and holds for 300ms after recovery. |
| 2 | GND | Ground reference for all internal circuits; must connect to system ground plane. |
| 3 | MR | Active-low manual reset input; internally pulled up to VCC (10kΩ); initiates reset when pulled low ≥1µs. |
| 4 | WDI | Watchdog input; rising or falling edge clears internal timer; static state >209s triggers reset. |
| 5 | VCC | Supply voltage input (1.2V–5.5V); monitored for brownout; bypass with 0.1µF to GND. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low ICC | 170nA typical supply current extends battery life in portable medical devices beyond 5 years. |
| Guaranteed reset validity | RESET remains functional down to VCC = +1.1V - ensures reliable reset assertion during deep brownout. |
| No external components | Integrated MR pullup, precision voltage reference, and watchdog timer eliminate BOM parts and layout area. |
| Transient immunity | Immune to VCC glitches ≤40µs at 100mV overdrive - prevents false resets in electrically noisy environments. |
| Watchdog edge sensitivity | Detects WDI pulses as short as 150ns - supports high-frequency software heartbeat signaling. |
Applications
| Glucose Monitoring Systems | Patient Vital Sign Monitors |
|---|---|
Use Scenario: Continuous glucose monitoring (CGM) patch worn for 7–14 days on lithium coin-cell power. IC Role / Device Role / Timing Role: Supervises VCC during battery discharge, asserts RESET on brownout, and triggers watchdog reset if firmware hangs during sensor calibration. Use Value: Prevents undetected firmware lockup and ensures safe restart before erroneous glucose readings are transmitted. |
Use Scenario: Portable ECG/SpO₂ monitor operating from AA alkaline cells in home healthcare settings. IC Role / Device Role / Timing Role: Monitors 3.3V rail derived from DC-DC converter; provides 300ms reset hold time and 209s watchdog timeout aligned with clinical measurement cycles. Use Value: Guarantees µP reset integrity during battery swap and eliminates risk of silent failure during critical patient data acquisition. |
| Industrial Handheld Scanners | Low-Power Wireless Sensors |
Use Scenario: Rugged barcode scanner powered by rechargeable Li-ion, subjected to ESD and supply noise during motor activation. IC Role / Device Role / Timing Role: Provides MR-initiated reset via button press and detects VCC droop during motor surge; uses push-pull RESET to drive ARM Cortex-M0+ reset pin directly. Use Value: Eliminates need for external RC network or level shifter while maintaining immunity to 40µs supply transients. |
Use Scenario: LoRaWAN soil moisture node deployed outdoors, powered by primary Li-SOCl₂ cell with 10-year target lifetime. IC Role / Device Role / Timing Role: Supervises 3.0V LDO output; asserts RESET if voltage falls below 3.9V threshold during cold-temperature discharge; watchdog verifies periodic sensor readout execution. Use Value: Enables deterministic recovery from firmware stalls without increasing quiescent current beyond 170nA. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6864UK39D3L+T | Same 3.9V threshold, 300ms timeout, and 209s watchdog, but features active-low push-pull RESET output. | Requires inverted reset logic on µP side; not drop-in compatible where active-high reset is mandatory. | Select when host µP accepts active-low reset and board layout already accommodates pullup-free interface. |
| TPS3838K33DBVR | 3.3V fixed threshold, no watchdog, 200ms timeout, 1.2µA ICC - 7× higher supply current than MAX6865UK39D3L+T. | Suitable only for non-watchdog applications with higher VCC margin; cannot replace watchdog functionality. | Choose only if cost is primary constraint and 209s watchdog monitoring is unnecessary. |
Compared with MAX6865UK39D3L+T, MAX6864UK39D3L+T offers identical supervision specs but inverted RESET polarity, while TPS3838K33DBVR lacks watchdog capability and consumes significantly more current - making MAX6865UK39D3L+T the sole choice for ultra-low-power, watchdog-enabled designs requiring active-high reset.
Availability
MAX6865UK39D3L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, industrial handheld scanners, and low-power wireless sensors requiring stable component supply across extended product lifecycles.
Supply support for MAX6865UK39D3L+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 interface applications in industrial, medical, and automotive markets.
The MAX6864–MAX6869 family was engineered specifically for nanopower, battery-critical systems requiring combined voltage monitoring, manual reset, and long-interval watchdog supervision - targeting portable medical and IoT endpoints.
FAQ
What is the exact reset threshold voltage of the MAX6865UK39D3L+T?
The MAX6865UK39D3L+T has a factory-trimmed reset threshold of 3.900V with ±2.5% tolerance (3.802V to 3.998V), as defined by the "39" suffix per Maxim's Threshold Suffix Guide. This value is guaranteed over -40°C to +85°C and ensures precise brownout detection for 3.3V and 3.6V systems. The MAX6865UK39D3L+T maintains this accuracy without external calibration.
Does the MAX6865UK39D3L+T require external components for basic operation?
No, the MAX6865UK39D3L+T requires no external components for core functionality: it includes an internal 10kΩ pullup on MR, precision voltage reference, and watchdog timer. Only a 0.1µF ceramic capacitor from VCC to GND is recommended for noise suppression. No pullup/pulldown resistors are needed for RESET due to its active-high push-pull output.
How does the watchdog timer in the MAX6865UK39D3L+T behave during reset assertion?
While RESET is asserted (high), the MAX6865UK39D3L+T watchdog timer is disabled and does not count. It resumes timing only after RESET deasserts. This prevents race conditions during recovery and ensures the watchdog monitors only active firmware execution - a behavior confirmed in the device's functional diagram and timing figures.
What is the minimum VCC voltage at which MAX6865UK39D3L+T guarantees valid RESET output?
The MAX6865UK39D3L+T guarantees RESET output validity down to VCC = +1.1V, as explicitly specified in the Electrical Characteristics table. Below this voltage, RESET may become indeterminate. This specification enables reliable reset assertion during deep battery discharge in medical and portable applications.
Can the MAX6865UK39D3L+T be used with a microcontroller that requires active-low reset?
No - the MAX6865UK39D3L+T provides only active-high push-pull RESET output. For active-low reset requirements, use the pin-compatible MAX6864UK39D3L+T (same threshold, timeout, and watchdog) or add an inverter stage. Direct connection to an active-low reset pin would invert system behavior and cause malfunction.
MAX6865UK39D3L+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:
- 150ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
MAX6865UK39D3L+T FAQ
1.How can I place an order for MAX6865UK39D3L+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6865UK39D3L+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 MAX6865UK39D3L+T reliable?
The price and inventory of MAX6865UK39D3L+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6865UK39D3L+T is usually 5 days.
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Once your MAX6865UK39D3L+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 MAX6865UK39D3L+T?
For technical support, including MAX6865UK39D3L+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6865UK39D3L+T requirements.
6.How does Aetrix verify that MAX6865UK39D3L+T is sourced from the original manufacturer or authorized distributors?
All MAX6865UK39D3L+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 MAX6865UK39D3L+T meets industry standards.
7.What is the process for return or replacement of MAX6865UK39D3L+T?
All MAX6865UK39D3L+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6865UK39D3L+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 MAX6865UK39D3L+T part is unused and in its original packaging.
Return procedure for MAX6865UK39D3L+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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