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Analog Devices Inc./Maxim Integrated MAX6865UK25D4S+T
- Part No.:
- MAX6865UK25D4S+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6865UK25D4S+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,008
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Product details
Overview
The MAX6865UK25D4S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring, manual reset input (MR), and watchdog timer (WDI) functionality. It asserts an active-low push-pull RESET output when VCC drops below 2.500V (factory-trimmed threshold), MR is pulled low, or the watchdog times out after 209s (typ). Designed for ultra-low-power systems, it draws only 170nA (typ) supply current and guarantees valid reset down to VCC = +1.1V - ideal for battery-powered glucose monitors and portable medical devices.
For engineers reviewing the MAX6865UK25D4S+T datasheet, MAX6865UK25D4S+T pinout, MAX6865UK25D4S+T application, or MAX6865UK25D4S+T equivalent, key selection criteria include its 2.5V reset threshold, 1200ms minimum reset timeout (D4), 209s watchdog period (S suffix), push-pull active-low reset output, and immunity to short VCC transients - all validated across –40°C to +85°C.
Technical Context
This device implements a dual-trigger reset architecture: one path responds to VCC falling below 2.500V ±2.5%, the second to MR assertion, and the third to WDI inactivity exceeding 209s (typ). The internal reset timeout timer (1200ms min) begins only after VCC rises above threshold *and* MR deasserts - ensuring robust power-up sequencing.
The watchdog circuit clears on any WDI edge (rising or falling) and remains disabled while RESET is asserted. Its 150ns pulse-width detection capability enables reliable monitoring of fast microcontroller I/O toggling, with guaranteed operation over full temperature range and supply voltage (1.2V–5.5V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold Voltage | 2.500V ±2.5% - factory-trimmed for precise brownout detection at nominal 2.5V rail |
| Supply Current (typ) | 170nA at VCC = 1.8V - enables multi-year battery life in always-on portable medical sensors |
| Reset Timeout Period | 1200ms minimum - ensures µP completes full initialization before release from reset |
| Watchdog Timeout | 209s typical (S suffix) - supports long idle intervals in low-duty-cycle embedded firmware |
| RESET Output Type | Push-pull active-low - eliminates need for external pullup; drives directly into CMOS reset inputs |
| VCC Validity Range | Guaranteed RESET validity down to VCC = +1.1V - maintains deterministic reset behavior during deep brownout |
| MR Input Pullup | Internal 10kΩ to VCC - enables momentary switch interface without external components |
Pinout & Package
Package: 5-pin SOT23-5, lead-free, surface-mount, footprint compatible with industry-standard 5-pin SOT23 layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET | Active-low push-pull reset output - sinks current when asserted; no external pullup required |
| 2 | GND | Ground reference - must be connected to system ground plane for noise immunity and timing accuracy |
| 3 | MR | Active-low manual reset input - internally pulled up to VCC; accepts CMOS logic levels or open-drain signals |
| 4 | WDI | Watchdog input - detects rising/falling edges; resets internal timer on each transition; immune to <150ns glitches |
| 5 | VCC | Supply voltage input - monitored for reset generation; requires 0.1µF bypass capacitor to GND per datasheet |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low ICC | 170nA typical supply current enables >10-year battery life in coin-cell-powered devices |
| Reset threshold hysteresis | 0.5% of VTH - prevents chatter during slow VCC recovery near threshold |
| Glitch rejection | 200ns MR input filtering - rejects EMI-induced false resets without compromising responsiveness |
| No external components | Self-contained supervision - requires only 0.1µF VCC bypass cap; no resistors, capacitors, or timing parts needed |
| VCC transient immunity | Immune to 100mV VCC glitches ≤40µs - avoids spurious resets in noisy automotive or industrial environments |
Applications
| Portable Glucose Monitors | Patient Vital Sign Loggers |
|---|---|
Use Scenario: Continuous glucose sensing with intermittent wireless transmission and long sleep cycles between measurements. IC Role / Device Role / Timing Role: Supervises 3.3V MCU power rail and triggers hardware reset if firmware hangs during BLE connection or sensor calibration. Use Value: 209s watchdog timeout aligns with maximum allowable sensor read interval; 170nA ICC extends CR2032 battery life beyond 3 years. |
Use Scenario: Wearable ECG/SpO₂ patch recording data every 5 minutes and transmitting hourly via Bluetooth Low Energy. IC Role / Device Role / Timing Role: Monitors 2.5V analog front-end and MCU supply; asserts reset on brownout or missed WDI toggle during deep-sleep wake-up sequence. Use Value: 2.500V threshold matches precision LDO output; 1200ms reset timeout ensures ADC and radio initialization complete before firmware resumes. |
| Handheld Medical Diagnostics | Low-Power Industrial Sensors |
Use Scenario: Battery-operated ultrasound probe with touch interface and real-time image processing. IC Role / Device Role / Timing Role: Provides fail-safe reset initiation via MR button and continuous watchdog supervision of ARM Cortex-M4 firmware execution. Use Value: Push-pull RESET drives high-capacitance display controller reset line directly; MR internal 10kΩ pullup eliminates BOM cost and layout area. |
Use Scenario: Wireless temperature/humidity node deployed in remote locations with 10-year battery target. IC Role / Device Role / Timing Role: Supervises 1.8V MCU and RF transceiver supply; uses WDI to verify periodic sensor reading and LoRaWAN transmission routines. Use Value: Guaranteed RESET validity to VCC = +1.1V ensures deterministic reset even as LiSOCl₂ battery discharges to end-of-life voltage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6864UK25D4S+T | Same 2.5V threshold, D4 timeout, S-watchdog, but active-high push-pull RESET output | Requires MCU with active-high reset input; incompatible with active-low reset designs without level-shifting | Select when interfacing to µPs requiring active-high reset assertion (e.g., certain STM32 variants) |
| TPS3836K25DBVR | 2.5V threshold, 1200ms timeout, no watchdog; 1.6µA ICC (vs. 170nA); SOT23-5 pin-compatible | Lacks WDI functionality; higher supply current reduces battery lifetime in always-on applications | Choose where watchdog is unnecessary and cost sensitivity outweighs ultra-low-power requirements |
Compared with MAX6864UK25D4S+T, the MAX6865UK25D4S+T provides active-low reset compatibility without external inversion; versus TPS3836K25DBVR, it delivers 9.4× lower supply current and integrated watchdog - critical for long-life, safety-critical portable medical systems.
Availability
MAX6865UK25D4S+T is available at Aetrix Electronics and suitable for portable medical diagnostics, battery-powered patient monitors, and low-power industrial sensor nodes requiring stable component supply across extended product lifecycles.
Supply support for MAX6865UK25D4S+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.
The MAX6865UK25D4S+T belongs to Maxim's nanopower µP supervisory family, engineered specifically for ultra-low-power, safety-critical portable medical and battery-constrained embedded systems requiring guaranteed reset integrity and long-term reliability.
FAQ
What is the exact reset threshold voltage of the MAX6865UK25D4S+T?
The MAX6865UK25D4S+T has a factory-trimmed reset threshold voltage of 2.500V ±2.5%, as indicated by the "25" suffix in the part number. This value is guaranteed over the full operating temperature range (–40°C to +85°C) and supply voltage (1.2V to 5.5V), with hysteresis of 0.5% of VTH to prevent oscillation during slow VCC recovery. The MAX6865UK25D4S+T datasheet specifies this parameter in the Electrical Characteristics table under VTH.
Does the MAX6865UK25D4S+T support both manual reset and watchdog functions simultaneously?
Yes, the MAX6865UK25D4S+T fully supports concurrent manual reset (MR) and watchdog (WDI) functionality. Assertion of either MR low or WDI inactivity beyond 209s (typ) will trigger the reset output. The internal timer holds RESET asserted for the full 1200ms minimum timeout period after both VCC exceeds threshold *and* MR deasserts *and* WDI activity resumes - ensuring deterministic behavior in complex fault scenarios. This dual-trigger capability is confirmed in the MAX6865UK25D4S+T functional diagram and timing specifications.
What is the watchdog timeout period for the MAX6865UK25D4S+T, and how is it selected?
The MAX6865UK25D4S+T features a watchdog timeout period of 209s (typ), denoted by the "S" suffix in the part number. This value is fixed and factory-configured - no external components or pin strapping is required to select it. The watchdog timer clears on any rising or falling edge at the WDI pin and begins counting anew upon reset deassertion. The 209s timeout is validated across temperature and supply voltage per the MAX6865UK25D4S+T Electrical Characteristics table (tWD parameter).
Is the MAX6865UK25D4S+T pin-compatible with other devices in the MAX68xx family?
The MAX6865UK25D4S+T uses the standard 5-pin SOT23-5 package with identical pinout to MAX6864/MAX6866/MAX6867/MAX6869 variants: Pin 1 = RESET, Pin 2 = GND, Pin 3 = MR, Pin 4 = WDI, Pin 5 = VCC. However, it is not pin-compatible with MAX6861–MAX6863 (which use CT instead of WDI on Pin 4) or MAX6854–MAX6856 (which lack WDI entirely). This specific pin mapping is documented in the MAX6865UK25D4S+T Pin Description section and Pin Configurations diagram.
What is the minimum supply voltage at which the MAX6865UK25D4S+T guarantees valid RESET output?
The MAX6865UK25D4S+T guarantees valid RESET output down to VCC = +1.1V, as explicitly stated in the datasheet's "Guaranteed Reset Valid to VCC = +1.1V" feature and confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables. Below this voltage, RESET may become indeterminate - though the device remains functional and will reassert RESET correctly once VCC recovers above 1.1V. This specification ensures reliable operation during deep brownout conditions common in aging primary batteries.
MAX6865UK25D4S+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:
- 2.5V
- 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
MAX6865UK25D4S+T FAQ
1.How can I place an order for MAX6865UK25D4S+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6865UK25D4S+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 MAX6865UK25D4S+T reliable?
The price and inventory of MAX6865UK25D4S+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6865UK25D4S+T is usually 5 days.
3.What payment methods are accepted for MAX6865UK25D4S+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6865UK25D4S+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6865UK25D4S+T?
MAX6865UK25D4S+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6865UK25D4S+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 MAX6865UK25D4S+T?
For technical support, including MAX6865UK25D4S+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6865UK25D4S+T requirements.
6.How does Aetrix verify that MAX6865UK25D4S+T is sourced from the original manufacturer or authorized distributors?
All MAX6865UK25D4S+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 MAX6865UK25D4S+T meets industry standards.
7.What is the process for return or replacement of MAX6865UK25D4S+T?
All MAX6865UK25D4S+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6865UK25D4S+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 MAX6865UK25D4S+T part is unused and in its original packaging.
Return procedure for MAX6865UK25D4S+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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