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Analog Devices Inc./Maxim Integrated MAX6865UK21D4L+T
- Part No.:
- MAX6865UK21D4L+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6865UK21D4L+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,959
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Product details
Overview
The MAX6865UK21D4L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (reset threshold = +2.100V), manual reset input (MR), and watchdog timer (timeout = 209s typ) with ultra-low 170nA typical supply current. It asserts an active-low push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 1200ms min after recovery - ideal for battery-powered glucose monitors and portable medical devices requiring long-term reliability and low quiescent power.
For engineers reviewing the MAX6865UK21D4L+T datasheet, MAX6865UK21D4L+T pinout, MAX6865UK21D4L+T application, or MAX6865UK21D4L+T equivalent, key selection criteria include its factory-trimmed 2.100V reset threshold, 1200ms minimum reset timeout, 209s watchdog period, guaranteed reset validity down to VCC = +1.1V, and immunity to short VCC transients - all critical for robust power-up sequencing and firmware fault recovery in space-constrained, energy-sensitive systems.
Technical Context
This device integrates a precision bandgap-based voltage monitor, a digital watchdog timer with edge-triggered WDI input, and a programmable reset timeout generator. Its internal 10kΩ MR pullup and glitch-rejecting MR input (200ns rejection) enable direct switch interfacing without external components.
The watchdog logic clears on any rising or falling edge at WDI and expires only if WDI remains static beyond 209s (typ); reset assertion persists for the full 1200ms timeout regardless of subsequent WDI activity - ensuring deterministic recovery from hung firmware states.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | +2.100V (factory-trimmed, ±2.5% tolerance; ensures reliable detection of 2.1V supply brownout) |
| Supply Current | 170nA typ at +2.5V (enables >10-year battery life in coin-cell–powered devices) |
| Reset Timeout | 1200ms min (D4 option; guarantees µP initialization completes before release) |
| Watchdog Timeout | 209s typ (L suffix; suitable for slow-cycle embedded control loops) |
| VCC Validity Range | Reset asserted valid down to VCC = +1.1V (supports operation through deep brownout) |
| MR Input Logic | Active-low, internally pulled up to VCC via 10kΩ (allows direct connection to momentary switch to GND) |
| WDI Pulse Width | 150ns min (ensures compatibility with low-duty-cycle MCU GPIO toggling) |
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 1.2mA at VCC ≥ 2.38V; no external pullup required |
| 2 | GND | Ground reference for all internal circuits; must be connected to system ground plane |
| 3 | MR | Active-low manual reset input; internally pulled up to VCC; 200ns glitch rejection prevents spurious resets |
| 4 | WDI | Watchdog input; edge-sensitive (rising/falling); clears internal timer on each transition; 20nA max leakage |
| 5 | VCC | Supply voltage input (1.2V to 5.5V); monitored for reset generation; bypass with 0.1µF to GND |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low ICC | 170nA typical supply current enables multi-year operation on CR2032 batteries |
| Guaranteed reset at low VCC | RESET remains valid down to VCC = +1.1V, supporting brownout resilience in low-voltage systems |
| No external components | Integrated 10kΩ MR pullup, no timing capacitors or resistors needed for basic operation |
| Watchdog edge sensitivity | Detects 150ns WDI pulses, allowing minimal GPIO toggle overhead in firmware watchdog routines |
| Transient immunity | Immune to ≤40µs VCC glitches at 100mV overdrive, reducing false resets in noisy environments |
Applications
| Portable Glucose Monitors | Patient Vital Sign Loggers |
|---|---|
|
Use Scenario: Continuous glucose sensing with Bluetooth LE transmission powered by single CR2032 cell. IC Role / Device Role / Timing Role: Supervises 2.1V LDO output; triggers hardware reset on brownout or firmware hang; provides 1200ms reset hold for BLE controller initialization. Use Value: Prevents data corruption during low-battery shutdown and ensures automatic recovery from sensor firmware lockups without user intervention. |
Use Scenario: Wearable ECG patch recording heart rate and SpO₂ for 72-hour clinical studies. IC Role / Device Role / Timing Role: Monitors main 3.3V supply; asserts reset if supply dips below 2.1V or if MCU fails to service watchdog within 209s. Use Value: Guarantees data integrity across multi-day deployments by enforcing periodic firmware sanity checks and safe power-cycle recovery. |
| Handheld Medical Diagnostic Tools | Low-Power Industrial Sensor Nodes |
|
Use Scenario: Battery-operated ultrasound probe with embedded ARM Cortex-M0+ processor. IC Role / Device Role / Timing Role: Provides 2.100V reset threshold aligned with SoC VDDIO spec; uses MR for technician-initiated calibration reset; leverages 209s watchdog for long-duration acquisition sequences. Use Value: Eliminates need for external RC timing networks while meeting IEC 62304 Class B reset timing requirements for medical firmware. |
Use Scenario: LoRaWAN soil moisture node deployed in remote agricultural fields for 5+ years. IC Role / Device Role / Timing Role: Supervises 3.0V LiSOCl₂ battery output; detects undervoltage during cold-weather discharge; watchdog enforces firmware watchdog cycle every ~3.5 minutes. Use Value: Extends field lifetime by minimizing quiescent drain (170nA) while ensuring autonomous recovery from EEPROM write failures or RF stack hangs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6864UK21D4L+T | No CT pin; identical reset threshold (2.100V), timeout (1200ms), and watchdog (209s), but lacks pin-selectable timeout option | Suitable where fixed timeout suffices; not usable if design requires runtime timeout reconfiguration | Select MAX6864UK21D4L+T when CT functionality is unnecessary and cost optimization is prioritized |
| TPS3836K21DBVR | Higher 4.5µA supply current; 2.13V reset threshold; no integrated watchdog; 200ms fixed reset timeout | Limited to basic voltage monitoring; cannot replace watchdog functionality in safety-critical firmware supervision | Choose TPS3836K21DBVR only for non-watchdog applications where ultra-low ICC is not required |
Compared with MAX6864UK21D4L+T, the MAX6865UK21D4L+T adds no functional redundancy but maintains identical core supervision specs while enabling future design flexibility via CT pin; versus TPS3836K21DBVR, it delivers 26× lower ICC and integrated watchdog - essential for battery longevity and autonomous fault recovery.
Availability
MAX6865UK21D4L+T is available at Aetrix Electronics and suitable for portable medical diagnostics, battery-powered patient monitors, and industrial wireless sensor nodes requiring stable component supply, long-lifecycle support, and guaranteed lead-free compliance.
Supply support for MAX6865UK21D4L+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 high-performance analog and mixed-signal ICs for power, sensing, and interface applications in industrial, medical, and communications markets.
The MAX6854–MAX6869 family targets ultra-low-power microprocessor supervision in battery-constrained systems, emphasizing nanopower operation, precise voltage thresholds, and integrated watchdog functionality for firmware reliability.
FAQ
What is the exact reset threshold voltage of the MAX6865UK21D4L+T?
The MAX6865UK21D4L+T has a factory-trimmed reset threshold of +2.100V, with guaranteed tolerance of ±2.5% over the -40°C to +85°C temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "21" corresponds to 2.100V nominal. The device asserts reset when VCC falls below this threshold and holds reset for the full 1200ms timeout after VCC recovers above it.
Does the MAX6865UK21D4L+T include a watchdog timer, and what is its timeout period?
Yes, the MAX6865UK21D4L+T includes a watchdog timer with a typical timeout period of 209 seconds, indicated by the "L" suffix in the part number. The watchdog monitors the WDI input and triggers reset if no edge (rising or falling) occurs within that period. The timer clears on each WDI transition, MR assertion, or reset assertion - ensuring reliable detection of firmware hangs in long-cycle embedded applications.
What is the function of Pin 4 (WDI) on the MAX6865UK21D4L+T?
Pin 4 on the MAX6865UK21D4L+T is the Watchdog Input (WDI), an edge-sensitive digital input that clears the internal watchdog timer on every rising or falling transition. It accepts CMOS-level signals, draws ≤20nA, and detects pulses as short as 150ns. If WDI remains static longer than 209s (typ), the watchdog expires and forces a reset - making it essential for validating ongoing firmware execution in safety-critical systems.
Is the MAX6865UK21D4L+T compatible with 1.8V systems?
Yes, the MAX6865UK21D4L+T operates across VCC = 1.2V to 5.5V and guarantees valid reset assertion down to VCC = +1.1V. Its 2.100V reset threshold is fully compatible with 1.8V systems when monitoring a dedicated 2.1V LDO output or using external resistor-divider feedback - and its 170nA supply current minimizes loading on low-voltage rails, making it suitable for modern ultra-low-power microcontroller domains.
What package type and lead finish does the MAX6865UK21D4L+T use?
The MAX6865UK21D4L+T uses a 5-pin SOT23-5 package with lead-free (RoHS-compliant) finish, indicated by the "+T" suffix. It features standard SOT23 footprint dimensions (2.9mm × 1.6mm × 1.1mm height), thermal pad omitted, and is optimized for reflow soldering. The package supports automated assembly and meets JEDEC MS-012 standards for mechanical and thermal reliability.
MAX6865UK21D4L+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:
- 2.1V
- 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
MAX6865UK21D4L+T FAQ
1.How can I place an order for MAX6865UK21D4L+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6865UK21D4L+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 MAX6865UK21D4L+T reliable?
The price and inventory of MAX6865UK21D4L+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6865UK21D4L+T is usually 5 days.
3.What payment methods are accepted for MAX6865UK21D4L+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6865UK21D4L+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6865UK21D4L+T?
MAX6865UK21D4L+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6865UK21D4L+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 MAX6865UK21D4L+T?
For technical support, including MAX6865UK21D4L+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6865UK21D4L+T requirements.
6.How does Aetrix verify that MAX6865UK21D4L+T is sourced from the original manufacturer or authorized distributors?
All MAX6865UK21D4L+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 MAX6865UK21D4L+T meets industry standards.
7.What is the process for return or replacement of MAX6865UK21D4L+T?
All MAX6865UK21D4L+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6865UK21D4L+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 MAX6865UK21D4L+T part is unused and in its original packaging.
Return procedure for MAX6865UK21D4L+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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