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Analog Devices Inc./Maxim Integrated MAX6865UK21D2L+T
- Part No.:
- MAX6865UK21D2L+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6865UK21D2L+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,667
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Product details
Overview
The MAX6865UK21D2L+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-high push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 40ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.
For engineers reviewing the MAX6865UK21D2L+T datasheet, MAX6865UK21D2L+T pinout, MAX6865UK21D2L+T application, or MAX6865UK21D2L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), fixed 40ms reset timeout, and compatibility with 1.2V–5.5V supply rails in space-constrained portable systems.
Technical Context
This device implements a precision bandgap-based voltage monitor with ±2.5% threshold accuracy over -40°C to +85°C, paired with a temperature-stable RC-based watchdog timer that expires after 209s (typ) if WDI remains static. The internal 10kΩ MR pullup enables direct connection to momentary switches without external components.
The active-high push-pull RESET output delivers VOH ≥ 0.8×VCC at ISOURCE = 500µA (VCC ≥ 2.38V) and VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.38V), ensuring robust logic-level compatibility with modern low-voltage µPs. Reset deassertion occurs only after both VCC exceeds VTH and the 40ms timeout elapses - no race condition between power recovery and timing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | +2.100V (factory-trimmed, ±2.5% tolerance; ensures reliable brownout detection at 2.1V rail) |
| Supply Current | 170nA typ at VCC = 1.8V (enables >10-year battery life in coin-cell–powered devices) |
| Reset Timeout | 40ms min (D2 option per Table 4; guarantees µP initialization completes before release) |
| Watchdog Timeout | 209s typ (L-suffix; prevents firmware lockup in infrequently updated embedded medical firmware) |
| Operating Voltage | 1.2V to 5.5V (supports single-cell Li-ion, 3.3V, and 5V systems without level-shifting) |
| Reset Validity | Guaranteed to VCC = +1.1V (ensures deterministic reset behavior during deep brownout) |
| MR Input Logic | Active-low, internally pulled up to VCC via 10kΩ (allows direct switch-to-GND interface; no external resistor needed) |
Pinout & Package
Package: 5-pin SOT23-5, lead-free, surface-mount. Compact 2.9mm × 1.6mm footprint with 0.95mm height - optimized for PCB area-constrained portable designs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET | Active-high push-pull output; drives high during fault conditions; sinks/source capability defined per electrical specs |
| 2 | GND | Ground reference for all internal circuitry; must connect to system ground plane with low-inductance path |
| 3 | MR | Active-low manual reset input; internally pulled up to VCC; accepts CMOS-compatible logic levels |
| 4 | WDI | Watchdog input; edge-sensitive (rising/falling); clears internal timer on transition; immune to <150ns glitches |
| 5 | VCC | Supply voltage input and monitored rail; requires 0.1µF ceramic bypass capacitor to GND for noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low ICC | 170nA typical supply current extends battery life in always-on medical sensors |
| No external components | Integrated MR pullup, precision voltage reference, and RC watchdog eliminate BOM cost and layout area |
| VCC transient immunity | Immune to 40µs VCC glitches at 100mV overdrive - prevents spurious resets in noisy environments |
| Guaranteed reset at low VCC | RESET remains valid down to VCC = +1.1V - critical for orderly shutdown in brownout scenarios |
| Watchdog edge sensitivity | Detects WDI transitions as short as 150ns - supports high-frequency firmware heartbeat signals |
Applications
| Glucose Monitoring Systems | Patient Vital Sign Monitors |
|---|---|
Use Scenario: Continuous glucose meters operating from CR2032 coin cells with intermittent sensor sampling and Bluetooth LE transmission. IC Role / Device Role / Timing Role: Supervises 1.8V MCU supply, triggers reset on brownout or firmware hang via WDI, and ensures safe power-down sequencing. Use Value: 170nA ICC enables >5-year battery life; 209s watchdog timeout accommodates long sensor calibration cycles without false resets. |
Use Scenario: Portable ECG/SpO₂ monitors requiring FDA-grade reliability and fail-safe boot integrity. IC Role / Device Role / Timing Role: Provides deterministic reset during AC/DC adapter switchover and detects MCU lockup during analog front-end acquisition. Use Value: Guaranteed RESET validity to VCC = +1.1V prevents undefined MCU state during battery depletion; ±2.5% VTH tolerance meets IEC 60601-1 margin requirements. |
| Handheld Medical Diagnostics | Low-Power Wearables |
Use Scenario: Battery-operated ultrasound probes with ARM Cortex-M4 MCU and analog beamforming ASICs. IC Role / Device Role / Timing Role: Monitors 3.3V system rail, asserts RESET on voltage sag during high-current pulse generation, and resets MCU if WDI stalls. Use Value: 40ms D2 reset timeout allows full PLL lock and memory initialization before firmware execution resumes. |
Use Scenario: Smart patches tracking respiration and skin impedance using sub-1V BLE SoCs. IC Role / Device Role / Timing Role: Supervises 1.2V supply derived from buck-boost converter; provides early brownout warning and watchdog safety net. Use Value: 1.2V–5.5V operating range matches ultra-low-voltage energy harvesting architectures; SOT23-5 footprint fits 8mm × 8mm wearable PCBs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6864UK21D2S+T | Same 2.100V threshold and 40ms timeout, but watchdog timeout = 3.3s (S-suffix) instead of 209s (L-suffix) | Better suited for fast-recovery systems requiring frequent watchdog refresh (e.g., real-time control loops) | Select MAX6864UK21D2S+T when shorter watchdog intervals align with firmware execution frequency |
| TPS3836K21DBVR | Pin-compatible Texas Instruments part; 2.1V threshold, 200ms min reset timeout (not 40ms); 2.5µA ICC (vs. 170nA) | Higher supply current limits battery life; longer timeout may delay system recovery in time-critical diagnostics | Choose TPS3836K21DBVR only if existing layout uses TI's footprint and 200ms timeout is acceptable |
Compared with MAX6865UK21D2L+T, the MAX6864UK21D2S+T offers faster watchdog response for dynamic firmware, while the TPS3836K21DBVR trades nanopower operation for broader vendor support - neither matches the 40ms/209s/170nA combination unique to MAX6865UK21D2L+T.
Availability
MAX6865UK21D2L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, handheld diagnostic tools, and low-power wearables requiring stable component supply across multi-year production cycles.
Supply support for MAX6865UK21D2L+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 demanding industrial, medical, and automotive applications - emphasizing low power, high reliability, and small form factor.
The MAX68xx family targets battery-powered medical and portable electronics, delivering nanopower supervision with integrated watchdog and manual reset in minimal SOT23 packaging - specifically engineered for FDA-regulated and energy-harvesting systems.
FAQ
What is the exact reset threshold voltage of the MAX6865UK21D2L+T?
The MAX6865UK21D2L+T has a factory-trimmed reset threshold of +2.100V, with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) where suffix "21" corresponds to 2.100V nominal, and electrical characteristics specify VTH = VTH ±2.5%. The MAX6865UK21D2L+T maintains this accuracy without external calibration.
Does the MAX6865UK21D2L+T support active-high or active-low reset outputs?
The MAX6865UK21D2L+T features an active-high push-pull RESET output, as confirmed by its pin description (Pin 1 = RESET, "Active-High Push-Pull") and Selector Guide entry. It drives high during reset assertion and low when deasserted - distinct from open-drain or active-low variants in the MAX68xx family. This matches µPs with active-high reset inputs without requiring inverters.
What is the watchdog timeout period for the MAX6865UK21D2L+T?
The MAX6865UK21D2L+T has a watchdog timeout period of 209s (typical), indicated by the "L" suffix in its part number. Table 3 confirms "L" = 95s (min) / 209s (typ) / 487s (max). This long timeout is designed for infrequent-firmware-update applications like medical diagnostics, where extended software execution windows are required before reset intervention.
Can the MAX6865UK21D2L+T operate from a 1.2V supply?
Yes, the MAX6865UK21D2L+T operates from 1.2V to 5.5V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. Its 170nA typical supply current at 1.8V and guaranteed reset validity down to VCC = +1.1V confirm functionality at 1.2V - enabling use with ultra-low-voltage energy harvesting or sub-1.8V battery chemistries.
Is the MAX6865UK21D2L+T pin-compatible with other MAX68xx supervisory circuits?
The MAX6865UK21D2L+T uses the standard 5-pin SOT23-5 package and shares identical pinout with MAX6864/MAX6866/MAX6867/MAX6869 (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) or MAX6854–MAX6856 (which lack WDI). Always verify function alignment before substitution.
MAX6865UK21D2L+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:
- 40ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
MAX6865UK21D2L+T FAQ
1.How can I place an order for MAX6865UK21D2L+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6865UK21D2L+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 MAX6865UK21D2L+T reliable?
The price and inventory of MAX6865UK21D2L+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6865UK21D2L+T is usually 5 days.
3.What payment methods are accepted for MAX6865UK21D2L+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6865UK21D2L+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6865UK21D2L+T?
MAX6865UK21D2L+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6865UK21D2L+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 MAX6865UK21D2L+T?
For technical support, including MAX6865UK21D2L+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6865UK21D2L+T requirements.
6.How does Aetrix verify that MAX6865UK21D2L+T is sourced from the original manufacturer or authorized distributors?
All MAX6865UK21D2L+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 MAX6865UK21D2L+T meets industry standards.
7.What is the process for return or replacement of MAX6865UK21D2L+T?
All MAX6865UK21D2L+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6865UK21D2L+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 MAX6865UK21D2L+T part is unused and in its original packaging.
Return procedure for MAX6865UK21D2L+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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