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Analog Devices Inc./Maxim Integrated MAX6866UK18D3L+T
- Part No.:
- MAX6866UK18D3L+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6866UK18D3L+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,634
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Product details
Overview
The MAX6866UK18D3L+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 1.8V reset threshold (±2.5%), 300ms minimum reset timeout (D3), and watchdog timer with 209s typical timeout (L suffix). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog expiration - designed for battery-critical portable medical and handheld devices.
For engineers reviewing the MAX6866UK18D3L+T datasheet, MAX6866UK18D3L+T pinout, MAX6866UK18D3L+T application, or MAX6866UK18D3L+T equivalent, this page delivers verified specifications, validated pin functions, confirmed reset timing behavior, and real-world use cases in glucose monitors and low-power embedded systems.
Technical Context
This device integrates three core supervision functions: precise VCC voltage monitoring with hysteresis (0.5% of VTH), a glitch-immune manual reset input (250ns MR-to-reset delay, 1µs minimum pulse width), and a watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). All functions operate down to VCC = 1.1V.
The MAX6866UK18D3L+T uses a BiCMOS process (2848 transistors) and features internal 10kΩ MR pullup, open-drain RESET output requiring external pullup, and immunity to VCC transients ≤40µs at 100mV overdrive - enabling reliable operation in noisy, battery-powered environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Current | 170nA typ at +25°C - enables multi-year battery life in always-on medical sensors. |
| Reset Threshold | 1.800V ±2.5% - factory-trimmed for stable brownout detection at Li-ion single-cell discharge endpoint. |
| Reset Timeout | 300ms min (D3 option) - ensures µP completes full power-up initialization before release. |
| Watchdog Timeout | 209s typ (L suffix) - supports long idle cycles in intermittent-sensing applications like patient monitors. |
| VCC Operating Range | 1.2V to 5.5V - compatible with 1.8V/3.3V logic domains and extends supervision down to 1.1V valid RESET. |
| MR Input Logic | Active-low, internally pulled up to VCC via 10kΩ - allows direct switch-to-GND interface without external components. |
| WDI Pulse Detection | 150ns minimum pulse width - reliably captures fast firmware heartbeat toggles even at high clock rates. |
Pinout & Package
Package: 5-pin SOT23-5 (lead-free, +T suffix), footprint-compatible with industry-standard 5-pin SOT23 layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET (open-drain active-low) | Asserts low during VCC undervoltage, MR assertion, or watchdog timeout; requires external pullup for logic-level compatibility. |
| 2 | GND | Ground reference for all internal circuits; must be connected to system ground plane with low-impedance path. |
| 3 | MR | Active-low manual reset input; internally pulled up to VCC (10kΩ); debounced by design - no external RC needed. |
| 4 | WDI | Watchdog input; rising/falling edges clear internal timer; static state >209s triggers reset - used for firmware liveness monitoring. |
| 5 | VCC | Primary supply input and monitored voltage rail; bypass with 0.1µF ceramic capacitor to GND for noise rejection. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low ICC | 170nA typical supply current - reduces quiescent drain in coin-cell-powered devices by >90% vs. legacy supervisors. |
| Valid RESET to 1.1V | Guaranteed reset assertion integrity down to VCC = 1.1V - ensures fail-safe behavior during deep brownout conditions. |
| Transient immunity | Immune to VCC glitches ≤40µs at 100mV overdrive - eliminates false resets in electrically noisy portable equipment. |
| No external components | Internal MR pullup, precision voltage reference, and watchdog oscillator - eliminates BOM cost and layout area. |
| Open-drain RESET | Level-shiftable output - interfaces directly to µP reset pins powered by different supply rails (0–5.5V). |
Applications
| Glucose Monitors | Patient Monitoring Devices |
|---|---|
Use Scenario: Continuous glucose sensing with Bluetooth LE transmission and 10-year battery target. IC Role / Device Role / Timing Role: Supervises 1.8V sensor analog front-end and 3.3V BLE SoC; asserts reset on battery sag below 1.8V or firmware hang. Use Value: Prevents corrupted sensor readings or radio lockups by enforcing clean restarts - critical for FDA Class II device reliability. |
Use Scenario: Portable ECG patch with intermittent sampling and wireless data upload. IC Role / Device Role / Timing Role: Monitors main 3.3V supply and watches firmware execution via WDI; triggers 300ms reset on missed heartbeat. Use Value: Ensures clinical-grade data integrity by eliminating silent firmware crashes during multi-hour wear periods. |
| Smart Wearables | Industrial Handheld Terminals |
Use Scenario: Fitness tracker with motion sensor, OLED display, and rechargeable LiPo cell. IC Role / Device Role / Timing Role: Provides brownout protection at 1.8V cutoff and watchdog supervision of activity-tracking firmware loop. Use Value: Extends usable battery life by minimizing supervisor current while guaranteeing recovery from stuck states. |
Use Scenario: Rugged barcode scanner operating in warehouse environments with variable temperature and ESD risk. IC Role / Device Role / Timing Role: Guards against power rail instability during motor actuation and detects firmware freezes in scanning engine. Use Value: Maintains operational uptime by preventing unresponsive units - reducing field service calls and downtime. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6864UK18D3L+T | Same 1.8V threshold, D3 timeout, L watchdog, but push-pull active-low RESET output instead of open-drain. | Requires VCC-referenced reset signaling; not suitable for level-shifting or mixed-voltage reset domains. | Select when µP reset pin is strictly 1.8V/3.3V referenced and no external pullup is desired. |
| TPS3838K33DBVR | 1.6V reset threshold, 200ms timeout, no watchdog; 3.3V fixed-supply version; 1.6µA ICC - 10× higher quiescent current. | Lacks watchdog functionality and nanopower operation - unsuitable for multi-year battery life requirements. | Consider only for cost-sensitive, non-battery-critical 3.3V systems where watchdog is unnecessary. |
Compared with MAX6866UK18D3L+T, the MAX6864UK18D3L+T offers identical supervision parameters but differs in RESET drive architecture, while the TPS3838K33DBVR trades off nanopower operation and watchdog capability for lower unit cost in simpler applications.
Availability
MAX6866UK18D3L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, smart wearables, and industrial handheld terminals requiring stable component supply across extended production lifecycles.
Supply support for MAX6866UK18D3L+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 connectivity in demanding industrial and medical applications.
The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-constrained portable electronics - prioritizing nanoscale current, guaranteed low-VCC operation, and integrated watchdog reliability.
FAQ
What is the exact reset threshold voltage of the MAX6866UK18D3L+T?
The MAX6866UK18D3L+T has a factory-trimmed reset threshold of 1.800V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "18" corresponds to 1.800V nominal. The device guarantees valid reset assertion down to VCC = 1.1V, making it suitable for single-cell Li-ion applications nearing end-of-discharge.
Does the MAX6866UK18D3L+T require external components for basic operation?
No, the MAX6866UK18D3L+T operates autonomously with no required external components. It includes an internal 10kΩ pullup on MR, precision voltage reference, and watchdog oscillator. Only a 0.1µF ceramic bypass capacitor on VCC is recommended for noise immunity - and an external pullup resistor on RESET is necessary due to its open-drain configuration.
How does the watchdog timer in the MAX6866UK18D3L+T function?
The MAX6866UK18D3L+T watchdog timer expires if the WDI pin remains static (high or low) for longer than 209s (typical, L suffix). Each rising or falling edge on WDI clears the timer. Reset is asserted for the full 300ms timeout period (D3) upon expiration. The timer remains disabled until VCC exceeds the 1.8V threshold and is immune to noise due to 150ns minimum pulse detection.
What is the meaning of the "D3L" suffix in MAX6866UK18D3L+T?
In MAX6866UK18D3L+T, "D3" specifies the 300ms minimum reset timeout period (per Table 4), and "L" denotes the 209s typical watchdog timeout (per Table 3). The "UK18" indicates the 1.800V reset threshold, "+T" confirms lead-free packaging, and the base "MAX6866" identifies it as a watchdog-enabled, open-drain RESET variant in the MAX6854–MAX6869 family.
Can the MAX6866UK18D3L+T interface with a microcontroller running at a different voltage than VCC?
Yes - the open-drain RESET output of the MAX6866UK18D3L+T can be pulled up to a voltage independent of VCC (0–5.5V), enabling level-shifting. For example, it can monitor a 1.8V supply (VCC) while driving a 3.3V µP reset pin. However, RESET sink capability degrades as VCC falls below 1.2V, so proper pullup selection is essential for robust low-VCC operation.
MAX6866UK18D3L+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:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 1.8V
- 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
MAX6866UK18D3L+T FAQ
1.How can I place an order for MAX6866UK18D3L+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6866UK18D3L+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 MAX6866UK18D3L+T reliable?
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5.How can I obtain technical support or documentation for MAX6866UK18D3L+T?
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6.How does Aetrix verify that MAX6866UK18D3L+T is sourced from the original manufacturer or authorized distributors?
All MAX6866UK18D3L+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 MAX6866UK18D3L+T meets industry standards.
7.What is the process for return or replacement of MAX6866UK18D3L+T?
All MAX6866UK18D3L+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6866UK18D3L+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 MAX6866UK18D3L+T part is unused and in its original packaging.
Return procedure for MAX6866UK18D3L+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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