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Analog Devices Inc./Maxim Integrated MAX6865UK21D3S+T
- Part No.:
- MAX6865UK21D3S+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6865UK21D3S+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,933
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Product details
Overview
The MAX6865UK21D3S+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 2.100V reset threshold (suffix '21'), 150ms minimum reset timeout (suffix 'D3'), and watchdog timer with 3.3s typical timeout (suffix 'S'). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog expiration - ideal for battery-powered glucose monitors and portable medical devices.
For engineers reviewing the MAX6865UK21D3S+T datasheet, MAX6865UK21D3S+T pinout, MAX6865UK21D3S+T application, or MAX6865UK21D3S+T equivalent, this page delivers verified electrical parameters, functional pin roles, real-world use cases, and validated alternative options for low-power embedded system design and BOM optimization.
Technical Context
The MAX6865UK21D3S+T integrates voltage monitoring, manual reset input (MR), and watchdog timer (WDI) in a single BiCMOS IC. Its reset logic asserts active-high push-pull RESET when VCC drops below 2.100V, MR is pulled low, or WDI remains static beyond 3.3s (typ). The internal timer guarantees reset assertion for ≥150ms after recovery.
It operates across VCC = 1.2V to 5.5V and remains functional down to VCC = 1.1V, with guaranteed reset validity and immunity to ≤40µs VCC transients at 100mV overdrive. The WDI input detects edges ≥150ns and clears the watchdog on any transition, MR assertion, or RESET activation.
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 | 2.100V ±2.5% - factory-trimmed for precise brownout detection at 2.1V rail |
| Reset Timeout | 150ms min - ensures reliable µP initialization after power recovery |
| Watchdog Timeout | 3.3s typ (S-suffix) - balances fault coverage and software execution margin |
| VCC Operating Range | 1.2V to 5.5V - supports single-cell Li-ion, 3.3V, and 5V systems |
| Reset Output Type | Active-high push-pull - eliminates external pullup and simplifies interface to µP reset pin |
| Guaranteed Reset Validity | To VCC = 1.1V - maintains deterministic reset behavior during deep brownout |
Pinout & Package
Package: 5-pin SOT23-5, lead-free, surface-mount, footprint-compatible with industry-standard 5-pin SOT23.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET (active-high) | Push-pull output asserted high during reset; sinks no current when deasserted; directly drives µP reset pin without pullup |
| 2 | GND | Ground reference for all internal circuits; must be connected to system ground plane for noise immunity |
| 3 | MR (active-low) | Manual reset input with 10kΩ internal pullup to VCC; accepts CMOS logic levels; 1µs minimum pulse width |
| 4 | WDI | Watchdog input that clears internal timer on rising/falling edge; rejects glitches <150ns; requires periodic toggling by firmware |
| 5 | VCC | Primary supply input monitored for reset; bypass with 0.1µF capacitor to GND for noise suppression |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low ICC | 170nA typical supply current enables >10-year battery life in always-on medical sensors |
| Factory-trimmed VTH | 2.100V ±2.5% threshold eliminates external resistor networks and calibration effort |
| Watchdog with edge-triggered clear | WDI resets timer on any edge - prevents false timeouts during software loops or interrupts |
| VCC transient immunity | Immune to ≤40µs VCC glitches at 100mV overdrive - avoids spurious resets in noisy environments |
| Valid reset down to 1.1V | Ensures deterministic reset assertion even during severe brownout conditions before µP lockup |
Applications
| Glucose Monitor System | Patient Vital Sign Logger |
|---|---|
|
Use Scenario: Continuous glucose monitoring device powered by CR2032 coin cell, operating for >3 years without battery replacement. IC Role / Device Role / Timing Role: Supervisory IC monitors 2.1V LDO output, asserts reset on brownout or firmware hang via WDI, and ensures clean µP restart. Use Value: 170nA quiescent current extends battery life; 150ms reset timeout accommodates slow analog sensor startup; 3.3s watchdog interval allows full ADC conversion and BLE transmission cycles. |
Use Scenario: Portable ECG/SpO₂ logger with intermittent wireless upload, requiring fail-safe recovery from firmware crashes. IC Role / Device Role / Timing Role: Resets ARM Cortex-M0+ MCU when WDI signal stalls, triggered by missed heartbeat interrupt or BLE stack deadlock. Use Value: Active-high push-pull RESET eliminates external components; 2.100V threshold matches low-voltage analog front-end supply; guaranteed reset to 1.1V prevents undefined state during battery depletion. |
| Industrial Handheld Scanner | Wearable Health Tracker |
|
Use Scenario: Rugged barcode scanner using single-cell Li-ion (2.7–4.2V), subjected to ESD and supply noise in warehouse environments. IC Role / Device Role / Timing Role: Provides VCC supervision, manual reset via button, and watchdog protection against bootloader corruption during firmware update. Use Value: Immunity to 40µs VCC transients prevents false resets near motors or RF sources; MR input with 10kΩ pullup enables direct switch connection without external resistors. |
Use Scenario: Fitness band with optical heart-rate sensor and Bluetooth LE, operating from 3.0V regulated supply with aggressive power gating. IC Role / Device Role / Timing Role: Monitors 3.0V rail, initiates reset if sensor firmware hangs, and synchronizes recovery with PMIC power sequencing. Use Value: 5-pin SOT23 footprint minimizes PCB area; 170nA ICC reduces load on buck-boost converter; 150ms timeout aligns with sensor initialization timing budget. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6864UK21D3S+T | Active-low push-pull RESET output; identical VTH, timeout, watchdog, and pinout | Requires µP with active-low reset input; incompatible with active-high reset pins without inversion | Select when target µP uses active-low reset and board layout cannot accommodate level-shifting |
| TPS3836K21DBVR | 2.1V threshold, 200ms timeout, no watchdog; 5-pin SOT23; 1.6µA ICC (vs. 0.17µA) | Lacks watchdog functionality; higher supply current reduces battery life in always-on designs | Choose only if watchdog is unnecessary and cost is prioritized over ultra-low power |
Compared with MAX6865UK21D3S+T, MAX6864UK21D3S+T offers identical supervision timing but inverted reset polarity, while TPS3836K21DBVR provides threshold compatibility at the expense of 9.4× higher supply current and no watchdog - making MAX6865UK21D3S+T optimal for safety-critical, long-life portable medical devices.
Availability
MAX6865UK21D3S+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, industrial handheld scanners, and wearable health trackers requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for MAX6865UK21D3S+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, medical, and automotive applications.
The MAX68xx family delivers nanopower supervisory solutions optimized for battery-constrained portable medical and IoT endpoints, combining ultra-low ICC, accurate voltage thresholds, and integrated watchdog functionality in minimal footprints.
FAQ
What is the exact reset threshold voltage of the MAX6865UK21D3S+T?
The MAX6865UK21D3S+T has a factory-trimmed reset threshold of 2.100V, with ±2.5% tolerance over temperature (−40°C to +85°C). This value is confirmed by the '21' suffix in the part number and is specified in Table 2 of the datasheet. The threshold remains stable across VCC range and exhibits <0.5% normalized drift from −40°C to +85°C per the Typical Operating Characteristics graph.
Does the MAX6865UK21D3S+T require external components for basic operation?
No, the MAX6865UK21D3S+T requires no external components for core supervision functionality. Its MR input features a 10kΩ internal pullup, and the active-high push-pull RESET output eliminates the need for an external pullup resistor. A 0.1µF ceramic capacitor from VCC to GND is recommended for noise immunity but is not strictly required for functional operation.
How does the watchdog timer in the MAX6865UK21D3S+T behave during reset assertion?
While RESET is asserted (high), the watchdog timer in the MAX6865UK21D3S+T is disabled and does not count. As soon as RESET deasserts (goes low), the watchdog timer resumes counting from zero. This behavior ensures the watchdog only monitors active firmware execution and prevents false timeouts during reset recovery or power-up sequences.
Can the MAX6865UK21D3S+T operate reliably at VCC = 1.15V?
Yes, the MAX6865UK21D3S+T guarantees valid RESET assertion down to VCC = 1.1V, as explicitly stated in the Electrical Characteristics table and confirmed in the Absolute Maximum Ratings section. At 1.15V, the device fully meets all specifications including reset threshold accuracy, timeout timing, and WDI responsiveness - critical for graceful shutdown in deeply depleted battery scenarios.
What is the meaning of the 'D3S' suffix in MAX6865UK21D3S+T?
The 'D3' denotes a 150ms minimum reset timeout period (per Table 4), and 'S' specifies a 3.3s typical watchdog timeout (per Table 3). Together, 'D3S' identifies the precise timing configuration: reset remains asserted ≥150ms after VCC recovery or MR release, and the watchdog triggers reset if WDI remains static for ≥3.3s (typ). This combination is validated for portable medical devices with moderate firmware cycle times.
MAX6865UK21D3S+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:
- 150ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
MAX6865UK21D3S+T FAQ
1.How can I place an order for MAX6865UK21D3S+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6865UK21D3S+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 MAX6865UK21D3S+T reliable?
The price and inventory of MAX6865UK21D3S+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6865UK21D3S+T is usually 5 days.
3.What payment methods are accepted for MAX6865UK21D3S+T?
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4.How is shipping managed for MAX6865UK21D3S+T?
MAX6865UK21D3S+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6865UK21D3S+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 MAX6865UK21D3S+T?
For technical support, including MAX6865UK21D3S+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6865UK21D3S+T requirements.
6.How does Aetrix verify that MAX6865UK21D3S+T is sourced from the original manufacturer or authorized distributors?
All MAX6865UK21D3S+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 MAX6865UK21D3S+T meets industry standards.
7.What is the process for return or replacement of MAX6865UK21D3S+T?
All MAX6865UK21D3S+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6865UK21D3S+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 MAX6865UK21D3S+T part is unused and in its original packaging.
Return procedure for MAX6865UK21D3S+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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