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Analog Devices Inc./Maxim Integrated MAX6861UK28+T
- Part No.:
- MAX6861UK28+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6861UK28+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,524
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Product details
Overview
MAX6861UK28+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.800V reset threshold (suffix '28'), and pin-selectable 10ms/150ms minimum reset timeout via CT input. It monitors VCC, asserts active-low push-pull RESET on brownout or manual reset, and guarantees valid reset down to VCC = +1.1V - used in battery-powered glucose monitors and portable medical devices.
For engineers reviewing the MAX6861UK28+T datasheet, MAX6861UK28+T pinout, MAX6861UK28+T application, or MAX6861UK28+T equivalent, key selection criteria include its 2.8V threshold accuracy (±2.5%), immunity to short VCC transients (<40µs at 100mV overdrive), CT-configurable reset delay, and compatibility with low-voltage µP systems operating down to 1.2V.
Technical Context
The MAX6861UK28+T integrates a precision voltage monitor, manual reset input (MR) with 10kΩ internal pullup and 1µs minimum pulse width, and a CT-controlled reset timeout generator selecting between D1 (10ms min) and D3 (150ms min) options. Its reset assertion is guaranteed valid across -40°C to +85°C and for VCC ≥ 1.1V.
Unlike watchdog-equipped variants (e.g., MAX6864–MAX6869), the MAX6861UK28+T omits WDI functionality but adds CT pin for flexible timeout selection - enabling design adaptation without changing BOM for varying µP initialization timing requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.800V ±2.5% - ensures reliable power-on reset for 2.8V nominal rails with margin against noise-induced false triggers |
| Supply Current | 170nA typ at 2.5V - enables multi-year operation on coin-cell batteries in portable medical sensors |
| Reset Timeout Options | 10ms or 150ms min (CT-selectable) - matches fast-boot µPs or slower analog subsystems requiring extended hold time |
| VCC Operating Range | 1.2V to 5.5V - supports wide-input battery systems including single Li-ion (2.7–4.2V) and dual alkaline (1.8–3.2V) |
| Reset Output Type | Push-pull active-low - eliminates need for external pullup resistor and ensures clean logic-level drive into µP reset pin |
| Valid Reset Down To | VCC = +1.1V - maintains deterministic reset state during deep brownout, preventing undefined µP behavior |
| MR Input Logic | Active-low, internally pulled up to VCC (10kΩ), 0.3×VCC max low threshold - compatible with CMOS outputs and open-drain switches |
Pinout & Package
Package: 5-pin SOT23-5, lead-free, surface-mount, footprint-compatible with industry-standard 5-pin supervisory ICs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | CT (Reset Timeout Select) | Logic input: low selects 10ms min timeout (D1), high selects 150ms min timeout (D3); no external bias required |
| 2 | GND | Ground reference for all internal circuits and reset output; must connect to system ground plane |
| 3 | MR | Active-low manual reset input; internally pulled up to VCC (10kΩ); 1µs minimum pulse width sufficient for tactile switch debounce |
| 4 | RESET | Push-pull active-low reset output; sinks 50µA at VCC ≥ 1.1V with VOL ≤ 0.3V - directly drives standard µP reset pins |
| 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 enables >10-year battery life in always-on wearable health monitors |
| Pin-selectable timeout | CT pin eliminates need for multiple SKUs - one part covers both fast-boot and slow-peripheral initialization timing |
| Guaranteed reset validity | RESET remains functional down to VCC = +1.1V, ensuring safe shutdown even during severe brownout |
| Transient immunity | Immune to VCC glitches <40µs duration at 100mV overdrive - prevents spurious resets in noisy automotive or industrial environments |
| No external components | Internal MR pullup and precise threshold trimming eliminate resistors, capacitors, and calibration effort |
Applications
| Glucose Monitoring Systems | Patient Vital Sign Monitors |
|---|---|
|
Use Scenario: Portable handheld glucose meter powered by CR2032 coin cell, requiring reliable power-on reset and long shelf life. IC Role / Device Role / Timing Role: Supervisory IC asserting active-low RESET to ARM Cortex-M0 µP during battery insertion and low-VCC conditions. Use Value: 170nA ICC extends battery life beyond 5 years in standby; 2.8V threshold aligns precisely with ADC reference rail stability point. |
Use Scenario: Battery-backed bedside patient monitor with ECG, SpO₂, and temperature sensing, needing fail-safe boot sequence. IC Role / Device Role / Timing Role: Voltage supervisor ensuring µP remains held in reset until analog front-end power rails stabilize post-brownout. Use Value: 150ms timeout (CT = high) provides margin for slow-starting LDOs powering sensor signal chains before firmware execution. |
| Portable ECG Holter Devices | Wireless Pulse Oximeters |
|
Use Scenario: 24-hour ambulatory ECG recorder using rechargeable LiPo, subject to intermittent charging and voltage droop. IC Role / Device Role / Timing Role: Brownout detector triggering hardware reset when battery voltage falls below 2.8V during discharge cycle. Use Value: ±2.5% threshold tolerance prevents premature reset during normal load transients; 10ms timeout (CT = low) enables rapid recovery after brief dips. |
Use Scenario: Bluetooth-enabled fingertip pulse oximeter with optical sensor and BLE SoC, operating from single AAA alkaline cell. IC Role / Device Role / Timing Role: Power supervisor coordinating reset assertion with LED driver turn-on sequence and BLE radio initialization. Use Value: Push-pull RESET eliminates external pullup, reducing component count and PCB area in space-constrained wearable form factor. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS3836K28DBVR | Fixed 2.8V threshold, 200ms reset timeout, 1.8µA ICC - higher quiescent current than MAX6861UK28+T's 170nA | Suitable for cost-sensitive industrial controllers where nanoscale ICC is not critical | Select TPS3836K28DBVR only if board layout allows for higher supply current and longer fixed timeout suffices |
| MAX6326UT28+T | Same 2.8V threshold, 1.6µA ICC, no CT pin - offers push-pull active-low RESET but lacks timeout flexibility | Better for legacy designs already using MAX6326 footprint and requiring identical timing | Choose MAX6326UT28+T when redesign is impractical but 2.8V supervision is mandatory and timeout is fixed |
Compared with TPS3836K28DBVR and MAX6326UT28+T, the MAX6861UK28+T uniquely delivers nanopower operation *and* field-selectable timeout in the same 5-pin SOT23 package - enabling one-part support for multiple product variants without sacrificing battery life or timing precision.
Availability
MAX6861UK28+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered wearables, and low-power IoT edge nodes requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX6861UK28+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 MAX6861UK28+T belongs to the MAX6854–MAX6869 nanopower µP supervisory family, designed specifically for ultra-low-power portable and medical electronics where battery longevity and deterministic reset behavior are critical.
FAQ
What is the exact reset threshold voltage of MAX6861UK28+T?
The MAX6861UK28+T has a factory-trimmed reset threshold of 2.800V, with guaranteed tolerance of ±2.5% over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix '28' corresponds to 2.730V (min), 2.800V (typ), and 2.870V (max). The MAX6861UK28+T uses this exact specification for reliable brownout detection in 2.8V-rail systems.
How does the CT pin configure the reset timeout on MAX6861UK28+T?
The CT pin on MAX6861UK28+T selects between two minimum reset timeout periods: connecting CT to GND selects D1 (10ms min), while connecting CT to VCC selects D3 (150ms min). This is defined in Table 1 and the MAX6861/MAX6862/MAX6863 Pin Description section. The MAX6861UK28+T implements this behavior with no external components - CT is a logic input with negligible leakage (<20nA), enabling simple strap-option configuration.
Does MAX6861UK28+T include a watchdog timer function?
No, the MAX6861UK28+T does not include a watchdog timer. Per the Selector Guide and Pin Configurations, MAX6861–MAX6863 variants feature CT but omit WDI - unlike MAX6864–MAX6869 which integrate watchdog input. The MAX6861UK28+T is strictly a voltage monitor + manual reset + CT-selectable timeout device, making it ideal for applications where software watchdog supervision is handled separately.
What is the supply voltage range supported by MAX6861UK28+T?
The MAX6861UK28+T operates from VCC = 1.2V to 5.5V, with guaranteed reset functionality down to VCC = +1.1V. Electrical Characteristics specify that supply current (ICC) and reset threshold (VTH) are characterized across this full range, and the device remains fully functional - including MR input recognition and RESET assertion - at 1.2V. This makes MAX6861UK28+T suitable for single-cell Li-ion, NiMH, and alkaline systems.
Is MAX6861UK28+T pin-compatible with other supervisory ICs?
Yes, the MAX6861UK28+T uses the standard 5-pin SOT23-5 package and shares pinout compatibility with TPS3836/TPS3837/TPS3838 series (as noted in Features). Pin 1 = CT (functionally equivalent to NC on TPS3836), Pin 2 = GND, Pin 3 = MR, Pin 4 = RESET, Pin 5 = VCC. While CT adds functionality, the MAX6861UK28+T can be substituted in existing layouts with minor trace modification - confirming true mechanical and electrical pin compatibility for drop-in evaluation.
MAX6861UK28+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:
- 2.8V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- Adjustable/Selectable
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
MAX6861UK28+T FAQ
1.How can I place an order for MAX6861UK28+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6861UK28+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 MAX6861UK28+T reliable?
The price and inventory of MAX6861UK28+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6861UK28+T is usually 5 days.
3.What payment methods are accepted for MAX6861UK28+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6861UK28+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6861UK28+T?
MAX6861UK28+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6861UK28+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 MAX6861UK28+T?
For technical support, including MAX6861UK28+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6861UK28+T requirements.
6.How does Aetrix verify that MAX6861UK28+T is sourced from the original manufacturer or authorized distributors?
All MAX6861UK28+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 MAX6861UK28+T meets industry standards.
7.What is the process for return or replacement of MAX6861UK28+T?
All MAX6861UK28+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6861UK28+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 MAX6861UK28+T part is unused and in its original packaging.
Return procedure for MAX6861UK28+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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