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Analog Devices Inc./Maxim Integrated MAX6805US31D3-T
- Part No.:
- MAX6805US31D3-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- TO-253-4, TO-253AA
- Datasheet:
-
MAX6805US31D3-T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT143-4
- Quantity:
- Payment:
- Shipping:
Inventory:2,622
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Product details
Overview
MAX6805US31D3-T from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit in a 4-pin SOT143 package, designed to monitor 3.08V power supplies with ±3% threshold accuracy over -40°C to +125°C and assert reset for ≥100ms after VCC rise or manual reset deassertion. It features 4.0µA supply current, 1.0V minimum operating voltage, and debounced manual-reset input. Used in portable battery-powered equipment requiring reliable brownout detection.
For engineers reviewing the MAX6805US31D3-T datasheet, MAX6805US31D3-T pinout, MAX6805US31D3-T application, or MAX6805US31D3-T equivalent, key selection criteria include its open-drain RESET output for bidirectional µP interface compatibility, factory-trimmed 3.08V reset threshold, guaranteed operation down to VCC = 1.0V, and 100ms minimum reset timeout period.
Technical Context
The MAX6805US31D3-T implements a precision bandgap-based reset comparator with factory-trimmed 3.08V threshold (±1.8% at +25°C, ±3% over full temperature range) and immunity to fast VCC transients up to 100µs at 100mV overdrive. Its internal 20kΩ MR pullup eliminates external components for manual reset.
As an open-drain device, MAX6805US31D3-T requires an external pullup resistor on RESET to interface with bidirectional microcontroller reset pins (e.g., Motorola 68HC11), enabling either the supervisor or µP to drive the line low. It does not guarantee valid RESET state below VCC = 1.0V due to reduced sink capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.08V ±3% over -40°C to +125°C - ensures accurate brownout detection for 3.3V systems |
| Reset Timeout Period | 100ms minimum - guarantees sufficient reset hold time for processor initialization |
| Supply Voltage Range | 1.0V to 5.5V - supports ultra-low-voltage operation during power ramp-down |
| Supply Current | 4µA at VCC = 3.0V - enables multi-year battery life in portable applications |
| RESET Output Type | Open-drain - allows wired-OR configuration and direct interface with bidirectional µP reset pins |
| MR Input Logic | Active-low with 20kΩ internal pullup - simplifies manual reset implementation with momentary switch to GND |
| VCC Transient Immunity | Rejects ≤100µs negative glitches at 100mV overdrive - prevents false resets from supply noise |
Pinout & Package
MAX6805US31D3-T is housed in a 4-pin SOT143 package (U4-1 outline, 21-0052 footprint), measuring 2.9mm × 1.6mm × 1.1mm, suitable for space-constrained PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: GND | Ground reference | Return path for all internal circuitry and MR input; must be connected to system ground plane |
| 2: RESET | Open-drain active-low reset output | Sinks current when asserted; requires external pullup resistor (typically 10–100kΩ) to VCC or another logic rail |
| 3: MR | Manual-reset input | Active-low; internally pulled up to VCC via 20kΩ resistor; connect to GND via momentary switch for reset initiation |
| 4: VCC | Power supply input | Monitored supply rail; operates from 1.0V to 5.5V; powers internal comparator and logic |
Key Features
| Feature | Design Value |
|---|---|
| Factory-trimmed 3.08V reset threshold | Eliminates external resistor divider calibration and improves system-level voltage monitoring accuracy |
| 100ms minimum reset timeout | Ensures reliable processor core and peripheral initialization across temperature and voltage variations |
| 4.0µA quiescent current at 3.0V | Reduces standby power consumption in always-on battery-backed systems |
| Debounced MR input with 20kΩ pullup | Removes need for external RC filter or Schmitt trigger, saving board space and BOM cost |
| Open-drain RESET output | Enables shared reset bus with multiple devices and compatibility with µPs having bidirectional reset pins |
Applications
| Portable Medical Sensors | Industrial PLC I/O Modules |
|---|---|
|
Use Scenario: Wearable ECG sensor continuously monitors patient vitals on coin-cell battery. IC Role / Device Role / Timing Role: Supervises 3.3V LDO output and asserts reset during battery voltage sag below 3.08V. Use Value: Prevents corrupted data logging by ensuring µC only operates within validated supply range, extending usable battery life via 4µA quiescent current. |
Use Scenario: Remote I/O module in factory automation endures wide ambient temperature swings (-40°C to +125°C). IC Role / Device Role / Timing Role: Monitors 3.3V system rail and provides 100ms reset pulse after cold start or brownout recovery. Use Value: Guarantees deterministic µP boot sequence under harsh thermal conditions with ±3% threshold stability over full temperature range. |
| Smart Meter Communication Units | Automotive Body Control Modules |
|
Use Scenario: NB-IoT modem in electricity meter wakes periodically to transmit usage data. IC Role / Device Role / Timing Role: Provides open-drain RESET signal tied to µP's bidirectional reset pin, allowing either device to initiate reset. Use Value: Enables coordinated reset between modem and host µP without additional level-shifting or arbitration logic. |
Use Scenario: BCM controls door locks and lighting using 3.3V domain powered from vehicle battery (9V–16V). IC Role / Device Role / Timing Role: Detects 3.08V brownout during cranking-induced voltage dip and holds reset for ≥100ms post-recovery. Use Value: Avoids erratic behavior during engine start by maintaining reset until stable 3.3V rail is re-established. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6804US31D3-T | Push/pull active-low RESET output; guaranteed correct state down to VCC = 0.7V | Preferred where no external pullup is desired and µP reset pin is unidirectional input | Select when board layout prohibits external pullup or system requires reset validity below 1.0V |
| MAX6315US31D3-T | Same 3.08V threshold and 100ms timeout, but includes watchdog timer function | Required where software hang detection is needed in addition to power-supply monitoring | Select when firmware reliability demands periodic watchdog refresh capability |
Compared with MAX6805US31D3-T, MAX6804US31D3-T eliminates the need for a pullup resistor but lacks bidirectional reset flexibility; MAX6315US31D3-T adds watchdog functionality at higher cost and current draw, making it suitable only when software supervision is mandatory.
Availability
MAX6805US31D3-T is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, smart meter communication units, and automotive body control modules requiring stable component supply and long-term production continuity.
Supply support for MAX6805US31D3-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 applications in industrial, automotive, and computing markets.
The MAX6805US31D3-T belongs to Maxim's µP supervisory product line, engineered specifically for low-power, high-reliability power-monitoring in space- and energy-constrained embedded systems.
FAQ
What is the factory-trimmed reset threshold voltage of the MAX6805US31D3-T?
The MAX6805US31D3-T has a factory-trimmed reset threshold of 3.08V, specified with ±1.8% tolerance at +25°C and ±3% over the full operating temperature range of -40°C to +125°C. This precise threshold ensures reliable detection of brownout conditions in 3.3V systems without external calibration components.
Does the MAX6805US31D3-T require an external pullup resistor on the RESET pin?
Yes, the MAX6805US31D3-T features an open-drain RESET output and requires an external pullup resistor (typically 10kΩ to 100kΩ) to VCC or another logic rail. This configuration enables wired-OR reset bus sharing and compatibility with microcontrollers that have bidirectional reset pins, such as the Motorola 68HC11.
What is the minimum supply voltage required for the MAX6805US31D3-T to maintain correct reset state?
The MAX6805US31D3-T is guaranteed to maintain correct reset state down to VCC = 1.0V over the full temperature range. Below this voltage, the open-drain output's sinking capability degrades, and RESET may drift to a non-active level due to the external pullup resistor-making it unsuitable for applications requiring valid reset down to 0V.
How long does the RESET signal remain asserted after VCC rises above the threshold in the MAX6805US31D3-T?
The MAX6805US31D3-T asserts RESET for a minimum of 100ms after VCC rises above the 3.08V threshold. This guaranteed timeout period-specified as 100ms min, 150ms typ, and 200ms max-ensures sufficient hold time for microprocessor and peripheral initialization before release.
Is the manual-reset input (MR) of the MAX6805US31D3-T debounced internally?
Yes, the MR input of the MAX6805US31D3-T is internally debounced, eliminating the need for external RC filtering or Schmitt-trigger circuits. It also includes a 20kΩ internal pullup resistor, allowing direct connection of a momentary switch from MR to GND for manual reset functionality without additional components.
MAX6805US31D3-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- TO-253-4, TO-253AA
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 3.08V
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 100ms Minimum
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-4
MAX6805US31D3-T FAQ
1.How can I place an order for MAX6805US31D3-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6805US31D3-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 MAX6805US31D3-T reliable?
The price and inventory of MAX6805US31D3-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6805US31D3-T is usually 5 days.
3.What payment methods are accepted for MAX6805US31D3-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6805US31D3-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6805US31D3-T?
MAX6805US31D3-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6805US31D3-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 MAX6805US31D3-T?
For technical support, including MAX6805US31D3-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6805US31D3-T requirements.
6.How does Aetrix verify that MAX6805US31D3-T is sourced from the original manufacturer or authorized distributors?
All MAX6805US31D3-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 MAX6805US31D3-T meets industry standards.
7.What is the process for return or replacement of MAX6805US31D3-T?
All MAX6805US31D3-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6805US31D3-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 MAX6805US31D3-T part is unused and in its original packaging.
Return procedure for MAX6805US31D3-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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