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Analog Devices Inc./Maxim Integrated MAX6805US44D3+T
- Part No.:
- MAX6805US44D3+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- TO-253-4, TO-253AA
- Datasheet:
-
MAX6805US44D3+T.pdf
- Description:
- IC RESET MPU LOW PWR SOT143-4
- Quantity:
- Payment:
- Shipping:
Inventory:2,706
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Product details
Overview
MAX6805US44D3+T from Maxim Integrated is an open-drain, active-low microprocessor supervisory circuit in SOT143 package, designed to monitor 4.38V power supplies with 100ms minimum reset timeout and guaranteed operation down to VCC = 1.0V. It features a debounced manual-reset input, factory-trimmed ±3% threshold accuracy over temperature, and 4.0µA supply current at 3.0V - enabling reliable brownout detection in battery-powered controllers and portable instrumentation.
For engineers reviewing the MAX6805US44D3+T datasheet, MAX6805US44D3+T pinout, MAX6805US44D3+T application, or MAX6805US44D3+T equivalent, key selection criteria include its open-drain RESET output for bidirectional µP interface compatibility (e.g., Motorola 68HC11), VCC operating range down to 1.0V, 4.38V reset threshold tolerance, and 100ms reset timeout period - all validated across –40°C to +125°C.
Technical Context
The MAX6805US44D3+T implements a precision voltage comparator with hysteresis-free threshold detection at 4.38V (±3% over –40°C to +125°C), coupled with a monostable timeout circuit that holds RESET asserted for ≥100ms after VCC rises above threshold or MR deasserts. Its open-drain output requires an external pullup resistor and supports wired-OR configurations with µP bidirectional reset pins.
Reset assertion is immune to transients ≤30µs at 10V/ms slew rate, and the internal 20kΩ MR pullup eliminates need for external components. The device operates without external capacitors or resistors, and its BiCMOS process ensures stable performance with <12µA typical supply current at 5.0V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.38V ±3% over –40°C to +125°C - ensures accurate brownout detection for 4.5V nominal rails |
| Reset Timeout Period | 100ms minimum - guarantees sufficient hold time for µP initialization sequences |
| Supply Voltage Range | 1.0V to 5.5V - enables valid reset assertion during deep brownout conditions |
| Supply Current | 4µA at VCC = 3.0V - supports ultra-low-power operation in battery-backed systems |
| RESET Output Type | Open-drain, active-low - allows direct interface with bidirectional µP reset pins and wired-OR bus sharing |
| MR Input Logic | Active-low with 20kΩ internal pullup - enables momentary switch connection to GND without external components |
| VCC Transient Immunity | Rejects negative-going glitches ≤30µs at 10V/ms - prevents false resets during switching noise |
Pinout & Package
MAX6805US44D3+T is housed in a 4-pin SOT143 package (outline 21-0052, land pattern 90-0183), measuring 2.9mm × 1.6mm × 1.1mm, with gull-wing leads and RoHS-compliant lead-free finish (+T suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - GND | Ground reference | Return path for internal comparator and reset logic; must be low-impedance connection 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 input with internal 20kΩ pullup; asserts reset when pulled to GND; tolerant of 50ns glitches |
| 4 - VCC | Supply voltage input | Monitored power rail input; absolute max rating is +6V; supports operation down to 1.0V for valid reset state |
Key Features
| Feature | Design Value |
|---|---|
| Factory-trimmed 4.38V threshold | Eliminates external resistor divider calibration and reduces BOM count in 4.5V system monitoring |
| 100ms min reset timeout | Meets µP power-on reset timing requirements for ARM Cortex-M0/M3 and 8051-based controllers |
| Open-drain RESET output | Enables direct connection to bidirectional reset pins (e.g., Motorola 68HC11) without level-shifting |
| Debounced MR input | Accepts mechanical switch inputs without external RC filtering or Schmitt-trigger circuits |
| Ultra-low 4µA supply current | Extends battery life in portable instruments and remote sensors where reset IC remains always-on |
Applications
| Industrial Controllers | Portable Medical Instruments |
|---|---|
|
Use Scenario: PLC I/O modules powered from 4.5V DC-DC converters subject to line transients and thermal cycling. IC Role / Device Role / Timing Role: Monitors VCC and asserts open-drain RESET to hold controller in reset until stable 4.5V rail is confirmed. Use Value: Prevents firmware corruption during brownout by guaranteeing ≥100ms reset hold time and rejecting 30µs noise spikes. |
Use Scenario: Handheld glucose meters using coin-cell batteries with declining voltage profiles. IC Role / Device Role / Timing Role: Detects 4.38V threshold crossing during battery discharge and triggers controlled shutdown sequence. Use Value: Enables deterministic low-battery reset before analog front-end or display driver fails due to undervoltage. |
| Automotive Body Control Modules | Smart Energy Meters |
|
Use Scenario: 12V-to-4.5V converted supply in BCMs exposed to load-dump and cold-crank conditions. IC Role / Device Role / Timing Role: Supervises post-regulation 4.5V rail and asserts RESET during cold-crank voltage sag below 4.38V. Use Value: Ensures MCU remains held in reset until post-cold-crank recovery stabilizes, avoiding erratic CAN communication. |
Use Scenario: Revenue-grade meter with isolated 4.5V auxiliary supply powering metrology ASIC and RTC. IC Role / Device Role / Timing Role: Provides fail-safe reset initiation when auxiliary rail drops due to isolation transformer fault or capacitor aging. Use Value: Guarantees meter retains calibrated state and prevents invalid energy accumulation during undervoltage events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6804US44D3+T | Push/pull active-low RESET output; guaranteed valid down to VCC = 0.7V | Requires no external pullup; better suited for systems with high-impedance µP reset inputs | Select when board layout lacks space for pullup resistor or µP reset pin cannot tolerate floating state |
| TPS3808G33DBVR | 3.3V fixed threshold; 200ms timeout; 2.5µA quiescent current; SOT-23-5 package | Higher integration (no MR pin); not pin-compatible; different footprint and threshold | Select when 3.3V rail monitoring is required and MR functionality is unnecessary |
Compared with MAX6805US44D3+T, the MAX6804US44D3+T offers push/pull drive eliminating external pullup needs but lacks open-drain flexibility, while TPS3808G33DBVR provides lower current and tighter threshold tolerance at the cost of losing manual reset and requiring PCB redesign.
Availability
MAX6805US44D3+T is available at Aetrix Electronics and suitable for industrial controllers, portable medical instruments, automotive body control modules, and smart energy meters requiring stable component supply with guaranteed long-term availability and RoHS-compliant packaging.
Supply support for MAX6805US44D3+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 industrial, automotive, and computing applications, with expertise in power management, sensing, and interface solutions.
The MAX6803/MAX6804/MAX6805 family was developed specifically for space-constrained, low-power microprocessor supervision - delivering factory-trimmed thresholds, multiple timeout options, and robust transient immunity in minimal 4-pin SOT143 form factor.
FAQ
What is the exact reset threshold voltage of MAX6805US44D3+T and how tightly is it specified?
The MAX6805US44D3+T has a factory-trimmed reset threshold of 4.38V, specified as ±1.8% at +25°C and ±3% over the full –40°C to +125°C operating temperature range. This tolerance ensures reliable detection of brownout on 4.5V nominal rails without requiring external calibration components, and is verified per Table 1 in the official datasheet.
Does MAX6805US44D3+T require an external pullup resistor on the RESET pin, and why?
Yes, MAX6805US44D3+T requires an external pullup resistor on the RESET pin because it features an open-drain output structure. Without this resistor, the RESET signal would float when deasserted, risking undefined logic states. A typical value is 10–100kΩ to VCC or another compatible rail, enabling wired-OR interfacing with bidirectional µP reset pins like those found on the Motorola 68HC11.
What is the minimum VCC voltage at which MAX6805US44D3+T guarantees correct reset assertion?
MAX6805US44D3+T guarantees correct reset assertion and output state validity down to VCC = 1.0V at –40°C to +125°C, and down to 1.2V across the full temperature range. This specification ensures reliable operation during deep brownout conditions where other supervisors may release reset prematurely, making it suitable for battery-powered equipment with steep discharge curves.
How does the manual-reset (MR) input of MAX6805US44D3+T behave, and what external components are needed?
The MR input of MAX6805US44D3+T is active-low with an internal 20kΩ pullup resistor, so it can be left unconnected if unused. To implement manual reset, connect a normally open momentary switch between MR and GND. No external debounce circuitry is required due to built-in glitch immunity (50ns) and internal debouncing - simplifying design and reducing component count.
What is the reset timeout period of MAX6805US44D3+T, and is it adjustable?
MAX6805US44D3+T has a fixed 100ms minimum reset timeout period, factory-programmed via the "D3" suffix in the part number. This timeout is non-adjustable and guaranteed over temperature (–40°C to +125°C). It ensures sufficient hold time for microcontroller initialization sequences, including flash memory setup and peripheral configuration, without requiring external timing capacitors.
MAX6805US44D3+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- TO-253-4, TO-253AA
- Packaging:
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.38V
- 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-143-4
MAX6805US44D3+T FAQ
1.How can I place an order for MAX6805US44D3+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6805US44D3+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 MAX6805US44D3+T reliable?
The price and inventory of MAX6805US44D3+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6805US44D3+T is usually 5 days.
3.What payment methods are accepted for MAX6805US44D3+T?
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4.How is shipping managed for MAX6805US44D3+T?
MAX6805US44D3+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6805US44D3+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 MAX6805US44D3+T?
For technical support, including MAX6805US44D3+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6805US44D3+T requirements.
6.How does Aetrix verify that MAX6805US44D3+T is sourced from the original manufacturer or authorized distributors?
All MAX6805US44D3+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 MAX6805US44D3+T meets industry standards.
7.What is the process for return or replacement of MAX6805US44D3+T?
All MAX6805US44D3+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6805US44D3+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 MAX6805US44D3+T part is unused and in its original packaging.
Return procedure for MAX6805US44D3+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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