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Analog Devices Inc./Maxim Integrated MAX6423US44
- Part No.:
- MAX6423US44
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- TO-253-4, TO-253AA
- Datasheet:
-
MAX6423US44.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT143-4
- Quantity:
- Payment:
- Shipping:
Inventory:2,009
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Product details
Overview
MAX6423US44 from Maxim Integrated is a low-power microprocessor supervisor IC with open-drain active-low reset output, 4.375V factory-trimmed reset threshold (±2.5% over -40°C to +125°C), capacitor-adjustable reset timeout (275µs base + 2.73s/F × CSRT), and guaranteed operation down to VCC = 1V. It monitors system supply voltage in portable, automotive, and medical equipment where precise brownout detection and flexible reset timing are critical.
For engineers reviewing the MAX6423US44 datasheet, MAX6423US44 pinout, MAX6423US44 application, or MAX6423US44 equivalent, key selection factors include its SOT143-4 open-drain output topology, 1.6µA typical quiescent current, immunity to sub-50µs VCC transients at 100mV overdrive, and compatibility with multi-rail logic interfacing via external pullup.
Technical Context
The MAX6423US44 uses an internal 240nA current source to charge an external capacitor (CSRT) connected between SRT and GND, generating a voltage ramp compared to a 0.65V internal reference to determine reset timeout. Its reset assertion occurs when VCC falls below 4.375V, with hysteresis of 4×VTH (≈17.5mV) to prevent chatter during slow supply transitions.
As an open-drain device, MAX6423US44 requires an external pullup resistor (10kΩ–100kΩ) to a logic rail independent of VCC - enabling interface with µPs operating at 1.8V, 3.3V, or 5V while maintaining valid reset signaling down to VCC = 1V. It is not rated for valid output below 1V without external biasing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.375V ±2.5% (factory-laser-trimmed suffix '44'), ensuring accurate brownout detection at nominal 3.3V/5V rails |
| Quiescent Current | 1.6µA typical at +25°C, enabling >10-year battery life in always-on monitoring applications |
| Reset Timeout Base | 275µs minimum (CSRT = 0), providing deterministic minimum reset hold time before timeout adjustment |
| VCC Operating Range | 1.0V to 5.5V, guaranteeing functional reset assertion even during deep brownout conditions |
| Output Type | Active-low open-drain RESET, allowing wired-OR configuration with auxiliary reset sources |
| Transient Immunity | Immune to VCC glitches ≤50µs duration when falling 100mV below threshold, reducing false resets |
| Temperature Range | -40°C to +125°C, qualified for under-hood automotive and industrial embedded environments |
Pinout & Package
MAX6423US44 is housed in a 4-pin SOT143-4 package (1.3mm × 1.3mm × 0.95mm, 0.95mm pitch), optimized for space-constrained portable and automotive PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VCC | Supply voltage and reset threshold monitor input | Primary power rail connection; internal bandgap reference and comparator derive reset threshold from this pin |
| 2 - GND | Ground reference | Analog and digital ground return; must be low-impedance to ensure accurate threshold sensing and SRT ramp stability |
| 3 - RESET | Active-low open-drain reset output | Drives low during reset; requires external pullup to define logic-high level and sink capability for µP reset input |
| 4 - SRT | Set Reset Timeout input | Connects to external timing capacitor; 240nA constant current charges CSRT to generate adjustable timeout delay |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-adjustable reset timeout | Enables precise tailoring of reset hold time (e.g., 100ms–1s) using standard ceramic capacitors without firmware or external logic |
| Open-drain RESET with multi-supply compatibility | Allows single MAX6423US44 to drive reset lines referenced to different voltage domains (e.g., 1.8V core + 3.3V I/O) |
| Guaranteed reset validity to VCC = 1V | Ensures reliable reset assertion during deep undervoltage events where most µPs lose functionality |
| Low 1.6µA quiescent current | Minimizes battery drain in always-on supervisory functions, critical for coin-cell-powered IoT sensors |
| Factory-trimmed 4.375V threshold (suffix '44') | Eliminates need for external resistor dividers or calibration, reducing BOM count and layout complexity |
Applications
| Automotive Body Control Module | Portable Medical Glucose Monitor |
|---|---|
|
Use Scenario: Monitors 5V system rail in BCM during cold-crank (VCC dip to 6.5V→3.2V) and load-dump transients. IC Role / Device Role / Timing Role: Voltage supervisor asserting active-low RESET to ARM Cortex-M4 until stable 5V is restored and timeout expires. Use Value: Prevents MCU lockup during engine start by holding reset for ≥200ms after VCC exceeds 4.375V, validated across -40°C to +125°C. |
Use Scenario: Powers on/off sequence control in battery-operated glucose meter with 3.3V LDO and BLE radio. IC Role / Device Role / Timing Role: Supervises main 3.3V rail and triggers controlled reset if battery drops below 3.4V (4.375V threshold scaled via divider). Use Value: Enables safe shutdown before EEPROM corruption; 1.6µA ICC extends AA battery life to >2 years in standby mode. |
| Industrial PLC I/O Module | Set-Top Box Power Management |
|
Use Scenario: Ensures deterministic startup of FPGA-based I/O controller after 24V DC-DC converter stabilizes. IC Role / Device Role / Timing Role: Generates reset pulse only after VCC > 4.375V and holds for 500ms (CSRT = 180nF) to allow FPGA configuration completion. Use Value: Eliminates need for RC network with temperature drift; ±2.5% threshold accuracy prevents premature release at high ambient. |
Use Scenario: Coordinates power sequencing between 1.2V SoC core, 3.3V memory, and 5V HDMI PHY in STB mainboard. IC Role / Device Role / Timing Role: Open-drain RESET pulled up to 3.3V domain, enabling shared reset line with other supervisors and PMICs. Use Value: Supports wired-OR reset architecture: external watchdog or thermal shutdown can extend system reset independently of MAX6423US44 timeout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6423XS44-T | Same electrical specs and reset threshold, but in SC70-4 package (1.25mm × 1.25mm); 0.65mm pitch vs. SOT143's 0.95mm | Preferred for ultra-dense layouts where 0.3mm² footprint reduction matters; thermal derating differs (3.1mW/°C vs. 4mW/°C) | Select MAX6423XS44-T only if board assembly supports finer-pitch SC70 reflow and thermal margin allows lower power dissipation limit. |
| NCP302LSN43T1G | Fixed 4.3V threshold (±2%), push-pull output, no adjustable timeout; 1.1µA ICC, SOT23-3 package | Lacks capacitor-adjustable delay and open-drain flexibility; requires PCB redesign for push-pull interface and no SRT pin | Choose NCP302LSN43T1G only when fixed 200ms timeout suffices and system reset logic is strictly single-rail with no wired-OR requirement. |
Compared with MAX6423US44, MAX6423XS44-T offers identical supervision functionality in a smaller footprint but reduced thermal margin, while NCP302LSN43T1G trades adjustability and interface flexibility for lower cost and simpler layout - neither is pin-compatible, requiring PCB revision for substitution.
Availability
MAX6423US44 is available at Aetrix Electronics and suitable for automotive body control modules, portable medical devices, industrial PLC I/O modules, and set-top box power management systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6423US44 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, mixed-signal, and power management ICs for demanding industrial, automotive, and computing applications.
The MAX6421–MAX6426 family delivers ultra-low-power, capacitor-programmable reset supervision for battery-sensitive and thermally harsh environments - specifically engineered for reliable µP reset assertion during brownout, cold-crank, and transient events.
FAQ
What is the exact reset threshold voltage of MAX6423US44 and how is it trimmed?
The MAX6423US44 has a factory-laser-trimmed reset threshold of 4.375V, with ±2.5% tolerance over -40°C to +125°C. This value is permanently set during wafer test using Maxim's BiCMOS process and corresponds to suffix '44' per Table 1 in the datasheet. No external components or calibration are needed to achieve this accuracy.
Can MAX6423US44 drive a reset line referenced to a different voltage than its VCC supply?
Yes - MAX6423US44 features an open-drain RESET output, so its logic-high level is defined solely by the external pullup resistor's connection point. For example, with VCC = 3.3V and pullup to 1.8V, MAX6423US44 can safely assert reset to a 1.8V-core µP without level-shifting circuitry, provided VOL ≤ 0.3V at ISINK = 500µA.
How do I calculate the capacitor value needed for a 500ms reset timeout with MAX6423US44?
Use the formula CSRT = (tRP − 275µs) / 2.73×10⁶, where tRP is in seconds. For 500ms: CSRT = (0.5 − 0.000275) / 2,730,000 ≈ 182nF. A standard 180nF X7R ceramic capacitor (low leakage <10nA) achieves ~495ms timeout, verified in Typical Operating Characteristics figure toc02.
Does MAX6423US44 remain functional when VCC drops below 1.0V?
No - MAX6423US44 guarantees valid RESET output only down to VCC = 1.0V. Below this, output drive strength collapses and logic state becomes indeterminate. For zero-voltage reset validity, add a 100kΩ pulldown from RESET to GND, as shown in Figure 3 of the datasheet - this ensures RESET stays low even as VCC approaches 0V.
What package type and dimensions does MAX6423US44 use, and is it RoHS-compliant?
MAX6423US44 uses the SOT143-4 package: 1.3mm × 1.3mm × 0.95mm body size with 0.95mm lead pitch. It is available in both leaded and lead-free versions; specify lead-free by ordering MAX6423US44+T (replacing '-T') per Maxim's packaging note. Thermal resistance is 4mW/°C above +70°C.
MAX6423US44 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:
- 4.375V
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- Adjustable/Selectable
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-4
MAX6423US44 FAQ
1.How can I place an order for MAX6423US44 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6423US44 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 MAX6423US44 reliable?
The price and inventory of MAX6423US44 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6423US44 is usually 5 days.
3.What payment methods are accepted for MAX6423US44?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6423US44 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6423US44?
MAX6423US44 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6423US44 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 MAX6423US44?
For technical support, including MAX6423US44 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6423US44 requirements.
6.How does Aetrix verify that MAX6423US44 is sourced from the original manufacturer or authorized distributors?
All MAX6423US44 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 MAX6423US44 meets industry standards.
7.What is the process for return or replacement of MAX6423US44?
All MAX6423US44 units undergo pre-shipment inspection (PSI). If there is an issue with MAX6423US44, 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 MAX6423US44 part is unused and in its original packaging.
Return procedure for MAX6423US44:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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