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Analog Devices Inc./Maxim Integrated MAX6420UK44-T
- Part No.:
- MAX6420UK44-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6420UK44-T.pdf
- Description:
- IC SUPERVISOR 2 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:12,500
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Product details
Overview
MAX6420UK44-T from Maxim Integrated is a low-power, dual-voltage microprocessor reset supervisor IC with one factory-trimmed VCC reset threshold (4.375V typical) and one adjustable RESET IN input for monitoring secondary voltages down to 1.26V. It features an active-low open-drain RESET output, capacitor-adjustable reset timeout delay, manual reset capability via external switch, and guaranteed valid reset assertion down to VCC = 1V. It is used in battery-powered controllers and automotive ECUs requiring dual-rail voltage supervision.
For engineers reviewing the MAX6420UK44-T datasheet, MAX6420UK44-T pinout, MAX6420UK44-T application, or MAX6420UK44-T equivalent, key selection criteria include its 4.375V fixed VCC threshold, open-drain output compatibility with mixed-supply µPs, 1.7µA quiescent current, -40°C to +125°C operation, and SOT23-5 package footprint.
Technical Context
The MAX6420UK44-T integrates two independent reset comparators: one laser-trimmed for VCC at 4.375V (±2.5% over temperature), and one adjustable comparator referenced to 1.26V on the RESET IN pin, enabling dual-voltage monitoring of rails like 5V/3.3V or 3.3V/1.8V. Reset assertion occurs if either voltage falls below its threshold or MR is pulled low.
Reset deassertion is delayed by an externally set timeout period determined by a capacitor on the SRT pin, using a precision 240nA ramp current charging to a 0.65V internal reference. The open-drain RESET output supports level-shifting across supply domains up to 5.5V, with leakage <1.0µA when inactive.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Reset Threshold | 4.375V (typ), ±2.5% over -40°C to +125°C - ensures reliable power-up reset for 5V systems with margin against brownout |
| RESET IN Threshold | 1.26V (fixed reference), enables monitoring of secondary rails ≥1.26V via external resistor divider |
| Quiescent Current | 1.7µA (typ at +25°C) - supports multi-year battery life in portable and automotive always-on modules |
| Reset Timeout Range | 0.275ms to >6ms (with CSRT = 0–1500pF) - configurable to match µP minimum reset pulse width requirements |
| Operating Temperature | -40°C to +125°C - qualified for under-hood automotive and industrial embedded applications |
| Output Type | Active-low open-drain - allows wired-OR configuration and interface to µPs with different I/O supply voltages (up to 5.5V) |
| VCC Validity Range | Guaranteed RESET assertion down to VCC = 1.0V - ensures robust reset behavior during deep brownout conditions |
Pinout & Package
Package: SOT23-5, surface-mount, RoHS-compliant, 5-pin plastic small-outline transistor package with 0.95mm pitch and 2.9mm × 1.6mm footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RESET | Active-low open-drain reset output | Drives µP reset input low; requires external pullup; compatible with 0–5.5V logic domains |
| 2 - GND | Ground reference | Primary return path for internal comparators, ramp current source, and output stage |
| 3 - RESET IN | Adjustable reset threshold input | High-impedance node (10nA leakage) for external resistor-divider; sets secondary rail trip point ≥1.26V |
| 4 - MR | Manual reset input | Active-low input with 20kΩ internal pullup; initiates reset when pulled to GND via momentary switch |
| 5 - SRT | Set reset timeout input | Connects to external timing capacitor; hosts precision 240nA current source for programmable delay |
Key Features
| Feature | Design Value |
|---|---|
| Dual-voltage supervision | Simultaneously monitors primary VCC (4.375V) and secondary rail (via RESET IN) - eliminates need for two discrete supervisors in multi-rail systems |
| Capacitor-adjustable timeout | Reset duration set by single external capacitor (0–1500pF), enabling precise matching to µP reset pulse width specs without firmware changes |
| Open-drain RESET output | Supports level translation and wired-OR reset buses - simplifies integration with mixed-voltage µPs and FPGA configuration logic |
| Low-power operation | 1.7µA typical supply current enables use in energy-constrained applications such as telematics modules and sensor nodes |
| Automotive-grade reliability | Specified from -40°C to +125°C with AEC-Q100 stress qualification - suitable for engine control, ADAS, and body electronics |
Applications
| Automotive Engine Control Unit | Medical Infusion Pump |
|---|---|
Use Scenario: Supervises both 5V main logic rail and 3.3V MCU core voltage in an ECU exposed to wide temperature and transient voltage variations. IC Role / Device Role / Timing Role: Dual-threshold supervisor asserting RESET if either rail drops below spec; timeout delay prevents spurious resets during cranking transients. Use Value: Ensures deterministic µP restart after cold-crank brownout (VCC dip to 3.2V) while maintaining secondary rail integrity - critical for ASIL-B functional safety compliance. | Use Scenario: Monitors battery-backed 3.3V system rail and isolated 1.8V analog sensor supply in a portable infusion pump with strict power budget. IC Role / Device Role / Timing Role: Provides fail-safe reset initiation on either rail collapse, with open-drain output interfacing to 3.3V µP and 5V display controller. Use Value: 1.7µA quiescent current extends battery runtime; dual monitoring prevents silent firmware lockup due to undervoltage on isolated analog domain. |
| Industrial PLC I/O Module | Smart Energy Meter |
Use Scenario: Embedded in DIN-rail mounted I/O module requiring supervision of 24V-to-5V DC/DC output and isolated 3.3V communication rail. IC Role / Device Role / Timing Role: Uses RESET IN to monitor 3.3V rail via resistor divider; VCC pin supervises 5V logic supply; MR supports field-service reset. Use Value: Eliminates need for separate voltage detectors; SOT23-5 footprint saves PCB area in space-constrained modules; -40°C to +125°C rating ensures outdoor deployment reliability. | Use Scenario: Supervises 3.3V metrology processor rail and 1.2V ADC reference rail in a revenue-grade electricity meter operating continuously for 15+ years. IC Role / Device Role / Timing Role: Factory-trimmed 3.3V threshold (via UK44 suffix) monitors main rail; RESET IN configured for 1.25V trip on reference rail using high-value resistors. Use Value: Laser-trimmed accuracy (±2.5%) ensures consistent reset behavior over lifetime; low leakage (<10nA) on RESET IN preserves long-term calibration stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-voltage reset supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6326UT44D3+ | Fixed 4.40V threshold, no adjustable RESET IN; push-pull active-low output; 1.2µA ICC | Single-rail only; lacks dual-monitoring capability; higher reset accuracy (±0.5%) but no secondary rail support | Select when only VCC supervision is needed and ultra-low ICC is prioritized over flexibility |
| TPS3808G33DBVR | Fixed 3.3V threshold, no adjustable input; open-drain output; 1.8µA ICC; includes watchdog timer | Single-rail supervision only; adds watchdog functionality but cannot monitor secondary voltage | Select when watchdog capability is required alongside basic reset, and dual-rail monitoring is unnecessary |
Compared with MAX6420UK44-T, MAX6326UT44D3+ offers tighter threshold tolerance but no dual-voltage capability, while TPS3808G33DBVR adds watchdog functionality at the cost of losing adjustable secondary rail monitoring - making MAX6420UK44-T uniquely suited for compact dual-rail systems needing flexible, low-power supervision.
Availability
MAX6420UK44-T is available at Aetrix Electronics and suitable for automotive engine control units, medical infusion pumps, industrial PLC I/O modules, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6420UK44-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 is a semiconductor company specializing in analog and mixed-signal ICs for power management, sensing, and interface applications, now part of Analog Devices.
The MAX64xx family was designed specifically for low-power, high-reliability microprocessor supervision in harsh environments - emphasizing dual-rail monitoring, capacitor-programmable timing, and extended temperature operation for automotive and industrial use.
FAQ
What is the exact VCC reset threshold voltage for MAX6420UK44-T?
The MAX6420UK44-T has a factory-trimmed VCC reset threshold of 4.375V (typical), with ±2.5% tolerance over the full -40°C to +125°C operating range. This value corresponds to the "44" suffix per Table 1 in the datasheet and is laser-trimmed for accuracy. The MAX6420UK44-T does not require external components to set this threshold - it is internally fixed and verified during production test.
How do I configure the MAX6420UK44-T to monitor a 3.3V secondary rail?
To monitor a 3.3V rail with the MAX6420UK44-T, connect the rail to the RESET IN pin through a resistor divider that scales 3.3V down to 1.26V - the internal reference voltage. Using R2 = 1MΩ, calculate R1 = R2 × (3.3V / 1.26V − 1) ≈ 1.61MΩ. The MAX6420UK44-T's high-impedance RESET IN input (10nA leakage) ensures minimal loading. No additional components are needed beyond the divider.
Does MAX6420UK44-T support manual reset, and how is it implemented?
Yes, the MAX6420UK44-T supports manual reset via the MR pin (Pin 4), which has an internal 20kΩ pullup resistor. To implement manual reset, connect a normally open momentary switch between MR and GND. When pressed, the switch pulls MR low, asserting RESET for the full timeout period after release. No external debounce circuitry is required due to the device's built-in glitch rejection (75ns) and long timeout configurability.
What capacitor value is needed for a 200ms reset timeout with MAX6420UK44-T?
The MAX6420UK44-T does not support 200ms timeout - its maximum achievable timeout is ~6ms with CSRT = 1500pF. The timeout formula is tRP = (2.71 × 10⁶) × CSRT + 275µs. Solving for CSRT at 200ms yields ~73.6nF, which exceeds the recommended 1500pF limit and introduces significant error due to leakage and parasitic effects. For timeouts >6ms, consider a microcontroller-based supervisor or a dedicated long-delay IC.
Can MAX6420UK44-T operate reliably at VCC = 1.2V?
Yes, the MAX6420UK44-T guarantees valid RESET assertion down to VCC = 1.0V, including at 1.2V. Its internal comparators and ramp circuit remain functional, and the open-drain RESET output maintains specified VOL and leakage performance. However, for applications requiring valid logic levels *below* 1.0V (e.g., down to 0V), an external pulldown resistor (e.g., 100kΩ) on the RESET pin is recommended - as documented in the "Ensuring a Valid RESET Down to VCC = 0V" section of the MAX6420UK44-T datasheet.
MAX6420UK44-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 2
- Voltage - Threshold:
- 4.375V, Adj
- 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-23-5
MAX6420UK44-T FAQ
1.How can I place an order for MAX6420UK44-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6420UK44-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 MAX6420UK44-T reliable?
The price and inventory of MAX6420UK44-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6420UK44-T is usually 5 days.
3.What payment methods are accepted for MAX6420UK44-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6420UK44-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6420UK44-T?
MAX6420UK44-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6420UK44-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 MAX6420UK44-T?
For technical support, including MAX6420UK44-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6420UK44-T requirements.
6.How does Aetrix verify that MAX6420UK44-T is sourced from the original manufacturer or authorized distributors?
All MAX6420UK44-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 MAX6420UK44-T meets industry standards.
7.What is the process for return or replacement of MAX6420UK44-T?
All MAX6420UK44-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6420UK44-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 MAX6420UK44-T part is unused and in its original packaging.
Return procedure for MAX6420UK44-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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