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Analog Devices Inc./Maxim Integrated MAX6426UK39+T
- Part No.:
- MAX6426UK39+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6426UK39+T.pdf
- Description:
- IC MPU/RESET CIRC 3.90V SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,618
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Product details
Overview
MAX6426UK39+T from Analog Devices is a low-power microprocessor supervisor IC with open-drain active-low reset output, 3.9V ±2.5% factory-trimmed reset threshold, capacitor-adjustable reset timeout (2.73×10⁶ × CSRT + 275µs), 1.6µA typical quiescent current, and guaranteed operation down to VCC = 1V - used for brownout protection in battery-powered embedded controllers.
For engineers reviewing the MAX6426UK39+T datasheet, MAX6426UK39+T pinout, MAX6426UK39+T application, or MAX6426UK39+T equivalent, key selection factors include its SOT23-5 open-drain RESET output, 3.9V threshold accuracy over –40°C to +125°C, capacitor-programmable timeout, immunity to sub-50µs VCC transients, and compatibility with multi-rail logic interfacing.
Technical Context
The MAX6426UK39+T implements a precision voltage-monitoring circuit with laser-trimmed internal resistors defining a 3.9V reset threshold, referenced to an internal 0.65V ramp comparator. Its SRT pin sources a stable 240nA current to charge an external capacitor, generating a programmable delay before reset deassertion.
It features open-drain RESET output requiring an external pullup, valid for VCC ≥ 1V, with VOL ≤ 0.4V at 3.2mA sink and leakage <1.0µA when not asserted. The device operates across –40°C to +125°C and supports wired-OR reset configurations via its open-drain topology.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.900V ±2.5% (–40°C to +125°C); ensures reliable brownout detection at nominal 3.3V/3.6V system rails |
| Quiescent Current | 1.6µA typical at VCC ≤ 2.0V; enables >10-year battery life in always-on portable equipment |
| Reset Timeout Range | 275µs to 5.75ms (with CSRT = 0 to 1500pF); accommodates µP power-up sequences from fast MCUs to slow ASICs |
| VCC Operating Range | 1.0V to 5.5V; guarantees functional reset assertion even during deep brownout conditions |
| Output Type | Active-low open-drain RESET; allows level-shifting, wired-OR with auxiliary reset sources, and multi-supply logic compatibility |
| Transient Immunity | No reset issued for VCC glitches ≤50µs duration when falling 100mV below threshold; suppresses noise-induced false resets |
| Temperature Range | –40°C to +125°C; qualified for automotive under-hood and industrial control environments |
Pinout & Package
MAX6426UK39+T is housed in a 5-pin SOT23-5 package (package code U5+2), RoHS-compliant, tape-and-reel format. Pin 1 = VCC, Pin 2 = GND, Pin 3 = SRT, Pin 4 = N.C., Pin 5 = RESET (open-drain).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VCC | Supply and threshold monitor input | Power rail input; internally monitored against 3.9V reference; must be ≥1.0V for valid reset operation |
| 2 - GND | Ground reference | Analog and digital ground return; required for accurate threshold sensing and SRT ramp current reference |
| 3 - SRT | Set Reset Timeout input | 240nA constant-current source pin; connects to external capacitor to program reset timeout period |
| 4 - N.C. | No internal connection | Unbonded die pad; may be left floating or tied to GND per layout best practice; no electrical function |
| 5 - RESET | Open-drain reset output | Active-low signal; requires external pullup (10kΩ–100kΩ) to any supply ≤5.5V; sinks up to 3.2mA |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-adjustable reset timeout | Enables precise tailoring of reset hold time (275µs–5.75ms) without firmware or external logic |
| Guaranteed reset validity to VCC = 1V | Ensures deterministic system behavior during deep undervoltage events common in Li-ion discharge profiles |
| Open-drain RESET output | Supports wired-OR reset arbitration, multi-voltage domain interfacing (0–5.5V pullup), and flexible logic-level translation |
| 240nA SRT ramp current | Provides stable, temperature-invariant timing base for reset timeout; minimizes capacitor leakage sensitivity |
| ±2.5% threshold accuracy over full temp range | Reduces design margin requirements vs. ±5% parts, enabling tighter supply rail tolerancing in space-constrained systems |
Applications
| Battery-Powered Medical Monitor | Automotive Body Control Module |
|---|---|
|
Use Scenario: Portable ECG device powered by single-cell Li-ion (2.8–4.2V) with ultra-low-power MCU and analog front-end. IC Role / Device Role / Timing Role: Supervises VCC to assert RESET during battery sag below 3.9V, holding µP in reset until stable supply returns and timeout expires. Use Value: Prevents corrupted memory writes or sensor misreads during transient brownout; 1.6µA ICC extends battery runtime beyond 5 years in standby. |
Use Scenario: Under-dash BCM operating across –40°C to +105°C ambient, powered from vehicle battery (9–16V) with local 3.3V LDO. IC Role / Device Role / Timing Role: Monitors 3.3V LDO output; triggers open-drain RESET to coordinate safe shutdown/restart during ignition cycling or load-dump recovery. Use Value: Open-drain output interfaces directly to 5V CAN transceiver reset line; AEC-Q100-aligned thermal performance ensures reliability in harsh automotive environment. |
| Industrial IoT Sensor Node | Set-Top Box Power Sequencing |
|
Use Scenario: LoRaWAN node with intermittent wake-up, powered by energy harvester or coin cell, requiring fail-safe boot integrity. IC Role / Device Role / Timing Role: Detects insufficient startup voltage on 3.3V rail; asserts RESET until VCC exceeds 3.9V and remains stable for programmable timeout. Use Value: Capacitor-adjustable timeout (e.g., 4.375ms with 1500pF) matches exact µP POR requirement; low ICC avoids draining weak energy sources. |
Use Scenario: Consumer STB with multiple voltage rails (12V, 5V, 3.3V, 1.2V); requires controlled power-up sequence and brownout recovery. IC Role / Device Role / Timing Role: Monitors critical 3.3V core rail; RESET output drives enable logic for downstream DC/DC converters and FPGA configuration. Use Value: Open-drain RESET allows wired-OR with other supervisors (e.g., 5V rail monitor), ensuring system-wide reset coordination without additional logic gates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor reset supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| NCP302LSN39T1G | Fixed 3.9V threshold, push-pull active-low RESET, 1.2µA ICC, SOT23-5 | Lacks capacitor-adjustable timeout; timeout fixed at 200ms; no SRT pin | Select when fixed long timeout suffices and board space prohibits external capacitor; not suitable for µPs needing <1ms reset hold. |
| PST9239TR | 3.9V threshold, open-drain RESET, 1.8µA ICC, SOT23-5, pin-compatible per datasheet | Reset timeout not adjustable; uses internal RC (typ. 200ms); no SRT pin or external timing option | Drop-in replacement only if fixed timeout is acceptable; MAX6426UK39+T preferred when precise, user-defined timeout is required. |
Compared with NCP302LSN39T1G and PST9239TR, the MAX6426UK39+T uniquely provides externally programmable reset timeout via SRT capacitor while retaining open-drain flexibility and ultra-low ICC - making it optimal for designs demanding both timing precision and multi-rail interoperability.
Availability
MAX6426UK39+T is available at Aetrix Electronics and suitable for battery-powered medical monitors, automotive body control modules, and industrial IoT sensor nodes requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6426UK39+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
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The MAX6426UK39+T belongs to the MAX6340/MAX6421–MAX6426 family of ultra-low-power microprocessor supervisors, designed specifically for reliable power-on reset and brownout protection in space- and energy-constrained embedded systems.
FAQ
What is the exact reset threshold voltage of MAX6426UK39+T and how tightly is it specified?
The MAX6426UK39+T has a nominal reset threshold of 3.900V, with ±1.5% accuracy at +25°C and ±2.5% over the full operating temperature range of –40°C to +125°C. This specification is laser-trimmed at wafer test and guaranteed per the datasheet's Electrical Characteristics table, ensuring consistent brownout detection across environmental extremes.
Can MAX6426UK39+T operate reliably when VCC drops below 2.0V?
Yes - the MAX6426UK39+T guarantees functional reset assertion and valid open-drain output down to VCC = 1.0V. Its internal circuitry remains active and the RESET output maintains defined logic states (low when asserted, high-impedance when released) even during deep brownout, supporting robust fail-safe behavior in Li-ion or supercapacitor-backed systems.
How do I calculate the external capacitor value needed for a specific reset timeout with MAX6426UK39+T?
Use the formula CSRT = (tRP − 275µs) / 2.735 × 10⁶, where tRP is your desired timeout in seconds and CSRT results in farads. For example, a 4.375ms timeout requires CSRT = (0.004375 − 0.000275) / 2.735e6 ≈ 1500pF. Use low-leakage ceramic capacitors (X7R/C0G) with <10nA leakage for accuracy.
Is MAX6426UK39+T pin-compatible with any industry-standard alternatives?
Yes - the MAX6426UK39+T is explicitly documented as pin-compatible with the PST92XX series (e.g., PST9239TR) in the MAX6421–MAX6426 datasheet. Both use identical 5-pin SOT23-5 pinout (VCC, GND, SRT, N.C., RESET), enabling direct PCB footprint reuse where timing adjustability is not required.
Does MAX6426UK39+T require an external pullup resistor on the RESET pin, and what value is recommended?
Yes - because MAX6426UK39+T features an open-drain RESET output, an external pullup resistor is mandatory. A value between 10kΩ and 100kΩ to any supply ≤5.5V is recommended. For 3.3V systems sinking 1.2mA, 10kΩ ensures VOL ≤ 0.3V; for higher-impedance loads, 100kΩ reduces current draw while maintaining noise margin.
MAX6426UK39+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:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 3.9V
- 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
MAX6426UK39+T FAQ
1.How can I place an order for MAX6426UK39+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6426UK39+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 MAX6426UK39+T reliable?
The price and inventory of MAX6426UK39+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6426UK39+T is usually 5 days.
3.What payment methods are accepted for MAX6426UK39+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6426UK39+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6426UK39+T?
MAX6426UK39+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6426UK39+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 MAX6426UK39+T?
For technical support, including MAX6426UK39+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6426UK39+T requirements.
6.How does Aetrix verify that MAX6426UK39+T is sourced from the original manufacturer or authorized distributors?
All MAX6426UK39+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 MAX6426UK39+T meets industry standards.
7.What is the process for return or replacement of MAX6426UK39+T?
All MAX6426UK39+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6426UK39+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 MAX6426UK39+T part is unused and in its original packaging.
Return procedure for MAX6426UK39+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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