My Inquiry
My Account
Analog Devices Inc./Maxim Integrated MAX6421US46+T
- Part No.:
- MAX6421US46+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- TO-253-4, TO-253AA
- Datasheet:
-
MAX6421US46+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT143-4
- Quantity:
- Payment:
- Shipping:
Inventory:1,015
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MAX6421US46+T from Analog Devices is a low-power microprocessor supervisor IC that monitors VCC supply voltage and asserts an active-low push-pull reset signal when voltage falls below 4.625V (typical), with capacitor-adjustable timeout (3.0–5.75ms at CSRT = 1500pF), guaranteed valid down to VCC = 1V, and quiescent current of 1.6µA (typ) - used in battery-powered controllers and portable equipment for reliable power-on reset sequencing.
For engineers reviewing the MAX6421US46+T datasheet, MAX6421US46+T pinout, MAX6421US46+T application, or MAX6421US46+T equivalent, key selection criteria include reset threshold accuracy (±1.5% at +25°C), SRT pin ramp current (240nA), open-drain vs. push-pull output compatibility, and SC70/SOT143 package constraints for space-constrained embedded designs.
Technical Context
The MAX6421US46+T implements a precision voltage-monitoring circuit with laser-trimmed internal resistors to set its 4.625V nominal reset threshold, referenced to a stable 0.65V internal bandgap. Its reset assertion logic is triggered by VCC falling below VTH, with hysteresis of 4×VTH (≈18.5mV) to prevent chatter during brownout recovery.
Reset deassertion timing is controlled by an external capacitor (CSRT) charged by a 240nA current source on the SRT pin; the capacitor must ramp to 0.65V to end the timeout period. The device guarantees functional operation across –40°C to +125°C and remains valid down to VCC = 1V, enabling robust supervision in deep-brownout scenarios.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.625V (typ), ±1.5% at +25°C - sets precise power-fail detection point for 5V systems |
| Quiescent Current | 1.6µA (typ) at VCC ≤ 2.0V - enables multi-year battery life in always-on monitoring |
| Reset Timeout | 3.0–5.75ms (CSRT = 1500pF) - configurable delay ensures µP initialization completes before release |
| VCC Valid Range | 1.0V to 5.5V - operates through deep brownout and supports wide-input industrial supplies |
| Output Type | Active-low push-pull - drives reset input directly without external pullup, simplifying BOM |
| Operating Temp | –40°C to +125°C - qualified for automotive under-hood and industrial control environments |
| Reset Delay tRD | 80µs (VCC falling at 1mV/µs) - fast response prevents spurious code execution during transients |
Pinout & Package
MAX6421US46+T is packaged in a 4-pin SOT143 (U4+1) surface-mount package, measuring 1.6mm × 2.1mm × 0.95mm, with gull-wing leads and RoHS-compliant lead-free finish (+T suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VCC | Supply voltage input and monitored rail - connects to system VCC; powers internal circuitry and threshold reference |
| 2 | GND | Analog ground reference - must be low-impedance connection to minimize noise coupling into SRT and threshold sensing |
| 3 | RESET | Active-low push-pull reset output - sinks up to 3.2mA at VCC ≥ 4.5V; drives µP reset pin directly without pullup |
| 4 | SRT | Set Reset Timeout input - accepts external capacitor (CSRT); 240nA current source charges it to 0.65V to define timeout |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-adjustable reset timeout | Enables precise tuning of reset hold time (275µs to >100ms) via single external capacitor - eliminates fixed-timing limitations |
| Guaranteed reset validity to VCC = 1V | Ensures deterministic reset behavior during deep brownout, preventing undefined µP states when supply collapses |
| Low 1.6µA quiescent current | Reduces standby power in battery-critical applications such as medical wearables and remote sensors |
| Immunity to short VCC transients | Rejects glitches ≤50µs at 100mV overdrive - avoids false resets caused by switching noise or ESD |
| Laser-trimmed reset threshold | Delivers ±1.5% accuracy at +25°C and ±2.5% over full temperature range - reduces need for system-level calibration |
Applications
| Battery-Powered Portable Controllers | Automotive Body Control Modules |
|---|---|
Use Scenario: Supervising microcontrollers in handheld test instruments powered by single-cell Li-ion batteries (2.7–4.2V). IC Role / Device Role / Timing Role: Monitors declining battery voltage and asserts RESET before brownout causes firmware corruption; timeout ensures full µP boot sequence completes. Use Value: Prevents erratic behavior during low-battery shutdown, extending usable runtime and ensuring safe state retention. | Use Scenario: Power-on reset generation for LIN bus nodes in door modules exposed to cold cranking (VCC dip to 3.5V). IC Role / Device Role / Timing Role: Detects VCC drop below 4.625V during engine start and holds µP in reset until stable 5V rail is restored and timeout expires. Use Value: Eliminates boot failures during transient undervoltage events, improving module reliability per AEC-Q100 requirements. |
| Medical Patient Monitoring Devices | Industrial Embedded Controllers |
Use Scenario: Ensuring deterministic startup of ECG acquisition processors after AC/DC adapter reconnection. IC Role / Device Role / Timing Role: Acts as primary power-good monitor; asserts RESET during adapter plug-in bounce and releases only after stable VCC and timeout. Use Value: Guarantees no partial initialization or memory corruption - critical for FDA Class II device certification. | Use Scenario: Supervising ARM Cortex-M4-based PLC I/O modules operating from unregulated 24V DC supplies with ripple. IC Role / Device Role / Timing Role: Provides accurate 4.625V threshold detection and adjustable timeout to accommodate slow-rising rails and long µP boot sequences. Use Value: Enables robust operation despite input ripple and thermal drift, reducing field returns due to boot failures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor reset supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6421XS46+T | Same electrical specs and reset threshold, but in 4-pin SC70 (X4+1) package - 0.8mm height vs. SOT143's 0.95mm | Preferred where board height is constrained; identical pinout but different land pattern and thermal mass | Select for ultra-thin portable designs requiring minimal Z-height; verify solder paste volume and reflow profile for SC70. |
| TLV803EB46DBZR | Fixed 4.63V threshold, 35µA ICC (vs. 1.6µA), no capacitor-adjustable timeout - uses internal timer (~200ms) | Suitable for cost-sensitive, non-adjustable timing applications; lacks fine-grained timeout control | Choose when timeout flexibility is unnecessary and lower BOM count outweighs quiescent current penalty. |
Compared with MAX6421XS46+T, the MAX6421US46+T offers identical functionality in a slightly taller but thermally superior SOT143 package; versus TLV803EB46DBZR, it delivers 22× lower quiescent current and programmable timeout - critical for energy harvesting and long-life battery systems.
Availability
MAX6421US46+T is available at Aetrix Electronics and suitable for battery-powered portable controllers, automotive body electronics, and medical patient monitors requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX6421US46+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 MAX6421US46+T belongs to the MAX6340/MAX6421–MAX6426 family of low-power µP 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 the MAX6421US46+T?
The MAX6421US46+T has a nominal reset threshold of 4.625V, with ±1.5% accuracy at +25°C and ±2.5% over the full –40°C to +125°C operating range. This value is laser-trimmed at wafer test and confirmed in the Electrical Characteristics table under VTH parameter. The "46" suffix in MAX6421US46+T explicitly denotes this 4.625V threshold per Table 1 in the datasheet.
Does the MAX6421US46+T require an external capacitor to function?
The MAX6421US46+T does not require an external capacitor to assert reset - it will trigger immediately upon VCC falling below threshold. However, the SRT pin must be connected to ground via a capacitor (CSRT) to enable the reset timeout feature. With CSRT = 0, timeout defaults to 275µs; typical values range from 1000pF (≈3ms) to 10nF (>25ms). Omitting CSRT disables adjustable delay.
Can the MAX6421US46+T operate with a 3.3V supply rail?
Yes, the MAX6421US46+T operates with VCC from 1.0V to 5.5V, so it functions correctly on a 3.3V rail. However, its 4.625V reset threshold means it will assert reset whenever VCC drops below that level - making it unsuitable for direct 3.3V supervision. It is intended for 5V systems or higher-supply applications where brownout detection occurs above 4.6V.
What is the maximum load the RESET pin of MAX6421US46+T can drive?
The RESET pin of MAX6421US46+T is an active-low push-pull output capable of sinking up to 3.2mA at VCC ≥ 4.5V (VOL ≤ 0.4V), 1.2mA at VCC ≥ 2.7V (VOL ≤ 0.3V), and 50µA at VCC ≥ 1.0V (VOL ≤ 0.3V). It cannot source current - it only pulls low. For driving high-capacitance or multi-load reset buses, verify total sink current stays within these limits.
Is the MAX6421US46+T AEC-Q100 qualified?
No, the MAX6421US46+T is not AEC-Q100 qualified. Only the MAX6340UK31/V+T variant in the same family carries AEC-Q100 qualification. The MAX6421US46+T is rated for –40°C to +125°C operation and meets industrial reliability standards, but it lacks the extended stress testing and failure analysis required for automotive qualification.
MAX6421US46+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- TO-253-4, TO-253AA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.625V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- Adjustable/Selectable
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-143-4
MAX6421US46+T FAQ
1.How can I place an order for MAX6421US46+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6421US46+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 MAX6421US46+T reliable?
The price and inventory of MAX6421US46+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6421US46+T is usually 5 days.
3.What payment methods are accepted for MAX6421US46+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6421US46+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6421US46+T?
MAX6421US46+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6421US46+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 MAX6421US46+T?
For technical support, including MAX6421US46+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6421US46+T requirements.
6.How does Aetrix verify that MAX6421US46+T is sourced from the original manufacturer or authorized distributors?
All MAX6421US46+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 MAX6421US46+T meets industry standards.
7.What is the process for return or replacement of MAX6421US46+T?
All MAX6421US46+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6421US46+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 MAX6421US46+T part is unused and in its original packaging.
Return procedure for MAX6421US46+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX6421US46+T Tags
-
MIC826SYMT-TR
Microchip Technology
-
APX803S-31SA-7
Diodes Incorporated
-
APX803L20-29SA-7
Diodes Incorporated
-
TPS3828-33DBVR
Texas Instruments
-
V6340RSP3B+
EM Microelectronic
-
EM6325CXSP5B-2.9+
EM Microelectronic
-
MCP120T-300I/TT
Microchip Technology
-
MCP130T-315I/TT
Microchip Technology
-
MCP120T-475I/TT
Microchip Technology
-
MCP111T-300E/TT
Microchip Technology
-
MCP120T-315I/TT
Microchip Technology
-
MCP809T-315I/TT
Microchip Technology
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
