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Analog Devices Inc./Maxim Integrated MAX6421XS29-T
- Part No.:
- MAX6421XS29-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-82A, SOT-343
- Datasheet:
-
MAX6421XS29-T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SC70-4
- Quantity:
- Payment:
- Shipping:
Inventory:16,781
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Product details
Overview
MAX6421XS29-T from Maxim Integrated is a low-power microprocessor reset supervisor IC with push-pull active-low RESET output, 2.925V factory-trimmed reset threshold, and capacitor-adjustable reset timeout delay. It monitors VCC from 1.6V to 5V, asserts reset below threshold, holds reset for user-defined timeout after VCC recovery, and operates down to VCC = 1V. Used in battery-powered controllers and portable equipment requiring precise brownout protection.
For engineers reviewing the MAX6421XS29-T datasheet, MAX6421XS29-T pinout, MAX6421XS29-T application, or MAX6421XS29-T equivalent, key selection criteria include its SC70-4 package, 1.6µA quiescent current, ±1.5% reset threshold accuracy at +25°C, guaranteed reset validity to VCC = 1V, and immunity to short VCC transients up to 50µs at 100mV overdrive.
Technical Context
This device implements a precision voltage comparator with laser-trimmed reference and hysteresis (4×VTH), combined with a 240nA constant-current ramp generator charging an external SRT capacitor to set timeout. Reset assertion occurs when VCC falls below the 2.925V threshold; deassertion requires both VCC > VTH and SRT capacitor voltage ≥ 0.65V.
The push-pull output drives RESET low with VOL ≤ 0.4V at ISINK = 3.2mA (VCC ≥ 4.5V) and high with VOH ≥ 0.8×VCC (VCC ≥ 4.5V, ISOURCE = 800µA), ensuring robust interface to CMOS µP reset inputs without external pull-up. All logic is valid for VCC ≥ 1.0V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V nominal, ±1.5% at +25°C - ensures reliable detection of 3.3V system brownout before µP malfunction |
| Quiescent Current | 1.6µA typical - enables multi-year operation on coin-cell batteries in portable systems |
| Supply Range | 1.0V to 5.5V - supports operation during deep brownout and compatibility with 1.8V/2.5V/3.3V/5V rails |
| Reset Timeout | Adjustable via external capacitor: tRP = 2.73×10⁶ × CSRT + 275µs - allows precise tailoring to µP reset timing requirements |
| VCC to Reset Delay | 80µs typical - provides fast response to supply collapse while rejecting sub-80µs noise glitches |
| Output Type | Active-low push-pull - eliminates need for external pull-up resistor and ensures defined logic state at all times |
| Operating Temp | -40°C to +125°C - qualified for automotive under-hood and industrial embedded environments |
Pinout & Package
MAX6421XS29-T is housed in a 4-pin SC70-4 package (outline 21-0098), with 0.65mm pitch, 2.0mm × 1.25mm body size, and thermal pad not present. Pin 1 is SRT (Set Reset Timeout), Pin 2 is GND, Pin 3 is RESET (active-low push-pull), Pin 4 is VCC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - SRT | Reset timeout capacitor input | 240nA constant-current source charges external capacitor; timeout determined by time to reach 0.65V reference |
| 2 - GND | Analog and digital ground reference | Common return path for internal comparator, ramp generator, and output stage; must be low-impedance |
| 3 - RESET | Active-low push-pull reset output | Drives µP reset pin directly; sinks ≥3.2mA / sources ≥800µA; valid down to VCC = 1V |
| 4 - VCC | Supply and monitored voltage input | Power source and reset threshold reference; monitors own supply for undervoltage detection |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-adjustable timeout | Enables precise reset hold time tuning (e.g., 100ms–1s) without changing IC - avoids fixed-delay limitations |
| Low 1.6µA supply current | Minimizes battery drain in always-on monitoring applications - extends shelf life and runtime |
| Guaranteed reset validity to VCC = 1V | Ensures deterministic reset behavior during deep brownout - prevents µP from executing corrupted code |
| ±1.5% reset threshold accuracy | Reduces design margin needed for threshold setting - improves system reliability without overspec'ing supply |
| Immunity to 50µs VCC transients | Rejects common power rail noise without false resets - eliminates need for additional filtering components |
Applications
| Portable Medical Sensors | Battery-Powered Industrial Controllers |
|---|---|
Use Scenario: Wearable ECG monitor powered by CR2032 coin cell, requiring reliable reset during battery voltage sag. IC Role / Device Role / Timing Role: Voltage supervisor asserting active-low RESET to ARM Cortex-M0 µP when VCC drops below 2.925V. Use Value: 1.6µA quiescent current preserves battery life; capacitor-adjustable timeout ensures µP completes safe shutdown before power loss. | Use Scenario: Remote RTU in oil-field telemetry system operating on LiSOCl₂ battery with wide temperature range. IC Role / Device Role / Timing Role: Brownout detector triggering controlled reboot of MSP430F5xx µP during cold-start voltage ramp. Use Value: -40°C to +125°C rating and 2.925V threshold match 3.3V LDO tolerance; push-pull output guarantees clean reset edge without pull-up. |
| Automotive Body Control Modules | Smart Energy Meters |
Use Scenario: BCM microcontroller reset during vehicle ignition sequence where battery dips to 6V then recovers. IC Role / Device Role / Timing Role: Supervisory circuit holding µP in reset until 12V system stabilizes above 2.925V with 200ms timeout. Use Value: Immunity to 50µs transients rejects alternator ripple; SC70-4 footprint saves PCB area in space-constrained modules. | Use Scenario: Revenue-grade meter with metrology SoC requiring deterministic reset after AC power interruption. IC Role / Device Role / Timing Role: Primary reset supervisor asserting RESET until VCC from backup supercapacitor exceeds 2.925V. Use Value: Valid operation down to VCC = 1V ensures reset remains asserted through full capacitor discharge; ±1.5% threshold minimizes calibration drift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor reset supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6421US29-T | Same electrical specs and reset threshold, but in 4-pin SOT143-4 package (larger footprint, 0.95mm pitch) | Suitable where SOT143 land pattern exists or thermal dissipation >320mW required | Select MAX6421US29-T only if SC70 assembly capability is unavailable or board layout constraints favor SOT143. |
| TLV803EB29DBZR | Fixed 2.93V threshold, 35µA IQ, no adjustable timeout - uses internal timer; SOT23-3 package | Lacks capacitor-based timeout flexibility; lower accuracy (±2.5%) and higher current limit system runtime | Choose TLV803EB29DBZR only for cost-sensitive, space-constrained designs where fixed 200ms timeout suffices and µA-level IQ is not critical. |
Compared with MAX6421XS29-T, MAX6421US29-T offers identical functionality in a larger package, while TLV803EB29DBZR trades timeout adjustability and ultra-low IQ for lower cost and smaller pin count - making MAX6421XS29-T optimal for battery-critical, precision-timing applications.
Availability
MAX6421XS29-T is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered industrial controllers, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6421XS29-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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and computing markets.
The MAX6421 series belongs to Maxim's microprocessor supervisory product line, designed specifically for ultra-low-power, precision voltage monitoring and configurable reset timing in space- and energy-constrained embedded systems.
FAQ
What is the exact reset threshold voltage of MAX6421XS29-T?
The MAX6421XS29-T has a factory-trimmed nominal reset threshold of 2.925V, with ±1.5% accuracy at +25°C and ±2.5% over the full -40°C to +125°C temperature range. This value corresponds to the "29" suffix per Table 1 in the datasheet and is laser-trimmed for precision.
Does MAX6421XS29-T require an external pull-up resistor on the RESET pin?
No, MAX6421XS29-T does not require an external pull-up resistor because it features an active-low push-pull RESET output. The output actively drives high (VOH ≥ 0.8×VCC) and low (VOL ≤ 0.4V), providing a fully defined logic state without external components - unlike open-drain variants such as MAX6423XS29-T.
How is the reset timeout period set for MAX6421XS29-T?
The reset timeout period for MAX6421XS29-T is set by connecting an external capacitor (CSRT) between the SRT pin and ground. The relationship is tRP = 2.73×10⁶ × CSRT + 275µs, where tRP is in seconds and CSRT in farads. A 1500pF capacitor yields ~4.375ms, and ceramic capacitors with leakage <10nA are recommended.
Can MAX6421XS29-T operate reliably below 1.6V supply voltage?
Yes, MAX6421XS29-T is specified to operate down to VCC = 1.0V, and its reset function remains valid to VCC = 1V. While the general operating range starts at 1.6V for full specification compliance, the device continues asserting RESET correctly even as VCC falls from 1.6V to 1.0V - critical for controlled brownout shutdown.
What package type and dimensions does MAX6421XS29-T use?
MAX6421XS29-T uses the SC70-4 package (package code X4+1, outline 21-0098): 2.0mm × 1.25mm body size, 0.65mm lead pitch, and 0.9mm maximum height. It has no thermal pad and is RoHS-compliant. Pin 1 is SRT, Pin 2 is GND, Pin 3 is RESET, and Pin 4 is VCC.
MAX6421XS29-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-82A, SOT-343
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.925V
- 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:
- SC-70-4
MAX6421XS29-T FAQ
1.How can I place an order for MAX6421XS29-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6421XS29-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 MAX6421XS29-T reliable?
The price and inventory of MAX6421XS29-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6421XS29-T is usually 5 days.
3.What payment methods are accepted for MAX6421XS29-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6421XS29-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6421XS29-T?
MAX6421XS29-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6421XS29-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 MAX6421XS29-T?
For technical support, including MAX6421XS29-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6421XS29-T requirements.
6.How does Aetrix verify that MAX6421XS29-T is sourced from the original manufacturer or authorized distributors?
All MAX6421XS29-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 MAX6421XS29-T meets industry standards.
7.What is the process for return or replacement of MAX6421XS29-T?
All MAX6421XS29-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6421XS29-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 MAX6421XS29-T part is unused and in its original packaging.
Return procedure for MAX6421XS29-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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