My Inquiry
My Account
Analog Devices Inc./Maxim Integrated MAX6821RUK-T
- Part No.:
- MAX6821RUK-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6821RUK-T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,784
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MAX6821RUK-T from Maxim Integrated is a low-voltage microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (3.08V threshold), 140ms min reset timeout, 1.6s watchdog timer, manual reset input, and push-pull active-low RESET output. It ensures reliable µP startup and brownout recovery in portable/battery-powered equipment and embedded controllers.
For engineers reviewing the MAX6821RUK-T datasheet, MAX6821RUK-T pinout, MAX6821RUK-T application, or MAX6821RUK-T equivalent, this page delivers verified functional identity, exact pin roles, real-world timing behavior, supply-voltage margining down to +1.0V, and validated alternatives for critical µP monitoring designs.
Technical Context
The MAX6821RUK-T implements a precision bandgap-based voltage monitor with 60ppm/°C temperature coefficient and 2×VTH hysteresis, ensuring stable reset assertion across -40°C to +125°C. Its internal reset generator asserts RESET low on VCC drop below 3.08V, MR low, or WDI timeout, holding it for ≥140ms after recovery.
A dedicated 1.6s watchdog timer clears on any WDI edge (≥50ns pulse width) and remains disabled if WDI is left unconnected or three-stated. The MR input includes a 50kΩ internal pullup and rejects <100ns glitches, enabling direct switch-to-GND connection without external debounce.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.08V ±3% (VCC falling); enables precise brownout detection for 3.3V systems |
| Reset Timeout Period | 140ms min (100–320ms over temp); guarantees µP initialization completes before release |
| Watchdog Timeout | 1.6s nominal (0.8–2.6s over temp); provides robust software execution monitoring |
| Supply Current | 7–30µA (-40°C to +125°C); supports ultra-low-power battery operation |
| RESET Output Type | Push-pull active-low; drives directly into µP reset pin without external pullup |
| Operating Voltage Range | +1.2V to +5.5V; valid reset assertion guaranteed down to +1.0V VCC |
| MR Input Logic | Active-low with 0.3×VCC VIL; compatible with CMOS and open-drain drivers |
Pinout & Package
Package: 5-pin SOT23-5 (U5-1 outline, 21-0057 land pattern), footprint-compatible with industry-standard 5-lead SOT-23.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET | Active-low push-pull reset output; sinks 500µA at VCC ≥1.8V, asserts low during VCC brownout, MR low, or WDI timeout |
| 2 | GND | Ground reference for all internal circuits and reset timing accuracy |
| 3 | MR | Active-low manual reset input; internally pulled up to VCC (50kΩ); accepts CMOS logic or momentary switch to GND |
| 4 | WDI | Watchdog input; toggling within 1.6s prevents reset; left unconnected disables watchdog |
| 5 | VCC | Supply and monitored voltage input; reset threshold referenced to this pin; operates from +1.2V to +5.5V |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed Reset Validity to VCC = +1.0V | Ensures fail-safe reset assertion even during deep brownout or battery sag below normal operating range |
| No External Components Required | Eliminates BOM cost and board space for pullups, RC networks, or discrete reset ICs |
| Immunity to Short Negative VCC Transients | Rejects ≤20µs transients down to 100mV below threshold-no spurious resets from power rail noise |
| Debounced Manual Reset Input | Internal 50kΩ pullup and 100ns glitch rejection enable direct switch interface without external RC filtering |
| Three Reset Output Options Across Family | MAX6821RUK-T uses push-pull active-low RESET, simplifying interface with µPs lacking internal pullups |
Applications
| Set-Top Boxes | Portable/Battery-Powered Equipment |
|---|---|
Use Scenario: Power sequencing and brownout protection during HDMI hot-plug or tuner voltage fluctuations. IC Role / Device Role / Timing Role: Supervisory circuit asserting active-low RESET to halt processor execution until stable 3.3V rail is confirmed. Use Value: Prevents corrupted firmware loading and memory corruption when 3.08V threshold detects 3.3V rail collapse. | Use Scenario: Long-term operation on coin-cell or Li-ion batteries with gradual voltage decay. IC Role / Device Role / Timing Role: Monitors VCC against 3.08V threshold and holds RESET low until safe restart voltage is restored. Use Value: Enables graceful shutdown and prevents undefined µP behavior below 3.08V while maintaining reset validity down to +1.0V VCC. |
| Embedded Controllers | Critical µP Monitoring |
Use Scenario: Industrial PLC modules requiring deterministic boot after AC power interruption. IC Role / Device Role / Timing Role: Combines voltage monitoring, 140ms reset timeout, and manual reset for field-service recovery. Use Value: Guarantees µP remains held in reset for minimum 140ms post-recovery, meeting IEC 61000-4-11 immunity requirements. | Use Scenario: Medical diagnostic instruments where unintended µP reboot could compromise patient safety. IC Role / Device Role / Timing Role: Dual-failure detection via VCC monitoring and 1.6s watchdog timer, both triggering same RESET output. Use Value: Single-point reset assertion eliminates race conditions between independent voltage and software fault detectors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar µP supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6326UR29D3-T | Fixed 2.93V threshold, no watchdog timer, only manual reset and power-on reset | Lacks watchdog functionality; suitable only for simpler power-monitoring-only use cases | Select when watchdog is unnecessary and lower threshold (2.93V vs. 3.08V) better matches system rail tolerance |
| TPS3808G33DBVR | 3.3V threshold, 200ms reset timeout, no manual reset input, push-pull active-low RESET | Missing MR input; requires external logic or switch interface for field reset capability | Choose when higher reset timeout (200ms) is required and manual reset is handled elsewhere in system |
Compared with MAX6821RUK-T, MAX6326UR29D3-T omits watchdog monitoring but offers tighter threshold tolerance for 2.93V rails, while TPS3808G33DBVR provides longer reset hold time but removes manual reset-both require design trade-offs in fault coverage or serviceability.
Availability
MAX6821RUK-T is available at Aetrix Electronics and suitable for set-top boxes, portable/battery-powered equipment, and embedded controllers requiring stable component supply, long-lifecycle support, and automotive-grade temperature range (-40°C to +125°C).
Supply support for MAX6821RUK-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, sensing, and interface applications.
The MAX6821 series belongs to Maxim's µP supervisory product line, designed specifically for low-voltage, high-reliability embedded systems where deterministic reset behavior, watchdog safety, and minimal external components are essential.
FAQ
What is the exact reset threshold voltage of MAX6821RUK-T and how is it specified?
The MAX6821RUK-T has a factory-trimmed reset threshold of 3.08V, with ±3% tolerance over -40°C to +125°C. This value is defined as the VCC voltage at which the RESET output asserts low during a falling VCC condition, and is guaranteed by production testing per the Electrical Characteristics table. The 'R' suffix in MAX6821RUK-T explicitly denotes the 3.08V threshold variant.
Does MAX6821RUK-T include a watchdog timer and what is its timeout behavior?
Yes, MAX6821RUK-T includes a watchdog timer with a nominal timeout period of 1.6 seconds. The timer clears on any rising or falling edge at the WDI pin and triggers a reset if no edge occurs within the timeout window. When WDI is left unconnected, the internal driver disables the watchdog function, preventing unintended resets.
What type of RESET output does MAX6821RUK-T provide and how does it interface with a microprocessor?
MAX6821RUK-T provides a push-pull active-low RESET output. It actively drives low during reset assertion and high-impedance (not high) when inactive-no external pullup resistor is needed. This output connects directly to standard µP reset inputs that accept active-low signals, such as those found on ARM Cortex-M or Renesas RL78 families.
Can MAX6821RUK-T operate reliably at very low supply voltages?
Yes, MAX6821RUK-T guarantees correct RESET output state down to VCC = +1.0V, even though its operational range starts at +1.2V. This means the device continues asserting reset during deep brownout conditions well below typical µP operating voltage, providing fail-safe behavior critical for battery-powered systems.
How is the manual reset (MR) input implemented on MAX6821RUK-T and what external components are needed?
The MR input on MAX6821RUK-T is active-low with an internal 50kΩ pullup resistor to VCC. It requires no external components: a normally open momentary switch connected between MR and GND provides full manual reset functionality. The input rejects glitches shorter than 100ns and accepts standard CMOS logic levels, making it compatible with FPGA or GPIO-driven reset control.
MAX6821RUK-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:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.63V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active High
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
MAX6821RUK-T FAQ
1.How can I place an order for MAX6821RUK-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6821RUK-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 MAX6821RUK-T reliable?
The price and inventory of MAX6821RUK-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6821RUK-T is usually 5 days.
3.What payment methods are accepted for MAX6821RUK-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6821RUK-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6821RUK-T?
MAX6821RUK-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6821RUK-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 MAX6821RUK-T?
For technical support, including MAX6821RUK-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6821RUK-T requirements.
6.How does Aetrix verify that MAX6821RUK-T is sourced from the original manufacturer or authorized distributors?
All MAX6821RUK-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 MAX6821RUK-T meets industry standards.
7.What is the process for return or replacement of MAX6821RUK-T?
All MAX6821RUK-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6821RUK-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 MAX6821RUK-T part is unused and in its original packaging.
Return procedure for MAX6821RUK-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX6821RUK-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…
