My Inquiry
My Account
Analog Devices Inc./Maxim Integrated MAX6821ZUK+T
- Part No.:
- MAX6821ZUK+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6821ZUK+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:20,000
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
MAX6821ZUK+T from Maxim Integrated is a low-voltage microprocessor supervisory IC in 5-pin SOT23 package, providing voltage monitoring (2.32V threshold), 140ms minimum 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 MAX6821ZUK+T datasheet, MAX6821ZUK+T pinout, MAX6821ZUK+T application, or MAX6821ZUK+T equivalent, this page delivers verified electrical specs, pin-level circuit roles, real-world use scenarios, and validated alternative parts for critical power-on reset and watchdog supervision tasks.
Technical Context
The MAX6821ZUK+T integrates a precision voltage detector with ±1.5% threshold accuracy over –40°C to +125°C, a monostable reset timer with guaranteed 140ms minimum assertion time, and a watchdog circuit that triggers reset if WDI remains static beyond 1.6s. Its internal 50kΩ MR pullup enables direct switch-to-GND connection without external components.
RESET output is push-pull active-low with VOL ≤ 0.3V at ISINK = 50µA (VCC ≥ 1.0V) and VOH ≥ 0.8 × VCC at ISOURCE = 1µA; it remains valid down to VCC = +1.0V. The device operates across 1.2V–5.5V supply range and rejects negative VCC transients < 20µs at 100mV overdrive.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.32V ±1.5% - precisely monitors +2.3V rails common in low-power µP cores and I/O domains |
| Reset Timeout Period | 140ms (min) - ensures sufficient hold time for full µP initialization and PLL lock before release |
| Watchdog Timeout | 1.6s nominal - provides robust software execution monitoring without excessive false triggers |
| Supply Current | 25µA max (–40°C to +125°C, VCC = +3.6V) - enables multi-year battery life in portable instrumentation |
| Operating Voltage Range | 1.2V to 5.5V - supports wide-input systems including single-cell Li-ion and 3.3V/5V logic domains |
| Reset Output Type | Push-pull active-low - drives µP reset pin directly without pull-up resistor; sinks 50µA at VCC ≥ 1.0V |
| MR Input Logic | Active-low with 50kΩ internal pullup - allows momentary switch interface; no external bias required |
Pinout & Package
Package: 5-pin SOT23-5 (U5-1 outline), RoHS-compliant, surface-mount, footprint compatible with standard 0.95mm pitch land pattern (Maxim land pattern #21-0057).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET (active-low) | Push-pull output asserted low during VCC undervoltage, MR activation, or watchdog timeout; holds low ≥140ms after recovery |
| 2 | GND | Ground reference for all internal comparators, timers, and output drivers; must be low-impedance return path |
| 3 | WDI | Watchdog input - toggling within 1.6s prevents reset; left unconnected disables watchdog function |
| 4 | MR | Manual reset input - logic-low pulse ≥1µs forces reset; internal 50kΩ pullup allows NC or VCC tie-off when unused |
| 5 | VCC | Power supply and monitored rail - powers internal circuitry and serves as voltage reference for threshold detection |
Key Features
| Feature | Design Value |
|---|---|
| No external components required | Integrates voltage reference, comparator, timer, and driver - eliminates discrete RC networks and reduces BOM count |
| Guaranteed reset validity to VCC = +1.0V | Ensures correct reset state during deep brownout or battery depletion, preventing µP runaway below 1.2V nominal operation |
| Immunity to short negative VCC transients | Rejects glitches ≤20µs at 100mV overdrive - avoids spurious resets in noisy power environments |
| Debounced manual reset input | Internal filtering eliminates need for external RC debounce; supports direct SPST switch to GND |
| 1.6s watchdog timeout with edge-triggered clear | Resets timer on any WDI rising/falling edge - enables flexible software polling points without fixed timing constraints |
Applications
| Portable/Battery-Powered Equipment | Embedded Controllers |
|---|---|
|
Use Scenario: Handheld test meters powered by single-cell Li-ion batteries experiencing voltage sag under load. IC Role / Device Role / Timing Role: Monitors VCC at 2.32V threshold and asserts RESET until battery recovers above threshold plus hysteresis, then holds reset for ≥140ms. Use Value: Prevents µP corruption during transient brownout; enables safe restart without manual intervention or external supervisor IC. |
Use Scenario: Industrial PLC modules requiring deterministic boot sequence after power cycle or firmware update. IC Role / Device Role / Timing Role: Generates clean, timed reset pulse synchronized to VCC ramp; manual reset input allows field technician-initiated recovery. Use Value: Eliminates race conditions between power rail stabilization and µP clock enable; guarantees known initial state before code execution. |
| Intelligent Instruments | Critical µP Monitoring |
|
Use Scenario: Digital multimeters with real-time measurement engines and EEPROM-based calibration storage. IC Role / Device Role / Timing Role: Supervises main µP supply and uses watchdog timer to detect firmware hangs during ADC conversion sequences. Use Value: Automatically recovers corrupted measurement state without user reset; preserves calibration integrity via controlled reboot. |
Use Scenario: Medical diagnostic devices where µP failure could compromise patient safety or data integrity. IC Role / Device Role / Timing Role: Provides dual-fault protection: voltage monitoring for power faults and watchdog for software faults, both triggering hardware reset. Use Value: Meets IEC 62304 Class C requirements for fail-safe behavior; independent of µP firmware reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6822ZUK+T | Open-drain RESET output instead of push-pull; identical threshold (2.32V), timeout (140ms), and watchdog (1.6s) | Required when interfacing with µPs having bidirectional reset pins (e.g., Motorola 68HC11) needing external pull-up | Select MAX6822ZUK+T only if system design mandates open-drain reset signaling; otherwise MAX6821ZUK+T simplifies layout with integrated drive. |
| TPS3808G33DBVR | Fixed 3.3V threshold (not 2.32V); 200ms reset timeout; no manual reset input; same SOT23-5 package | Suitable for 3.3V-only systems without manual reset requirement; lacks MR and WDI functionality of MAX6821ZUK+T | Choose TPS3808G33DBVR only for cost-sensitive 3.3V applications where watchdog and manual reset are unnecessary. |
Compared with MAX6822ZUK+T, MAX6821ZUK+T offers simpler reset drive but less flexibility with bidirectional µP pins; versus TPS3808G33DBVR, it provides lower-voltage monitoring, manual reset, and watchdog - essential for battery-powered and safety-critical designs.
Availability
MAX6821ZUK+T is available at Aetrix Electronics and suitable for portable/battery-powered equipment, embedded controllers, intelligent instruments, and critical µP monitoring applications requiring stable component supply across industrial temperature ranges.
Supply support for MAX6821ZUK+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) designs precision analog and mixed-signal ICs for power, sensing, and interface applications in industrial, medical, and communications systems.
The MAX6821–MAX6825 family was engineered specifically for low-voltage microprocessor supervision in space-constrained, battery-sensitive systems - delivering integrated voltage monitoring, watchdog, and manual reset in a 5-pin SOT23 package.
FAQ
What is the exact reset threshold voltage of the MAX6821ZUK+T?
The MAX6821ZUK+T has a factory-trimmed reset threshold of 2.32V with ±1.5% accuracy over –40°C to +125°C. This value is confirmed in the Threshold Suffix Guide (suffix 'Z') and Electrical Characteristics table, where VTH is specified as 2.24V (min) to 2.40V (max) at full temperature range.
Does the MAX6821ZUK+T include a watchdog timer, and what is its timeout period?
Yes, the MAX6821ZUK+T includes a watchdog timer with a nominal timeout period of 1.6s. The datasheet specifies tWD as 1.12s (min) to 2.40s (max) over –40°C to +85°C, and 0.80s (min) to 2.60s (max) over –40°C to +125°C - enabling robust software execution monitoring in embedded systems.
Can the MAX6821ZUK+T operate reliably at VCC = +1.0V?
Yes, the MAX6821ZUK+T guarantees correct RESET output state down to VCC = +1.0V, as explicitly stated in the General Description and Electrical Characteristics. This ensures fail-safe reset assertion even during severe brownout or battery depletion conditions before the device ceases operation.
What is the function of Pin 3 (WDI) on the MAX6821ZUK+T, and how is it used?
Pin 3 (WDI) is the watchdog input on the MAX6821ZUK+T. Toggling WDI (rising or falling edge) within 1.6s clears the internal watchdog timer; failure to do so triggers a reset pulse. Leaving WDI unconnected disables the watchdog feature, as the internal driver automatically services the timer every ~1.4s.
Is the manual reset input (MR) on the MAX6821ZUK+T internally pulled up, and what is its value?
Yes, the MR input on the MAX6821ZUK+T features an internal 50kΩ pullup resistor to VCC, as documented in the Pin Description and Applications Information sections. This allows MR to be left unconnected or tied to VCC when unused, and supports direct interface with a normally-open switch to GND without external components.
MAX6821ZUK+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:
- 2.32V
- 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
MAX6821ZUK+T FAQ
1.How can I place an order for MAX6821ZUK+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6821ZUK+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 MAX6821ZUK+T reliable?
The price and inventory of MAX6821ZUK+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6821ZUK+T is usually 5 days.
3.What payment methods are accepted for MAX6821ZUK+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6821ZUK+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6821ZUK+T?
MAX6821ZUK+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6821ZUK+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 MAX6821ZUK+T?
For technical support, including MAX6821ZUK+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6821ZUK+T requirements.
6.How does Aetrix verify that MAX6821ZUK+T is sourced from the original manufacturer or authorized distributors?
All MAX6821ZUK+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 MAX6821ZUK+T meets industry standards.
7.What is the process for return or replacement of MAX6821ZUK+T?
All MAX6821ZUK+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6821ZUK+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 MAX6821ZUK+T part is unused and in its original packaging.
Return procedure for MAX6821ZUK+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX6821ZUK+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…
