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Analog Devices Inc./Maxim Integrated MAX6303CUA+T
- Part No.:
- MAX6303CUA+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX6303CUA+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL 8UMAX
- Quantity:
- Payment:
- Shipping:
Inventory:4,595
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Product details
Overview
MAX6303CUA+T from Maxim Integrated is a +5V, low-power microprocessor supervisory circuit with active-low push-pull reset output, adjustable reset threshold (≥1.22V), adjustable reset timeout (via external capacitor on SRT), and adjustable watchdog timeout with 500× multiplier (via WDS pin). It operates from VCC = 1.31V to 5.5V, draws only 4µA supply current, and guarantees RESET assertion down to VCC = 1V - used in battery-powered medical instruments and embedded controllers requiring reliable brownout detection and software hang protection.
For engineers reviewing the MAX6303CUA+T datasheet, MAX6303CUA+T pinout, MAX6303CUA+T application, or MAX6303CUA+T equivalent, this page delivers verified electrical parameters, µMAX-8 package layout guidance, real-world timeout capacitor design equations, transient immunity data, and validated alternative options for reset supervision in space-constrained, low-quiescent-current systems.
Technical Context
The MAX6303CUA+T implements a precision bandgap-based reset comparator with 1.22V internal reference, enabling user-defined thresholds via external resistor divider on RESET IN. Its reset timeout is generated by a 500nA current source charging CSRT, yielding tRP = 2.67 × CSRT (CSRT in pF → tRP in µs).
Watchdog timing uses the same 500nA current source on SWT, with mode selection via WDS: normal mode (WDS = GND) gives tWD in ms; extended mode (WDS = VCC) multiplies tWD by 500, enabling timeouts up to ~22 minutes with 1µF. WDI accepts ≥30ns pulses and clears the timer on any edge.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 1.31V to 5.5V - supports operation during deep brownout and standard +5V rails. |
| Quiescent Supply Current | 4.0µA typical - enables multi-year battery life in portable equipment. |
| Reset Threshold Reference | 1.22V ±25mV - stable bandgap reference enabling precise external voltage monitoring. |
| Reset Timeout Accuracy | ±30% over temperature - determined by external CSRT capacitor leakage and tolerance. |
| Watchdog Timeout Multiplier | 500× when WDS = VCC - extends basic timeout (ms range) to minutes/hours without firmware changes. |
| RESET Output Type | Push-pull, active-low - drives high/low directly; no external pull-up required for µP reset input. |
| Power-Supply Transient Immunity | Withstands ≤50µs, 100mV VCC glitches below VRST - prevents false resets in noisy environments. |
Pinout & Package
MAX6303CUA+T is housed in an 8-pin µMAX® package (3mm × 3mm, 0.8mm height), RoHS-compliant and lead-free (indicated by '+' suffix), with exposed pad for thermal enhancement and mechanical stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RESET IN | High-impedance reset threshold input | Connects to center tap of R1/R2 divider; sets VRST = 1.22 × (R1 + R2)/R2; <±1nA leakage ensures minimal divider error. |
| 2 - GND | Ground reference | Return path for all internal currents; must be low-impedance and adjacent to bypass capacitor. |
| 3 - SRT | Reset timeout capacitor connection | Sinks 500nA to ground; tRP = 2.67 × CSRT (pF → µs); requires low-leakage ceramic capacitor. |
| 4 - SWT | Watchdog timeout capacitor connection | Sinks 500nA to ground; tWD = 2.67 × CSWT (pF → µs); same capacitor type requirement as SRT. |
| 5 - WDS | Watchdog mode select | Logic input: GND = normal mode (ms timeout), VCC = extended mode (500× timeout); edge-triggered reset of watchdog timer. |
| 6 - WDI | Watchdog input | Edge-sensitive input; rising or falling transition within timeout period clears watchdog; ≥30ns pulse width sufficient. |
| 7 - RESET | Active-low push-pull reset output | Drives µP reset pin directly; VOH = VCC − 0.4V (min), VOL = 0.4V (max at 3.2mA sink); no external pull-up needed. |
| 8 - VCC | Supply voltage input | Must be bypassed with 0.1µF ceramic capacitor placed <2mm from pin; supports operation down to 1.31V. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable reset threshold | Settable from 1.22V upward using two external resistors - enables monitoring of 3.3V, 2.5V, or custom supply rails. |
| Guaranteed RESET assertion at VCC ≥ 1V | Ensures valid reset signal even during severe brownout - critical for fail-safe shutdown in medical and industrial systems. |
| 500× watchdog timeout multiplier | Extends basic timeout from milliseconds to >20 minutes with same capacitor - reduces BOM count and PCB area vs. discrete timers. |
| Power-supply transient immunity | Rejects VCC glitches ≤50µs wide and ≤100mV deep - eliminates need for additional filtering in EMI-prone applications. |
| Low-leakage timing inputs (SRT/SWT) | 500nA precision current sources tolerate <10nA capacitor leakage - enables use of standard X7R ceramics instead of expensive NP0/C0G. |
Applications
| Portable Medical Monitors | Battery-Powered Data Loggers |
|---|---|
Use Scenario: Continuous ECG/SpO₂ monitoring powered by coin-cell or Li-ion battery with undervoltage cutoff. IC Role / Device Role / Timing Role: Supervises main supply rail; asserts RESET if VBAT drops below 2.7V; uses extended-mode watchdog to wake µP every 10 minutes for sensor sampling. Use Value: Prevents corrupted measurements during brownout; eliminates need for separate RTC or wake-up timer IC - saves 2.5mm² PCB area and 3µA quiescent current. |
Use Scenario: Remote environmental sensor node logging temperature/humidity every hour, sleeping between readings. IC Role / Device Role / Timing Role: Generates precise sleep/wake cycle via extended-mode watchdog; monitors backup LDO output for system integrity during deep-sleep mode. Use Value: Achieves <5µA average system current; replaces discrete 555 timer + voltage monitor - improves long-term calibration stability and reduces component count. |
| Industrial PLC I/O Modules | Set-Top Box Power Sequencing |
Use Scenario: DIN-rail mounted controller with isolated 24V input, generating 5V/3.3V rails for FPGA and communication ICs. IC Role / Device Role / Timing Role: Monitors 5V rail for brownout; provides 100ms reset pulse after power-up; disables watchdog during firmware update via WDS control. Use Value: Guarantees FPGA configuration starts only after stable 5V; avoids partial configuration lockup - increases field reliability by eliminating unexplained boot failures. |
Use Scenario: Consumer STB with multiple power domains (main SoC, tuner, USB, HDMI) requiring controlled ramp-up and fault isolation. IC Role / Device Role / Timing Role: Supervises 5V standby rail; triggers system-wide reset if 5V collapses during channel change; uses manual reset switch (parallel to R2) for customer recovery. Use Value: Enables "hard reset" without unplugging; prevents HDMI hot-plug glitches from propagating to SoC - reduces RMA rate by 12% in production testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6304CUA+T | Active-high push-pull RESET output; identical timing, threshold, and package - differs only in reset polarity. | Required when µP reset pin is active-high (e.g., ARM Cortex-M series with nRST inverted internally). | Select MAX6304CUA+T only if system-level reset logic demands active-high assertion; pinout and footprint are identical. |
| TPS3808G125DBVR | Fixed 1.25V threshold; 2.9µA ICC; no adjustable watchdog; SOT-23-6 package (6-pin, smaller than µMAX-8). | Suitable for cost-sensitive, fixed-threshold applications where extended watchdog or manual reset is unnecessary. | Choose TPS3808G125DBVR for simplified BOM and smaller footprint when adjustable timing is not required - but verify µP reset polarity compatibility. |
Compared with MAX6304CUA+T, the MAX6303CUA+T offers identical adjustability and low power but targets active-low µP reset pins; versus TPS3808G125DBVR, it trades fixed-threshold simplicity for full configurability and extended watchdog capability - critical for firmware-recovery-critical systems.
Availability
MAX6303CUA+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered data loggers, industrial PLC modules, and set-top box power sequencing requiring stable component supply across extended product lifecycles.
Supply support for MAX6303CUA+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, mixed-signal, and power-management ICs for demanding industrial, medical, and communications applications.
The MAX6301–MAX6304 family was engineered specifically for ultra-low-power microprocessor supervision in space-constrained, battery-operated, and safety-critical systems - emphasizing adjustability, transient immunity, and guaranteed operation down to 1V.
FAQ
What is the minimum VCC required for MAX6303CUA+T to assert RESET reliably?
The MAX6303CUA+T guarantees RESET assertion when VCC ≥ 1V. Below 1V, RESET output drive strength degrades significantly; for applications requiring valid reset down to 0V, a 100kΩ pulldown resistor from RESET to GND is recommended per Maxim's application note. This behavior is confirmed in the Electrical Characteristics table under "Guaranteed RESET Asserted At or Above VCC = 1V (MAX6301/MAX6303)" - a key differentiator from competitors with higher minimum-VCC requirements.
How do I calculate the capacitor value for a 100ms reset timeout using MAX6303CUA+T?
Use the formula CSRT = tRP / 2.67, where tRP is in microseconds. For 100ms = 100,000µs, CSRT = 100,000 / 2.67 ≈ 37,450pF (37.5nF). Select a low-leakage ceramic capacitor (X7R or better, <10nA leakage) rated ≥10V. The MAX6303CUA+T's 500nA SRT current source ensures this yields ~100ms ±30% tolerance over temperature - verified in Figure 3 and the Typical Operating Characteristics section.
Can MAX6303CUA+T monitor a 3.3V supply directly, and what resistor values are recommended?
Yes - connect the 3.3V rail to RESET IN via a resistor divider. With VRST = 3.3V and VTH = 1.22V, solve R1 = R2 × (VRST/VTH − 1) ≈ R2 × 1.71. Using R2 = 1MΩ gives R1 ≈ 1.71MΩ. Both resistors should be ≥1MΩ to limit divider current to <1.2µA - preserving the MAX6303CUA+T's 4µA quiescent advantage. This configuration is explicitly validated in Figure 4 ("Monitoring Voltages Other than VCC") and the Reset Threshold section.
What happens to the watchdog timer when WDS is toggled during operation?
Toggling WDS resets the watchdog timer to zero immediately - regardless of current timeout state. If WDS transitions from GND to VCC, the timer restarts in extended mode; if from VCC to GND, it restarts in normal mode. This behavior is documented in the Pin Description for WDS ("A change in the state of this pin resets the watchdog timer to zero") and illustrated in Figures 2a/2b. It enables dynamic timeout scaling - e.g., extending watchdog period during sleep mode and shortening it during active firmware execution.
Is MAX6303CUA+T compatible with bidirectional µP reset pins like those on the Motorola 68HC11?
No - the MAX6303CUA+T features a push-pull RESET output, not open-drain. For bidirectional µP reset pins, the MAX6301CUA+T (open-drain, active-low) or MAX6302CUA+T (open-drain, active-high) are required. This distinction is clearly defined in the Selector Guide and Pin Description: MAX6303CUA+T's RESET pin is specified as "Push-Pull, Active-Low Reset Output", making direct connection to bidirectional pins unsafe without external logic. Maxim confirms this in the "Interfacing to µPs with Bidirectional Reset Pins" section using MAX6301 as the example.
MAX6303CUA+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- Adjustable/Selectable
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- 2.8ms Minimum
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-uMAX/uSOP
MAX6303CUA+T FAQ
1.How can I place an order for MAX6303CUA+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6303CUA+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 MAX6303CUA+T reliable?
The price and inventory of MAX6303CUA+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6303CUA+T is usually 5 days.
3.What payment methods are accepted for MAX6303CUA+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6303CUA+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6303CUA+T?
MAX6303CUA+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6303CUA+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 MAX6303CUA+T?
For technical support, including MAX6303CUA+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6303CUA+T requirements.
6.How does Aetrix verify that MAX6303CUA+T is sourced from the original manufacturer or authorized distributors?
All MAX6303CUA+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 MAX6303CUA+T meets industry standards.
7.What is the process for return or replacement of MAX6303CUA+T?
All MAX6303CUA+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6303CUA+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 MAX6303CUA+T part is unused and in its original packaging.
Return procedure for MAX6303CUA+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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