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Analog Devices Inc./Maxim Integrated MAX6746KA29
- Part No.:
- MAX6746KA29
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6746KA29.pdf
- Description:
- IC SUPERVISOR UP RESET CIRCUIT
- Quantity:
- Payment:
- Shipping:
Inventory:10,991
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Product details
Overview
MAX6746KA29 from Maxim Integrated is a low-power microprocessor supervisory circuit with factory-trimmed 2.925V ±2% VCC reset threshold, capacitor-adjustable reset timeout (tRP), and watchdog timeout (tWD), designed for automotive-grade single-voltage monitoring in battery-powered and embedded controllers. It asserts active-low RESET during VCC brownout, manual reset, or watchdog fault, with guaranteed operation down to VCC ≥ 1V and 3.7µA supply current at VCC ≤ 2.0V.
For engineers reviewing the MAX6746KA29 datasheet, MAX6746KA29 pinout, MAX6746KA29 application, or MAX6746KA29 equivalent, this device supports precise power-on reset timing, transient-immune brownout detection, and configurable watchdog supervision in space-constrained SOT23-8 layouts for critical µP systems.
Technical Context
The MAX6746KA29 implements a fixed-threshold VCC monitor with 2.925V ±2% trip point and a manual reset input (MR) that triggers reset when pulled low for ≥1µs. Its reset timeout period (tRP) and watchdog timeout (tWD) are set independently via external capacitors CSRT and CSWT using linear ramp-based timing circuits with 200–300nA ramp current and 1.235V ramp threshold.
This variant belongs to the MAX6746–MAX6751 subgroup: it features normal/extended watchdog mode selection via WDS, push-pull or open-drain RESET output, and no windowed watchdog or SET0/SET1 pins - distinguishing it from MAX6752/MAX6753 and MAX6748–MAX6751 variants.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Reset Threshold | 2.925V ±2% (factory-trimmed; enables reliable 3.0V system brownout detection) |
| Supply Current | 3.7µA typical at VCC ≤ 2.0V (enables multi-year battery life in portable equipment) |
| Reset Timeout Range | 0.506ms to 9.487ms (set by 100pF–1500pF CSRT; covers µP initialization from fast boot to complex firmware load) |
| Watchdog Timeout Range | 0.506ms to 9.487ms (normal mode); up to 1214.4ms (extended mode ×128; supports long-loop firmware execution) |
| Operating Temperature | −40°C to +125°C (fully specified for under-hood automotive and industrial control environments) |
| RESET Output Type | Active-low push-pull or open-drain (supports direct µP reset input or level-shifted interfacing to 0–6V logic) |
| Power-Supply Transient Immunity | Rejects ≤50µs transients 100mV below VTH (prevents spurious resets during switching noise or load dumps) |
Pinout & Package
MAX6746KA29 is housed in an 8-pin SOT23-8 package (2.9mm × 1.6mm × 1.1mm), optimized for high-density PCB layouts in automotive and portable applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | MR (Manual Reset Input) | Internally pulled-up to VCC; falling edge ≥1µs asserts RESET; immune to 100ns glitches |
| 2 | RESET IN | Not connected in MAX6746KA29 (this variant monitors only VCC, not external voltage) |
| 3 | SWT (Watchdog Timeout Input) | Capacitor-to-GND sets tWD; grounded to disable watchdog; supports ×128 extension via WDS |
| 4 | SRT (Reset Timeout Input) | Capacitor-to-GND sets tRP; determines minimum reset assertion duration after fault clearance |
| 5 | WDS (Watchdog Select Input) | Ground = normal mode; VCC = extended mode (×128 tWD); state change clears watchdog timer |
| 6 | WDI (Watchdog Input) | Falling edge within tWD clears timer; missing edge triggers RESET for full tRP duration |
| 7 | RESET (Active-Low Output) | Push-pull or open-drain; sinks ≥50µA at VCC ≥1V; valid logic state guaranteed down to VCC = 1V |
| 8 | VCC (Supply Voltage) | 1.2V to 5.5V operation; powers internal comparators, timers, and RESET driver; monitored for 2.925V threshold |
Key Features
| Feature | Design Value |
|---|---|
| Factory-trimmed reset threshold | 2.925V ±2% ensures accurate 3.0V rail monitoring without external resistor divider calibration |
| Capacitor-adjustable timing | Independent CSRT and CSWT selection enables precise matching to µP boot time and software loop duration |
| Extended watchdog mode | WDS-controlled ×128 timeout scaling allows one hardware design to support both short- and long-interval supervision |
| Transient-immune reset assertion | Guaranteed immunity to ≤50µs supply dips 100mV below VTH prevents false resets in noisy automotive environments |
| Low-voltage operation | Valid RESET output and functional supervision down to VCC = 1.2V supports ultra-low-power brownout detection |
Applications
| Automotive Engine Control Unit (ECU) | Portable Medical Monitor |
|---|---|
Use Scenario: Monitors 3.3V microcontroller supply during cold-crank battery dip (down to 6V system voltage). IC Role / Device Role / Timing Role: Asserts RESET when VCC falls below 2.925V; holds reset for 5ms (CSRT = 680pF) to ensure full µP core reset before restart. Use Value: Prevents code corruption during 12V system transients while enabling rapid recovery post-dip. |
Use Scenario: Supervises ARM Cortex-M4 in handheld glucose meter powered by single Li-ion cell (2.8–4.2V range). IC Role / Device Role / Timing Role: Provides VCC brownout reset at 2.925V and watchdog supervision with 250ms timeout (CSWT = 500pF, WDS = GND). Use Value: Guarantees safe shutdown on battery depletion and detects firmware lockup during sensor acquisition. |
| Industrial PLC I/O Module | Smart Energy Meter MCU |
Use Scenario: Ensures deterministic startup of dual-core µP after 24V DC-DC converter stabilization in factory automation cabinet. IC Role / Device Role / Timing Role: Uses MR pin for external emergency stop reset; RESET remains asserted for 8ms (CSRT = 1200pF) to synchronize peripheral initialization. Use Value: Eliminates race conditions between µP core and FPGA configuration during power-up sequencing. |
Use Scenario: Supervises metrology SoC in ANSI C12.22-compliant electricity meter exposed to grid surges and lightning-induced transients. IC Role / Device Role / Timing Role: Leverages ±2% VTH tolerance and transient immunity to avoid false resets during 6kV surge events. Use Value: Maintains data integrity and regulatory compliance by preventing uncontrolled reboots during EMI stress testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar µP supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6326UR29 | Fixed 2.93V reset threshold; no watchdog; 1.6µA ICC; SOT23-5 package | Lacks capacitor-adjustable timing and watchdog - suitable only for basic reset-only use cases | Select when minimal footprint and ultra-low ICC outweigh need for supervision flexibility |
| TPS3808G33 | 2.93V threshold; adjustable reset delay (no watchdog); 16µA ICC; enable input; SOT23-6 | Requires external RC for delay; no manual reset or watchdog - limited to simple power-good signaling | Choose for TI-based designs requiring enable-controlled activation and lower cost, but accept reduced feature set |
Compared with MAX6746KA29, MAX6326UR29 offers lower quiescent current but omits watchdog and timing adjustability, while TPS3808G33 provides enable control but lacks manual reset and true watchdog supervision - making MAX6746KA29 uniquely suited for automotive and industrial systems requiring full-feature, capacitor-tuned µP supervision in SOT23-8.
Availability
MAX6746KA29 is available at Aetrix Electronics and suitable for automotive engine control units, portable medical monitors, industrial PLC modules, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6746KA29 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 automotive, industrial, and computing applications, with emphasis on reliability and performance under harsh conditions.
The MAX6746–MAX6753 product line delivers capacitor-programmable µP supervisors targeting automotive-grade systems where deterministic reset timing, watchdog supervision, and transient immunity are mandatory for functional safety compliance.
FAQ
What is the exact factory-trimmed reset threshold voltage for MAX6746KA29?
The MAX6746KA29 has a factory-trimmed VCC reset threshold of 2.925V with ±2% tolerance over −40°C to +125°C. This value is confirmed in Table 2 of the datasheet (suffix "29" corresponds to 2.925V nominal), and is laser-trimmed during production to ensure accuracy without external calibration components.
Does MAX6746KA29 support dual-voltage monitoring?
No, MAX6746KA29 does not support dual-voltage monitoring. It monitors only the VCC supply using its internal 2.925V threshold comparator. The RESET IN pin (Pin 2) is unused in this variant - dual monitoring requires MAX6750 or MAX6751, which integrate both factory-trimmed VCC and adjustable RESET IN thresholds.
How is the watchdog timeout configured on MAX6746KA29?
On MAX6746KA29, the watchdog timeout is set by capacitor CSWT connected between SWT (Pin 3) and GND. In normal mode (WDS = GND), tWD = 5.06 × 10⁶ × CSWT seconds; in extended mode (WDS = VCC), tWD is multiplied by 128. WDI (Pin 6) must toggle within this period to prevent reset assertion.
What is the minimum VCC required for valid RESET output operation in MAX6746KA29?
MAX6746KA29 guarantees valid RESET logic state (correct HIGH/LOW assertion) for VCC ≥ 1V. Below 1V, RESET current sinking capability degrades; for applications requiring valid reset down to 0V, a 100kΩ pulldown resistor must be added to the push-pull RESET output per Figure 7 in the datasheet.
Is MAX6746KA29 pin-compatible with other devices in the MAX6746–MAX6753 family?
MAX6746KA29 shares the same 8-pin SOT23-8 package and pinout as all MAX6746–MAX6751 variants (e.g., MAX6746KA16, MAX6747KA29), including identical MR, SWT, SRT, WDS, WDI, RESET, and VCC assignments. However, it is not pin-compatible with MAX6752/MAX6753 (which replace WDS with SET0/SET1) or MAX6748/MAX6749 (which repurpose Pin 2 as RESET IN).
MAX6746KA29 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-8
- 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:
- 5.692ms Minimum
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-8
MAX6746KA29 FAQ
1.How can I place an order for MAX6746KA29 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6746KA29 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 MAX6746KA29 reliable?
The price and inventory of MAX6746KA29 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6746KA29 is usually 5 days.
3.What payment methods are accepted for MAX6746KA29?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6746KA29 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6746KA29?
MAX6746KA29 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6746KA29 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 MAX6746KA29?
For technical support, including MAX6746KA29 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6746KA29 requirements.
6.How does Aetrix verify that MAX6746KA29 is sourced from the original manufacturer or authorized distributors?
All MAX6746KA29 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 MAX6746KA29 meets industry standards.
7.What is the process for return or replacement of MAX6746KA29?
All MAX6746KA29 units undergo pre-shipment inspection (PSI). If there is an issue with MAX6746KA29, 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 MAX6746KA29 part is unused and in its original packaging.
Return procedure for MAX6746KA29:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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