MAX6746
µP Reset Circuits with Capacitor-Adjustable Reset/Watchdog Timeout Delay
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The MAX6746–MAX6753 low-power microprocessor (µP) supervisory circuits monitor single/dual system supply voltages from 1.575V to 5V and provide maximum adjustability for reset and watchdog functions. These devices assert a reset signal whenever the VCC supply voltage or RESET IN falls below its reset threshold or when manual reset is pulled low. The reset output remains asserted for the reset timeout period after VCC and RESET IN rise above the reset threshold. The reset function features immunity to power-supply transients.
The MAX6746–MAX6753 have ±2% factory-trimmed reset threshold voltages in approximately 100mV increments from 1.575V to 5.0V and/or adjustable reset threshold voltages using external resistors.
The reset and watchdog delays are adjustable with external capacitors. The MAX6746–MAX6751 contain a watchdog select input that extends the watchdog timeout period by 128x. The MAX6752/MAX6753 contain a window watchdog timer that looks for activity outside an expected window of operation.
The MAX6746–MAX6753 are available with a push-pull or open-drain active-low RESET output. The MAX6746–MAX6753 are available in an 8-pin SOT23 package and are fully specified over the automotive temperature range (-40°C to +125°C).
Design Solution: Build in Automotive Insurance with Supervisor and Watchdog Policies ›
Key Features
- Configurable Reset and Watchdog Options EnablesWide Variety of Applications
- Factory-Set Reset Threshold Options from 1.575V to 5V in ～ 100mV Increments
- Adjustable Reset Threshold Options
- Single/Dual Voltage Monitoring
- Capacitor-Adjustable Reset Timeout
- Capacitor-Adjustable Watchdog Timeout
- Min/Max (Windowed) Watchdog Option
- Manual-Reset Input Option
- Push-Pull or Open-Drain Active-Low RESET Output Options
- 3.7µA Supply Current Reduces System Power Consumption
- Integrated Power Supply Protection Increases Robustness
- Power-Supply Transient Immunity
- Guaranteed Active-Low RESET Valid for VCC ≥ 1V
- 8-Pin SOT23 Packages Saves Board Space
- AEC-Q100 Qualified. Refer to Ordering Information for Specific /V Trim Variants
Applications/Uses
- Automotive
- Battery-Powered Computers/Controllers
- Computers
- Critical µP Monitoring
- Embedded Controllers
- Intelligent Instruments
- Medical Equipment
- Portable Equipment
- Set-Top Boxes
| Reset Thresh. (V) | 1.2 to 1.8 1.8 to 2.5 2.5 to 3.3 3.3 to 5.5 |
| Reset Thresh. Accur. (%) (@ +25°C) | 2 |
| Reset Out | Active Low Push-Pull |
| Interface | Factory Fixed R/C Adjustable |
| tRESET (min) | 1ms to 15ms 15ms to 85ms 85ms to 300ms 300ms to 1s <1ms >1s Adjustable |
| Watchdog Feature | Cap Adjustable Input (WDI) |
| Watchdog Timeout | 1s to 2s <1s >2s Adjustable |
| Supervisor Features | Adjustable Reset Input |
| ICC (µA) (max) | 10 |
| Package/Pins | SOT23/8 |
| Budgetary Price (See Notes) | $1.65 @1k |
| Reset Thresh. (V) | 1.2 to 1.8 1.8 to 2.5 2.5 to 3.3 3.3 to 5.5 |
| Reset Thresh. Accur. (%) (@ +25°C) | 2 |
| Reset Out | Active Low Push-Pull |
| tRESET (min) | 1ms to 15ms 15ms to 85ms 85ms to 300ms 300ms to 1s <1ms >1s Adjustable |
| Watchdog Feature | Cap Adjustable Input (WDI) |
| Watchdog Timeout | 1s to 2s <1s >2s Adjustable |
| Supervisor Features | Manual Reset |
| ICC (µA) (max) | 10 |
| Package/Pins | SOT23/8 |
| Budgetary Price (See Notes) | $1.86 @1k |
Simplified Block Diagram
MAX6746, MAX6747, MAX6748, MAX6749, MAX6750, MAX6751: Typical Operating Circuit
Technical Docs
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Parameters
| Reset Thresh. (V) | 1.2 to 1.8 1.8 to 2.5 2.5 to 3.3 3.3 to 5.5 |
| Reset Thresh. Accur. (%) (@ +25°C) | 2 |
| Reset Out | Active Low Push-Pull |
| Interface | Factory Fixed R/C Adjustable |
| tRESET (min) | 1ms to 15ms 15ms to 85ms 85ms to 300ms 300ms to 1s <1ms >1s Adjustable |
| Watchdog Feature | Cap Adjustable Input (WDI) |
| Watchdog Timeout | 1s to 2s <1s >2s Adjustable |
| Supervisor Features | Adjustable Reset Input |
| ICC (µA) (max) | 10 |
| Package/Pins | SOT23/8 |
| Budgetary Price (See Notes) | $1.65 @1k |
| Reset Thresh. (V) | 1.2 to 1.8 1.8 to 2.5 2.5 to 3.3 3.3 to 5.5 |
| Reset Thresh. Accur. (%) (@ +25°C) | 2 |
| Reset Out | Active Low Push-Pull |
| tRESET (min) | 1ms to 15ms 15ms to 85ms 85ms to 300ms 300ms to 1s <1ms >1s Adjustable |
| Watchdog Feature | Cap Adjustable Input (WDI) |
| Watchdog Timeout | 1s to 2s <1s >2s Adjustable |
| Supervisor Features | Manual Reset |
| ICC (µA) (max) | 10 |
| Package/Pins | SOT23/8 |
| Budgetary Price (See Notes) | $1.86 @1k |
Key Features
- Configurable Reset and Watchdog Options EnablesWide Variety of Applications
- Factory-Set Reset Threshold Options from 1.575V to 5V in ～ 100mV Increments
- Adjustable Reset Threshold Options
- Single/Dual Voltage Monitoring
- Capacitor-Adjustable Reset Timeout
- Capacitor-Adjustable Watchdog Timeout
- Min/Max (Windowed) Watchdog Option
- Manual-Reset Input Option
- Push-Pull or Open-Drain Active-Low RESET Output Options
- 3.7µA Supply Current Reduces System Power Consumption
- Integrated Power Supply Protection Increases Robustness
- Power-Supply Transient Immunity
- Guaranteed Active-Low RESET Valid for VCC ≥ 1V
- 8-Pin SOT23 Packages Saves Board Space
- AEC-Q100 Qualified. Refer to Ordering Information for Specific /V Trim Variants
Applications/Uses
- Automotive
- Battery-Powered Computers/Controllers
- Computers
- Critical µP Monitoring
- Embedded Controllers
- Intelligent Instruments
- Medical Equipment
- Portable Equipment
- Set-Top Boxes
Description
The MAX6746–MAX6753 low-power microprocessor (µP) supervisory circuits monitor single/dual system supply voltages from 1.575V to 5V and provide maximum adjustability for reset and watchdog functions. These devices assert a reset signal whenever the VCC supply voltage or RESET IN falls below its reset threshold or when manual reset is pulled low. The reset output remains asserted for the reset timeout period after VCC and RESET IN rise above the reset threshold. The reset function features immunity to power-supply transients.
The MAX6746–MAX6753 have ±2% factory-trimmed reset threshold voltages in approximately 100mV increments from 1.575V to 5.0V and/or adjustable reset threshold voltages using external resistors.
The reset and watchdog delays are adjustable with external capacitors. The MAX6746–MAX6751 contain a watchdog select input that extends the watchdog timeout period by 128x. The MAX6752/MAX6753 contain a window watchdog timer that looks for activity outside an expected window of operation.
The MAX6746–MAX6753 are available with a push-pull or open-drain active-low RESET output. The MAX6746–MAX6753 are available in an 8-pin SOT23 package and are fully specified over the automotive temperature range (-40°C to +125°C).
Design Solution: Build in Automotive Insurance with Supervisor and Watchdog Policies ›
Simplified Block Diagram
MAX6746, MAX6747, MAX6748, MAX6749, MAX6750, MAX6751: Typical Operating Circuit Technical Docs
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal
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