Low-Cost Reset + Watchdog ICs
| Status |
| Active: In Production. |
| Description |
The MAX705–MAX708/MAX813L microprocessor (µP) supervisory circuits reduce the complexity and number of components required to monitor power-supply and battery functions in µP systems. These devices significantly improve system reliability and accuracy compared to separate ICs or discrete components.
The MAX705/MAX706/MAX813L provide four functions:
- A reset output during power-up, power-down, and brownout conditions.
- An independent watchdog output that goes low if the watchdog input has not been toggled within 1.6 seconds.
- A 1.25V threshold detector for power-fail warning, low-battery detection, or for monitoring a power supply other than +5V.
- An active-low manual-reset input.
The MAX707/MAX708 are the same as the MAX705/MAX706, except an active-high reset is substituted for the watchdog timer. The MAX813L is the same as the MAX705, except RESET is provided instead of active-low RESET.
Two supply-voltage monitor levels are available: The MAX705/MAX707/MAX813L generate a reset pulse when the supply voltage drops below 4.65V, while the MAX706/MAX708 generate a reset pulse below 4.40V. All four parts are available in 8-pin DIP, SO and µMAX® packages. |
| Key Features |
|
Applications/Uses |
- µMAX Package: Smallest 8-Pin SO
- Guaranteed Active-Low RESET Valid at VCC = 1V
- Precision Supply-Voltage Monitor
- 4.65V in MAX705/MAX707/MAX813L
- 4.40V in MAX706/MAX708
- 200ms Reset Pulse Width
- Debounced TTL/CMOS-Compatible Manual-Reset Input
- Independent Watchdog Timer—1.6sec Timeout (MAX705/MAX706)
- Active-High Reset Output (MAX707/MAX708/MAX813L)
- Voltage Monitor for Power-Fail or Low-Battery Warning
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| Key Specifications: Supervisors (1 Monitored Voltage) |
| Part Number |
Reset Thresh.
(V) |
Reset Out |
Reset Out |
tRESET |
Watchdog Feature |
Watchdog Timeout |
Supervisor Features |
Reset Thresh. Accur.
(%) |
ICC
(µA) |
Price |
| Active Low |
Active High |
min |
@ +25°C |
max |
See Notes |
| MAX705 |
3.3 to 5.5 |
Push-Pull |
- |
85ms to 300ms |
| Input (WDI) |
| Input/Output (WDI/WDO) | |
1s to 2s |
| Adjustable Reset Input |
| Manual Reset |
| Power Fail Comparator/Low Battery Detect | |
2.5 |
350 |
$1.58 @1k |
| MAX706 |
- |
| Input (WDI) |
| Input/Output (WDI/WDO) | |
1s to 2s |
$1.58 @1k |
| MAX707 |
Push-Pull |
No Watchdog |
- |
$1.52 @1k |
| MAX708 |
Push-Pull |
No Watchdog |
- |
$1.52 @1k |
| See All Supervisors (1 Monitored Voltage) (274) |
| Diagram |
Typical Operating Circuit |
source：ShenZhen henlito electronic co.,ltd.
web:www.henlito.com
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