3.3 V

V

DD

100 nF

V

DD

RESET

RESET

TPS3823-33-Q1

MSP430C325

MR

WDI

I/O

GND

GND

TPS3820-33-Q1, TPS3820-50-Q1, TPS3823-25-Q1

TPS3823-30-Q1, TPS3823-33-Q1, TPS3823-50-Q1, TPS3824-30-Q1, TPS3824-33-Q1

TPS3824-50-Q1, TPS3825-33-Q1, TPS3825-50-Q1, TPS3828-33-Q1, TPS3828-50-Q1

www.ti.com

SGLS143C – DECEMBER 2002 – REVISED DECEMBER 2015

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

The TPS382x-xx-Q1 family of devices are very small supervisory circuits that monitor fixed supply voltages of

2.5 V, 3 V, 3.3 V, and 5 V. The TPS382x-xx-Q1 family operates from 1.1 V to 5.5 V. Orderable options include

versions with either push-pull or open-drain outputs, versions that use active-high or active-low logic for output

signals, versions with a manual reset pin, and versions with a watchdog timer. See the Device Comparison Table

for an overview of device options.

9.2 Typical Applications

9.2.1 Supply Rail Monitoring with Watchdog Time-out and 200-ms Delay

The TPS3823-xx-Q1 can be used to monitor the supply rail for devices such as microcontrollers. The

signal if the WDI input is not periodically triggered by a positive or negative transition at WDI. When the

Some applications require a shorter reset signal than the 200 ms that most of the TPS382x-xx-Q1 family provide.

In these cases, the TPS3820-xx-Q1is a good choice because it has a delay time of only 25 ms. If an open-drain

output is needed, replace the TPS3823-xx-Q1 with the TPS3828-xx-Q1 (if the WDI input must be active while

RESET is low, see Decoupling WDI During Reset Event). Figure 9 shows the TPS3823-33-Q1 in a typical

application.

Figure 9. Supply Rail Monitoring With Watchdog Time-out

9.2.1.1 Design Requirements

The TPS3823-33-Q1 must drive the enable pin of a MSP430C325 using a logic-high signal to signify that the

supply voltage is above the minimum operating voltage of the device and monitor the I/O pin to determine if the

microcontroller is operating correctly.

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Product Folder Links: TPS3820-33-Q1 TPS3820-50-Q1 TPS3823-25-Q1 TPS3823-30-Q1 TPS3823-33-Q1 TPS3823-

50-Q1 TPS3824-30-Q1 TPS3824-33-Q1 TPS3824-50-Q1 TPS3825-33-Q1 TPS3825-50-Q1 TPS3828-33-Q1

TPS3828-50-Q1