ATA5021 Digital Window Watchdog Timer DATASHEET Features Low current consumption: I < 25A VDD RC oscillator Internal reset during power-up and supply voltage drops (POR) Short trigger window for active mode Long trigger window for sleep mode Cyclical wake-up of the microcontroller in sleep mode Trigger input Single wake-up input Reset output Enable output 9145I-AUTO-10/141. Description The digital window watchdog timer, Atmel ATA5021, is designed in Atmels state-of-the-art 0.8m SOI technology SMART-I.S. 1. In applications where safety is critical, it is especially important to monitor the microcontroller. Normal microcontroller operation is indicated by a cyclically transmitted trigger signal, which is received by a window watchdog timer within a defined time window. A missing or a wrong trigger signal causes the watchdog timer to reset the microcontroller. The IC is tailored for microcontrollers, which can work in both full-power and sleep mode. With an additional voltage monitoring (power-on reset and supply voltage drop reset), the Atmel ATA5021 offers a complete monitoring solution for micro-systems in automotive and industrial applications. Figure 1-1. Block Diagram with External Circuit C V DD 10nF R 1 R 2 6 V DD OSC 8 RC oscillator C 1 OSC Reset 5 Micro- State machine controller OSC External 4 switching 2 Trigger Input signal circuitry Enable conditioning Power-on POR POR reset Test logic 3 Mode 1 7 Wake-up GND 2 ATA5021 DATASHEET 9145IAUTO10/14