R EM MICROELECTRONIC - MARIN SA EM6151/52 Windowed Watchdog IC with 5V LDO Description Features The EM6151/52 are microprocessor voltage supervisory circuits including voltage monitoring, reset timeout period and windowed watchdog. Moreover, the EM6152 includes a 5V low-dropout voltage regulator on-chip. The watchdog timer, the reset timeout period and the voltage threshold are set by external resistors. The windowed watchdog timer function offers increased security compared to a standard watchdog timer. Windowed watchdog function Benefits Open-drain active-low RESET output Push-pull active-low ENABLE output Greatly improves security: 9 Prevents endless loops 9 Reinitializes the system in case of SW code errors 9 Avoids conflict between master and slaves MCUs 9 Catches a malfunctioning crystal oscillator Increased flexibility: 9 Short or long ratio for opened/closed watchdog window 9 Parameters set by external resistors Detects events that are expected within a time interval that has both a minimum and a maximum Better heat dissipation (EM6152) One-chip solution to reduce drastically PCB size and mounting costs (EM6152) Voltage monitoring and power-on reset function Separate ENABLE output for peripheral: the circuit waits 3 acknowledgements from μP to ensure full working system before activation of peripheral (e.g. motor drivers, actuators) CAN sleep mode function -40°C to +125°C operating temperature Low supply current: 35µA / 145µA (EM6151/52) 5V LDO Voltage Regulator, up to 400mA (EM6152) SO-8 and PSOP-16 power package (EM6152) High Flexibility and Accuracy Adjustable reset threshold voltage with ±3% accuracy Adjustable watchdog timer (TWD = 10ms to 1sec, accuracy ±10%) using one external resistor Adjustable reset timeout period TPOR using one external resistor Typical Application Windowed Watchdog EM6152 A sophisticated watchdog timer detects when the processor is running outside of an expected (opened) window of operation. A reset is asserted whenever a TCL is not received while the watchdog window is opened. Two ratios for the opened/closed windows are available: 33%/67% for increased security or 67%/33% for increased programming flexibility. Window: Opened Opened Closed Closed Unregulated V DD (up to +40V) VDD 5V regulated V DD VDD VDD To adjust voltage threshold Opened Closed LDO Voltage Regulator VIN RES RESET (open-drain) Closed TCL MPU,MCU I/O EM6151 TCL incorrect - too fast RES will go active: ROSC EN TCL incorrect - too slow To adjust TWD and T POR RES will go active: GND EN Peripheral, Actuator GND GND TCL correct RES will NOT go active: Product Offering 3 correct TCL service EN goes active: t Copyright © 2005, EM Microelectronic-Marin SA Subject to change without notice Rev. A, 08/05 Part Number LDO Voltage Regulator (VOUT / VDROPOUT @ IOUT) Input Voltage Package EM6151_SO8 - 1.2 to 5.5V SO-8 EM6152_SO8 5V / 250mV @ 100mA 2.3 to 40V SO-8 EM6152_PS16 5V / 250mV @ 250mA 2.3 to 40V PSOP-16 Phone: +41.32.755-5111, Fax: +41.32.755-5403 www.emmicroelectronic.com [email protected]