The TEA5170 is designed to work in the secondary part of an off-line SMPS, sending pulses to the slaved TEA2260/61 which are located on the primary side of the main transformer. An accurate regulated voltage is obtained by duty cycle control. The TEA5170 can be externally synchronized by higher or lower frequency signal, then it could be used in applications like TV set ones. For more details, refer to application note AN408/0591. PIN CONNECTIONS