National semiconductor 3a buck voltage regulators lm2576t national semiconductor lm2576t 50 step down voltage regulator 5v output voltage single output 3a output current 4 voltage accuracy 8v to 40v supply voltage 52khz switching frequency 40 to 125c 5 to 220 case requires only 4 external components ttl shutdown capability low power standby mode high efficiency thermal shutdown and current limit protection p product enhancement tested suitable for high efficiency step dow