Low operating current shunt regulator reduces standby power dissipation

New from Diodes Incorporated, the AP431i adjustable shunt regulator features a 50µA minimum cathode current that is significantly lower than equivalent industry standard 431 devices. This enables manufacturers of switch-mode power supplies to target applications that require very low power dissipation, particularly 12V/19V adaptors/chargers, but also TVs and monitors where standby power consumption is of great importance. With reliable thermal stability over its full operating range, the competitively-priced AP431i three-terminal adjustable shunt regulator features fast turn-on characteris¬tics, a low temperature coefficient and low output imped¬ance. The AP431i has the same electrical specifications as a standard 431, while having an advantage in being able to regulate with a low minimum cathode current, typically 50µA. This key differentiator makes it well suited as a Zener diode substitute in switch-mode power supplies (SMPS). The output voltage of AP431i can be set to any value between VREF (2.5V) and the corresponding maximum cathode voltage (36V). Two grades of initial voltage tolerance are offered, 0.5% and 1%, with three package options available: TO-92 (ammo-pack), SOT-23 and SOT-89. The packages are fully RoHS compliant and totally lead-, halogen- and antimony-free 'green' devices.