ACE533J

500mA, Micropower, VLDO Linear Regulator

VER 1.2

8

Pin Function

SHDN : Shutdown, Active Low. This pin is used to put the ACE533J into shutdown. The SHDN pin

cannot be left floating and must be tied to the input pin if not used.

GND: Ground and Heat Sink. Solder to a ground plane or large pad to maximize heat dissipation. VIN:

Power for ACE533J and Load. Power is supplied to the devices through the VIN pin. The VIN pin should

be locally bypassed to ground if the ACE533J series are more than a few inches away from another

source of bulk capacitance.

VOUT: Voltage Regulated Output. The VOUT pin supplies power to the load. A minimum output capacitor

of 1μF is required to ensure stability. Larger output capacitors may be required for applications with large

transient loads to limit peak voltage transients.

NC: Not Connected.

FB: Output voltage feedback. This terminal is used to set the output voltage.

Output Voltage Setting

The output voltage of the ACE533J adjustable regulator is programmed using an external resistor divider

as shown in Figure 2. The output voltage is calculated using:

Resistors R1 and R2 should be chosen for approximately 3-

5μA divider current. Lower value resistors can

be used but offer no inherent advantage and waste more power. Higher values should be avoided, as

leakage currents at FB increase the output voltage error. The recommended design procedure is to

choose R2=200kΩ to set the divider current at 5μA and then calculate R1 using: