CM2838
300mA L
OW
E
SR
CMOS LDO W
ITH
E
NABLE
DETAILED DESCRIPTION
The CM2838 family of CMOS regulators contain a PMOS pass transistor, voltage reference, error amplifier, over-current
protection, thermal shutdown.
The P-channel pass transistor receives data from the error amplifier, over-current protection, and thermal protection circuits.
During normal operation, the error amplifier compares the output voltage to a precision reference. Over-current and Thermal
shutdown circuits become active when the junction temperature exceeds 150℃, or the current exceeds 300mA. During thermal
shutdown, the output voltage remains low. Normal operation is restored when the junction temperature drops below 120℃.
The CM2838 switches from voltage mode to current mode when the load exceeds the rated output current. This prevents
over-stress.
ENABLE
The Enable pin normally floats high. When actively, pulled low, the PMOS pass transistor shut off, and all internal circuits are
powered down. In this state, the quiescent current is less than 2μA. This pin behaves much like an electronic switch.
EXTERNAL CAPACITOR
The CM2838 is stable with a Low ESR output capacitor to ground of 1.0μF or greater. It can keep stable even with higher ESR
capacitors. A second capacitor is recommended between the input and ground to stabilize VIN. The input capacitor should be
larger than 0.1μF to have a beneficial effect. All capacitors should be placed in close proximity to the pins. A “quiet” ground
termination is desirable.
2006/10/11
Rev. 1.3
Champion Microelectronic Corporation
Page 5
CHAMP [ CHAMPION MICROELECTRONIC CORP. ]
