MIC37139
By virtue of its low-dropout voltage, this device does not
saturate into dropout as readily as similar NPN-based de-
signs. When converting from 3.3V to 2.5V, 2.5V to 1.8V or
1.65V, or 2.5V to 1.5V, the NPN-based regulators are already
operating in dropout, with typical dropout requirements of
1.2V or greater. To convert down to 2.5V without operating in
dropout, NPN-based regulators require an input voltage of
3.7V at the very least. The MIC37139 regulator will provide
excellent performance with an input as low as 3.0V or 2.25V,
respectively. This gives the PNP-based regulators a distinct
advantage over older, NPN-based linear regulators.
Micrel
Minimum Load Current
The MIC37139 regulator is specified between finite loads. If
the output current is too small, leakage currents dominate
and the output voltage rises. A 10mA minimum load current
is necessary for proper operation.
November 2003
9
M9999-112003
MICREL [ MICREL SEMICONDUCTOR ]
