MIC2210_06 Datasheet, PDF (10/11 Pages) Micrel Semiconductor – Dual μCap LDO with Open-Drain Driver

Micrel, Inc.
Functional Description
The MIC2210 is a high performance, low quiescent
current power management IC consisting of two µCap
low dropout regulators, an open-drain driver. The first
regulator is capable of sourcing 150mA at output
voltages from 1.25V to 5V. The second regulator is
capable of sourcing 300mA of current at output voltages
from 1.25V to 5V. An open-drain driver completes the
power management chipset, offering the capability of
driving LEDs for keypad backlighting in applications such
as cell phones.
Enable 1 and 2
The enable inputs allow for logic control of both output
voltages with individual enable inputs. The enable input
is active high, requiring 1.8V for guaranteed operation.
The enable input is CMOS logic and cannot by left
floating.
Open-Drain Driver (DRV)
The drive (DRV) pin is an open-drain output capable of
sinking 150mA of current. This output is controlled by a
logic level input, the switch (SW) pin. The switch pin is
an active high input and cannot be left floating.
Input Capacitor
Good bypassing is recommended from input to ground
to help improve AC performance. A 1µF capacitor or
greater located close to the IC is recommended.
MIC2210
Bypass Capacitor
The internal reference voltage of the MIC2210 can be
by-passed with a capacitor to ground to reduce output
noise and increase power supply rejection (PSRR). A
quick-start feature allows for quick turn-on of the output
voltage regardless of the size of the capacitor. The
recommended nominal bypass capacitor is 0.01µF, but it
can be increased without limit.
Output Capacitor
Each regulator output requires a 1µF ceramic output
capacitor for stability. The output capacitor value can be
increased to improve transient response, but perform-
ance has been optimized for a 1µF ceramic type output
capacitor.
X7R/X5R dielectric-type ceramic capacitors are recom-
mended because of their temperature performance.
X7R-type capacitors change capacitance by 15% over
their operating temperature range and are the most
stable type of ceramic capacitors. Z5U and Y5V
dielectric capacitors change value by as much as 50%
and 60% respectively over their operating temperature
ranges. To use a ceramic chip capacitor with Y5V
dielectric, the value must be much higher than a X7R
ceramic capacitor to ensure the same minimum capaci-
tance over the equivalent operating temperature range.
November 2006
10
M9999-112006