MIC2214 Datasheet, PDF (9/11 Pages) Micrel Semiconductor – Portable Power Management IC

MIC2214
Functional Diagram
VIN
LDO1
EN
OUT1
SET
CBYP
SW
LDO2
POR & Delay
OUT2
POR
Reference
SW Logic
GND
DRV
NGND
MIC2214 Fixed Voltage Block Diagram
Micrel
VIN1
EN1
LDO1
OUT1
ADJ1
VIN2
EN2
SET
CBYP
SW
Quickstart
Reference
LDO2
SW Logic
GND
POR & Delay
OUT2
ADJ2
POR
DRV
NGND
MIC2214 Adjustable Voltage Block Diagram
Functional Description
The MIC2214 is a high performance, low quiescent current
power management IC consisting of two µCap low dropout
regulators, a power-on reset (POR) circuit and 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. The second regulator has a POR circuit that
monitors its output voltage and indicates when the output
voltage is within 5% of nominal. The POR offers a delay time
that is externally programmable with a single capacitor to
ground. An open-drain driver completes the power manage-
ment chipset, offering the capability of driving LEDs for
keypad backlighting in applications such as cellphones.
Enable
The enable input allows for logic control of both output
voltages with one enable input. The enable input is active
high, requiring 1.8V for guaranteed operation. The enable
input is CMOS logic and cannot by left floating.
Power-On Reset (POR)
The power-on reset output is an open-drain N-Channel
device, requiring a pull-up resistor to either the input voltage
or output voltage for proper voltage levels. The POR output
has a delay time that is programmable with a capacitor from
the SET pin to ground. The delay time can be programmed to
be as long as 1 second.
The SET pin is a current source output that charges a
capacitor that sets the delay time for the power-on reset
output. The current source is a 1µA current source that
charges a capacitor up from 0V. When the capacitor reaches
1.25V, the output of the POR is allowed to go high.
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.
August 2004
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MIC2214