MIC2211-AABML TR Micrel Inc, MIC2211-AABML TR Datasheet - Page 9

• Manufacturer Part Number: MIC2211-AABML TR
• Description: IC REG LDO DUAL 3X3 10-MLF
• Manufacturer: Micrel Inc

Specifications of MIC2211-AABML TR

• Regulator Topology: Positive Adjustable
• Voltage - Output: 1.25 ~ 5 V
• Voltage - Input: 2.25 ~ 5.5 V
• Voltage - Dropout (typical): 0.12V @ 150mA, 0.24V @ 300mA
• Number Of Regulators: 2
• Current - Output: 150mA, 300mA
• Current - Limit (min): 150mA, 300mA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 10-MLF®, QFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: MIC2211-AABMLTR; MIC2211-AABMLTR

Functional Description
The MIC2211 is a high performance, low quiescent current,
power management IC consisting of two µCap low dropout
regulators. 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.
Enable 1 and 2
The enable inputs allow for logic control of both output volt-
ages 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.
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.
Bypass Capacitor
The internal reference voltage of the MIC2211 can be bypassed
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 capaci-
tor for stability. The output capacitor value can be increased
to improve transient response, but performance 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 operat-
ing temperature ranges. To use a ceramic chip capacitor with
Y5V dielectric, the value must be much higher than an X7R
ceramic capacitor to ensure the same minimum capacitance
over the equivalent operating temperature range.
October 2005
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Adjustable Regulator Design
The MIC2211 allows the programming of the output voltages
1 and 2 anywhere between 1.25V and 5.5V, the maximum
operating rating of the part. Two resistors are required for each
output. Appropriate resistor values are required to prevent
the low quiescent current performance being compromised.
Resistor values recommended are between 100kΩ and
500kΩ.
The resistor values are calculated by:
where V
rately for each output.
OUT
R1
R2
MIC2211 Adjustable Regulator Design
is the desired output voltage. Calculate sepa-
R1 = R2
VOUT1
ADJ1
GND
1.250
V
OUT
– 1
VOUT2
ADJ2
M9999-101805
R1
R2