MIC2177-5.0BWM Micrel Inc, MIC2177-5.0BWM Datasheet - Page 10

• Manufacturer Part Number: MIC2177-5.0BWM
• Description: IC REG SYNCBUCK 2.5A 5.0V 20SOIC
• Manufacturer: Micrel Inc
• Type: Step-Down (Buck)r

Specifications of MIC2177-5.0BWM

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 5V
• Current - Output: 2.5A
• Frequency - Switching: 200kHz
• Voltage - Input: 4.5 ~ 16.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

given in the “Applications Information” section. Note that
∆I
causes I
voltage changes by a factor of two, I
from 130mA to 250mA.
During low-dropout operation, the minimum current
thresh-old circuit reduces the minimum value of I
for
decreasing to almost zero when the difference between
V
Changing from Skip to PWM Mode
The MIC2177 will automatically change from skip to
PWM mode when I
mode operation, it can supply up to 300mA, and when
I
value. At this point, the MIC2177 begins operating in
PWM mode. Note that the maximum value of I
skip mode is greater than the minimum value required
for PWM mode. This current hysteresis prevents the
MIC2177 from toggling between modes when I
the range of 100mA to 300mA.
LOAD
Micrel, Inc.
April 2008
IN
L
and V
varies as a function of input voltage, and this also
PWM
exceeds this limit, V
MIN
OUT
operation.
is very low.
to vary. In applications where the input
LOAD
This
exceeds 300mA. During skip-
OUT
will fall below its nominal
compensates
MIN
will typically vary
LOAD
for
LOAD
L1(peak)
is in
∆I
for
L1
10
The low output comparator determines when V
enough for the regulator to change operating modes. It
detects when the feedback voltage is 3% below nominal,
and pulls the AUTO pin to ground. When AUTO is less
than 1.6V, the PWM/skip-mode select logic places the
MIC2177 into PWM operation. The external 2.2nF
capacitor connected to AUTO is charged by a 10µA
current source after the regulator begins operating in
PWM mode. As a result, AUTO stays below 1.6V for
several switching cycles after PWM operation begins,
forcing the MIC2177 to remain in PWM mode during this
transition.
External PWM-Mode Selection
The MIC2177 can be forced to operate in only PWM
mode by connecting AUTO to ground. This prevents
skip-mode operation in applications that are sensitive to
switching noise.
M9999-042108
MIC2177
OUT
is low