Buck Regulator. MIC2177 Datasheet

MIC2177 Regulator. Datasheet pdf. Equivalent

MIC2177 Datasheet
Recommendation MIC2177 Datasheet
Part MIC2177
Description 2.5A Synchronous Buck Regulator
Feature MIC2177; MIC2177 2.5A Synchronous Buck Regulator General Description Features The Micrel MIC2177 is a 200k.
Manufacture Micrel Semiconductor
Datasheet
Download MIC2177 Datasheet




Micrel Semiconductor MIC2177
MIC2177
2.5A Synchronous Buck Regulator
General Description
Features
The Micrel MIC2177 is a 200kHz synchronous buck (step-
down) switching regulator designed for high-efficiency,
battery-powered applications.
The MIC2177 operates from a 4.5V to 16.5V input and
features internal power MOSFETs that can supply up to 2.5A
output current. It can operate with a maximum duty cycle of
100% for use in low-dropout conditions. It also features a
shutdown mode that reduces quiescent current to less than
5µA.
The MIC2177 achieves high efficiency over a wide output
current range by switching between PWM and skip mode.
Operating mode is automatically selected according to output
conditions. Switching frequency is preset to 200kHz and can
be synchronized to an external clock signal of up to 300kHz.
The MIC2177 uses current-mode control with internal current
sensing. Current-mode control provides superior line
regulation and makes the regulator control loop easy to
compensate. The output is protected with pulse-by-pulse
current limiting and thermal shutdown. Undervoltage lockout
turns the output off when the input voltage is less than 4.5V.
4.5V to 16.5V input voltage range
Dual-mode operation for high efficiency (up to 96%)
– PWM mode for > 200mA load current
– Skip mode for < 200mA load current
100minternal power MOSFETs at 12V input
200kHz preset switching frequency
Low quiescent current
– 1.0mA in PWM mode
– 500µA in skip mode
– < 5µA in shutdown mode
100% duty cycle for low dropout operation
Current-mode control
– Simplified loop compensation
– Superior line regulation
Current limit
Thermal shutdown
Undervoltage lockout
The MIC2177 is packaged in a 20-pin wide power SO
package with an operating temperature range of –40°C to
+85°C.
See the MIC2178 for externally selected PWM or skip-mode
operation.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Applications
High-efficiency, battery-powered supplies
Buck (step-down) dc-to-dc converters
Cellular telephones
Laptop computers
Hand-held instruments
Battery Charger
_________________________________________________________________________________________________________
Typical Application
VIN
5.4V to 18V
C1
22µF
35V
ENABLE
SHUTDOWN
U1 1,2,9
VIN
20
18
11
EN
SYNC
AUTO
OUT
MIC SW
2177-5.0 PGND
10
3,8
4–7
FB 12
L1, 50µH
D1
MBRS130L
COMP SGND BIAS
2.2
nF
R1 13
14–17
19
10k
CC
C3
0.01µF
6.8nF
R1
10k
VOUT
5V/1A
C2
100µF
10V
5V Output
Efficiency
100
95
90 VIN = 6V
85
80
75
70
10
SKIP
PWM
100 1000 2500
OUTPUT CURRENT (mA)
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
April 2008
M9999-042108



Micrel Semiconductor MIC2177
Micrel, Inc.
Ordering Information
Part Number
MIC2177-3.3BWM
MIC2177-5.0BWM
MIC2177BWM
MIC2177-3.3YWM
Output
Voltage
3.3V
5.0V
Adj.
3.3V
MIC2177
Switching
Frequency
200kHz
200kHz
200kHz
200kHz
Temperature Range
Package
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
20-Pin Wide SOIC
20-Pin Wide SOIC
20-Pin Wide SOIC
20-Pin Wide SOIC
Lead Finish
Standard
Standard
Standard
Pb-Free
Pin Configuration
VIN 1
VIN 2
SW 3
PGND 4
PGND 5
PGND 6
PGND 7
SW 8
VIN 9
OUT 10
20 EN
19 BIAS
18 S Y NC
17 SGND
16 SGND
15 SGND
14 SGND
13 COMP
12 FB
11 AUTO
20-Pin Wide SOIC (WM)
April 2008
2 M9999-042108



Micrel Semiconductor MIC2177
Micrel, Inc.
MIC2177
Pin Description
Pin Number
1, 2, 9
3, 8
4, 5, 6, 7
10
11
12
13
14, 15, 16, 17
18
19
20
Pin Name
VIN
SW
PGND
OUT
AUTO
FB
COMP
SGND
SYNC
BIAS
EN
Pin Function
Supply Input: Controller and switch supply. Unregulated supply input to internal
regulator, output switches, and control circuitry. Requires bypass capacitor to PGND.
All three pins must be connected to VIN.
Switch (Output): Internal power MOSFET switch output. Both pins must be
externally connected together.
Power Ground: Output stage ground connections. Connect all pins to a common
ground plane.
Output Voltage Sense (Input): Senses output voltage to determine minimum switch
current for PWM operation. Connect directly to VOUT.
Automatic Mode: Connect 2.2nF timing capacitor for automatic PWM-/skip-mode
switching. Regulator operates exclusively in PWM mode when pin is pulled low.
Feedback (Input): Error amplifier inverting input. For adjustable output version,
connect FB to external resistive divider to set output voltage. For 3.3V and 5V fixed
output versions, connect FB directly to output.
Compensation: Internal error amplifier output. Connect to capacitor or series RC
network to compensate the regulator control loop.
Signal Ground: Ground connection of control section. Connect all pins to common
ground plane.
Frequency Synchronization (Input): Optional clock input. Connect to external clock
signal to synchronize oscillator. Leading edge of signal above 1.7V terminates
switching cycle. Connect to SGND if not used.
Bias Supply: Internal 3.3V bias supply output. Decouple with 0.01µF bypass
capacitor and 10kto SGND. Do not apply any external load.
Enable (Input): Logic high enables operation. Logic low shuts down regulator. Do
not allow pin to float.
April 2008
3 M9999-042108







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