MIC2177_08 Datasheet, PDF (7/15 Pages) Micrel Semiconductor – 2.5A Synchronous Buck Regulator

Micrel, Inc.
Functional Diagram
V_IN
4.5V to 16.5V
MIC2177
C_IN
VIN 1 2 9
UVLO,
Thermal
Shutdown
Enable
EN
Shutdown
20
BIAS
19
10k 0.01µF
3.3V
Regulator
internal
supply
voltage
SYNC
18
200kHz
Oscillator
Auto-Mode
AUTO
PWM
11
2.2nF
Output
Control
Logic
I_LIMIT
Comp.
PWM/
Skip-Mode
Select Logic
I_MIN
Comp.
CORRECTIVE RAMP
3.3V
10µA
COMP
13
R_C
C_C
MIC2177 [Adjustable]
RESET PULSE
R
Q
S
PWM
Comp.
I_SENSE
Amp.
100m
P-channel
100m
N-channel
V_OUT
=
1.245
(
R1
R2
+
1)
SW
3
L1
8
V_OUT
D
PGND
4
5
6
7
C_OUT
Bold lines indicate
high current traces
I_MIN
Thrshld.
OUT
10
Low Output
Comp.
R1
FB
12
R2
Skip-Mode
Comp.
40mV
Error
Amp.
V_REF
1.245V
SGND ^{14 15 16 17}
April 2008
7
M9999-042108