MIC2208 Datasheet, PDF (14/19 Pages) Micrel Semiconductor – 3mmx3mm 1MHz 3A PWM Buck Regulator

Micrel, Inc.
TYPE III compensation
Type III in our case, is a dominant pole (C3 and R1)
followed by a zero (C3 and R4) and an additional
zero (C5 and R4), allowing the final pole to be
provided by the output inductor and output capacitor.
This mode of compensation is required when using
low ESR output capacitors, such as ceramic
capacitors. The additional zero offsets the double
pole created by the inductor/output capacitor filter.
MIC2208
Type III Open Loop Gain Response
Dominant
Pole
Zero
Zero
LC
Frequency
20dB/Decade
Frequency (Hz)
80
70
60
50
40
30
20
10
-10
-20
100
Type III Compensation
V IN=5V IN
VOUT=1.0V
IOUT=3A
COUT=47µF
Gain
Phase
1k
10k
100k
Frequency (KHz)
288
252
216
180
144
108
72
36
0
-36
-72
1M
MIC2208
Bill of Materials
Item
Part Number
Description
C2012JB0J106K
10uF Ceramic Capacitor X5R 0805 6.3V
C1a,C1b GRM219R60J106KE19 10uF Ceramic Capacitor X5R 0805 6.3V
08056D106MAT
10uF Ceramic Capacitor X5R 0805 6.3V
C2
0402ZD104MAT
0.1uF Ceramic Capacitor X5R 0402 10V
C3
0402ZD103MAT
1nF Ceramic Capacitor X5R 0402 10V
C3216X5R0J476K
47uF Ceramic Capacitor X5R 1206 6.3V
C4
GRM32ER60J476ME20 47uF Ceramic Capacitor X5R 1206 6.3V
12106D476MAT2A
47uF Ceramic Capacitor X5R 1210 6.3V
C5
VJ0402A330KXAA
33pF Ceramic Capacitor 0402
D1
SSA33L
3A Schottky 30V SMA
L1
RLF7030-1R0N6R4
1uH Inductor 8.8mOhm 7.1mm(L) x 6.8mm (W)x 3.2mm(H)
744 778 9001
1uH Inductor 12mOhm 7.3mm(L)x7.3mm(W)x3.2mm(H)
IHLP2525AH-01 1
1uH Inductor 17.5mΩ (L)6.47mmx(W)6.86mmx(H) 1.8mm
R1
CRCW04024992F
49.9KΩ 1% 0402 resistor
Manufacturer Qty
TDK
Murata
2
AVX
AVX
1
AVX
2
TDK
Murata
1
AVX
Vishay VT
1
Vishay Semi
1
TDK
Wurth Electronik
Vishay Dale
1
Vishay Dale
1
September 2005
14
M9999-092905
www.micrel.com