MIC2208_10 Datasheet, PDF (14/18 Pages) Micrel Semiconductor – 3mm x 3mm 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
Dominan t
Pole
Zero
Zero
LC
Frequen cy
20d B/De cad e
80
70
60
50
40
30
20
10
-10
-20
100
Type III Compensation
V_IN=5V_IN
V_OUT=1.0V
I_OUT=3A
C_OUT=47µF
Gain
Phase
1k
10k
100k
Frequency (KHz)
288
252
216
180
144
108
72
36
0
-36
-72
1M
Frequency (Hz)
MIC2208
Bill of Materials
Item
Part Number
Manufacturer
Description
Qty.
C2012JB0J106K
TDK⁽¹⁾
C1a, C1b GRM219R60J106KE19
Murata⁽²⁾
10µF Ceramic Capacitor X5R 0805 6.3V
2
08056D106MAT
AVX⁽³⁾
C2
0402ZD104MAT
AVX⁽³⁾
0.1µF Ceramic Capacitor X5R 0402 10V
1
C3
0402ZD103MAT
AVX⁽³⁾
1nF Ceramic Capacitor X5R 0402 10V
1
C3216X5R0J476K
C4
GRM32ER60J476ME20
TDK⁽¹⁾
Murata⁽²⁾
47µF Ceramic Capacitor X5R 1206 6.3V
1
12106D476MAT2A
AVX⁽³⁾
47µF Ceramic Capacitor X5R 1210 6.3V
C5
VJ0402A330KXAA
Vishay VT⁽⁴⁾
33pF Ceramic Capacitor 0402
1
D1
SSA33L
Vishay Semi⁽⁴⁾
3A Schottky 30V SMA
1
RLF7030-1R0N6R4
TDK⁽¹⁾
1µH Inductor 8.8mΩ 7.1mm(L) x 6.8mm (W)x 3.2mm(H)
L1
744 778 9001
Wurth Elektronik⁽⁵⁾
1µH Inductor 12mΩ 7.3mm(L)x7.3mm(W)x3.2mm(H)
1
IHLP2525AH-01 1
Vishay Dale⁽⁴⁾
1µH Inductor 17.5mΩ (L)6.47mmx(W)6.86mmx(H) 1.8mm
May 2010
14
M9999-051410-D