SMPS Capacitors
Capacitor Selection and Performance
ASMLC CAPACITOR SELECTION
SMPS Design Information (SM, CH, CV, RH and SK Styles)
Absolute Maximum Output Capacitance
Assuming no ESL and no ESR
25
20
15
500 KHz
10
5
0
0
5
10
15
Maximum Output Filter Capacitance
( F)
20
250 KHz
2 MHz
1 MHz
Load Current - Amps
50 mV Noise
Due to
Capacitance
Absolute Maximum Capacitance ESL
Assuming no ESR - Capacitive Induced Ripple
25
20
15
10
5
0
0
5
10
15
Maximum Output Filter Capacitance ESL
½
(nH)
20
DIP Leads
SK Series
50 mV Noise
Due to ESL
250 KHz
500 KHz
1 MHz
2 MHz
Absolute Maximum Capacitance ESR
Assuming no ESL - Capacitive Induced Ripple
25
20
15
10
DIP Leads
5
0
0
10
20
30
Maximum Output Filter Capacitance ESR
(mOhm)
40
SK Series
50 mV Noise
Due to ESR
ASMLC CAPACITOR PERFORMANCE
Capacitance as Measured from dv/dt Slope
200 mA/ns Current Pulse
Measurement starts after Inductive Ring Decay
16
14
AI Electrolytic
15 F
12
MLC SM02
10 F
Capacitance ( F)
10
Wet Ta
10 F
8
Solid Ta
5.6 F
6
4
MLC SM04
4.7 F
2
0
10
-9
Load Current - Amps
Load Current - Amps
10
-8
10
-7
Time (Seconds)
10
-6
10
-5
5