PI33XX-X0 Datasheet, PDF (38/42 Pages) List of Unclassifed Manufacturers – 8V to 36Vin Cool-Power ZVS B uck Regulator Family

PI33XX-X0
Filter Considerations
The PI33XX requires input bulk storage capacitance
as well as low impedance ceramic X5R input
capacitors to ensure proper start up and high
frequency decoupling for the power stage. The
PI33XX will draw nearly all of the high frequency
current from the low impedance ceramic capacitors
when the main high side MOSFET is conducting.
During the time the high side MOSFET is off, they are
replenished from the bulk capacitor. If the input
impedance is high at the switching frequency of the
converter, the bulk capacitor must supply all of the
average current into the converter, including
replenishing the ceramic capacitors. This value has
been chosen to be 100µF so that the PI33XX can
start up into a full resistive load and supply the
output capacitive load with the default minimum
soft start capacitor when the input source
impedance is 50 Ohms at 1MHz. The ESR for this
capacitor should be approximately 20mΩ. The RMS
ripple current in this capacitor is small, so it should
not be a concern if the input recommended ceramic
capacitors are used. Table 6 shows the
recommended input and output capacitors to be
used for the various models as well as expected
transient response, RMS ripple currents per
capacitor, and input and output ripple voltages.
Table 7 includes the recommended input and output
ceramic capacitors.
Device VIN ILOAD
(V) (A)
PI3311 24 ¹⁰
5
PI3318 24 10
5
PI3312 24 10
5
PI3301 ₂₄ 10
5
PI3302 24 10
5
PI3303 24 8
4
PI3305 24 8
4
CINPUT
Bulk
Elec.
100µF
50V
100µF
50V
100µF
50V
100µF
50V
100µF
50V
100µF
50V
100µF
50V
CINPUT
Ceramic
X5R
4X4.7µF
50V
4X4.7µF
50V
4X4.7µF
4X4.7µF
4X4.7µF
4X4.7µF
4X4.7µF
COUTPUT
Ceramic
X5R
8X100µF
2X1 µF
1X0.1 µF
6X100µF
2X1 µF
1X0.1 µF
4X100µF
2X1 µF
1X0.1 µF
4X100µF
2X1 µF
1X0.1 µF
4X47µF
2X1 µF
1X0.1 µF
4X22µF
2X1 µF
1X0.1 µF
4X22µF
2X1 µF
1X0.1 µF
CINPUT
Ripple
Current
(IRMS)
0.5
0.5
1
1.05
1.2
1.3
1.38
COUTPUT
Ripple
Current
(IRMS)
0.8
0.8
1.75
1.625
1.5
1.36
1.2
Input
Ripple
(mVpp)
120
100
120
100
150
100
200
125
220
140
275
150
280
160
Output
Ripple
(mVpp)
20
15
20
15
50
24
40
33
50
30
100
60
150
75
Transient
Deviation
(mVpk)
-/+40
-/+40
-/+80
-/+100
-/+170
-/+300
-/+400
Recovery
Time
(µs)
40
40
25
20
30
30
30
Load
Step
(A)
(Slew/µs)
5
(5A/µs)
5
(5A/µs)
5
(10A/µs)
5
(10A/µs)
5
(5A/µs)
4
(10A/µs)
4
(10A/µs)
Table 6 - Recommended input and output capacitance
MURATA PART NUMBER
GRM188R71C105KA12D
GRM319R71H104KA01D
GRM31CR60J107ME39L
DESCRIPTION
1uF 16V 0603 X7R
0.1uF 50V 1206 X7R
100uF 6.3V 1206 X5R
MURATA PART NUMBER
GRM31CR71H475KA12K
GRM31CR61A476ME15L
GRM31CR61E226KE15L
DESCRIPTION
4.7uF 50V 1206 X7R
47uF 10V 1206 X5R
22uF 25V 1206 X5R
Table 7 - Capacitor manufacturer part numbers
vicorpower.com
800 735.6200
Rev 1.4
11/2012
Cool-Power^®
Page 38 of 42