PI3303-00-LGIZ Datasheet, PDF (36/42 Pages) Vicor Corporation – 8 V to 36 Vin Cool-Power ZVS Buck Regulator Family

PI33xx-x0
Inductor Pairing
The PI33xx-x0 utilizes an external inductor. This inductor has been
optimized for maximum efficiency performance. Table 4 details
the specific inductor value and part number utilized for each
PI33xx-x0 device which are available from Coiltronics and Eaton.
Data sheets are available at:
http://www.cooperindustries.com
Device
PI3311-x0
Inductor
[nH]
125
Inductor
Part Number
FPV1006-125-R
PI3318-x0
150
FPV1006-150-R
PI3312-x0
200
FPT705-200-R
PI3301-x0
200
FPT705-200-R
PI3302-x0
200
FPT705-200-R
PI3303-x0
230
FPT705-230-R
PI3305-x0
230
FPT705-230-R
Table 4 — PI33xx-x0 Inductor pairing
Manufacturer
Eaton
Eaton
Coiltronics
Coiltronics
Coiltronics
Coiltronics
Coiltronics
Thermal Derating
Thermal de-rating curves are provided that are based on
component temperature changes versus load current, input
voltage and air flow. It is recommended to use these curves as a
guideline for proper thermal de-rating. These curves represent
the entire system and are inclusive to both the Picor regulator and
the external inductor. Maximum thermal operation is limited by
either the MOSFETs or inductor depending upon line and load
conditions.
Thermal measurements were made using a standard
PI33xx-x0 Evaluation board which is 3 x 4 inches in area and uses
4-layer, 2 oz copper. Thermal measurements were made on the
three main power devices, the two internal MOSFETs and the
external inductor, with air flows of 0, 200, and 400 LFM.
Filter Considerations
The PI33xx-x0 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-x0 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 100 µF so that the PI33xx-x0 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 1 MHz. The ESR for this
capacitor should be approximately 20 mΩ. 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 5 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
6 includes the recommended input and output
ceramic capacitors.
Device
V_IN
(V)
I_LOAD
(A)
C_INPUT
Ceramic
X5R
C_INPUT
Bulk
Elec.
C_OUTPUT
Ceramic
X5R
PI3311 24
10
5
4 x 4.7 µF
50 V
100 µF
50 V
8 X 100 µF
2 X 1 µF
1 X 0.1 µF
PI3318 24
10
5
4 x 4.7 µF
50 V
100 µF
50 V
6 X 100 µF
2 X 1 µF
1 X 0.1 µF
PI3312 24
10
5
4 x 4.7 µF
100 µF
50 V
4 X 100 µF
2 X 1 µF
1 X 0.1 µF
PI3301 24
10
5
4 x 4.7 µF
100 µF
50 V
4 X 100 µF
2 X 1 µF
1 X 0.1 µF
PI3302 24
10
5
4 x 4.7 µF
100 µF
50 V
4 X 47 µF
2 X 1 µF
1 X 0.1 µF
PI3303 24
8
4
4 x 4.7 µF
100 µF
50 V
4 X 22 µF
2 X 1 µF
1 X 0.1 µF
PI3305 24
8
4
4 x 4.7 µF
100 µF
50 V
4 X 22 µF
2 X 1 µF
1 X 0.1 µF
Table 5 — Recommended input and output capacitance
C_INPUT
Ripple
Current
(I_RMS)
0.5
0.5
1
1.05
1.2
1.3
1.38
C_OUTPUT
Ripple
Current
(I_RMS)
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
Output
Ripple
(mVpp)
Recovery
Time
(µs)
Load
Step
(A)
(Slew/µs)
-/+40
40
5
(5 A/µs)
-/+40
40
5
(5 A/µs)
-/+80
25
5
(10 A/µs)
-/+100
20
5
(1 0A/µs)
-/+170
30
5
(5 A/µs)
-/+300
30
4
(10 A/µs)
-/+400
30
4
(10 A/µs)
Cool-Power®
Page 36 of 42
Rev 2.0
02/2016
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