DPA422 Datasheet, PDF (17/34 Pages) Power Integrations, Inc. – Highly Integrated DC-DC Converter ICs for Power over Ethernet & Telecom Applications

DPA422-426
Forward power tables: Tables 1 (upper half), 3 and 4
• Output power figures are based on forward topology using
Schottky diode rectification. Up to 5% higher output power is
possible using synchronous rectification.
• Dissipation data assumes a diode loss representing 6% of the
total output power and combined loss in magnetic compo-
nents representing 6% of the total output power.
DPA-Switch losses are based on a ratio between conduction
and switching losses of approximately 3:1. These assump-
tions are typical for a single 5 V output forward converter
design using Schottky rectification and adequately designed
magnetic components.
Flyback power tables: Tables 1 (lower half), 5 and 6
• Output power and dissipation figures are based on a 5 V
output using Schottky diode rectification with an efficiency of
85%. Values are generated by calculation based on
I² × R_DS(ON) losses and characterization of switching losses,
correlated to bench measurement of each DPA-Switch device.
• Device dissipations above 1.5 W are possible using the
R package. However the forward converter topology is
recommended for such higher power designs.
The power tables provide two types of information. The first is
the expected device dissipation for a given output power. The
second is the maximum power output. Each table specifies the
input voltage range and assumes a single 5 V output using
Schottky diode rectification.
For example, referring to Table 1, for 36 VDC to 75 VDC input
range, DPA424 would typically dissipate 1 W in a 23 W forward
converter and has a maximum power capacity of 35 W. In the
same converter, DPA425 would dissipate 0.5 W. Selecting
DPA425 with associated reduced dissipation would increase
overall converter efficiency by approximately 2%.
Issues Affecting Dissipation:
1. Using synchronous rectification will tend to reduce device
dissipation.
2. Designs with lower output voltages and higher currents will
tend to increase the device dissipation listed in the power
table.
3. Reduced input voltage decreases the available output power
for the same device dissipation. Tables 3 to 6 are the power
tables for 16 VDC and 24 VDC input voltages. Input voltages
below 16 V are possible, but since the internal start-up
current source is not specified at voltages below 16 V, an
external chip supply current should be fed into the
CONTROL pin approximately equal to but less than I_CD1.
DPA-Switch Selection
Use Tables 1 and 3 through 6 to select the DPA-Switch based
on device dissipation. Selecting the optimum DPA-Switch
depends upon required maximum output power, efficiency,
heat sinking constraints and cost goals. With the option to
externally reduce current limit, a larger DPA-Switch may be
used for lower power applications where higher efficiency is
needed or minimal heat sinking is available. Generally, selecting
the next larger device, than is required for power delivery will
give the highest efficiency. Selecting even larger devices may
Output Power Table
16-32 VDC Range (Forward)²
Total Device
Dissipation _{0.5 W 1 W 2.5 W 4 W}
Product³
DPA422
DPA423
DPA424
DPA425
DPA426
3.5 W
5W
7W
10 W
12 W
4.5 W
7W
10 W
14 W
16.5 W
-
-
15 W
22 W
25 W
-
-
-
27 W
31 W
Max
6 W Power
Output¹
-
-
-
-
37 W
5.0 W
7.5 W
15.5 W
31 W
43 W
Table 3. Output Power Table for 16-32 VDC Input Voltage.
Notes:
1. Limited by device internal current limit.
2. See text in this section for a complete description of assumptions.
3. See Part Ordering Information.
Output Power Table
24-48 VDC Range (Forward)²
Total Device
Dissipation _{0.5 W 1 W 2.5 W 4 W}
Product³
DPA422
DPA423
DPA424
DPA425
DPA426
5.5 W
8W
11 W
16 W
18 W
7W
11 W
16 W
22 W
25 W
-
-
23.5 W
35 W
39 W
-
-
-
43 W
48 W
Max
6 W Power
Output¹
-
-
-
-
58 W
8W
11.5 W
25 W
47 W
65 W
Table 4. Output Power Table for 24-48 VDC Input Voltage
(See Table 3 for Notes).
Output Power Table
16-32 VDC Input Range (Flyback)²
Total Device
Dissipation _{0.5 W 0.75 W 1 W}
Product³
1.5 W
DPA422
DPA423
DPA424
DPA425
3W
5W
6.5 W
7W
-
-
8.5 W
10 W
-
-
10 W
12 W
-
-
-
15 W
Max
Power
Output¹
4.5 W
6W
11 W
22 W
Table 5. Flyback Output Power Table for 16-32 VDC Input Voltage
(See Table 3 for Notes).
Output Power Table
24-48 VDC Input Range (Flyback)²
Total Device
Dissipation _{0.5 W 0.75 W 1 W}
Product^3,4
1.5 W
DPA422
3W
-
-
-
DPA423
7W
-
-
-
DPA424
8.5 W 11.5 W 14 W
-
Max
Power
Output¹
7W
8.5 W
17 W
Table 6. Flyback Output Power Table for 24-48 VDC Input Voltage.
Notes:
1. Maximum output power is limited by device internal current limit.
2. See text in this section for a complete description of assumptions.
3. See Part Ordering Information.
4. Higher switching losses may prevent DPA425 from delivering more power than a
smaller device.
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Rev. T 12/12