Data Sheet
April 2009
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are absolute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess
of those given in the operations sections of the data sheet. Exposure to absolute maximum ratings for extended
periods can adversely affect device reliability.
Symbol
Min
Max
Unit
Input Voltage Continuous
Parameter
VI
—
50
V
I/O Isolation Voltage:
dc
Transient (1 minute)
—
—
—
—
500
850
V
V
Operating Case Temperature
TC
– 40
100
°C
Storage Temperature
Tstg
– 55
125
°C
Electrical Specifications
Unless otherwise indicated, specifications apply to all modules over all operating input voltage, resistive load, and
temperature conditions.
Table 1. Input Specifications
Parameter
Symbol
Min
Typ
Max
Unit
VI
18
28
36
Vdc
II, max
—
—
3.0
A
Inrush Transient
i2t
—
—
0.2
A2s
Input Reflected-ripple Current, Peak-to-peak
(5 Hz to 20 MHz, 12 µH source impedance;
TC = 25 °C; see Figure 18 and Design
Considerations section.)
—
—
30
—
mAp-p
Input Ripple Rejection (120 Hz)
—
—
60
—
dB
Operating Input Voltage
Maximum Input Current
(VI = 0 V to 36 V; IO = IO, max; see Figure 1.)
Fusing Considerations
CAUTION: This power module is not internally fused. An input line fuse must always be used.
This encapsulated power module can be used in a wide variety of applications, ranging from simple stand-alone
operation to an integrated part of a sophisticated power architecture. To preserve maximum flexibility, internal fusing is not included; however, to achieve maximum safety and system protection, always use an input line fuse. The
safety agencies require a normal-blow, dc fuse with a maximum rating of 5 A in series with the ungrounded input
lead. Based on the information provided in this data sheet on inrush energy and maximum dc input current, the
same type of fuse with a lower rating can be used. Refer to the fuse manufacturer’s data for further information.
22
Lineage Power
Data Sheet
April 2009
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Electrical Specifications (continued)
Table 2. Output Specifications
Parameter
Device
Symbol
Min
Typ
Max
Unit
Output Voltage
(Over all operating input voltage, resistive
load, and temperature conditions until end
of life. See Figure 20.)
DC025ABK-M
VO1
VO2
VO3
VO1
VO2
VO3
4.80
10.80
–10.80
4.80
13.77
–13.77
—
—
—
—
—
—
5.20
13.70
–13.70
5.20
17.20
–17.20
Vdc
Vdc
Vdc
Vdc
Vdc
Vdc
Output Voltage Set Point
(VI = 28 V; TC = 25 °C; IO1 = 2.0 A,
IO2 = IO3 = 0.5 A)
DC025ABK-M
VO1, set
VO2, set
VO3, set
VO1, set
VO2, set
VO3, set
4.90
11.83
–11.83
4.90
14.84
–14.84
5.00
12.20
–12.20
5.00
15.30
–15.30
5.10
12.57
–12.57
5.10
15.76
–15.76
Vdc
Vdc
Vdc
Vdc
Vdc
Vdc
All
All
—
VO1
—
—
0.1
0.1
0.2
0.2
%
%
All
VO1
—
0.5
1.5
%
All
VO1
VO2, VO3
VO1
VO2, VO3
—
—
—
—
—
—
—
—
25
30
100
150
mVrms
mVrms
mVp-p
mVp-p
IO1
IO2, IO3
IO1
IO2, IO3
0.5
0.1
0.5
0.1
—
—
—
—
5.0
1.0
5.0
0.83
A
A
A
A
IO1
IO2, IO3
IO1
IO2, IO3
—
—
—
—
6
2
6
2
7.5
3.0
7.5
3.0
A
A
A
A
IO1
IO2, IO3
IO1
IO2, IO3
—
—
—
—
8
3
8
3
10.5
4.5
10.5
4.5
A
A
A
A
η
η
79
79
82
82
—
—
%
%
DC025ACL-M
DC025ACL-M
Output Regulation:
Line (VI = 18 V to 36 V)
Load (See Figures 5—8.)
(IO1 = IO, min to IO, max, IO2 = IO3 = IO, min)
Temperature (See Figures 2—4.)
(TC = –40 °C to +100 °C)
Output Ripple and Noise
(See Figure 19.):
RMS
Peak-to-peak (5 Hz to 20 MHz)
All
Output Current
(At IO < IO, min, the modules may exceed
output ripple specifications.)
DC025ABK-M
Output Current-limit Inception
(VO = 90% of VO, nom and minimum load on
other outputs. See Figures 9—12.)
DC025ABK-M
Output Short-circuit Current
(VO = 1 V and minimum load on other
outputs.)
DC025ABK-M
Efficiency
(VI = 28 V; TC = 25 °C; see Figures 13, 14,
and 20.):
IO1 = 2.5 A, IO2 = IO3 = 0.5 A
IO1 = 2.0 A, IO2 = IO3 = 0.5 A
Lineage Power
DC025ACL-M
DC025ACL-M
DC025ACL-M
DC025ABK-M
DC025ACL-M
3
Data Sheet
April 2009
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Electrical Specifications (continued)
Table 2. Output Specifications (continued)
Parameter
Device
Symbol
Min
Typ
Max
Unit
All
All
VO1
—
—
—
80
1
—
—
mV
ms
All
All
VO1
—
—
—
80
0.5
—
—
mV
ms
Dynamic Response
(ýIO/ýt = 1 A/10 µs, VI = 28 V, TC = 25 °C):
Load Change from IO = 50% to 75% of
IO, max:
Peak Deviation
Settling Time (VO < 10% peak
deviation)
Load Change from IO = 50% to 25% of
IO, max:
Peak Deviation
Settling Time (VO < 10% peak
deviation)
Table 3. Isolation Specifications
Min
Typ
Max
Unit
Isolation Capacitance
Parameter
—
0.02
—
µF
Isolation Resistance
10
—
—
MΩ
Max
Unit
General Specifications
Parameter
Min
Calculated MTBF (IO = 80% of IO, max; TC = 40 °C)
Weight
44
Typ
2,906,000
—
—
hours
113 (4.0)
g (oz.)
Lineage Power
Data Sheet
April 2009
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Feature Specifications
Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature
conditions. See Feature Descriptions and Design Considerations for further information.
Parameter
Device
Symbol
Min
Typ
Max
Unit
Remote On/Off
(VI = 0 V to 36 V; open collector or equivalent
compatible; signal referenced to VI(–) terminal.
See Figures 17 and 21 and Feature
Descriptions.):
DC025XXX-M (positive logic):
Logic Low—Module Off
Logic High—Module On
DC025XXX1-M (negative logic):
Logic Low—Module On
Logic High—Module Off
Module Specifications:
On/Off Current—Logic Low
On/Off Voltage:
Logic Low
Logic High (Ion/off = 0)
Open Collector Switch Specifications:
Leakage Current During Logic High
(Von/off = 10 V)
Output Low Voltage During Logic Low
(Ion/off = 1 mA)
Turn-on Time
(IO = 80% of IO, max; VO within ±1% of steady
state)
Output Voltage Overshoot (See Figure 17.)
All
Ion/off
—
—
1.0
mA
All
All
Von/off
Von/off
0
—
—
—
1.2
10
V
V
All
Ion/off
—
—
50
µA
All
Von/off
—
—
1.2
V
All
—
—
5
—
ms
All
—
—
0
5
%
DC025ABK-M
VO1
VO2
VO3
VO1
VO2
VO3
—
—
—
—
—
—
6
15
–15
6
19
–19
6.8
17
–17
6.8
21
–21
V
V
V
V
V
V
—
90
—
110
% VO, nom
Output Overvoltage Clamp
DC025ACL-M
Output Voltage Set-point Adjustment Range
5
All
Lineage Power
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Data Sheet
April 2009
Characteristic Curves
OUTPUT VO LTA GE, VO (V)
12.30
2.0
INPUT CURRENT, I I (A)
1.8
1.6
1.4
1.2
1.0
0.8
0.6
12.20
12.15
12.10
12.05
12.00
11.95
–40
0.4
0.2
0.0
0
12.25
–20
0
20
40
60
80
100
CASE TEM PERATURE, T (°C)
5
10
15
20
25
30
35
40
INPUT VOL TAGE, V I (V)
8-1077(C)
Figure 1. DC025 Triple Output-Series Typical Input
Characteristics
8-1079(C)
Figure 3. DC025 Triple Output-Series Typical
Output Voltage Variation of 12 V Output
Over Ambient Temperature Range
15.60
15.55
OUTPUT VO LTAGE , V O (V)
O UTPUT VOLTAGE, V O1 (V)
5.01
5.00
4.99
4.98
4.97
15.30
15.25
15.20
15.10
–40
–20
0
20
40
60
80
100
–20
0
20
40
60
80
100
CASE TEM PERATURE, T (°C)
8-1080(C)
CASE TEMPERATURE, T (°C)
8-1078(C)
Figure 2. DC025 Triple Output-Series Typical
Output Voltage Variation of 5 V Output
Over Ambient Temperature Range
6
15.40
15.35
15.15
4.96
4.95
–40
15.50
15.45
Figure 4. DC025 Triple Output-Series Typical
Output Voltage Variation of 15 V Output
Over Ambient Temperature Range
Lineage Power
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Data Sheet
April 2009
Characteristic Curves (continued)
O UTPUT VO LTA GE, V O2 (V)
16. 3
O UT PUT VOLTA GE, V O2 (V)
13.5
13.0
V I = 2 7 V , IO1 = 2.5 A, I O3 = 0.5 A
12.5
12.0
15. 3
14. 8
V I = 27 V, I O1 = 0.5 A, IO3 = 0.1 A
14. 3
13. 8
0.0
11.5
V I = 27 V , IO 1 = 0.5 A, I O3 = 0.1 A
11.0
0.0
V I = 27 V, I O1 = 2.5 A, IO3 = 0.45 A
15. 8
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
OU TPU T CURRENT, IO 2 (A)
0.1
0.2
0.3
0.4
0 .5
0.6
0 .7
0.8
0. 9 1.0
OUTP UT CURRENT, IO2 (A)
8-1081(C)
8-1083(C)
Figure 7. DC025ACL-M Typical Load Regulation
Figure 5. DC025ABK-M Typical Load Regulation
O UT PUT VOLTA GE, V O2 (V)
16.8
O UTPUT VO LTAG E, V O2 (V)
13.5
13.0
V I = 2 7 V, IO2 = I O3 = 0.1 A
12.5
12.0
16.3
V I = 27, I O2 = IO 3 = 0.1 A
15.8
15.3
14.8
V I = 27 V, IO2 = I O3 = 0.45 A
14.3
V I = 27 V, IO2 = IO3 = 0.5 A
11.5
11.0
0.0
13.8
0.0
0 .5
1.0
1.5
2. 0
2.5
3.0
3.5
4.0
O UTPUT CURRENT, I O1 (A)
0.5
1.0
1.5
2.0
2. 5
3.0
3.5
4.0 4 .5
OUTPUT CURRENT, I O1 (A)
8-1082(C)
8-1084(C)
Figure 8. DC025ACL-M Typical Cross Regulation
with Respect to IO1
Figure 6. DC025ABK-M Typical Cross Regulation
with Respect to IO1
Note: Given the same load conditions, Output 3 has regulation characteristics similar to Output 2, except the
polarity is negative.
Lineage Power
7
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Data Sheet
April 2009
Characteristic Curves (continued)
OUTPUT VOLTAGE, VO1 (V)
6
5
4
VI = 36 V, IO2 = IO3 = 0.1 A
VI = 27 V
VI = 36 V, IO 2 = IO3 = 0.5 A
VI = 27 V
3
VI = 18 V
VI = 18 V
2
1
0
0
1
2
3
4
5
6
7
8
9
OUTPUT CURRENT, IO1 (A)
8-1085(C)
Figure 9. DC025ABK-M Typical 5 V Output Characteristics
OUT PU T VO LT AGE, VO2 (V)
14
12
10
V I = 36 V, IO1 = 2.5 A,
I O3 = 0.5 A
8
VI = 36 V, I O1 = 0.5 A,
IO3 = 0.1 A
V I = 18 V
V I = 27 V
6
VI = 27 V
VI = 18 V
4
2
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3 .5
OUTPUT C URREN T, I O2 (A )
8-1086(C)
Figure 10. DC025ABK-M Typical 12 V Output Characteristics
5.0
OU TP UT VOLTAG E, V O1 (V )
4.5
4.0
3.5
V I = 36 V, IO2 = I O3 = 0. 1 A
3.0
VI = 36 V, IO 2 = IO3 = 0.45 A
2.5
V I = 27 V
2. 0
V I = 27 V
1.5
V I = 18 V
V I = 18 V
1.0
0.5
0.0
0
1
2
3
4
5
6
7
8
9
OU TPU T CU RR ENT , I O1 (A)
8-1087(C)
Figure 11. DC025ACL-M Typical 5 V Output Characteristics
8
Lineage Power
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Data Sheet
April 2009
Characteristic Curves (continued)
16
OUT PUT VOL TAGE, V O2 (V)
14
12
VI = 36 V, IO1 = 0.5 A,
IO 3 = 0.1 A
VI = 36 V, IO 1 = 2.5 A,
I O3 = 0.45 A
10
V I = 27 V
8
V I = 27 V
V I = 18 V
6
V I = 18 V
4
2
0
0.0
0.5
1.0
2. 0
1. 5
2.5
OUTP UT CU RRENT, IO2 (A)
8-1088(C)
Figure 12. DC025ACL-M Typical 15 V Output Characteristics
85
85
VI = 18 V
VI = 18 V
80
EFFICIENCY, η (%)
EFFICIENCY, η (%)
80
75
V I = 27 V
70
V I = 36 V
65
V I = 27 V
70
V I = 36 V
65
60
60
55
0
75
20
40
60
80
100
120
55
0
20
40
60
80
8-1090(C)
8-1089(C)
Note: Loads varied proportionately from minimum to 50% of full
load.
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120
PERCEN T OF FULL LO AD (%)
PERCEN T OF FULL LO AD (%)
Figure 13. DC025ABK-M Typical Converter
Efficiency
100
Note: Loads varied proportionately from minimum to 50% of full
load.
Figure 14. DC025ACL-M Typical Converter
Efficiency
9
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Data Sheet
April 2009
10 2%
10 0%
50 %
6
0%
10 1%
99 %
75%
50%
REMOTE ON/OFF
(2 V/div)
4
10 0%
OUTPUT CURRENT, IO (A)
(% OF I O, ma x)
OUTPUT VO LTAGE, VO (V)
(% OF V O, s et)
OUTPUT VOLTAGE , VO (V)
(% OF V O, s et )
Characteristic Curves (continued)
2
0
25%
TIME, t (2 ms/div)
8-1100(C)
TIME, t (100 µs/div)
8-1098(C)
Figure 15. DC025 Triple Output-Series Typical
Output Voltage for a Step Load Change
from 75% to 50% of Full Load on
Output 1
Figure 17. DC025 Triple Output-Series Typical
Output Voltage Start-Up when Signal
Applied to Remote On/Off
Test Configurations
OUTPUT VOL TA GE, V O ( V)
(% OF VO, se t )
TO OSCILLOSCOPE
LTEST
V I (+)
12 µH
BATTERY
101%
OUTPUT CUR RENT, IO (A)
(% OF I O, m ax )
100%
CS 220 µF
IMPEDANCE < 0.1 Ω
@ 20 ˚C, 100 kHz
V I (–)
99%
75%
8-489(C).a
50%
Note: Input reflected-ripple current is measured with a simulated
source impedance (LTEST) of 12 µH. Capacitor C S offsets possible battery impedance. Current is measured at the input of
the module.
25%
Figure 18. Input Reflected-Ripple Test Setup
TIME , t (100 µs/div)
8-1099(C)
Figure 16. DC025 Triple Output-Series Typical
Output Voltage for a Step Load Change
from 25% to 50% of Full Load on
Output 1
10
Lineage Power
Data Sheet
April 2009
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Test Configurations (continued)
Design Considerations
Input Source Impedance
C O PPER STRIP
V O 1 (+)
SCOPE
0.1 µF
R LO A D1
CO M
The power module should be connected to a low
ac-impedance input source. Highly inductive source impedances can affect the stability of the power module. A
33 µF electrolytic capacitor (ESR < 0.7 ¾ at 100 kHz)
mounted close to the power module helps to ensure
the stability of the unit.
SCO PE
0.47 µF SCOPE
Safety Considerations
R LO AD2
R LO AD 3
V O 2 (+)
For safety-agency approval of the system in which the
power module is used, the power module must be
installed in compliance with the spacing and separation
requirements of the end-use safety agency standard,
i.e., UL-1950, CSA 22.2-950, and EN60950.
0.47 µF
V O3 (–)
8-811(C).a
Note: Use the specified ceramic capacitor. Scope measurement
should be made by using a BNC socket. Position the load
between 50 mm (2 in.) and 75 mm (3 in.) from the
module.
Figure 19. Output Noise Measurement Test Setup
For the converter output to be considered meeting the
requirements of safety extra-low voltage (SELV), the
input must meet SELV requirements.
If the input meets extra-low voltage (ELV) requirements, then the converter’s output is considered ELV.
The input to these units is to be provided with a maximum 5 A normal-blow fuse in the ungrounded lead.
SENSE
COM
SENSE
V O1 (+)
CONTACT AND
DISTRIBUTION LOSSES
V O1 (+)
IO1
V I (+)
LOAD1
COM
II
SUPPLY
LOAD2
V O2 (+)
V I (– )
IO2
CONTACT
RESISTANCE
LOAD3
V O3 (– )
IO3
SENSE
V O2(+)
8-749(C).b
Note: All measurements are taken at the module terminals. When
socketing, place Kelvin connections at module terminals to
avoid measurement errors due to socket contact resistance.
3
∑ [V
Oj
( + ) – V COM ]I Oj
j=1
η = ----------------------------------------------------------- × 100
[ V I ( + ) + ( – V I ( – ) ) ]I I
Figure 20. Triple Output Voltage and Efficiency
Measurement Test Setup
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11
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Data Sheet
April 2009
Feature Descriptions
Remote On/Off
Output Overvoltage Clamp
Two remote on/off options are available. Positive logic
remote on/off turns the module on during a logic high
voltage on the REMOTE ON/OFF pin, and off during a
logic low. Negative logic remote on/off, suffix code “1,”
turns the module off during a logic high and on during a
logic low.
The output overvoltage clamp consists of control circuitry, independent of the primary regulation loop, that
monitors the voltage on the output terminals. The control loop of the clamp has a higher voltage set point
than the primary loop (see Feature Specifications
table). This provides a redundant voltage control that
reduces the risk of output overvoltage.
Current Limit
To provide protection in a fault (output overload) condition, the unit is equipped with internal current-limiting
circuitry. At the point of current-limit inception, the unit
shifts from voltage control to current control. If the output voltage is pulled very low during a severe fault, the
current-limit circuit can exhibit either foldback or
tailout characteristics (output current decrease or
increase). The unit operates normally once the output
current is brought back into its specified range.
To turn the power module on and off, the user must
supply a switch to control the voltage between the on/
off terminal and the VI(–) terminal (Von/off). The switch
can be an open collector or equivalent (see Figure 21).
A logic low is Von/off = 0 V to 1.2 V. The maximum Ion/off
during a logic low is 1 mA. The switch should maintain
a logic low voltage while sinking 1 mA.
During a logic high, the maximum Von/off generated by
the power module is 10 V. The maximum allowable
leakage current of the switch at Von/off = 10 V is 50 µA.
V I(+)
V I(–)
–
Von/off
Output Voltage Set-Point Adjustment
+
Ion/off
The output voltage adjustment feature provides the
capability of increasing or decreasing the output voltage set point of a module. This can be accomplished
by using an external resistor connected between the
TRIM pin and either the VO1(+) or common pins. With
an external resistor between the TRIM and common
pins (Radj-up), the output voltage set point (VO, adj)
increases.
REMOTE
ON/OFF
8-758(C).a
Figure 21. Remote On/Off Implementation
42.35
kΩ
R adj-up = ---------------------------------V O, adj – V O, nom
Note: The output voltage adjustment range must not
exceed 110% of the nominal output voltage
between the VO1(+) and common terminals.
With an external resistor connected between the TRIM
and VO1(+) pins (Radj-down), the output voltage set point
(VO, adj) decreases.
( V O, adj – 2.5 ) × 16.94
R adj-down = -------------------------------------------------- k Ω
V O, nom – V O, adj
Note: The output voltage adjustment must be 90% or
more of the nominal output voltage between the
VO1(+) and common terminals.
12
Lineage Power
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Data Sheet
April 2009
Thermal Considerations
12.7 (0.50)
WIND TUNNEL WALL
MEASURE CASE
TEMPERATURE AT
THIS POINT
27.9
(1.1)
27.9
(1.1)
AIRFLOW
dc-dc POWER MODULE
CONNECTORS TO
LOADS, POWER
SUPPLIES, AND
DATALOGGER,
6.35 (0.25) TALL
MADE IN USA
203.2
(8.00)
50.8
(2.00)
AIRFLOW
101.6
(4.00)
AIR VELOCITY PROBE
12.7 (0.50)
203.2 (8.00)
AMBIENT TEMPERATURE
THERMOCOUPLE
9.7 (0.38)
19.1 (0.75)
8-866(C).b
Note: Dimensions are in millimeters and (inches). Drawing is not to scale.
Figure 22. Thermal Test Setup
The 25 W triple output power modules are designed to
operate in a variety of thermal environments. As with
any electronic component, sufficient cooling must be
provided to ensure reliable operation. Heat dissipating
components inside the module are thermally coupled
to the case to enable heat removal by conduction, convection, and radiation to the surrounding environment.
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The thermal data presented is based on measurements taken in a wind tunnel. The test setup shown in
Figure 22 was used to collect data. Actual performance
can vary depending on the particular application
environment.
13
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Thermal Considerations (continued)
Basic Thermal Performance
The maximum operating temperature of the DC025 Triple Output-Series Power Modules at a given operating
condition can be predicted by combining the power dissipation curves (Figures 23 through 27), the power derating curve (Figure 28), and the thermal resistance
curve (Figure 28).
Use Figures 23 through 28 and the steps below to predict the safe operating region for many different operating and environmental conditions.
1. Calculate the total output power.
POtotal = (IO1 x VO1) + (IO2 x VO2) + (IO3 x VO3)
2. Use POtotal with the appropriate figure (Figure 23
or 25) to determine the fixed losses (PP) associated with operating at POtotal. These losses are
independent of which output the load is being
drawn from.
3. Use the desired output current (IO1) with Figure 25
to determine PS1, which is the additional power
being dissipated due to loading of the main output.
4. Repeat Step 3 for outputs 2 and 3 using the appropriate figure (Figure 23 or 27) to determine PS2 and
PS3, which is the power dissipated due to loading of
the auxiliary outputs.
5. Find the total power dissipated (PDtotal) by adding
the four power dissipations obtained in Steps 2
through 4.
PDtotal = PP + PS1 + PS2 + PS3
6. Use the estimated total power dissipated (PDtotal)
along with Figure 28 to determine the maximum
ambient temperature allowable for a given air
velocity.
Data Sheet
April 2009
Figure 28 shows that in natural convection the maximum operating ambient temperature for this module is
approximately 66 °C.
Keep in mind that the procedure above provides
approximations of the temperature and air velocities
required to keep the case temperature below its maximum rating. The maximum case temperature, as monitored at the point shown in Figure 22, should be
maintained at 100 °C or less under all conditions.
Air Velocity
The air velocity required to maintain a desired maximum case temperature for a given power dissipation
and ambient temperature can be calculated using
Figure 28 and the following equation:
Cmax – T A
θ CA = T
---------------------------P Dtotal
where:
■
θCA is the thermal resistance from case-to-ambient
air (°C/W)
■
TCmax is the desired maximum case temperature (°C)
■
TA is the ambient inlet temperature (°C)
■
PDtotal is the total power dissipated by the module
(W) at the desired operating condition
For example, to maintain a maximum case temperature
of 85 °C with an ambient inlet temperature of 65 °C and
a power dissipation of 4.86 W, the thermal resistance is:
85 °C – 65 °C
θ CA ð ------------------------------------- = 4.1°C/W
4.86 W
This corresponds to an airflow greater than 0.38 ms–1
(75 fpm) in Figure 28.
For example, consider the DC025ABK power module
operating with 27 V input and output currents
IO1 = 2.5 A, IO2 = 0.5 A, IO3 = 0.5 A.
The total output power (POtotal) is 24.5 W. The total
power dissipation is PDtotal = 4.86 W, which is obtained
by adding:
PP
PS1
PS2
PS3
14
= 4.5 W (from Figure 23)
= 0.22 W (from Figure 25)
= 0.07 W (from Figure 23)
= 0.07 W (from Figure 23)
Lineage Power
Data Sheet
April 2009
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Thermal Considerations (continued)
1.6
POWER DI SSIPATI ON, P D (W)
Air Velocity (continued)
POWER DI SSIPATI ON, P D (W)
6.0
5.5
5.0
4.5
36 V
4.0
3.5
27 V
3.0
1.4
1.2
1.0
V I = 18 V
0.8
0.4
V I = 36 V
0.2
0.0
0.0
2.5
V I = 27 V
0.6
0.5
1. 0
18 V
2.0
1. 5
2.0
2.5
3.0
3.5
4.0
4.5 5 .0
OUTPUT CURRE NT, IO1 (A)
8-1093(C)
1.5
1.0
0
5
10
15
20
25
30
Figure 25. DC025ABK-M, DC025ACL-M Losses,
Associated with 5 V Output, PS1
O UTPUT PO WER, P O (W)
8-1091(C)
Figure 23. DC025ABK-M Fixed Losses, PP
POWER DISSIPATION, P D (W )
0.40
6.0
POWER DI SSIPATI ON, P D (W)
5.5
5.0
4.5
36 V
4.0
27 V
3.5
3.0
2.5
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0.0
18 V
2.0
0.35
0.1
0.2
0. 3
0.4
0. 5
0.6
0 .7
0.8
0.9 1 .0
OUTP UT CU RRENT, I O2 O R IO3 (A)
1.5
8-1094(C)
1.0
0
5
10
15
20
25
30
O UTPUT PO WER, P O (W)
Figure 26. DC025ABK-M, Losses Associated with
±12 V Output, PS2/PS3
8-1092(C)
Figure 24. DC025ACL-M Fixed Losses, PP
Lineage Power
15
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Data Sheet
April 2009
Thermal Considerations (continued)
8.0
Air Velocity (continued)
THERMAL RE SISTANCE (°C/W)
CASE -TO-A MB IENT
7.0
POWER DISSIPATION, P D (W )
0 .6
0 .5
0 .4
0 .3
6.0
5.0
4.0
3.0
2.0
1.0
0.0
1.02
1.2 7
1.52
0.51
2.03
0.76
1.7 8
NA T 0.25
CO NV (50 .0 ) (10 0.0) ( 150.0) ( 200.0) (250 .0) (300.0) (350 .0) (400.0)
0 .2
V ELOCITY, ms –1 (ft./min.)
0 .1
8-1101(C)
0 .0
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8 0 .9
Figure 29. Case-to-Ambient Thermal Resistance vs.
Air Velocity
OUTP UT CU RRENT, I O2 O R IO3 (A)
8-1095(C)
Use of Heat Sinks and Cold Plates
T OTAL PO WER DIS SIPA TION, P D T OTAL (W)
Figure 27. DC025ACL-M Losses Associated with
±15 V Output, PS2/PS3
The DC025 Triple Output-Series case includes
through-threaded M3 x 0.5 mounting holes allowing
attachment of heat sinks or cold plates from either side
of the module. The mounting torque must not exceed
0.56 N/m (5 in.-lb).
8.0
7.0
The following thermal model can be used to determine
the required thermal resistance of the sink to provide
the necessary cooling:
Ts
Tc
TA
PD
θSA
θCS
6.0
5.0
4.0
3.0
2.0
•
0.51 ms –1 (100 ft./min .)
1.02 ms –1 (200 ft./min .)
2.03 ms –1 (400 ft./min .)
NATURA L
CONVECTION
1.0
0.0
40
50
60
70
80
90
100
LOCA L A MB IENT TEMPERATURE, TA (°C)
8-1130(C)
Figure 28. Total Power Dissipation vs. Local
Ambient Temperature and Air Velocity
16
where PD is the power dissipated by the module, θCS
represents the interfacial contact resistance between
the module and the sink, and θSA is the sink-to-ambient
thermal impedance (°C/W). For thermal greases or
foils, a value of θCS = 0.1 °C/W to 0.3 °C/W is typical.
The required θSA is calculated from the following equation:
θ SA
C – TA
= T
---------------- – θ CS
P D total
Note that this equation assumes that all dissipated
power must be shed by the sink. Depending on the
user-defined application environment, a more accurate
model including heat transfer from the sides and rear of
the module can be used. This equation provides a conservative estimate in such instances.
For further thermal information on these modules, refer
to the Thermal Management for CC-, CW, DC, DWSeries 25 W to 30 W Board-Mounted Power Modules
Technical Note.
Lineage Power
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Data Sheet
April 2009
Outline Diagram
Dimensions are in millimeters and (inches).
Copper paths must not be routed beneath the power module standoffs.
Tolerances: x.x ± 0.5 mm (0.02 in.), x.xx ± 0.25 mm (0.010 in.).
Top View
71.1 (2 .80) MAX
PIN 1 INDICATOR
61.0
(2.40)
MAX
M3
DC-DC Power Modul e
MADE IN CHINA
Side View
12.7 (0.50)
MA X
0.5 1
( 0.02 0)
5.1 (0 .2 0)
MIN
1.02 (0.040 ) ± 0.08 (0 .003) DIA
TIN-P LATED
B RAS S, 9 PLACES
Bottom View
STA ND-OFF,
4 PLA CES
4.8 ( 0.19 )
5.1 (0.2 0)
7.1 (0.2 8)
5
V O3(–)
4
6
VI (+)
VO 2(+)
VI(–)
COM
10.16 (0.400)
10.16 (0.400)
7
3
10 .16 (0.400)
50.8
( 2.00)
10.16 (0.40 0)
2
20.32
(0.800)
8
CASE
1
30.5
(1.20)
20.3 2
(0.80 0)
ON/O FF
VO 1(+)
M OUNTING INS ERTS
M 3 x 0.5 THRO UG H,
9
4 PLACES
TR IM
20.32
(0.800)
48 .3 (1.90)
11 .4 (0.45 )
63.5 0 ± 0.38 (2 .500 ± 0.015)
3.8 ( 0.15)
8-846(C)
Lineage Power
17
DC025 Triple Output-Series Power Modules:
18 Vdc to 36 Vdc Input; 25 W
Data Sheet
April 2009
Recommended Hole Pattern
Component-side footprint.
Dimensions are in millimeters and (inches).
Recommended hole size for pin: 1.27 mm (0.050 in.)
CAS E OUTLINE
M3 x 0.5 CLE ARA NCE HOLE
4 PLACE S (O PTIO NAL)
1
9
2
8
3
7
4
6
30.5
( 1.20 )
20.32
( 0.800)
10.16 (0.400)
61.0
(2.40 )
MAX
20.32
(0.800)
10.16 (0.400)
10.16 (0.4 00)
50 .8
(2.00 )
10.16 (0.400 )
20.32
(0.800 )
5
5.1 (0 .20)
48.3 (1.90)
1 1.4 (0.45)
63.50 ± 0 .38 (2.500 ± 0.01 5)
3.8 (0.1 5)
71.1 (2.80) MAX
8-846(C)
18
Lineage Power
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