Advance Data Sheet
March 1999
LW025 Single-Output-Series Power Modules:
36 Vdc to 75 Vdc Inputs; 25 W
Features
■
Low profile: 9.91 mm (0.390 in.) with 0.38 mm
(0.015 in.) standoffs, 9.53 mm (0.375 in.) with
standoffs recessed
Wide input voltage range: 36 Vdc to 75 Vdc
Input-to-output isolation
Operating case temperature range: –40 °C to
+110 °C
Metal case
Overcurrent protection
Remote on/off
Output voltage adjust: 90% to 110% of V
O, nom
Output overvoltage protection
■
■
■
■
■
■
■
The LW025 Single-Output-Series Power Modules use
advanced, surface-mount technology and deliver high-quality,
compact, dc-dc conversion at an economical price.
■
■
UL*
1950 Recognized,
CSA
†
C22.2 No. 950-95
Certified, VDE 0805 (EN60950, IEC950) Licensed
CE mark meets 73/23/EEC and 93/68/EEC
directives
‡
Within FCC and EN55022 (CISPR 22) Class A
radiated limits
Options
■
■
■
■
■
Choice of on/off configuration
Case ground pin
Synchronization
Short pins: 2.79 mm ± 0.25 mm
(0.110 in. ± 0.010 in.)
Short pins: 3.68 mm ± 0.25 mm
(0.145 in. ± 0.010 in.)
■
Applications
■
■
■
Distributed power architectures
Telecommunications
Description
The LW025 Single-Output-Series Power Modules are low-profile dc-dc converters that operate over an input
voltage range of 36 Vdc to 75 Vdc and provide precisely regulated outputs. The output is isolated from the
input, allowing versatile polarity configurations and grounding connections. The module has a maximum power
rating of 25 W at a typical full-load efficiency of 79%.
The power modules feature remote on/off and output voltage adjustments of 90% to 110% of the nominal out-
put voltage. Built-in filtering for both input and output minimizes the need for external filtering.
*
UL
is a registered trademark of Underwriters Laboratories, Inc.
†
CSA
is a registered trademark of Canadian Standards Association.
‡ This product is intended for integration into end-use equipment. All the required procedures for CE marking of end-use equipment should
be followed. (The CE mark is placed on selected products.)
LW025 Single-Output-Series Power Modules:
36 Vdc to 75 Vdc Inputs; 25 W
Advance Data Sheet
March 1999
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the devices. These are
absolute stress ratings only. Functional operation of the devices 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.
Parameter
Input Voltage:
Continuous
Transient (100 ms)
Operating Case Temperature (See Figure 16.)
Storage Temperature
I/O Isolation Voltage
Symbol
V
I
V
I, trans
T
C
T
stg
—
Min
0
0
–40
–40
—
Max
80
100
110*
120
1500
Unit
Vdc
V
°C
°C
Vdc
* Maximum case temperature varies based on power dissipation. See derating curves, Figures 15—16, for details.
Electrical Specifications
Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature
conditions.
Table 1. Input Specifications
Parameter
Operating Input Voltage
Maximum Input Current
(V
I
= 0 V to V
I, max
; I
O
= I
O, max
; see Figures 1 and 2.)
Inrush Transient
Input Reflected-ripple Current
(50 Hz to 20 MHz; 12 µH source impedance,
T
C
= 25 °C; see Figure 10.)
Input Ripple Rejection (100 Hz—120 Hz)
Symbol
V
I
I
I, max
i
2
t
I
I
Min
36
—
—
—
Typ
48
—
—
3
Max
75
1.2
0.1
—
Unit
Vdc
A
A
2
s
mAp-p
—
—
60
—
dB
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 fus-
ing is not included; however, to achieve maximum safety and system protection, always use an input line fuse. The
safety agencies require a normal-blow fuse with a maximum rating of 5 A (see Safety Considerations section).
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.
2
Tyco Electronics Corp.
Advance Data Sheet
March 1999
LW025 Single-Output-Series Power Modules:
36 Vdc to 75 Vdc Inputs; 25 W
Electrical Specifications
(continued)
Table 2. Output Specifications
Parameter
Output Voltage Set Point
(V
I
= 48 V; I
O
= I
O, max
; T
C
= 25 °C)
Output Voltage
(Over all line, load, and temperature conditions
until end of life; see Figure 12.)
Output Regulation:
Line (V
I
= 36 V to 75 V)
Load (I
O
= I
O, min
to I
O, max
)
Temperature (T
C
= –40 °C to +100 °C)
Output Ripple and Noise (See Figure 11.):
RMS
Peak-to-peak (5 Hz to 20 MHz)
Output Current
(At I
O
< I
O, min
, the modules may exceed output
ripple specifications.)
Output Current-limit Inception
(V
O
= 90% x V
O, set
; see Figures 3 and 4.)
Output Short-circuit Current (V
O
= 250 mV)
Efficiency
(V
I
= V
I, nom
; I
O
= I
O, max
; T
C
= 25 °C; see Figures 5,
6, and 12.)
Switching Frequency
Dynamic Response
(½I
O
/½t = 1 A/10 µs, V
I
= V
I, nom
, T
A
= 25 °C):
Load Change from I
O
= 50% to 75% of I
O, max
:
Peak Deviation
Settling Time (V
O
< 10% peak deviation)
Load Change from I
O
= 50% to 25% of I
O, max
:
Peak Deviation
Settling Time (V
O
< 10% peak deviation)
Table 3. Isolation Specifications
Parameter
Isolation Capacitance
Isolation Resistance
Min
—
10
Typ
0.002
—
Max
—
—
Unit
µF
M¾
Device
LW025F
LW025A
LW025F
LW025A
Symbol
V
O, set
V
O, set
V
O
V
O
Min
3.25
4.92
3.17
4.85
Typ
3.3
5.0
—
—
Max
3.35
5.08
3.43
5.15
Unit
Vdc
Vdc
Vdc
Vdc
All
All
All
All
All
All
—
—
—
—
—
I
O
—
—
—
—
—
0.4
0.01
0.05
0.5
—
20
—
0.1
0.4
1.0
40
100
5.0
%V
O
%V
O
%V
O
mVrms
mVp-p
A
All
All
LW025F
LW025A
All
I
O
I
O
η
η
—
103
—
75
77
—
—
135
77
79
256
150
200
—
—
—
%I
O, max
%I
O, max
%
%
kHz
All
All
All
All
—
—
—
—
—
—
—
—
1
0.5
1
0.5
—
—
—
—
%V
O, set
ms
%V
O, set
ms
General Specifications
Parameter
Calculated MTBF (I
O
= 80% of I
O, max
; T
C
= 40 °C)
Weight
—
Min
Typ
5,500,000
—
54 (1.9)
Max
Unit
hours
g (oz.)
Tyco Electronics Corp.
3
LW025 Single-Output-Series Power Modules:
36 Vdc to 75 Vdc Inputs; 25 W
Advance Data Sheet
March 1999
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
Remote On/Off Signal Interface:
(V
I
= 0 V to V
I, max
; open collector or equivalent
compatible; signal referenced to V
I
(–) terminal. See
Figure 13 and Feature Descriptions.):
Negative Logic: Device Code Suffix “1”:
Logic Low—Module On
Logic High—Module Off
Positive Logic: If Device Code Suffix “1” Is Not
Specified:
Logic Low—Module Off
Logic High—Module On
Module Specifications:
On/Off Current:
Logic Low
On/Off Voltage:
Logic Low
Logic High (I
on/off
= 0)
Open Collector Switch Specifications:
Leakage Current During Logic High
(V
on/off
= 10 V)
Output Low Voltage During Logic Low
(I
on/off
= 1 mA)
Turn-on Delay and Rise Times
(at 80% of I
O, max
; T
A
= 25 °C):
Case 1: On/Off Input Is Set for Unit On and Then
Input Power Is Applied (delay from point at which
V
I
= 48 V until V
O
= 10% of V
O, nom
).
Case 2: 48 V Input Is Applied for at Least One
Second, and Then the On/Off Input Is Set to Turn
the Module On (delay from point at which on/off
input is toggled until V
O
= 10% of V
O, nom
).
Output Voltage Rise Time (time for V
O
to rise from
10% of V
O, nom
to 90% of V
O, nom
)
Output Voltage Overshoot (at 80% of I
O, max
;
T
A
= 25 °C)
Output Voltage Set-point Adjustment Range
Output Overvoltage Protection (clamp)
Device
Symbol
Min
Typ
Max
Unit
All
All
All
All
All
I
on/off
V
on/off
V
on/off
I
on/off
V
on/off
—
–0.7
—
—
—
—
—
—
—
—
1.0
1.2
10
50
1.2
mA
V
V
µA
V
All
T
delay
—
27
50
ms
All
T
delay
—
2
10
ms
All
All
All
LW025F
LW025A
T
rise
—
—
V
O, clamp
V
O, clamp
—
—
90
3.9
5.6
1.5
—
—
—
—
3.0
5
110
5.0
7.0
ms
%
%V
O, nom
V
V
4
Tyco Electronics Corp.
Advance Data Sheet
March 1999
LW025 Single-Output-Series Power Modules:
36 Vdc to 75 Vdc Inputs; 25 W
Characteristics Curves
0.8
0.7
INPUT CURRENT, I
I
(A)
0.6
0.5
0.4
0.3
0.2
0.1
I
O
= 0.4 A
I
O
= 2.5 A
I
O
= 5 A
OUTPUT VOLTAGE, V
O
(V)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
0
1
2
3
4
5
6
7
8
OUTPUT CURRENT, I
O
(A)
V
I
= 75 V
V
I
= 48 V
V
I
= 36 V
0.0
0
10
20
30
40
50
60
70
80
INPUT VOLTAGE, V
I
(V)
8-2233(C)
8-2234(C)
Figure 3. LW025F Typical Output Characteristics
Figure 1. LW025F Typical Input Characteristics
6
OUTPUT VOLTAGE, V
O
(V)
5
4
3
2
1
0
0.2
0.0
0
10
20
30
40
50
60
70
80
INPUT VOLTAGE, V
I
(V)
8-1982(C).b
1.2
1.0
INPUT CURRENT, I
I
(A)
0.8
0.6
0.4
I
O
= 0.4 A
I
O
= 2.5 A
I
O
= 5 A
V
I
= 75 V
V
I
= 48 V
V
I
= 36 V
0
1
2
3
4
5
6
7
OUTPUT CURRENT, I
O
(A)
8-1983(C)
Figure 4. LW025A Typical Output Characteristics
Figure 2. LW025A Typical Input Characteristics
Tyco Electronics Corp.
5
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