Data Sheet
April 2008
QW050A1 and QW075A1 Power Modules:
dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
Applications
nDistributed power architectures
nWorkstations
nComputer equipment
nCommunications equipment
Options
nHeat sinks available for extended operation
nAuto-restart after overcurrent shutdown
Features
nSmall size: 36.8 mm x 57.9 mm x 12.7 mm
(1.45 in. x 2.28 in. x 0.50 in.)
nHigh power density
nHigh efficiency: 84% typical
nLow output noise
nConstant frequency
nIndustry-standard pinout
nMetal baseplate
n2:1 input voltage range
nOvervoltage and overcurrent protection
nRemote on/off
nRemote sense
nAdjustable output voltage
nOvertemperature protection
nISO* 9001 Certified manufacturing facilities
nUL†1950 Recognized, CSA‡ C22.2 No. 950-95
Certified, and VDE § 0805 (EN60950, IEC950)
Licensed
nCE mark meets 73/23/EEC and 93/68/EEC direc-
tives**
* ISO is a registered trademark of the International Organization
for Standardization.
† UL is a registered trademark of Underwriters Laboratories, Inc.
‡ CSA is a registered trademark of Canadian Standards Associa-
tion.
§ VDE is a trademark of Verband Deutscher Elektrotechniker e.V.
** This product is intended for integration into end-use equipment.
All the required procedures for CE marking of end-use equip-
ment should be followed. (The CE mark is placed on selected
products.)
The QW Series Power Modules use advanced, surface-mount
technology and deliver high-quality, efficient, and compact
dc-dc conversion.
Description
The QW050A1 and QW075A1 Power Modules are dc-dc converters that operate over an input voltage range of
36 Vdc to 75 Vdc and provide a precisely regulated dc output. The outputs are fully isolated from the inputs,
allowing versatile polarity configurations and grounding connections. The modules have maximum power rat-
ings from 50 W to 75 W at a typical full-load efficiency of 84%.
The sealed modules offer a metal baseplate for excellent thermal performance. Threaded-through holes are pro-
vided to allow easy mounting or addition of a heat sink for high-temperature applications. The standard feature set
includes remote sensing, output trim, and remote on/off for convenient flexibility in distributed power applications.
2Lineage Power
Data Sheet
April 2008dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are abso-
lute 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.
Electrical Specifications
Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature
conditions.
Table 1. Input Specifications
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 3 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.
Parameter Symbol Min Max Unit
Input Voltage:
Continuous
Transient (100 ms)
VI
VI, trans
—
—
75
100
Vdc
V
Operating Case Temperature
(See Thermal Considerations section; see
Figure 22.)
TC–40 100 °C
Storage Temperature Tstg –55 125 °C
I/O Isolation Voltage (for 1 minute) — — 1500 Vdc
Parameter Symbol Min Typ Max Unit
Operating Input Voltage VI36 48 75 Vdc
Maximum Input Current
(VI = 0 V to 75 V; IO = IO, max; see Figures 1 and
2):
QW050A1
QW075A1
II, max
II, max
—
—
—
—
2.5
3.5
A
A
Inrush Transient i2t——1.3A
2s
Input Reflected-ripple Current, Peak-to-peak
(5 Hz to 20 MHz, 12 µH source impedance;
see Figure 13.)
II —10—mAp-p
Input Ripple Rejection (120 Hz) — — 60 — dB
Lineage Power 3
Data Sheet
April 2008 dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
Electrical Specifications (continued)
Table 2. Output Specifications
* Consult your sales representative or the factory.
† These are manufacturing test limits. In some situations, results may differ.
Table 3. Isolation Specifications
Parameter Device Symbol Min Typ Max Unit
Output Voltage Set Point
(VI = 48 V; IO = IO, max; TC = 25 °C)
All VO, set 4.92 5.0 5.08 Vdc
Output Voltage
(Over all operating input voltage, resistive load,
and temperature conditions until end of life. See
Figure 15.)
All VO4.85 — 5.15 Vdc
Output Regulation:
Line (VI = 36 V to 75 V)
Load (IO = IO, min to IO, max)
Temperature (TC = –40 °C to +100 °C)
All
All
All
—
—
—
—
—
—
0.01
0.05
15
0.1
0.2
50
%VO
%VO
mV
Output Ripple and Noise Voltage
(See Figure 14.):
RMS
Peak-to-peak (5 Hz to 20 MHz)
All
All
—
—
—
—
—
—
40
150
mVrms
mVp-p
External Load Capacitance All — 0 — *µF
Output Current
(At IO < IO, min, the modules may exceed output
ripple specifications.)
QW050A1
QW075A1
IO
IO
0.5
0.5
—
—
10
15
A
A
Output Current-limit Inception
(VO = 90% of VO, nom)
QW050A1
QW075A1
IO, cli
IO, cli
—
—
15
20
20†
26†
A
A
Efficiency (VI = 48 V; IO = IO, max; TC = 70 °C) QW050A1
QW075A1
η
η
—
—
84
84
—
—
%
%
Switching Frequency All — — 380 — kHz
Dynamic Response
(ýIO/ýt = 1 A/10 µs, VI = 48 V, TC = 25 °C; tested
with a 1000 µF aluminum and a 1.0 µF ceramic
capacitor across the load.):
Load Change from IO = 50% to 75% of IO, max:
Peak Deviation
Settling Time (VO < 10% of peak deviation)
Load Change from IO = 50% to 25% of IO, max:
Peak Deviation
Settling Time (VO < 10% of peak deviation)
All
All
All
All
—
—
—
—
—
—
—
—
5
700
5
700
—
—
—
—
%VO, set
µs
%VO, set
µs
Parameter Min Typ Max Unit
Isolation Capacitance — 2500 — pF
Isolation Resistance 10 — — M¾
4Lineage Power
Data Sheet
April 2008dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
General Specifications
Feature Specifications
Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature
conditions. See Feature Descriptions for additional information.
* These are manufacturing test limits. In some situations, results may differ.
Solder, Cleaning, and Drying Considerations
Post solder cleaning is usually the final circuit-board assembly process prior to electrical testing. The result of inad-
equate circuit-board cleaning and drying can affect both the reliability of a power module and the testability of the
finished circuit-board assembly. For guidance on appropriate soldering, cleaning, and drying procedures, refer to
the Board-Mounted Power Modules Soldering and Cleaning Application Note (AP97-021EPS).
Parameter Min Typ Max Unit
Calculated MTBF (IO = 80% of IO, max; TC = 40 °C):
QW050A1
QW075A1
4,000,000
3,500,000
hours
hours
Weight — — 75 (2.7) g (oz.)
Parameter Symbol Min Typ Max Unit
Remote On/Off Signal Interface
(VI = 0 V to 75 V; open collector or equivalent compatible;
signal referenced to VI(–) terminal; see Figure 16 and
Feature Descriptions.):
Logic Low—Module On
Logic High—Module Off
Logic Low:
At Ion/off = 1.0 mA
At Von/off = 0.0 V
Logic High:
At Ion/off = 0.0 µA
Leakage Current
Turn-on Time (See Figures 11 and 12.)
(IO = 80% of IO, max; VO within ±1% of steady state)
Von/off
Ion/off
Von/off
Ion/off
—
0
—
—
—
—
—
—
—
—
20
1.2
1.0
15
50
35
V
mA
V
µA
ms
Output Voltage Adjustment (See Feature Descriptions.):
Output Voltage Remote-sense Range
Output Voltage Set-point Adjustment Range (trim)
—
—
—
60
—
—
0.5
110
V
%VO, nom
Output Overvoltage Protection VO, sd 5.7* — 6.8* V
Overtemperature Protection TC—105— °C
dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:Data Sheet
April 2008
Lineage Power 5
Characteristic Curves
The following figures provide typical characteristics for the power modules. The figures are identical for both on/off
configurations.
8-2949 (F)
Figure 1. Typical QW050A1 Input Characteristics at
Room Temperature
8-2327 (C)
Figure 2. Typical QW075A1 Input Characteristics at
Room Temperature
8-2950 (F)
Note: Pending improvement will add 1% to the above curves.
Figure 3. Typical QW050A1 Converter Efficiency
vs. Output Current at Room Temperature
8-2951 (F)
Note: Pending improvement will add 1% to the above curves.
Figure 4. Typical QW075A1 Converter Efficiency
vs. Output Current at Room Temperature
2.5
2.0
1.5
0.5
0.0
20 30 40 45 50 55 60 65 70
INPUT VOLTAGE, VI (V)
INPUT CURRENT, II (A)
75
1.0
35
25
IO = 10 A
IO = 6 A
IO = 1 A
30 35 40 45 75
0.0
INPUT VOLTAGE, V I (V)
INPUT CURRENT, II (A)
3.5
20 50 55 60 65 70
0.5
2.5
3.0
25
1.0
1.5
2.0
IO = 15 A
IO = 7.5 A
IO = 1.5 A
85
84
83
81
79
77
75
2345678910
OUTPUT CURRENT, IO (A)
EFFICIENCY, η (%)
82
80
78
76
VI = 36 V
VI = 48 V
VI = 75 V
85
82
81
80
79
78
77
76
75
3 4 7 101112131415
84
OUTPUT CURRENT, IO (A)
EFFICIENCY, η (%)
5 6 8 9
83
VI = 36 V
VI = 54 V
VI = 75 V
6Lineage Power
Data Sheet
April 2008dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
Characteristic Curves (continued)
8-2062 (C)
Figure 5. Typical QW050A1 Output Ripple Voltage
at Room Temperature and IO = IO, max
8-2298 (C)
Note: See Figure 14 for test conditions.
Figure 6. Typical QW075A1 Output Ripple Voltage
at Room Temperature and IO = IO, max
8-2952 (F)
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 7. Typical QW050A1 Transient Response to
Step Decrease in Load from 50% to 25%
of IO, max at Room Temperature and
54 Vdc Input (Waveform Averaged to
Eliminate Ripple Component.)
8-2953 (F)
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 8. Typical QW075A1 Transient Response to
Step Decrease in Load from 50% to 25%
of IO, max at Room Temperature and
54 Vdc Input (Waveform Averaged to
Eliminate Ripple Component.)
TIME, t (1 µs/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
VI = 75 V
VI = 54 V
VI = 36 V
TIME, t (1 µs/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
VI = 36 V
VI = 54 V
VI = 75 V
TIME, t (500 μs/div)
OUTPUT VOLTAGE, VO (V)
(100 mV/div)
OUTPUT CURRENT, IO (A)
(1 A/div)
5 A
2.5 A
TIME, t (200 ns/div)
OUTPUT VOLTAGE, VO (V)
(100 mV/div)
OUTPUT CURRENT, IO (A)
(1 A/div)
7.5 A
3.75 A
Lineage Power 7
Data Sheet
April 2008 dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
Characteristic Curves (continued)
8-2954 (F)
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 9. Typical QW050A1 Transient Response to
Step Increase in Load from 50% to 75% of
IO, max at Room Temperature and 54 Vdc
Input (Waveform Averaged to Eliminate
Ripple Component.)
8-2955 (F)
Note: Tested with a 220 µF aluminum and a 1.0 µF ceramic capacitor
across the load.
Figure 10. Typical QW075A1 Transient Response
to Step Increase in Load from 50% to
75% of IO, max at Room Temperature and
54 Vdc Input (Waveform Averaged to
Eliminate Ripple Component.)
8-3027 (F)
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 11. QW050A1 Typical Start-Up from Remote
On/Off; IO = IO, max
8-2956 (F)
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 12. QW075A1 Typical Start-Up from Remote
On/Off; IO = IO, max
TIME, t (500 μs/div)
OUTPUT VOLTAGE, VO (V)
(100 mV/div)
OUTPUT CURRENT, IO (A)
(1 A/div)
7.5 A
5.0 A
TIME, t (200 μs/div)
OUTPUT VOLTAGE, VO (V)
(100 mV/div)
OUTPUT CURRENT, IO (A)
(1 A/div)
11.25 A
7.5 A
TIME, t (5 ms/div)
OUTPUT VOLTAGE, VO (V)
(2 V/div)
REMOTE, ON/OFF
VON/OFF (V)
TIME, t (2 ms/div)
REMOTE ON/OFF,
VON/OFF (V)
OUTPUT VOLTAGE, VO (V)
(1 V/div)
QW050A1 and QW075A1 Power Modules:
88 Lineage Power
Data Sheet
April 2008dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
Test Configurations
8-203 (C).l
Note: Measure input reflected-ripple current with a simulated source
inductance (LTEST) of 12 µH. Capacitor CS offsets possible bat-
tery impedance. Measure current as shown above.
Figure 13. Input Reflected-Ripple Test Setup
8-513 (C).d
Note: Use a 1.0 µF ceramic capacitor and a 10 µF aluminum or tan-
talum capacitor. Scope measurement should be made using a
BNC socket. Position the load between 51 mm and 76 mm
(2 in. and 3 in.) from the module.
Figure 14. Peak-to-Peak Output Noise
Measurement Test Setup
8-749 (C)
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.
Figure 15. Output Voltage and Efficiency
Measurement Test Setup
Design Considerations
Input Source Impedance
The power module should be connected to a low
ac-impedance input source. Highly inductive source
impedances can affect the stability of the power mod-
ule. For the test configuration in Figure 13, a 33 µF
electrolytic capacitor (ESR < 0.7 ¾ at 100 kHz)
mounted close to the power module helps ensure sta-
bility of the unit. For other highly inductive source
impedances, consult the factory for further application
guidelines.
Safety Considerations
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., UL1950, CSA C22.2 No. 950-95, and VDE 0805
(EN60950, IEC950).
If the input source is non-SELV (ELV or a hazardous
voltage greater than 60 Vdc and less than or equal to
75 Vdc), for the module’s output to be considered
meeting the requirements of safety extra-low voltage
(SELV), all of the following must be true:
nThe input source is to be provided with reinforced
insulation from any hazardous voltages, including the
ac mains.
nOne VI pin and one VO pin are to be grounded, or
both the input and output pins are to be kept floating.
nThe input pins of the module are not operator acces-
sible.
nAnother SELV reliability test is conducted on the
whole system, as required by the safety agencies, on
the combination of supply source and the subject
module to verify that under a single fault, hazardous
voltages do not appear at the module’s output.
Note: Do not ground either of the input pins of the
module without grounding one of the output pins.
This may allow a non-SELV voltage to appear
between the output pin and ground.
The power module has extra-low voltage (ELV) outputs
when all inputs are ELV.
The input to these units is to be provided with a maxi-
mum 3 A normal-blow fuse in the ungrounded lead.
TO OSCILLOSCOPE
12 µH
C
S
220 µF
ESR < 0.1 Ω
@ 20 ˚C, 100 kHz
V
I
(+)
V
I
(-)
BATTERY 33 µF
CURRENT
PROBE
L
TEST
ESR < 0.7 Ω
@ 100 kHz
VO(+)
VO(–)
1.0 µF RESISTIVE
LOAD
SCOPE
COPPER STRIP
10 µF
V
I
(+)
I
I
I
O
SUPPLY
CONTACT
RESISTANCE
CONTACT AND
DISTRIBUTION LOSSES
LOAD
SENSE(+)
V
I
(–)
V
O
(+)
V
O
(–)
SENSE(–)
ηVO(+) – VO(–)[]IO
VI(+) – VI(–)[]II
------------------------------------------------
⎝⎠
⎛⎞
x100=%
Lineage Power 9
Data Sheet
April 2008 dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
Feature Descriptions
Overcurrent Protection
To provide protection in a fault (output overload) condi-
tion, the unit is equipped with internal current-limiting
circuitry and can endure current limiting for up to one
second. If overcurrent exists for more than one second,
the unit will shut down.
At the point of current-limit inception, the unit shifts
from voltage control to current control. If the output volt-
age is pulled very low during a severe fault, the current-
limit circuit can exhibit either foldback or tailout charac-
teristics (output current decrease or increase).
The module is available in two overcurrent configura-
tions. In one configuration, when the unit shuts down it
will latch off. The overcurrent latch is reset by either
cycling the input power or by toggling the ON/OFF pin
for one second. In the other configuration, the unit will
try to restart after shutdown. If the output overload con-
dition still exists when the unit restarts, it will shut down
again. This operation will continue indefinitely until the
overcurrent condition is corrected.
Remote On/Off
Negative logic remote on/off turns the module off dur-
ing a logic high and on during a logic low. To turn the
power module on and off, the user must supply a
switch to control the voltage between the on/off termi-
nal and the VI(–) terminal (Von/off). The switch can be an
open collector or equivalent (see Figure 16). 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 15 V. The maximum allowable
leakage current of the switch at Von/off = 15 V is 50 µA.
If not using the remote on/off feature, short the ON/OFF
pin to VI(–).
8-720 (C).c
Figure 16. Remote On/Off Implementation
Remote Sense
Remote sense minimizes the effects of distribution
losses by regulating the voltage at the remote-sense
connections. The voltage between the remote-sense
pins and the output terminals must not exceed the out-
put voltage sense range given in the Feature Specifica-
tions table, i.e.:
[VO(+) – VO(–)] – [SENSE(+) – SENSE(–)] ð 0.5 V
The voltage between the VO(+) and VO(–) terminals
must not exceed the minimum output overvoltage pro-
tection value shown in the Feature Specifications table.
This limit includes any increase in voltage due to
remote-sense compensation and output voltage set-
point adjustment (trim). See Figure 17.
If not using the remote-sense feature to regulate the
output at the point of load, then connect SENSE(+) to
VO(+) and SENSE(–) to VO(–) at the module.
Although the output voltage can be increased by both
the remote sense and by the trim, the maximum
increase for the output voltage is not the sum of both.
The maximum increase is the larger of either the
remote sense or the trim. Consult the factory if you
need to increase the output voltage more than the
above limitation.
The amount of power delivered by the module is
defined as the voltage at the output terminals multiplied
by the output current. When using remote sense and
trim, the output voltage of the module can be
increased, which at the same output current would
increase the power output of the module. Care should
be taken to ensure that the maximum output power of
the module remains at or below the maximum rated
power.
SENSE(+)
V
O
(+)
SENSE(–)
V
O
(–)
V
I
(-)
+
–
I
on/off
ON/OFF
V
I
(+)
LOAD
V
on/off
QW050A1 and QW075A1 Power Modules:
1010 Lineage Power
Data Sheet
April 2008dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
Feature Descriptions (continued)
Remote Sense (continued)
8-651 (C).m
Figure 17. Effective Circuit Configuration for
Single-Module Remote-Sense Operation
Output Voltage Set-Point Adjustment
(Trim)
Output voltage trim allows the user to increase or
decrease the output voltage set point of a module. This
is accomplished by connecting an external resistor
between the TRIM pin and either the SENSE(+) or
SENSE(–) pins. The trim resistor should be positioned
close to the module.
If not using the trim feature, leave the TRIM pin open.
With an external resistor between the TRIM and
SENSE(–) pins (Radj-down), the output voltage set point
(VO, adj) decreases (see Figure 18). The following equa-
tion determines the required external-resistor value to
obtain a percentage output voltage change of ý%.
The test results for this configuration are displayed in
Figure 19. This figure applies to all output voltages.
With an external resistor connected between the TRIM
and SENSE(+) pins (Radj-up), the output voltage set
point (VO, adj) increases (see Figure 20).
The following equation determines the required exter-
nal-resistor value to obtain a percentage output voltage
change of ý%.
The test results for this configuration are displayed in
Figure 21.
The voltage between the VO(+) and VO(–) terminals
must not exceed the minimum output overvoltage pro-
tection value shown in the Feature Specifications table.
This limit includes any increase in voltage due to
remote-sense compensation and output voltage set-
point adjustment (trim). See Figure 17.
Although the output voltage can be increased by both
the remote sense and by the trim, the maximum
increase for the output voltage is not the sum of both.
The maximum increase is the larger of either the
remote sense or the trim. Consult the factory if you
need to increase the output voltage more than the
above limitation.
The amount of power delivered by the module is
defined as the voltage at the output terminals multiplied
by the output current. When using remote sense and
trim, the output voltage of the module can be
increased, which at the same output current would
increase the power output of the module. Care should
be taken to ensure that the maximum output power of
the module remains at or below the maximum rated
power.
8-748 (C).b
Figure 18. Circuit Configuration to Decrease
Output Voltage
8-2577 (C)
Figure 19. Resistor Selection for Decreased
Output Voltage
VO(+)
SENSE(+)
SENSE(–)
VO(–)
VI(+)
VI(-)
IOLOAD
CONTACT AND
DISTRIBUTION LOSSES
SUPPLY II
CONTACT
RESISTANCE
Radj-down 510
Δ%
----------10.2–
⎝⎠
⎛⎞
kΩ=
Radj-up 5.1VO100 Δ%+()
1.225Δ%
-----------------------------------------------510
Δ%
----------
–10.2
–
⎝⎠
⎛⎞
kΩ=
VI(+)
VI(–)
ON/OFF
CASE
VO(+)
VO(–)
SENSE(+)
TRIM
SENSE(–)
Radj-down
RLOAD
10 20 30 40
1k
10k
100k
0
1M
ADJUSTMENT RESISTOR VALUE (Ω)
% CHANGE IN OUTPUT VOLTAGE (Δ%)
Lineage Power 11
Data Sheet
April 2008 dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
Feature Descriptions (continued)
Output Voltage Set-Point Adjustment
(Trim) (continued)
8-715 (C).b
Figure 20. Circuit Configuration to Increase
Output Voltage
8-2855 (F)
Figure 21. Resistor Selection for Increased Output
Voltage
Output Overvoltage Protection
The output overvoltage protection consists of circuitry
that monitors the voltage on the output terminals. If the
voltage on the output terminals exceeds the overvolt-
age protection threshold, then the module will shut
down and latch off. The overvoltage latch is reset by
either cycling the input power for 1.0 second or by tog-
gling the on/off signal for 1.0 second.
Overtemperature Protection
These modules feature an overtemperature protection
circuit to safeguard against thermal damage. The cir-
cuit shuts down and latches off the module when the
maximum case temperature is exceeded. The module
can be restarted by cycling the dc input power for at
least 1.0 second or by toggling the remote on/off signal
for at least 1.0 second.
Thermal Considerations
Introduction
The power modules operate in a variety of thermal
environments; however, sufficient cooling should be
provided to help ensure reliable operation of the unit.
Heat-dissipating components inside the unit are ther-
mally coupled to the case. Heat is removed by conduc-
tion, convection, and radiation to the surrounding
environment. Proper cooling can be verified by mea-
suring the case temperature. Peak temperature (TC)
occurs at the position indicated in Figure 22.
8-2104 (C)
Note: Top view, pin locations are for reference only.
Measurements shown in millimeters and (inches).
Figure 22. Case Temperature Measurement
Location
The temperature at this location should not exceed
100 °C. The output power of the module should not
exceed the rated power for the module as listed in the
Ordering Information table.
Although the maximum case temperature of the power
modules is 100 °C, you can limit this temperature to a
lower value for extremely high reliability.
VI(+)
VI(–)
ON/OFF
CASE
VO(+)
VO(-)
SENSE(+)
TRIM
SENSE(–)
Radj-up
RLOAD
10M
1M
100k
0246810
% CHANGE IN OUTPUT VOLTAGE ( Δ%)
ADJUSTMENT RESISTOR VALUE (Ω)
14
(0.55)
VI(-)
ON/OFF
VI(+)
VO(–)
TRIM
VO(+)
(+)SENSE
(-)SENSE
33 (1.30)
QW050A1 and QW075A1 Power Modules:
1212 Lineage Power
Data Sheet
April 2008dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
Thermal Considerations (continued)
Heat Transfer Without Heat Sinks
Increasing airflow over the module enhances the heat
transfer via convection. Figure 25 shows the maximum
power that can be dissipated by the module without
exceeding the maximum case temperature versus local
ambient temperature (TA) for natural convection
through 4 m/s (800 ft./min.).
Note that the natural convection condition was mea-
sured at 0.05 m/s to 0.1 m/s (10 ft./min. to 20 ft./min.);
however, systems in which these power modules may
be used typically generate natural convection airflow
rates of 0.3 m/s (60 ft./min.) due to other heat dissipat-
ing components in the system. The use of Figure 25 is
shown in the following example.
Example
What is the minimum airflow necessary for a QW050A1
operating at VI = 54 V, an output current of 10 A, and a
maximum ambient temperature of 40 °C?
Solution
Given: VI = 54 V
IO = 10 A
TA = 40 °C
Determine PD (Use Figure 23.):
PD = 10 W
Determine airflow (v) (Use Figure 25.):
v = 1.25 m/s (250 ft./min.)
Note: Pending improvement will lower the power dissi-
pation and reduce the airflow needed.
8-2957 (F)
Note: Pending improvement will lower the power dissipation.
Figure 23. QW050A1 Power Dissipation vs.
Output Current at 25 °C
8-2958 (F)
Note: Pending improvement will lower the power dissipation.
Figure 24. QW075A1 Power Dissipation vs.
Output Current at 25 °C
11
10
9
8
7
6
5
4
3
12345678910
POWER DISSIPATION, PD (W)
OUTPUT CURRENT, IO (A)
VI = 75 V
VI = 48 V
VI = 36 V
SEE NOTE
16
14
12
10
8
6
4
123456789
10 11 12 13 14 15
OUTPUT CURRENT, IO (A)
POWER DISSIPATION, PD (W)
VI = 75 V
VI = 54 V
VI = 36 V
SEE NOTE
Lineage Power 13
Data Sheet
April 2008 dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
Thermal Considerations (continued)
Heat Transfer Without Heat Sinks (continued)
8-2306 (C).a
Figure 25. Forced Convection Power Derating with
No Heat Sink; Either Orientation
Heat Transfer with Heat Sinks
The power modules have through-threaded, M3 x 0.5
mounting holes, which enable heat sinks or cold plates
to attach to the module. The mounting torque must not
exceed 0.56 N-m (5 in.-lb.). For a screw attachment
from the pin side, the recommended hole size on the
customer’s PWB around the mounting holes is 0.130
± 0.005 inches. If a larger hole is used, the mounting
torque from the pin side must not exceed 0.25 N-m
(2.2 in.-lbs.).
Thermal derating with heat sinks is expressed by using
the overall thermal resistance of the module. Total
module thermal resistance (θca) is defined as the max-
imum case temperature rise (ΔTC, max) divided by the
module power dissipation (PD):
The location to measure case temperature (TC) is
shown in Figure 22. Case-to-ambient thermal resis-
tance vs. airflow is shown, for various heat sink config-
urations, heights, and orientations, as shown in
Figures 26 and 27. Longitudinal orientation is defined
as the long axis of the module that is parallel to the air-
flow direction, whereas in the transverse orientation,
the long axis is perpendicular to the airflow. These
curves were obtained by experimental testing of heat
sinks, which are offered in the product catalog.
8-2107 (C)
Figure 26. Case-to-Ambient Thermal Resistance
Curves; Transverse Orientation
8-2108 (C)
Figure 27. Case-to-Ambient Thermal Resistance
Curves; Longitudinal Orientation
10 20 30 40 50 60
0
10
LOCAL AMBIENT TEMPERATURE, T
A (˚C)
5
20
1000
15
4.0 m/s (800 ft./min.)
3.5 m/s (700 ft./min.)
3.0 m/s (600 ft./min.)
2.5 m/s (500 ft./min.)
2.0 m/s (400 ft./min.)
1.5 m/s (300 ft./min.)
1.0 m/s (200 ft./min.)
0.5 m/s (100 ft./min.)
0.1 m/s (20 ft./min.)
NATURAL CONVECTION
POWER DISSIPATION, PD
(W)
70 80 90
θca ΔTCmax,
PD
--------------------- TCTA–()
PD
------------------------
==
0.5
(100)
1.5
(300)
2.0
(400)
2.5
(500)
3.0
(600)
NAT
CONV
1.0
(200)
0
9
7
6
8
11
10
5
4
3
2
1
RESISTANCE, θCA (˚C/W)
CASE-TO-AMBIENT THERMAL
1 IN. HEAT SINK
1/2 IN. HEAT SINK
NO HEAT SINK
1/4 IN. HEAT SINK
AIR VELOCITY, m/s (ft./min.)
0.5
(100)
1.0
(200)
1.5
(300)
2.0
(400)
2.5
(500)
0
9
AIR VELOCITY, m/s (ft./min.)
7
6
8
11
3.0
(600)
NAT
CONV
10
5
4
3
2
1
1 IN. HEAT SINK
1/2 IN. HEAT SINK
NO HEAT SINK
1/4 IN. HEAT SINK
RESISTANCE, θCA
(˚C/W)
CASE-TO-AMBIENT THERMAL
QW050A1 and QW075A1 Power Modules:
1414 Lineage Power
Data Sheet
April 2008dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
Thermal Considerations (continued)
Heat Transfer with Heat Sinks (continued)
8-2380 (C)
Figure 28. Heat Sink Power Derating Curves;
Natural Convection; Transverse
Orientation
8-2381 (C)
Figure 29. Heat Sink Power Derating Curves;
Natural Convection; Longitudinal
Orientation
8-2382 (C)
Figure 30. Heat Sink Power Derating Curves;
1.0 m/s (200 lfm); Transverse
Orientation
8-2383 (C)
Figure 31. Heat Sink Power Derating Curves;
1.0 m/s (200 lfm); Longitudinal
Orientation
These measured resistances are from heat transfer
from the sides and bottom of the module as well as the
top side with the attached heat sink; therefore, the
case-to-ambient thermal resistances shown are gener-
ally lower than the resistance of the heat sink by itself.
The module used to collect the data in Figures 26 and
27 had a thermal-conductive dry pad between the case
and the heat sink to minimize contact resistance. The
use of Figures 26 and 27 are shown in the following
example.
10 20 30 40 50 60
LOCAL AMBIENT TEMPERATURE, TA (˚C)
1000
POWER DISSIPATION, PD (W)
70 80 90
0
18
14
12
16
20
10
8
6
4
2
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
10 20 30 40 50 60
LOCAL AMBIENT TEMPERATURE, T
A (˚C)
1000
POWER DISSIPATION, PD (W)
70 80 90
0
18
14
12
16
20
10
8
6
4
2
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
10 20 30 40 50 60
LOCAL AMBIENT TEMPERATURE, T
A
(˚C)
1000
POWER DISSIPATION, P
D
(W)
70 80 90
0
18
14
12
16
20
10
8
6
4
2
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
10 20 30 40 50 60
LOCAL AMBIENT TEMPERATURE, T
A
(˚C)
1000
POWER DISSIPATION, P
D
(W)
70 80 90
0
18
14
12
16
20
10
8
6
4
2
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
Lineage Power 15
Data Sheet
April 2008 dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
Thermal Considerations (continued)
Heat Transfer with Heat Sinks (continued)
Example
If an 85 °C case temperature is desired, what is the
minimum airflow necessary? Assume the QW075A1
module is operating at VI = 54 V and an output current
of 15 A, maximum ambient air temperature of 40 °C,
and the heat sink is 1/2 inch. The module is oriented in
the transverse direction.
Solution
Given: VI = 54 V
IO = 15 A
TA = 40 °C
TC = 85 °C
Heat sink = 1/2 inch
Determine PD by using Figure 24:
PD = 16 W
Then solve the following equation:
Use Figure 26 to determine air velocity for the 1/2 inch
heat sink.
The minimum airflow necessary for the QW075A1
module is 1.2 m/s (240 ft./min.).
Note: Pending improvement will lower the power dissi-
pation and reduce the airflow needed.
Custom Heat Sinks
A more detailed model can be used to determine the
required thermal resistance of a heat sink to provide
necessary cooling. The total module resistance can be
separated into a resistance from case-to-sink (θcs) and
sink-to-ambient (θsa) as shown in Figure 32.
8-1304 (C)
Figure 32. Resistance from Case-to-Sink and
Sink-to-Ambient
For a managed interface using thermal grease or foils,
a value of θcs = 0.1 °C/W to 0.3 °C/W is typical. The
solution for heat sink resistance is:
This equation assumes that all dissipated power must
be shed by the heat sink. Depending on the user-
defined application environment, a more accurate
model, including heat transfer from the sides and bot-
tom of the module, can be used. This equation pro-
vides a conservative estimate for such instances.
EMC Considerations
For assistance with designing for EMC compliance,
please refer to the FLTR100V10 data sheet
(DS99-294EPS).
Layout Considerations
Copper paths must not be routed beneath the power
module mounting inserts. For additional layout guide-
lines, refer to the FLTR100V10 data sheet
(DS99-294EPS).
θca TCTA–()
PD
------------------------
=
θca 85 40–()
16
------------------------
=
θca 2.8 °C/W=
PD
TCTSTA
θcs θsa
→
θsa TCTA–()
PD
------------------------ θcs–=
16 Lineage Power
Data Sheet
April 2008dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
Outline Diagram
Dimensions are in millimeters and (inches).
Tolerances: x.x mm ± 0.5 mm (x.xx in. ± 0.02 in.)
x.xx mm ± 0.25 mm (x.xxx in. ± 0.010 in.)
Top View
Side View
Bottom View
8-1769 (F).b
* Side label includes Lineage name, product designation, safety agency markings, input/output voltage and current ratings, and bar code.
57.9
(2.28)
36.8
(1.45)
1.02 (0.040) DIA
SOLDER-PLATED
BRASS, 6 PLACES
1.57 (0.062) DIA
SOLDER-PLATED
BRASS, 2 PLACES
12.7
(0.50)
4.1 (0.16) MIN, 2 PLACES
0.51
(0.020)
4.1 (0.16) MIN,
6 PLACES
SIDE LABEL*
3.5 (0.14) MIN
3.6
(0.14)
10.9
(0.43)
5.3
(0.21)
26.16
(1.030)
15.24
(0.600)
5.3
(0.21)
MOUNTING INSERTS
M3 x 0.5 THROUGH,
4 PLACES
– SENSE
TRIM
+ SENSE
ON/OFF
3.81
(0.150)
7.62
(0.300)
11.43
(0.450)
15.24
(0.600)
50.80
(2.000)
7.62
(0.300) 47.2
(1.86)
VO(+)
VO(–)
VI(–)
VI(+)
11.2
(0.44)
12.7
(0.50)
RIVETED CASE PIN (OPTIONAL)
1.09 x 0.76 (0.043 x 0.030)
Lineage Power 17
Data Sheet
April 2008 dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
Recommended Hole Pattern
Component-side footprint.
Dimensions are in millimeters and (inches).
8-1769 (F).b
Ordering Information
Table 4. Device Codes
Optional features can be ordered using the suffixes shown in Table 5. The suffixes follow the last letter of the
device code and are placed in descending order. For example, the device codes for a QW050A1 module with the
following options are shown below:
Auto-restart after overcurrent shutdown QW050A41
Table 5. Device Options
Input
Voltage
Output
Voltage
Output
Power
Remote On/Off
Logic
Device
Code Comcode
48 V 5 V 50 W Negative QW050A1 108153669
48 V 5 V 75 W Negative QW075A1 107967218
Option Suffix
Auto-restart after overcurrent shutdown 4
3.6
(0.14)
10.9
(0.43)
26.16
(1.030)
15.24
(0.600)
7.62
(0.300)
5.3
(0.21)
MOUNTING INSERTS
M3 x 0.5 THROUGH,
4 PLACES
– SENSE
TRIM
+ SENSE
ON/OFF
5.3
(0.21)
47.2
(1.86)
15.24
(0.600)7.62
(0.300)
11.43
(0.450)
3.81
(0.150)
VO(+)
VO(–)
VI(–)
VI(+)
CASE PIN (OPTIONAL)
11.2
(0.44) 12.7
(0.50)
50.80
(2.000)
QW050A1 and QW075A1 Power Modules:
1818 Lineage Power
Data Sheet
April 2008dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
Ordering Information (continued)
Table 6. Device Accessories
Dimensions are in millimeters and (inches).
8-2473 (F)
Figure 33. Longitudinal Heat Sink
8-2472 (F)
Figure 34. Transverse Heat Sink
Accessory Comcode
1/4 in. transverse kit (heat sink, thermal pad, and screws) 848060992
1/4 in. longitudinal kit (heat sink, thermal pad, and screws) 848061008
1/2 in. transverse kit (heat sink, thermal pad, and screws) 848061016
1/2 in. longitudinal kit (heat sink, thermal pad, and screws) 848061024
1 in. transverse kit (heat sink, thermal pad, and screws) 848061032
1 in. longitudinal kit (heat sink, thermal pad, and screws) 848061040
1.030 ± 0.005
(26.16 ± 0.13)
2.280 ± 0.015
(57.91 ± 0.38)
1/4 IN.
1/2 IN.
1 IN.
1.450 ± 0.015
(36.83 ± 0.38)
1.850 ± 0.005
(47.24 ± 0.13)
1/4 IN.
1/2 IN.
1 IN.
Lineage Power 19
Data Sheet
April 2008 dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
Notes
Data Sheet
April 2008dc-dc Converters; 36 to 75 Vdc Input, 5 Vdc Output; 50 W and 75 W
QW050A1 and QW075A1 Power Modules:
April 2008
DS00-179EPS (Replaces DS00-178EPS)
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