Data Sheet
February 2001
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
Applications
■Distributed power architectures
■Communications equipment
■Computer equipment
Options
■Heat sinks available for extended operation
■Auto-restart after overtemperature, overvoltage, or
overcurrent shutdown
■Case ground pin
■Short pins
Features
■Small size: 36.8 mm x 57.9 mm x 12.7 mm
(1.45 in. x 2.28 in. x 0.50 in.)
■High power density
■Extra high efficiency: 82% typical
■Low output noise
■Constant frequency
■Industry-standard pinout
■Metal baseplate
■2:1 input voltage range
■Overvoltage and overcurrent protection
■Negative remote on/off
■Remote sense
■Adjustable output voltage
■Overtemperature protection
■
ISO
* 9001 and
ISO
14001 Certified manufacturing
facilities
■
UL
†1950
Recognized,
CSA
‡ C22.2 No. 950-95
Certified, and
VDE
§ 0805 (EN60950, IEC950)
Licensed
■CE 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 QHW Series Power Modules use advanced, surface-
mount technology and deliver high-quality, efficient, and com-
pact dc-dc conversion.
Description
The QHW050Y1, QHW075Y1, and QHW100Y1 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 maxi-
mum power ratings from 18 W to 36 W at a typical full-load efficiency of 82%.
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.
2Tyco Electronics Corp.
Data Sheet
February 2001
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 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 20 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
—
—
80
100
Vdc
V
Operating Case Temperature
(See Thermal Considerations section.)
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—3:
QHW050Y1
QHW075Y1
QHW100Y1
VI = 36 V to 75 V; I O = IO, max:
QHW050Y1
QHW075Y1
QHW100Y1
II, max
II, max
II, max
II, max
II, max
II, max
—
—
—
—
—
—
—
—
—
—
—
—
2.5
3.5
4.5
2.0
2.5
3.0
A
A
A
A
A
A
Inrush Transient i2t——1.0A
2s
Input Reflected-ripple Current, Peak-to-peak
(5 Hz to 20 MHz, 12 µH source impedance;
see Figure 17.)
II—10—mAp-p
Input Ripple Rejection (100—120 Hz) — — 60 — dB
Tyco Electronics Corp. 3
Data Sheet
February 2001 dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 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 1.77 1.8 1.83 Vdc
Output Voltage
(Over all operating input voltage, resistive
load, and temperature conditions until end of
life. See Figure 19.)
All VO1.74 — 1.86 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
8
0.1
0.2
25
%VO
%VO
mV
Output Ripple and Noise Voltage
(See Figure 18.):
RMS
Peak-to-peak (5 Hz to 20 MHz)
All
All
—
—
—
—
—
—
40
150
mVrms
mVp-p
External Load Capacitance All — 0 — *µF
Output Current QHW050Y1
QHW075Y1
QHW100Y1
IO
IO
IO
0
0
0
—
—
—
10
15
20
A
A
A
Output Current-limit Inception
(VO = 90% of VO, nom)
QHW050Y1
QHW075Y1
QHW100Y1
IO, cli
IO, cli
IO, cli
—
—
—
12
18
24
20†
25†
30†
A
A
A
Efficiency (VI = 48 V; IO = IO, max ; TC = 70 °C;
see Figure 19.)
QHW050Y1
QHW075Y1
QHW100Y1
η
η
η
—
—
—
81
82
82
—
—
—
%
%
%
Switching Frequency All — — 380 — kHz
Dynamic Response
(∆IO/∆t = 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
—
—
—
—
—
—
—
—
80
300
80
300
—
—
—
—
mV
µs
mV
µs
Parameter Min Typ Max Unit
Isolation Capacitance — 2500 — pF
Isolation Resistance 10 — — MΩ
4Tyco Electronics Corp.
Data Sheet
February 2001
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
General Specifications
Feature Specifications
Unless otherwise indicated, specifications apply over all operating input voltage, resistive load, and temperature
conditions. See the Feature Descriptions section 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
Tyco Electronics
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) 2,245,000 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):
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 Figure 16.)
(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:
Output Voltage Remote-sense Range
Output Voltage Set-point Adjustment Range (trim)
—
—
—
90
—
—
0.5
110
V
%VO, nom
Output Overvoltage Protection
(measured at the VO(+) and VO(–) output terminals)
VO, sd 2.2* — 2.8* V
Overtemperature Protection
Note: If auto-restart option is chosen, the unit will continually
attempt restart in “hiccup” mode.
TC— 105 — °C
Data Sheet
February 2001
Tyco Electronics Corp. 5
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Characteristic Curves
The following figures provide typical characteristics for the power modules.
1-0021
Figure 1. Typical QHW050Y1 Input Characteristics
at Room Temperature
1-0022
Figure 2. Typical QHW075Y1 Input Characteristics
at Room Temperature
8-3461(F)
Figure 3. Typical QHW100Y1 Input Characteristics
at Room Temperature
1-0023
Figure 4. Typical QHW050Y1 Converter Efficiency
vs. Output Current at Room Temperature
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
25 30 35 40 45 50 55 60 65 70 75
INPUT CURRENT, II (A)
INPUT VOLTAGE, VI (V)
IO = 10 A
IO = 5 A
IO = 1 A
1.2
1.0
0.8
0.6
0.4
0.2
0
25 30 35 40 45 50 55 60 65 70 75
INPUT CURRENT, II (A)
INPUT VOLTAGE, VI (V)
IO = 15 A
IO = 7.5 A
IO = 1.5 A
1.6
1.4
0
INPUT VOLTAGE, VI (V)
INPUT CURRENT, II (A)
1.2
1
0.8
0.6
0.4
10 20 30 40 50 60 70 80
IO = 20 A
IO = 10 A
IO = 2 A
0.2
0
90
80
70
60
50
40
30
012345678910
EFFICIENCY, η (%)
OUTPUT CURRENT, IO (A)
VI = 36 V
VI = 48 V
VI = 75 V
6Tyco Electronics Corp.
Data Sheet
February 2001
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Characteristic Curves (continued)
1-0024
Figure 5. Typical QHW075Y1 Converter Efficiency
vs. Output Current at Room Temperature
8-3462(F)
Figure 6. Typical QHW100Y1 Converter Efficiency
vs. Output Current at Room Temperature
1-0025
Note: See Figure 18 for test conditions.
Figure 7. Typical QHW050Y1, Output Ripple
Voltage at Room Temperature; IO = IO, max
1-0026
Note: See Figure 18 for test conditions.
Figure 8. Typical QHW075Y1, Output Ripple
Voltage at Room Temperature; IO = IO, max
85
80
75
70
65
60
23456789101112131415
EFFICIENCY, η (%)
OUTPUT CURRENT, IO (A)
VI = 36 V
VI = 48 V
VI = 75 V
85
2
OUTPUT CURRENT, IO (A)
EFFICIENCY, η (%)
80
75
70
65
345678910
60
11 12 13 14 15 16 17 18 19 20
VI = 75 V
VI = 48 V
VI = 36 V
TIME, t (1 µs/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
VI = 75 V
VI = 48 V
VI = 36 V
TIME, t (1 µs/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
VI = 75 V
VI = 48 V
VI = 36 V
Tyco Electronics Corp. 7
Data Sheet
February 2001 dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Characteristic Curves (continued)
1-0027
Note: See Figure 18 for test conditions.
Figure 9. Typical QHW100Y1, Output Ripple
Voltage at Room Temperature; IO = IO, max
1-0082
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 10. Typical QHW050Y1 Transient Response
to Step Increase in Load from 50% to 75%
of Full Load at Room Temperature and
48 Vdc Input (Waveform Averaged to
Eliminate Ripple Component.)
1-0083
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 11. Typical QHW075Y1 Transient Response
to Step Increase in Load from 50% to 75%
of Full Load at Room Temperature and
48 Vdc Input (Waveform Averaged to
Eliminate Ripple Component.)
1-0084
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 12. Typical QHW100Y1 Transient Response
to Step Increase in Load from 50% to
75% of Full Load at Room Temperature
and 48 Vdc Input (Waveform Averaged to
Eliminate Ripple Component.)
TIME, t (1 µs/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
VI = 75 V
VI = 48 V
VI = 36 V
TIME, t (200 µs/div)
OUTPUT CURRENT, IO (A)
(2 A/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
7.5 A
5.0 A
TIME, t (100 µs/div)
OUTPUT CURRENT, IO (A)
(2 A/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
7.50 A
11.25 A
TIME, t (200 µs/div)
OUTPUT CURRENT, IO (A)
(5 A/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
15 A
10 A
88 Tyco Electronics Corp.
Data Sheet
February 2001
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Characteristic Curves (continued)
1-0085
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 13. Typical QHW050Y1 Transient Response
to Step Decrease in Load from 50% to
25% of Full Load at Room Temperature
and 48 Vdc Input (Waveform Averaged to
Eliminate Ripple Component.)
1-0086
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 14. Typical QHW075Y1 Transient Response
to Step Decrease in Load from 50% to
25% of Full Load at Room Temperature
and 48 Vdc Input (Waveform Averaged to
Eliminate Ripple Component.)
1-0087
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 15. Typical QHW100Y1 Transient Response
to Step Decrease in Load from 50% to
25% of Full Load at Room Temperature
and 48 Vdc Input (Waveform Averaged to
Eliminate Ripple Component.)
1-0033
Note: Tested with a 1000 µF aluminum and a 1.0 µF ceramic capaci-
tor across the load.
Figure 16. QHW100Y1 Typical Start-Up from
Remote On/Off; IO = IO, max
TIME, t (100 µs/div)
OUTPUT CURRENT, IO (A)
(2 A/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
2.5 A
5.0 A
TIME, t (100 µs/div)
OUTPUT CURRENT, IO (A)
(2 A/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
TIME, t (200 µs/div)
OUTPUT CURRENT, IO (A)
(5 A/div)
OUTPUT VOLTAGE, VO (V)
(50 mV/div)
5 A
10 A
REMOTE ON/OFF,
V
ON/OFF
(V)
OUTPUT VOLTAGE, V
O
(V)
(1 V/div)
TIME, t (20 ms/div)
Tyco Electronics Corp. 9
Data Sheet
February 2001 dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Test Configurations
8-203(F).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 17. Input Reflected-Ripple Test Setup
8-513(F).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 18. Peak-to-Peak Output Noise
Measurement Test Setup
8-749(F)
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 19. 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 17, a 33 µF
electrolytic capacitor (ESR < 0.7 Ω 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.,
UL
1950,
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:
■The input source is to be provided with reinforced
insulation from any hazardous voltages, including the
ac mains.
■One VI pin and one V O pin are to be grounded, or
both the input and output pins are to be kept floating.
■The input pins of the module are not operator acces-
sible.
■Another 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 20 A normal-blow fuse in the ungrounded lead.
TO OSCILLOSCOPE
CURRENT
PROBE
BATTERY
LTEST
12 µH
CS 220 µF
ESR < 0.1 Ω
@ 20 °C, 100 kHz 33 µF
ESR < 0.7 Ω
@ 100 kHz
VI(+)
VI(–)
1.0 µFRESISTIVE
SCOPE
COPPER STRIP
10 µFLOAD
VO(+)
VO(–)
VI(+)
IIIO
SUPPLY
CONTACT
CONTACT AND
LOAD
SENSE(+)
VI(–)
VO(+)
VO(–)
SENSE(–)
RESISTANCE
DISTRIBUTION LOSSES
ηVO(+) –VO(–)[]IO
VI(+) –VI(–)[]II
------------------------------------------------
x100=%
1010 Tyco Electronics Corp.
Data Sheet
February 2001
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 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 terminal and
the VI(–) terminal (Von/off). The switch can be an open
collector or equivalent (see Figure 20). 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(F).c
Figure 20. 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(–)] ≤ 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 21.
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.
SENSE(+)
VO(+)
SENSE(–)
VO(–)
VI(–)
+
–
Ion/off
ON/OFF
VI(+)
LOAD
Von/off
Tyco Electronics Corp. 11
Data Sheet
February 2001 dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Feature Descriptions (continued)
Remote Sense (continued)
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.
8-651(F).m
Figure 21. 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 22). The following equa-
tion determines the required external-resistor value to
obtain a percentage output voltage change of ∆%.
With an external resistor connected between the TRIM
and SENSE(+) pins (Radj-up), the output voltage set
point (VO, adj) increases (see Figure 23).
The following equation determines the required exter-
nal-resistor value to obtain a percentage output voltage
change of ∆%.
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 21.
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(F).b
Figure 22. Circuit Configuration to Decrease
Output Voltage
SENSE(+)
SENSE(–)
VI(+)
VI(–)
IOLOAD
CONTACT AND
SUPPLY II
CONTACT
VO(+)
VO(–)
DISTRIBUTION LOSSESRESISTANCE
Radj-down 511
∆%
---------- 10.22–
kΩ=
Radj-up 5.11VO100 ∆%+()
1.225∆%
-------------------------------------------------- 511
∆%
----------
–10.22
–
kΩ=
VI
(+)
VI(–)
ON/OFF
CASE
VO(+)
VO(–)
SENSE(+)
TRIM
SENSE(–)
Radj-down
RLOAD
1212 Tyco Electronics Corp.
Data Sheet
February 2001
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Feature Descriptions (continued)
Output Voltage Set-Point Adjustment (Trim)
(continued)
8-715(F).b
Figure 23. Circuit Configuration to Increase
Output Voltage
Note: The output voltage of this module may be
increased by a maximum of 0.5 V. The 0.5 V is
the combination of both the remote-sense and
the output voltage set-point adjustment (trim).
Do not exceed 2.3 V between the V O(+) and
VO(–) terminals.
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 one second or by tog-
gling the on/off signal for one second. If the auto-restart
option is chosen, the unit will “hiccup” until the tempera-
ture is within specification.
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 one second or by toggling the remote on/off signal
for at least one second. If the auto-restart option is cho-
sen, the unit will “hiccup” until the temperature is within
specification.
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 24.
8-2104(F)
Note: Top view, pin locations are for reference only.
Measurements shown in millimeters and (inches).
Figure 24. 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.
Heat Transfer Without Heat Sinks
Increasing airflow over the module enhances the heat
transfer via convection. Figures 25 and 26 show the
maximum power that can be dissipated by the module
without exceeding the maximum case temperature ver-
sus local ambient temperature (TA) for natural convec-
tion through 3 m/s (600 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.
VI
(+)
VI(–)
ON/OFF
CASE
VO(+)
VO(–)
SENSE(+)
TRIM
SENSE(–)
Radj-up
RLOAD
ON/OFF TRIM
(+)SENSE
(–)SENSE
33 (1.30)
14
(0.55) VI (+)
VI (–)V
O (–)
VO (+)
Tyco Electronics Corp. 13
Data Sheet
February 2001 dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Thermal Considerations (continued)
Heat Transfer Without Heat Sinks (continued)
Example
What is the minimum airflow necessary for a
QHW100Y1 operating at VI = 48 V, an output current of
20 A, transverse orientation, and a maximum ambient
temperature of 40 °C?
Solution
Given: VI = 48 V
IO = 20 A
TA = 40 °C
Determine PD (Use Figure 29):
PD = 8.0 W
Determine airflow (v) (Use Figure 25):
v = 0.5 m/s (100 ft./min.)
8-2321(F)
Figure 25. Forced Convection Power Derating with
No Heat Sink; Transverse Orientation
8-2318(F).a
Figure 26. Forced Convection Power Derating with
No Heat Sink; Longitudinal Orientation
1-0034
Figure 27. QHW050Y1 Power Dissipation vs.
Output Current at 25 °C
0
LOCAL AMBIENT TEMPERATURE, TA (°C)
POWER DISSIPATION, PD (W)
20
15
10
5
0
10 20 30 40 50 60 70 80
3.0 m/s (600 ft./min.)
2.0 m/s (400 ft./min.)
1.0 m/s (200 ft./min.)
0.1 m/s (20 ft./min.)
90 100
NATURAL
CONVECTION
0
LOCAL AMBIEMT TEMPERATURE, TA (°C)
POWER DISSIPATION, PD (W)
20
15
10
5
0
10 20 30 40 50 60 70 80
3.0 m/s (600 ft./min.)
2.0 m/s (400 ft./min.)
1.0 m/s (200 ft./min.)
0.1 m/s (20 ft./min.)
90 100
NATURAL
CONVECTION
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
POWER DISSIPATION, PD (W)
OUTPUT CURRENT, IO (A)
12345678910
VI = 75 V
VI = 48 V
VI = 36 V
1414 Tyco Electronics Corp.
Data Sheet
February 2001
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Thermal Considerations (continued)
Heat Transfer Without Heat Sinks (continued)
1-0035
Figure 28. QHW075Y1 Power Dissipation vs.
Output Current at 25 °C
8-3465(F)
Figure 29. QHW100Y1 Power Dissipation vs.
Output Current at 25 °C
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 ( 5in.-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. 25N-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 (∆TC, max) divided by the
module power dissipation (PD):
The location to measure case temperature (TC) is
shown in Figure 24. Case-to-ambient thermal resis-
tance vs. airflow is shown, for various heat sink config-
urations, heights, and orientations, as shown in Figures
30 and 31. Longitudinal orientation is defined as when
the long axis of the module is parallel to the airflow
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.
8-2323(F)
Figure 30. Case-to-Ambient Thermal Resistance
Curves; Transverse Orientation
8
7
6
5
4
3
2
1
0
POWER DISSIPATION, PD (W)
OUTPUT CURRENT, IO (A)
0123456789101112131415
VI = 75 V
VI = 48 V
VI = 36 V
10
2
OUTPUT CURRENT, IO (A)
POWER DISSIPATION, PD (W)
345678910
9
8
7
6
5
4
3
2
1
0
11 12 13 14 15 16 17 18 19 20
VI = 75 V
VI = 48 V
VI = 36 V
θca ∆TCmax,
PD
---------------------TCTA
–()
PD
------------------------
==
0
VELOCITY, m/s (ft./min.)
CASE-TO-ANBIENT THERMAL
10
0
0.5 1.0 1.5 2.0 2.5 3.0
RESISTANCE, θCA (°C/W)
9
8
7
6
5
4
3
2
1
(100) (200) (300) (400) (500) (600)
NO HEAT SINK
1/4 IN. HEAT SINK
1/2 IN. HEAT SINK
1 IN. HEAT SINK
Tyco Electronics Corp. 15
Data Sheet
February 2001 dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Thermal Considerations (continued)
Heat Transfer with Heat Sinks (continued)
8-2324(F)
Figure 31. Case-to-Ambient Thermal Resistance
Curves; Longitudinal Orientation
8-2889(F)
Figure 32. Heat Sink Power Derating Curves;
Natural Convection; Transverse
Orientation
8-2890(F)
Figure 33. Heat Sink Power Derating Curves;
Natural Convection; Longitudinal
Orientation
8-2891(F)
Figure 34. Heat Sink Power Derating Curves;
1.0 m/s (200 lfm); Transverse Orientation
0
VELOCITY, m/s (ft./min.)
CASE-TO-ANBIENT THERMAL
10
00.5 1.0 1.5 2.0 2.5 3.0
RESISTANCE, θCA (°C/W)
9
8
7
6
5
4
3
2
1
(100) (200) (300) (400) (500) (600)
11
NO HEAT SINK
1/4 IN. HEAT SINK
1/2 IN. HEAT SINK
1 IN. HEAT SINK
0
LOCAL AMBIENT TEMPERATURE, TA (°C)
POWER DISSIPATION, PD (W)
20
15
10
5
0
10 20 30 40 50 60 70 80
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
90 100
0
LOCAL AMBIEMT TEMPERATURE, TA (°C)
POWER DISSIPATION, PD (W)
20
15
10
5
0
10 20 30 40 50 60 70 80 90 100
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
0
LOCAL AMBIENT TEMPERATURE, T
A (°C)
POWER DISSIPATION, PD (W)
20
15
10
5
0
10 20 30 40 50 60 70 80 90 100
1 IN. HEAT SINK
1/2 IN. HEAT SINK
1/4 IN. HEAT SINK
NO HEAT SINK
1616 Tyco Electronics Corp.
Data Sheet
February 2001
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Thermal Considerations (continued)
Heat Transfer with Heat Sinks (continued)
8-2892(F)
Figure 35. 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 Figure 30 had a
thermal-conductive dry pad between the case and the
heat sink to minimize contact resistance. The use of
Figure 30 is shown in the following example.
Example
If an 85 °C case temperature is desired, what is the
minimum airflow necessary? Assume the QHW100Y1
module is operating at VI = 48 V and an output current
of 20 A, maximum ambient air temperature of 4 0°C,
and the heat sink is 1/2 inch. The module is oriented in
the transverse direction.
Solution
Given: VI = 48 V
IO = 20 A
TA = 40 °C
TC = 85 °C
Heat sink = 1/2 inch
Determine PD by using Figure 29:
PD = 8.0 W
Then solve the following equation:
Use Figure 30 to determine air velocity for the
1/2 inch heat sink.
The minimum airflow necessary for this module is
0.4 m/s (80 ft./min.).
20
0
LOCAL AMBIENT TEMPERATURE, TA (°C)
POWER DISSIPATION, PD (W)
10 20 30 40 50 60 70 80 90 100
15
10
5
0
NO HEAT SINK
1/4 IN. HEAT SINK
1/2 IN. HEAT SINK
1 IN. HEAT SINK
θca TCTA
–()
PD
------------------------
=
θca 85 40–()
8.0
------------------------
=
θca 5.63 °C/W=
Tyco Electronics Corp. 17
Data Sheet
February 2001 dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
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 36.
8-1304(F).e
Figure 36. 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 Filter Module
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 Filter Module
Data
Sheet (DS99-294EPS).
PDTCTSTA
θcs θsa
θsa TCTA
–()
PD
-------------------------θcs–=
18 Tyco Electronics Corp.
Data Sheet
February 2001
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 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 Tyco 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 3.5 (0.14) MIN
SIDE LABEL*
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)
Tyco Electronics Corp. 19
Data Sheet
February 2001 dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Recommended Hole Pattern
Component-side footprint.
Dimensions are in millimeters and (inches).
8-1769(F).b
Ordering Information
Please contact your Tyco Electronics Account Manager or Field Application Engineer for pricing and availability.
Table 4. Device Codes
Optional features can be ordered using the suffixes shown in Table 5. To order more than one option, list device
codes suffixes in numerically descending order. For example, the device code for a QHW100Y1 module with the
following option is shown below:
Table 5. Device Options
Input
Voltage
Output
Voltage
Output
Power
Output
Current
Remote On/Off
Logic
Device
Code Comcode
48 Vdc 1.8 Vdc 18 W 10 A Negative QHW050Y1 108844333
48 Vdc 1.8 Vdc 27 W 15 A Negative QHW075Y1 108448176
48 Vdc 1.8 Vdc 36 W 20 A Negative QHW100Y1 108448218
Negative logic and auto-restart after overtemperature,
overvoltage, or overcurrent shutdown
QHW100Y41
Option Device Code
Suffix
Case ground pin 7
Short pins: 3.68 mm ± 0.25 mm
(0.145 in. ± 0.010 in.)
6
Auto-restart after overtemperature, over-
voltage, or 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)
Data Sheet
February 2001
dc-dc Converters: 36 to 75 Vdc Input, 1.8 Vdc Output; 18 W to 36 W
QHW050Y1, QHW075Y1, and QHW100Y1 Power Modules;
Printed on
Recycled Paper
Tyco Electronics Power Systems, Inc.
3000 Skyline Drive, Mesquite, TX 75149, USA
+1-800-526-7819 FAX: +1-888-315-5182
(Outside U.S.A.: +1-972-284-2626, FAX: +1-972-284-2900)
http://power.tycoelectronics.com
Tyco Electronics Corporation reserves the right to make changes to the product(s) or information contained herein without notice. No liability is assumed as a result of their use or application.
No rights under any patent accompany the sale of any such product(s) or information.
© 2001 Tyco Electronics Corporation, Harrisburg, PA. All International Rights Reserved.
Printed in U.S.A.
February 2001
DS99-214EPS (Replaces PB00-002EPS)
Ordering Information (continued)
Table 6. Device Accessories
Dimensions are in millimeters and (inches).
8-2473(F)
Figure 37. Longitudinal Heat Sink
8-2472(F)
Figure 38. 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
26.16 ± 0.13
(1.030 ± 0.005)
57.91 ± 0.38
(2.280 ± 0.015)
1/4 IN.
1/2 IN.
1 IN.
36.83 ± 0.38
(1.450 ± 0.015)
47.24 ± 0.13
(1.850 ± 0.005)
1/4 IN.
1/2 IN.
1 IN.
