FEATURES
High efficiency : 94.7% @ 12V/18A
Size:
57.9x36.8x11.2mm (2.28”x1.45”x0.44”)
(w/o heat spreader)
57.9*36.8*12.7mm(2.28”*1.45”0.50”)
(with heat spreader)
Standard footprint
Industry standard pin out
Fixed frequency operation
Input UVLO, Output OCP, OVP, OTP
Hiccup output over current protection
(OCP)
Hiccup output over voltage protection
(OVP)
Auto recovery OTP and UVLO
2250V isolation and basic insulation
No minimum load required
ISO 9001, TL 9000, ISO 14001, QS9000,
OHSAS18001 certified manufacturing
facility
UL/cUL 60950-1 (US & Canada)
recognized
Delphi Series Q48SK, Quarter Brick Family
DC/DC Power Modules:
36~75V in, 12V/18A out, 216W
The Delphi series Q48SK12018, quarter brick, 36~75V input, single output,
OPTIONS
Latched over current protection
Positive On/Off logic
isolated DC/DC converter is the latest offering from a world leader in power
system and technology and manufacturing ― Delta Electronics, Inc. This
Heat spreader available for
extended operation.
product provides up to 216 watts of power in an industry standard footprint
and pin out. With creative design technology and optimization of component
placement, these converters possess outstanding electrical and thermal
performances, as well as extremely high reliability under highly stressful
operating conditions. The Q48SK12018 12V offers more than 94.7% high
efficiency at 18A full load. The Q48SK12018 is fully protected from abnormal
input/output voltage, current, and temperature conditions and meets all
safety requirements with basic insulation.
DATASHEET
DS_Q48SK12018_01062011
APPLICATIONS
Telecom / Datacom
Wireless Networks
Optical Network Equipment
Server and Data Storage
Industrial / Testing Equipment
TECHNICAL SPECIFICATIONS
(TA=25°C, airflow rate=300 LFM, Vin=48Vdc, nominal Vout unless otherwise noted;
PARAMETER
NOTES and CONDITIONS
Q48SK12018 (Standard)
Min.
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Continuous
Transient
Operating Case Temperature (Without heat spreader)
Operating Case Temperature (With heat spreader)
Storage Temperature
Input/Output Isolation Voltage
INPUT CHARACTERISTICS
Operating Input Voltage
Input Under-Voltage Lockout
Turn-On Voltage Threshold
Turn-Off Voltage Threshold
Lockout Hysteresis Voltage
Maximum Input Current
No-Load Input Current
Off Converter Input Current
Inrush Current (I2t)
Input Reflected-Ripple Current
Input Voltage Ripple Rejection
OUTPUT CHARACTERISTICS
Output Voltage Set Point
Output Voltage Regulation
Over Load
Over Line
Over Temperature
Total Output Voltage Range
Output Voltage Ripple and Noise
Peak-to-Peak
RMS
Operating Output Current Range
Output DC Current-Limit Inception
DYNAMIC CHARACTERISTICS
Output Voltage Current Transient
Positive Step Change in Output Current
Negative Step Change in Output Current
Settling Time (within 1% Vout nominal)
Turn-On Transient
Start-Up Time, From On/Off Control
Start-Up Time, From Input
Maximum Output Capacitance
EFFICIENCY
100% Load
60% Load
ISOLATION CHARACTERISTICS
Input to Output
Isolation Resistance
Isolation Capacitance
FEATURE CHARACTERISTICS
Switching Frequency
ON/OFF Control, Negative Remote On/Off logic
Logic Low (Module On)
Logic High (Module Off)
ON/OFF Control, Positive Remote On/Off logic
Logic Low (Module Off)
Logic High (Module On)
ON/OFF Current (for both remote on/off logic)
Leakage Current (for both remote on/off logic)
Output Over-Voltage Protection
GENERAL SPECIFICATIONS
MTBF(without heat spreader)
Weight(without heat spreader)
Weight(with heat spreader)
Over-Temperature Shutdown ( Without heat spreader)
Over-Temperature Shutdown
(With heat spreader)
DS_Q48SK12018_01062011
100ms
Refer to figure 18 for measuring point
Refer to figure 20 for measuring point
Typ.
-40
-40
-55
Max.
Units
80
100
121
112
125
2250
Vdc
Vdc
°C
°C
°C
Vdc
36
48
75
Vdc
32.0
30.0
34.0
32.0
2
36.0
34.0
Vdc
Vdc
Vdc
A
mA
mA
A2s
mA
dB
100% Load, 36Vin
Vin=48V, Io=0A
Vin=48V, Io=0A
150
10
9
P-P thru 12µH inductor, 5Hz to 20MHz
120 Hz
10
-30
1
Vin=48V, Io=0, Tc=25°C
Vin=48V, Io=Io,min to Io,max
Vin=36V to 75V, Io=Io min
Vin=48V , Tc=-40°C to 85°C
over sample load, line and temperature
5Hz to 20MHz bandwidth
Full Load, 1µF ceramic, 10µF tantalum
Full Load, 1µF ceramic, 10µF tantalum
Output Voltage 10% Low
11.4
11.7
12.0
Vdc
±30
±50
±100
±80
11.2
12.0
mV
mV
mV
Vdc
0
110
120
50
18
140
mV
mV
A
%
48V, 10µF Tan & 100µF Ceramic load cap, 0.1A/µs
50% Io.max to 75% Io.max
75% Io.max to 50% Io.max
300
300
300
mV
mV
µs
70
80
ms
ms
µF
Low ESR CAP (OSCON), 100% Load;
6000
Vin=48V
Vin=48V
94.7
94.5
%
%
2250
1000
Vdc
MΩ
pF
160
kHz
10
Von/off at Ion/off=1.0mA
Von/off at Ion/off=0.0 µA
Von/off at Ion/off=1.0mA
Von/off at Ion/off=0.0 µA
Ion/off at Von/off=0.0V
Logic High, Von/off=15V
Over full temp range; % of nominal Vout
Io=80% of Io, max; Tc=25°C;Airflow=300LFM
Refer to figure 18 for measuring point
Refer to figure 20 for measuring point
0
2
0.8
50
V
V
0
2
0.8
50
1
50
140
V
V
mA
uA
%
115
3.49
50.5
65.5
127
121
M hours
grams
grams
°C
°C
2
16
98
96
94
92
90
88
86
84
82
80
78
76
74
72
70
14
12
LOSS (W)
EFFICIENCY (%)
ELECTRICAL CHARACTERISTICS CURVES
10
8
6
4
36V
48V
75V
36V
2
48V
75V
0
0
2
4
6
8
10 12 14
OUTPUT CURRENT (A)
16
18
20
0
Figure 1: Efficiency vs. load current for minimum, nominal, and
maximum input voltage at 85°C.
2
4
6
8
10 12 14
OUTPUT CURRENT (A)
16
18
20
Figure 2: Power dissipation vs. load current for minimum,
nominal, and maximum input voltage at 85°C.
6.5
6
INPUT CURRENT (A)
5.5
5
4.5
4
3.5
3
2.5
2
30
35
40
45
50
55
60
INPUT VOLTAGE (V)
65
70
75
Figure 3: Typical full load input characteristics at room
temperature.
DS_Q48SK12018_01062011
3
ELECTRICAL CHARACTERISTICS CURVES
For Negative Remote On/Off Logic
Figure 4: Turn-on transient at zero load current) (20ms/div).
Top Trace: Vout; 5V/div; Bottom Trace: ON/OFF input: 2V/div.
Figure 5: Turn-on transient at full rated load current (20
ms/div). Top Trace: Vout: 5V/div; Bottom Trace: ON/OFF input:
2V/div.
For Input Voltage Start up
Figure 6: Turn-on transient at zero load current (20 ms/div).
Top Trace: Vout; 5V/div; Bottom Trace: input voltage: 30V/div.
DS_Q48SK12018_01062011
Figure 7: Turn-on transient at full rated load current (20
ms/div). Top Trace: Vout; 5V/div; Bottom Trace: input voltage:
30V/div.
4
ELECTRICAL CHARACTERISTICS CURVES
Figure 8: Output voltage response to step-change in load
current (75%-50% of Io, max; di/dt = 0.1A/µs). Load cap: 10µF,
tantalum capacitor and 1µF ceramic capacitor. Top Trace: Vout;
100mV/div; Bottom Trace: output current: 10A/div; Time:
200us/div
Figure 9: Output voltage response to step-change in load
current (50%-75% of Io, max; di/dt = 0.1A/µs). Load cap: 10µF,
tantalum capacitor and 1µF ceramic capacitor. Top Trace: Vout;
100mV/div; Bottom Trace: output current: 10A/div; Time:
200us/div
Figure 10: Test set-up diagram showing measurement points
for Input Terminal Ripple Current and Input Reflected Ripple
Current.
Note: Measured input reflected-ripple current with a simulated
source Inductance (LTEST) of 12 µH. Capacitor Cs offset
possible battery impedance. Measure current as shown above.
Figure 11: Input Terminal Ripple Current, ic, at full rated output
current and nominal input voltage with 12µH source impedance
and 33µF electrolytic capacitor (200 mA/div，2us/div).
DS_Q48SK12018_01062011
5
ELECTRICAL CHARACTERISTICS CURVES
Figure 12: Input reflected ripple current, is, through a 12µH
source inductor at nominal input voltage and rated load current
(20 mA/div，2us/div).
Figure 13: Output voltage noise and ripple measurement test
setup.
14
OUTPUT VOLTAGE (V)
12
10
8
6
4
2
0
0
4
8
12
16
20
24
OUTPUT CURREN (A)
Figure 14: Output voltage ripple at nominal input voltage and
rated load current (Io=18A)(20 mV/div, 2us/div)
Load capacitance: 1µF ceramic capacitor and 10µF tantalum
capacitor. Bandwidth: 20 MHz.
DS_Q48SK12018_01062011
Figure 15: Output voltage vs. load current showing typical
current limit curves and converter shutdown points.
6
DESIGN CONSIDERATIONS
Input Source Impedance
The input source must be insulated from the ac
mains by reinforced or double insulation.
The input terminals of the module are not operator
accessible.
If the metal baseplate is grounded, the output must
be also grounded.
Layout and EMC Considerations
Delta’s DC/DC power modules are designed to operate
in a wide variety of systems and applications. For design
assistance with EMC compliance and related PWB
layout issues, please contact Delta’s technical support
team. An external input filter module is available for
easier EMC compliance design. Application notes to
assist designers in addressing these issues are pending
release.
A SELV reliability test is conducted on the system
where the module is used, in combination with the
module, to ensure that under a single fault,
hazardous voltage does not appear at the module’s
output.
When installed into a Class II equipment (without
grounding), spacing consideration should be given to
the end-use installation, as the spacing between the
module and mounting surface have not been evaluated.
The impedance of the input source connecting to the
DC/DC power modules will interact with the modules
and affect the stability. A low ac-impedance input source
is recommended. If the source inductance is more than
a few µH, we advise adding a 10µF to 100µF electrolytic
capacitor (ESR < 0.7 Ω at 100 kHz) mounted close to
the input of the module to improve the stability.
Safety Considerations
The power module must be installed in compliance with
the spacing and separation requirements of the
end-user’s safety agency standard, i.e., UL60950-1,
CAN/CSA-C22.2, No. 60950-1 and EN60950-1+A11 and
IEC60950-1, if the system in which the power module is
to be used must meet safety agency requirements.
Basic insulation based on 75 Vdc input is provided
between the input and output of the module for the
purpose of applying insulation requirements when the
input to this DC-to-DC converter is identified as TNV-2
or SELV. An additional evaluation is needed if the
source is other than TNV-2 or SELV.
When the input source is SELV circuit, the power module
meets SELV (safety extra-low voltage) requirements. If
the input source is a hazardous voltage which is greater
than 60 Vdc and less than or equal to 75 Vdc, for the
module’s output to meet SELV requirements, all of the
following must be met:
DS_Q48SK12018_01062011
The power module has extra-low voltage (ELV) outputs
when all inputs are ELV.
This power module is not internally fused. To achieve
optimum safety and system protection, an input line fuse
is highly recommended. The safety agencies require a
normal-blow fuse with 30A maximum rating to be
installed in the ungrounded lead. A lower rated fuse can
be used based on the maximum inrush transient energy
and maximum input current.
Soldering and Cleaning Considerations
Post solder cleaning is usually the final board assembly
process before the board or system undergoes electrical
testing. Inadequate cleaning and/or drying may lower the
reliability of a power module and severely affect the
finished circuit board assembly test. Adequate cleaning
and/or drying is especially important for un-encapsulated
and/or open frame type power modules. For assistance
on appropriate soldering and cleaning procedures,
please contact Delta’s technical support team.
7
FEATURES DESCRIPTIONS
Over-Current Protection
The modules include an internal output over-current
protection circuit, which will endure current limiting for
an unlimited duration during output overload. If the
output current exceeds the OCP set point, the modules
will automatically shut down (hiccup mode).
The modules will try to restart after shutdown. If the
overload condition still exists, the module will shut down
again. This restart trial will continue until the overload
condition is corrected.
Figure 16: Remote on/off implementation
Over-Voltage Protection
The modules include an internal output over-voltage
protection circuit, which monitors the voltage on the
output terminals. If this voltage exceeds the
over-voltage set point, the protection circuit will
constrain the max duty cycle to limit the output voltage, if
the output voltage continuously increases the modules
will shut down, and then restart after a hiccup-time
(hiccup mode).
Over-Temperature Protection
The over-temperature protection consists of circuitry
that provides protection from thermal damage. If the
temperature exceeds the over-temperature threshold
the module will shut down. The module will restart after
the temperature is within specification.
Remote On/Off
The remote on/off feature on the module can be either
negative or positive logic. Negative logic turns the
module on during a logic low and off during a logic high.
Positive logic turns the modules on during a logic high
and off during a logic low.
Remote on/off can be controlled by an external switch
between the on/off terminal and the Vi (-) terminal. The
switch can be an open collector or open drain.
For negative logic if the remote on/off feature is not
used, please short the on/off pin to Vi (-). For positive
logic if the remote on/off feature is not used, please
leave the on/off pin to floating.
DS_Q48SK12018_01062011
8
THERMAL CONSIDERATIONS
Thermal management is an important part of the system
design. To ensure proper, reliable operation, sufficient
cooling of the power module is needed over the entire
temperature range of the module. Convection cooling is
usually the dominant mode of heat transfer.
Hence, the choice of equipment to characterize the
thermal performance of the power module is a wind
tunnel.
Thermal Testing Setup
Delta’s DC/DC power modules are characterized in
heated vertical wind tunnels that simulate the thermal
environments encountered in most electronics
equipment. This type of equipment commonly uses
vertically mounted circuit cards in cabinet racks in which
the power modules are mounted.
The following figure shows the wind tunnel
characterization setup. The power module is mounted
on a test PWB and is vertically positioned within the
wind tunnel. The space between the neighboring PWB
and the top of the power module is constantly kept at
6.35mm (0.25’’).
PWB
FACING PWB
MODULE
AIR VELOCITY
AND AMBIENT
TEMPERATURE
MEASURED BELOW
THE MODULE
50.8 (2.0”)
AIR FLOW
12.7 (0.5”)
Note: Wind Tunnel Test Setup Figure Dimensions are in millimeters and (Inches)
Figure 17: Wind tunnel test setup
Thermal Derating
Heat can be removed by increasing airflow over the
module. To enhance system reliability, the power
module should always be operated below the maximum
operating temperature. If the temperature exceeds the
maximum module temperature, reliability of the unit may
be affected.
DS_Q48SK12018_01062011
9
THERMAL CURVES
(WITH HEAT SPREADER)
THERMAL CURVES
(WITHOUT HEAT SPREADER)
Figure 18: Temperature measurement location
Figure 20: Temperature measurement location
* The allowed maximum hot spot temperature is defined at 121℃ * The allowed maximum hot spot temperature is defined at 112℃
Output Current(A)
Q48SK12018(Standard) Output Current vs. Ambient Temperature and Air Velocity
@Vin = 48V (Transverse Orientation)
18
Output Current(A)
Q48SK12018(Standard) Output Current vs. Ambient Temperature and Air Velocity
@Vin = 48V (Transverse Orientation;With Heatspreader)
18
16
16
Natural
Convection
14
Natural
Convection
14
100LFM
12
12
200LFM
10
100LFM
10
300LFM
8
200LFM
8
400LFM
6
6
300LFM
500LFM
4
4
2
2
0
0
25
30
35
40
45
50
55
60
65
70
75
80
85
Ambient Temperature (℃)
Figure 19: Output current vs. ambient temperature and air
velocity @Vin=48V(Transverse Orientation, without heat
spreader)
DS_Q48SK12018_01062011
25
30
35
40
45
50
55
60
65
70
75
80
85
Ambient Temperature (℃)
Figure 21: Output current vs. ambient temperature and air
velocity @Vin=48V(Transverse Orientation, with heat spreader)
10
MECHANICAL DRAWING (WITH HEAT SPREADER)
* For modules with through-hole pins and the optional heatspreader, they are intended for wave soldering assembly
onto system boards; please do not subject such modules through reflow temperature profile.
DS_Q48SK12018_01062011
11
MECHANICAL DRAWING (WITHOUT HEAT SPREADER)
Pin No.
1
2
3
4
5
6
Name
Function
+Vin
ON/OFF
Case
-Vin
-Vout
+Vout
Positive input voltage
Remote ON/OFF
Optional
Negative input voltage
Negative output voltage
Positive output voltage
Pin Specification:
Pins 1-4
Pins 5 &6
1.00mm (0.040”) diameter
1.50mm (0.059”) diameter
All pins are copper with Tin plating.
DS_Q48SK12018_01062011
12
PART NUMBERING SYSTEM
Q
48
S
Form
Input
Factor
Voltage
Outputs
Q - Quarter
48-36V~75V
S - Single
K
120
18
N
R
Output
Output
ON/OFF
Pin
Series
Voltage
Current
Logic
Length
K- QB high
120 - 12V
18 - 18A
N - Negative
R - 0.170”
P - Positive
N - 0.146”
Number of Product
Brick
power
series
F
A
Option Code
K - 0.110”
F- RoHS 6/6
A - Std. Functions
(Lead Free)
without case pin
Space- RoHS5/6
H-with heat spreader
and case pin
N- with heat spreader
without case pin
MODEL LIST
MODEL NAME
INPUT
OUTPUT
EFF @ 100% LOAD
Q48SK12018NRFH
36V~75V
9A
12V
18A
94.7%
Q48SK12018NRFA
36V~75V
9A
12V
18A
94.7%
Default remote on/off logic is negative and pin length is 0.170”
For different remote on/off logic and pin length, please refer to part numbering system above or contact your local sales
* For modules with through-hole pins and the optional heatspreader, they are intended for wave soldering assembly
onto system boards; please do not subject such modules through reflow temperature profile.
CONTACT: www.delta.com.tw/dcdc
USA:
Telephone:
East Coast: (888) 335 8201
West Coast: (888) 335 8208
Fax: (978) 656 3964
Email: DCDC@delta-corp.com
Europe:
Phone: +41 31 998 53 11
Fax: +41 31 998 53 53
Email: DCDC@delta-es.com
Asia & the rest of world:
Telephone: +886 3 4526107
ext 6220~6224
Fax: +886 3 4513485
Email: DCDC@delta.com.tw
WARRANTY
Delta offers a two (2) year limited warranty. Complete warranty information is listed on our web site or is available upon
request from Delta.
Information furnished by Delta is believed to be accurate and reliable. However, no responsibility is assumed by Delta for its
use, nor for any infringements of patents or other rights of third parties, which may result from its use. No license is granted
by implication or otherwise under any patent or patent rights of Delta. Delta reserves the right to revise these specifications
at any time, without notice.
DS_Q48SK12018_01062011
13
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