LQN D12 Models
Non-Isolated, Single Output, 12V
in
, 0.8-5V
out
45-50 Amp, ¼-Brick, DC/DC Converters
FEATURES
n
3-phase buck regulators for new
distributed 12V power architectures
n
input (10.2-13.8V range)
12V
n
0.8/1/1.2/1.5/1.8/2/2.5/3.3/5V
out
@ 45-50A
n
Non-isolated, fixed-frequency,
synchronous-rectifier topology
n
¼-brick size, through hole or SMT
n
setpoint accuracy
±1%
n
Efficiencies to 93.5% @ 45 Amps
n
Noise as low as 20mVp-p
n
Stable no-load operation
n
On/Off control, trim & sense functions
n
Output overvoltage protection
n
Over/Undervoltage lockout
Input
n
Thermal shutdown
n
Designed to meet UL/IEC/EN60950-1
n
compliant
EMC
Typical unit
PRODUCT OVERVIEW
The LQN D12 Series of non-isolated quarter bricks
are ideal building blocks for emerging, on-board
power-distribution schemes in which isolated 12V
buses deliver power to any number of non-isolated,
step-down buck regulators. LQN D12 DC/DCs
accept a 12V input (10.2V to 13.8V input range) and
convert it, with the highest efficiency in the smallest
space, to a 0.8, 1, 1.2, 1.5, 1.8, 2, 2.5, 3.3 or 5 Volt
output fully rated at 45-50 Amps.
LQN D12s are ideal POLPPs (point-of-use/load
power processors) and they typically require no ex-
ternal components. They occupy the standard quarter
brick board space (1.45" x 2.3") and come in either
through-hole packages or surface-mount packages
with a profile of only 0.4" (0.5" including heatsink).
The LQNs best-in-class power density is
achieved with a fully synchronous, fixed-frequency,
3-phase buck topology that delivers extremely
high efficiency (95% for 5V
out
models), low noise
(20mVp-p typ.), tight line/load regulation (±0.25%
max.), quick step response (70µsec), stable no-load
operation, and no output reverse conduction.
The fully functional LQN's feature input over/
undervoltage lockout, output overvoltage and
overcurrent detection, continuous short-circuit
protection, overtemperature protection, an output-
voltage trim function, a remote on/off control pin,
and sense pin. High efficiency enables the LQN
D12s to deliver rated output currents of 50 Amps
at high ambient temperatures and minimal
air flow.
If your new system boards call for multiple
supply voltages, check out the economics of
on-board 12V distributed power. If you don't need
to pay for multiple isolation barriers, MPS's non-
isolated LQN D12 brick's will save you money.
Typical topology is shown.
Figure 1. Simplified Schematic
➀
Only one phase of three shown.
For full details go to
www.murata-ps.com/rohs
www.murata-ps.com
Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MDC_LQN D12 Models.B03
Page 1 of 14
LQN D12 Models
Performance Specifications and Ordering Guide
➀
Output
V
out
(Volts)
0.8
1
1.2
1.5
1.8
2
2.5
3.3
5
I
out
(Amps)
50
50
50
50
50
50
45
45
45
R/N (mVp-p)
➁
Typ.
30
30
20
20
20
20
20
30
20
Max.
50
50
50
50
50
50
50
50
40
Regulation (Max.)
➂
Line
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.05%
Load
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.05%
V
in
Nom.
(Volts)
12
12
12
12
12
12
12
12
12
Non-Isolated, Single Output, 12V
in
, 0.8-5V
out
45-50 Amp, ¼-Brick, DC/DC Converters
Input
Range
(Volts)
10.2–3.8
10.2–3.8
10.2–3.8
10.2–3.8
10.2–3.8
10.2–3.8
10.2–3.8
10.2–3.8
10.2–3.8
I
in
➃
(mA/A)
240/3.92
240/4.84
240/5.59
240/6.87
240/8.24
240/9.16
240/10.14
240/13.38
240/20.05
Efficiency
Min.
82%
80%
87%
88.5%
88.5%
88.5%
90%
90%
94%
Typ.
85%
86%
89.5%
91%
91%
91%
92.5%
92.5%
95%
Package
(Case, Pinout)
C41, C42, P62
C41, C42, P62
C41, C42, P62
C41, C42, P62
C41, C42, P62
C41, C42, P62
C41, C42, P62
C41, C42, P62
C41, C42, P62
Models
LQN-0.8/50-D12-C
LQN-1/50-D12-C
LQN-1.2/50-D12-C
LQN-1.5/50-D12-C
LQN-1.8/50-D12-C
LQN-2/50-D12-C
LQN-2.5/45-D12-C
LQN-3.3/45-D12-C
LQN-5/45-D12-C
➀
Typical at T
a
= +25°C under nominal line voltage and full-load conditions, unless
otherwise noted. All models are tested and specified with external 33µF input
capacitor and 470µF poscap output capacitor paralleled with a 100µF ceramic
output capacitor.
➁
Ripple/Noise (R/N) is tested/specified over a 20MHz bandwidth.
➂
These devices have no minimum-load requirements and will regulate under no-
load conditions. Regulation specifications describe the output-voltage deviation as
the line voltage or load is varied from its nominal/midpoint value to either extreme.
MECHANICAL SPECIFICATIONS
0.44*
(11.2)
2.22 (56.4)
A
➃
Nominal line voltage, no-load/full-load conditions.
➄
The operating input voltage is 10.2V to 13.8V. However, 10.8V
in
is required for the
DC/DC to properly start up under all line, load and temperature conditions. The 10.8V
potential must be maintained across the inputs until the output is up and regulating.
After the output is regulating, the operating input range is 10.2V to 13.8V.
➅
Please see part number structure for full part numbers and additional options.
0.44*
(11.2)
2.22 (56.4)
A
PLASTIC STANDOFFS
ARE RELIEVED 0.030 (0.8)
IN SOLDER JOINT AREA
0.180 MIN.
(4.6)
PINS 2-4, 10:
0.040 ±0.001
(1.016 ±0.025)
PINS 1, 5-9:
0.062 ±0.001
(1.575 ±0.025)
COPPER SMT LEADS
COPLANAR TO 0.004
0.025
(0.6)
A
2.30 (58.4)
0.125 TYP.
(3.2)
B
B
1
2
3
4
5
6
1.35 (34.3)
7
8
9
10
1
2
0.110 TYP.
(2.8)
3
4
5
6
8
9
10
1.35 (34.3)
7
BOTTOM VIEW
*0.50 (12.7) WITH THE ADDITION
OF OPTIONAL HEATSINK OR BASEPLATE
0.600 (15.24)
4 EQ. SP. @ 0.150 (3.81)
BOTTOM VIEW
*0.50 (11.2) WITH THE ADDITION
OF OPTIONAL HEATSINK OR BASEPLATE.
0.79 (20.1) WITH HEAT SHIELD.
0.600 (15.24)
4 EQ. SP. @ 0.150 (3.81)
C41 Through-Hole Package
Dimensions are in inches (mm shown for ref. only).
Third Angle Projection
C42 Surface-Mount Package
Pin
1
2
3
4
5
I/O Connections
Function P62
Pin
Input Common
6
V
out
Trim
7
N.C.*
8
Off/On Control
9
+Input
10
Function P62
Output Common
+Output
Output Common
+Output
+Sense In
*A "Power Good" output
is available on pin 3 under
special order.
Contact Murata Power
Solutions.
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25)
Angles ± 2˚
Components are shown for reference only.
See page 12 for LQN Series baseplate, heat sink,
and heat shield mechanical specifications.
www.murata-ps.com
Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MDC_LQN D12 Models.B03
Page 2 of 14
B
B
0.122
(3.1)
2.00 (50.8)
A
LQN D12 Models
Non-Isolated, Single Output, 12V
in
, 0.8-5V
out
45-50 Amp, ¼-Brick, DC/DC Converters
Performance/Functional Specifications
Typical at T
a
= +25°C under nominal input line voltage, nominal output voltage,
natural convection, external caps and full-load conditions unless otherwise noted.
[1]
Input
Line/Load Regulation
[10]
Efficiency
Maximum Capacitive Loading
V
out
Trim Range
Current Limit Inception
(98% of V
OUT
):
1 & 1.8V models
2.5 & 3.3V models
Short Circuit Detection
Short Circuit Protection Method
Short Circuit Current
Short Circuit Duration
Overvoltage Protection
See Ordering Guide
See Ordering Guide
10,000µF (low ESR
≤0.004Ω)
±10% of V
NOMINAL
82A (cold start), 60A (warmed up)
85A (cold start), 70A (warmed up)
See Note 6
Hiccup with autorecovery
See Technical Notes
22 Amps typical, 25 Amps maximum
Continuous, output shorted to ground
120% of V
OUT
Method: comparator feedback
Dynamic Characteristics
Input Voltage Range
Start-Up Threshold
Overvoltage Shutdown
Undervoltage Shutdown
Input Current:
Normal Operating Conditions
Standby Mode (Off, Under Voltage)
Inrush transient
Output Short-Circuit Condition
Low Line Voltage (V
IN
= V
MIN
):
LQN-0.8/50-D12
LQN-1/50-D12
LQN-1.2/50-D12
LQN-1.5/50-D12
LQN-1.8/50-D12
LQN-2/50-D12
LQN-2.5/45-D12
LQN-3.3/45-D12
LQN-5/45-D12
Input Reflected Ripple Current
[2]
Input Filter Type
Overvoltage Protection
Reverse-Polarity Protection
No-load Input Current
Remote On/Off Control
[5]
Remote Control On/Off Current
Remote Sense Input Range
10.2-13.8 Volts (12V nominal)
[13]
9.4-10.8 Volts
14.3 Volts typical
9.5 Volts typical
See Ordering Guide
TBD mA
TBD A
2
sec
350mA
4.56 Amps
5.63 Amps
6.54 Amps
8.04 Amps
9.64 Amps
10.71 Amps
11.86 Amps
15.57 Amps
23.34 Amps
40mAp-p
Capacitive, 88µF
None
See external fuse information
240mA
Off = +2.8V to +V
IN
max.
On = open pin to +2V max.
1mA pulldown
+10% of V
OUT
nominal
Output
Dynamic Load Response
(50% - 75% - 50% load step to ±2% of V
OUT
final value)
All models
70µsec
Start-Up Time
(On/Off or V
IN
on to V
OUT
regulated)
Switching Frequency
Maximum Output Capacitive Load
Calculated MTBF
[4]
10msec for V
OUT
= nominal
690kHz ±30kHz
10,000µF, low ESR, 0.004Ω
TBC Hours
Environmental
Operating Temperature Range:
(Ambient)
[9]
See Derating Curves
–40 to +85°C, with derating
Storage Temperature Range
Thermal Protection/Shutdown
Relative Humidity
Outline Dimensions
Pin Material
[11]
Weight
(no heatsink)
Flammability Rating
Electromagnetic Interference
(conducted or radiated)
Safety
–40 to +125°C
+115°C (PC board)
To +85%/+85°C, non-condensing
Physical
See Mechanical Specifications
Through-hole: Gold-plated copper alloy
Surface mount: Pure tin over nickel-plated
copper alloy
1.1 ounces (31 grams)
UL94V-0
FCC Part 15, EN55022, Class A
UL/cUL 60950-1, CSA-C22.2 No.234
IEC/EN 60950-1
Total Output Power
(V
OUT
x I
OUT
must not exceed maximum power)
[3]
LQN-0.8/50-D12
LQN-1/50-D12
LQN-1.2/50-D12
LQN-1.5/50-D12
LQN-1.8/50-D12
LQN-2/50-D12
LQN-2.5/45-D12
LQN-3.3/45-D12
LQN-5/45-D12
Voltage Output Accuracy:
Initial
Temperature Coefficient
Extreme
[12]
Minimum Loading
[1]
Ripple/Noise
(20 MHz bandwidth)
[8]
40 Watts
50 Watts
60 Watts
75 Watts
90 Watts
100 Watts
112.5 Watts
148.5 Watts
225 Watts
±1% of V
NOMINAL
±0.02% of V
OUT
per
°C
±3% of V
NOMINAL
No minimum load
See Ordering Guide
www.murata-ps.com
Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MDC_LQN D12 Models.B03
Page 3 of 14
LQN D12 Models
Non-Isolated, Single Output, 12V
in
, 0.8-5V
out
45-50 Amp, ¼-Brick, DC/DC Converters
NOTES
1] All models are tested and specified with an external 33µF tantalum input capaci-
tor, 470µF Poscap output cap paralled with a 100µF ceramic output capacitor.
These capacitors are necessary to accommodate our test equipment and may
not be required to achieve specified performance in your applications. All models
are stable and regulate within spec under no-load conditions.
[2] Input Ripple Current is tested and specified over a 5-20MHz bandwidth. Input
filtering is C
in
= 200µF tantalum (100 || 100), C
bus
= 1000µF electrolytic,
L
bus
= 1µH.
[3] Note that Maximum Power Derating curves indicate an
average
current at
nominal input voltage. At higher temperatures and/or lower airflow, the DC/DC
converter will tolerate shorter full current outputs if the total RMS current over
time does not exceed the Derating curve.
[4] Mean Time Before Failure is calculated using the Telcordia (Belcore) SR-332
Method 1, Case 3, ground fixed conditions, TPCBOARD = +25°C, full output
load, natural air convection.
[5] The On/Off Control (pin 4) may be driven with external logic or by applying
appropriate external voltages which are referenced to Common, pin 1. The
On/Off Control Input should use either an open collector/open drain transistor
or logic gate which does not exceed +V
in
.
The On/Off Control may be supplied with positive logic (LO = off, HI = on) under
special quantity order.
[6] Short circuit shutdown begins when the output voltage degrades approximately
2% from the selected setting.
[7] The outputs are not intended to sink appreciable reverse current. If the outputs
are forced to sink excessive current, damage may result.
[8] Output noise may be further reduced by adding an external filter. See I/O Filtering
and Noise Reduction.
[9] All models are fully operational and meet published specifications, including
“cold start” at –40°C.
[10] Regulation specifications describe the deviation as the line input voltage or
output load current is varied from a nominal midpoint value to either extreme.
[11] Alternate pin length and/or other output voltages available under special quantity
order.
[12] Extreme accuracy refers to all combinations of trim adjustment, temperature,
airflow and load current.
[13] See Performance Specifications note 5.
[14] Output Capacitive Loading
Exceeding the maximum output capacitive load specification (at the indicated
ESR) may interfere with the Soft Start mode and possibly cause overcurrent shut-
down at startup while attempting to charge output caps. This risk increases with
combinations of high output capacitance and low Equivalent Series Resistance
(ESR) inside the capacitors, especially newer ceramic caps. Use just enough
output capacitance to achieve your noise suppression or energy storage needs
and no more. Thoroughly test your application with all components installed.
Be cautious when using the On/Off control in conjunction with high output capaci-
tance. If the output capacitors are not allowed to bleed down their voltage suf-
ficiently after shutdown, certain converters may be damaged by lingering output
voltage applied as reverse current into the outputs. Most converters include a
warning to strictly limit the amount of current sourced back into the converter.
[15]
Always
connect the sense pins. If they are not connected to a remote load, wire
each sense pin to its respective voltage output at the converter pins.
PART NUMBER STRUCTURE
Model options
L QN
-
1.8
/
50
-
D12 M B
-
C
Output
Configuration:
L
= Unipolar
Low Voltage
Non-Isolated Quarter Brick
Nominal Output Voltage:
0.8, 1, 1.2, 1.5, 1.8,
2, 2.5, 3.3 or 5 Volts
Maximum Rated Output
Current in Amps
*
Contact Murata Power Solutions for availability.
RoHS-6 hazardous
substance compliant*
Heat Transfer:
Blank =
No heatsink
or baseplate, standard
B =
Baseplate installed,
optional
H =
Heatsink installed,
optional
Mounting Method:
Blank
= Through-hole package,
standard
M =
Surface-mount package,
optional
Input Voltage Range:
D12
= 10.2 to 13.8 Volts
(12V nominal)
Note:
Some model number combinations may not be
available. Contact Murata Power Solutions (Datel).
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Continuous or Transient
On/Off Control
(pin 4)
Input Reverse Polarity Protection
Output Overvoltage Protection
Output Current
.
Storage Temperature
Lead Temperature
(soldering 10 sec. max.)
15.5 Volts maximum
+V
IN
maximum
See Fuse section
V
OUT
+20% maximum
Current-limited (See note 7)
Devices can withstand sustained
short circuit without damage.
–55 to +125°C.
+300°C. Refer to solder profile.
Absolute maximums are stress ratings. Exposure of devices to any of these conditions may
adversely affect long-term reliability. Proper operation under conditions other than those
listed in the Performance/Functional Specifications Table is not implied nor recommended.
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Technical enquiries
email: sales@murata-ps.com, tel:
+1 508 339 3000
MDC_LQN D12 Models.B03
Page 4 of 14
LQN D12 Models
Non-Isolated, Single Output, 12V
in
, 0.8-5V
out
45-50 Amp, ¼-Brick, DC/DC Converters
TECHNICAL NOTES
Input Fusing
Certain applications and/or safety agencies may require the installation of
fuses at the inputs of power conversion components. Fuses should also be
used if the possibility of sustained, non-current-limited, input-voltage polarity
reversals exists. For MPS LQN series DC/DC converters, we recommend the
use of a time delay fuse, installed in the ungrounded input supply line, with a
value no greater than the following:
Model
Fuse Value
LQN-1/50-D12
12.5 Amps
LQN-1.8/50-D12
15 Amps
LQN-2.5/45-D12
25 Amps
LQN-3.3/45-D12
30 Amps
As a rule of thumb however, we recommend the use of a normal-blow or
slow-blow fuse with a typical value about twice the maximum input current,
calculated at low line with the converter's minimum efficiency.
All relevant national and international safety standards and regulations must
be observed by the installer. For system safety agency approvals, the convert-
ers must be installed in compliance with the requirements of the end-use
safety standard, i.e. IEC/EN/UL60950-1.
Input Reverse-Polarity Protection
If the input voltage polarity is accidentally reversed, an internal diode will
become forward biased and likely draw excessive current from the power
source. If this source is not current limited or the circuit appropiately fused, it
could cause permanent damage to the converter.
Start-Up Time
The V
IN
to V
OUT
Start-Up Time is the time interval between the point at which
the ramping input voltage crosses the Start-Up Threshold and the fully loaded
output voltage enters and remains within its specified accuracy band. Actual
measured times will vary with input source impedance, external input capaci-
tance, and the slew rate and final value of the input voltage as it appears at the
converter. The LQN Series implements a soft start circuit to limit the duty cycle
of its PWM controller at power up, thereby limiting the input inrush current.
The On/Off Control to V
OUT
start-up time assumes the converter has its
nominal input voltage applied but is turned off via the On/Off Control pin. The
specification defines the interval between the point at which the converter is
turned on (released) and the fully loaded output voltage enters and remains
within its specified accuracy band.
Similar to the V
IN
to V
OUT
start-up, the On/Off Control to V
OUT
start-up time is
also governed by the internal soft start circuitry and external load capacitance.
The difference in start up time from V
IN
to V
OUT
and from On/Off Control to V
OUT
is therefore insignificant.
Input Undervoltage Shutdown and Start-Up Threshold
Under normal start-up conditions, devices will not begin to regulate properly
until the ramping-up input voltage exceeds the Start-Up Threshold Voltage.
Once operating, devices will not turn off until the input voltage drops below the
Undervoltage Shutdown limit. Subsequent re-start will not occur until the input
is brought back up to the Start-Up Threshold. This built in hysteresis prevents
any unstable on/off situations from occurring at a single input voltage.
Input Overvoltage Shutdown
All LQN DC/DC's are equipped with input overvoltage protection. Input voltages
exceeding the input overvoltage shutdown specification listed in the Perfor-
mance/Functional Specifications will cause the device to shut down. A built-in
hysterisis for all models will not allow the converter to restart until the input
voltage is sufficiently reduced.
Input Source Impedance
The input of LQN converters must be driven from a low ac-impedance source.
The DC/DC's performance and stability can be compromised by the use of
highly inductive source impedances. The input circuit shown in Figure 2 is a
practical solution that can be used to minimize the effects of inductance in the
input traces. For optimum performance, components should be mounted close
to the DC/DC converter.
I/O Filtering, Input Ripple Current, and Output Noise
All LQN Series models are tested/specified for input reflected ripple current and
output noise using the specified external input/output components/circuits and
layout as shown in the following two figures. External input capacitors (C
IN
in
Figure 2) serve primarily as energy-storage elements, minimizing line voltage
variations caused by transient IR drops in conductors from backplane to the
DC/DC. Input caps should be selected for bulk capacitance (at appropriate
frequencies), low ESR, and high rms-ripple-current ratings.
Figure 2. Measuring Input Ripple Current
The switching nature of DC/DC converters requires that dc voltage sources
have low ac impedance as highly inductive source impedance can affect
system stability. In Figure 2, C
BUS
and L
BUS
simulate a typical dc voltage bus.
Your specific system configuration may necessitate additional considerations.
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Technical enquiries
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+1 508 339 3000
MDC_LQN D12 Models.B03
Page 5 of 14
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