PRELIMINARY
®
®
INNOVATION and EXCELLENCE
Single Output
LQN D12 Models
Non Isolated, 12V
IN
, 0.8-5V
OUT
45-50 Amp, ¼-Brick DC/DC Converters
Features
■
3-phase buck regulators for new
distributed 12V power architectures
12V input (10.2-13.8V range)
0.8/1/1.2/1.5/1.8/2/2.5/3.3/5V
OUT
@ 45-50A
Non-isolated, fixed-frequency,
synchronous-rectifier topology
¼-brick size, through hole or SMT
Current share/N+1 redundancy
±1% setpoint accuracy
Efficiencies to 94% @ 45 Amps
Noise as low as 20mVp-p
Stable no-load operation
On/Off control, trim & sense functions
Output Overvoltage Protection
Input Over/Undervoltage lockout
Thermal shutdown
Designed to meet UL/EN/IEC60950
EMC compliant
■
■
■
■
■
■
■
■
■
■
■
■
■
■
■
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/DC's
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 D12's are ideal POLPP's (point-of-use/load power processors) and they
typically require no external 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 LQN's 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 over-
voltage and overcurrent detection, continuous short-circuit protection, overtempera-
ture protection, an output-voltage trim function, a remote on/off control pin, a sense
pin and a current share function (optional). High efficiency enables the LQN D12's to
deliver rated output currents of 50 Amps at high ambient temperatures and minimal
air flow½.
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, DATEL's non-isolated LQN D12 brick's will save you money.
½½½½½½
½½½
½½½½½½½
½½½½½
➀
½½½½½½
½½½½
½½½½½
½½½½½½
½½½
½½½½½½½½
½½½½½
½
½½
½½½½½½
½½½½½½½
½½½
½½½½½½
½½½½½½
½½½½½½
½½½½½½½
½½½
½½½½½½½½½½
½½½½½½½½½½½
½½½½½½½½½
½
½½½
½½½½
½½½
➀
Only one phase of three shown.
Figure 1. Simplified Schematic
DATEL, Inc., Mansfield, MA 02048 (USA) · Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 · Email: sales@datel.com · Internet: www.datel.com
LXN D12 Series
N O N - I S O L AT E D , 4 5 - 5 0 A Q UA R T E R B R I C K , D C / D C C O N V E R T E R S
Performance Specifications and Ordering Guide
Output
Model
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
➀
Input
Regulation (Max.)
➂
Line
Load
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
±0.25%
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.
Max.
30
30
30
20
20
20
20
30
30
50
50
50
50
50
50
50
50
50
V
IN
Nom. Range
➄
(Volts)
(Volts)
12
12
12
12
12
12
12
12
12
10.2-13.8
10.2-13.8
10.2-13.8
10.2-13.8
10.2-13.8
10.2-13.8
10.2-13.8
10.2-13.8
10.2-13.8
I
IN
➃
(mA/A)
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
TBD
Efficiency
Full Load
½ Load
Min.
TBD%
TBD%
TBD%
TBD%
TBD%
TBD%
TBD%
TBD%
TBD%
Typ.
83%
85%
87%
88%
89.5%
90%
91.5%
93%
95%
Typ.
83%
86%
87.5%
88%
89.5%
90%
92%
93.5%
95.5%
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
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.
➃
Nominal line voltage, no-load/full-load conditions.
➄
The operating input voltage is 10.2V to 13.8V. However, under full load the startup voltage must
be 10.8V minimum for reliable startup. Once running, the operating voltage may decay to 10.2V.
See page 9 for Part Number Structure.
M E C H A N I C A L
S P E C I F I C A T I O N S
½½½½½
½½½½½½½
½½½½½½½½½½½½
½
½½½½½
½½½½½½½
½½½½½½½½½½½½
½
½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½
½½½½½½
½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½
½½½½½
½½½½½½
½½½½½½½½½½½½
½½½½½½½½½½
½½½½½½
½
½
½
½
½
½
½
½
½½½½½½½½½½½½
½
½
½
½
½
½
½
½
½
½
½½
½
½½½½½½½½½½
½½½½½½
½
½
½
½½
½½½½½½½½½½½
½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½
½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
C41 Through-Hole Package
I/O Connections
Function P62
Pin
Function P62
Input Common
6
Output Common
V
OUT
Trim
7
+Output
N.C.*
8
Output Common
On/Off Control
9
+Output
+Input
10
+Sense In
C42 Surface-Mount Package
Pin
1
2
3
4
5
* A "Power Good" output is available
on pin 3 under special order.
Contact DATEL.
2
½½½½½½½½½½½½
½
½½½½½
½½½½½½
½½½½½½½½½½½½
½
N O N - I S O L AT E D , 4 5 - 5 0 A Q UA R T E R B R I C K , D C / D C C O N V E R T E R S
LQN D12 Models
Performance/Functional Specifications
Input
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-1/50-D12
LQN-1.8/50-D12
LQN-2.5/45-D12
LQN-3.3/45-D12
Input Reflected Ripple Current
[2]
Input Filter Type
Overvoltage Protection
Reverse-Polarity Protection
No-load Input Current
Remote On/Off Control
[5]
Positive Logic
Remote Control On/Off Current
Remote Sense Input Range
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]
Dynamic Characteristics
Dynamic Load Response
(50% - 75% - 50% load step to ±2% of V
OUT
final value)
LQN-1/50-D12
70µsec
LQN-1.8/50-D12
70µsec
LQN-2.5/45-D12
50µsec
LQN-3.3/45-D12
80µsec
Start-Up Time
(On/Off or V
IN
on to V
OUT
regulated)
Switching Frequency
Calculated MTBF
[4]
10msec for V
OUT
= nominal
690 kHz ±30kHz
10.2-13.8 Volts (12V nominal)
[13]
9.7 Volts typical
14.3 Volts typical
9.5 Volts typical
See Ordering Guide
TBD mA
TBD A
2
sec
350mA
5.63 Amps
9.64 Amps
11.26 Amps
15.57 Amps
40mAp-p
Capacitive, 88µF
None
See external fuse information
240mA
Off = ground pin to +0.4 V max.
On = open pin to +V
IN
max.
1mA pulldown
+10% of V
OUT
nominal
Environmental
TBC Hours
Operating Temperature Range
(Ambient)
[9]
No derating, natural convection,
–40 to +TBD °C
With derating
See Derating Curves
Storage Temperature Range
Thermal Protection/Shutdown
Density Altitude
Relative Humidity
Outline Dimensions
Pin Material
[11]
(through-hole models)
Weight
(no heatsink)
Flammability Rating
Electromagnetic Interference
(conducted or radiated)
Safety
–40 to +125 °C
+115°C (PC board)
0 to 10,000 feet
0% to 90%, non-condensing
Physical
See Mechanical Specifications
Round copper with tin-lead solder
plate over nickel underplate
0.6 ounces (17 grams)
UL94V-0
FCC Part 15, EN55022, Class A
UL/cUL 60950, CSA-C22.2 No.234
IEC/EN 60950
Output
Total Output Power
(V
OUT
x I
OUT
must not exceed maximum power)
[3]
LQN-1/50-D12
50.75 Watts
LQN-1.8/50-D12
91.35 Watts
LQN-2.5/45-D12
112.5 Watts
LQN-3.3/45-D12
150 Watts
Voltage Output Accuracy
[11]
Initial
Temperature Coefficient
Extreme
[12]
Minimum Loading
[1]
Ripple/Noise
(20 MHz bandwidth)
[8]
Line/Load Regulation
[10]
Efficiency
Maximum Capacitive Loading
Vout 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
LQN-1/50-D12
LQN-1.8/50-D12
LQN-2.5/45-D12
LQN-3.3/45-D12
Short Circuit Duration
Overvoltage Protection
±1% of V
NOMINAL
±0.02% of V
OUT
per
°C
±3% of V
NOMINAL
No minimum load
See Ordering Guide
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
TBD Amps
TBD Amps
TBD Amps
22 Amps
Continuous, output shorted to ground
120% of V
OUT
Method: comparator feedback
1] All models are tested and specified with an external 33µF tantalum input capacitor,
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 filter-
ing 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, T
PCBOARD
= +25°C, full output load, natural air
convection.
[5] The On/Off Control (pin 4) may be driven with external logic or by applying appropri-
ate 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.
3
LXN D12 Series
N O N - I S O L AT E D , 4 5 - 5 0 A Q UA R T E R B R I C K , D C / D C C O N V E R T E R S
Absolute Maximum Ratings
Input Voltage
Continuous
Transient (100 mSec. Max.)
On/Off Control
(pin 4)
Input Reverse Polarity Protection
Output Overvoltage Protection
Output Current
13.8 Volts maximum
15 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.
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 capaci-
tance. 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
Performance/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 induc-
tance 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/cir-
cuits and layout as shown in the following two figures. External input capaci-
tors (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.
Storage Temperature
Lead Temperature
(soldering 10 sec. max.)
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.
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 DATEL 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 con-
verters must be installed in compliance with the requirements of the end-use
safety standard, i.e. IEC/EN/UL60950.
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.
½½½
½½½½½½½½½½½½
½½½½½½½
½½½½½
½
½½½
½
½½½½½½
½
½
½½
½
½
½½½
½
½½
½
½½½½½½
½
½½
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
½
½½½
½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½½
½
½½½
½½½½½½
Figure 2. Measuring Input Ripple Current
4
N O N - I S O L AT E D , 4 5 - 5 0 A Q UA R T E R B R I C K , D C / D C C O N V E R T E R S
LQN D12 Models
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.
Minimum Output Loading Requirements
LQN converters employ a synchronous-rectifier design topology and all
models regulate within spec and are stable under no-load to full load condi-
tions. Operation under no-load conditions however might slightly increase the
output ripple and noise.
Thermal Shutdown
The LQN converters are equipped with thermal-shutdown circuitry. If envi-
ronmental conditions cause the temperature of the DC/DC converter to rise
above the designed operating temperature, a precision temperature sensor
will power down the unit. When the internal temperature decreases below the
threshold of the temperature sensor, the unit will self start. See Performance/
Functional Specifications.
Output Overvoltage Protection
The LQN output voltage is monitored for an overvoltage condition using a
comparator. The signal is optically coupled to the primary side and if the
output voltage rises to a level which could be damaging to the load, the sens-
ing circuitry will power down the PWM controller causing the output voltage
to decrease. Following a time-out period the PWM will restart, causing the
output voltage to ramp to its appropriate value. If the fault condition persists,
and the output voltage again climbs to excessive levels, the overvoltage
circuitry will initiate another shutdown cycle. This on/off cycling is referred to
as "hiccup" mode.
The LQN Series will withstand higher external sources several volts above
the nominal output. However, if there is a chance of consistent overvoltage,
users should provide an external voltage clamp or other protection.
Output Overcurrent Detection
Overloading the power converter's output for an extended time will invariably
cause internal component temperatures to exceed their maximum ratings
and eventually lead to component failure. High-current-carrying components
such as inductors, FET's and diodes are at the highest risk. LQN Series
DC/DC converters incorporate an output overcurrent detection and shutdown
function that serves to protect both the power converter and its load.
If the output current exceeds it maximum rating by typically 40% or if the
output voltage drops to less than 98% of it original value, the LQN's internal
overcurrent-detection circuitry immediately turns off the converter, which then
goes into a "hiccup" mode. While hiccupping, the converter will continuously
attempt to restart itself, go into overcurrent, and then shut down. Under these
conditions, both the average output current and the average input current will
be kept extremely low. Once the output short is removed, the converter will
automatically restart itself.
Output Voltage Trimming
Allowable trim ranges are ±10%. Trimming is accomplished with either a
trimpot or a single fixed resistor. The trimpot should be connected between
+Output and Common with its wiper connected to the Trim pin as shown in
Figure 3 below.
A trimpot can be used to determine the value of a single fixed resistor
which can then be connected, as shown in Figure 4, between the Trim pin
and +Output to trim down the output voltage, or between the Trim pin and
Common to trim up the output voltage. Fixed resistors should have absolute
TCR’s less than 100ppm/°C to ensure stability.
The equations below can be used as starting points for selecting specific trim-
resistor values. Recall, untrimmed devices are guaranteed to be
±1%
accurate.
Adjustment beyond the specified adjustment range is not recommended. If trim
is not desired, leave the Trim pin open.
½½½½½½½
½½½½½½
½½½½
½½½½½½
½½½½½½
½½½½
½½½½
½½½½½
½½½½
Figure 3. Trim Connections Using a Trimpot
½½½½½½½
½½½½½½
½½½½
½½½½½½
½½½½½½
½½½½½ ½
½½
½½½½ ½
½½½½
½½½½
Note:
Install either a fixed
trim-up resistor
or a fixed trim-down
resistor depending upon
desired output voltage.
Figure 4. Trim Connections Using Fixed Resistors
Trim Equations
½
½½½½½½½½½½½½
½½½½½½
½½½½
½½½½½½
½½
½½½½½½½
½
½½½½½
½½½½
½
½½½
½½½
½½½
½
½½½½½½½
½½½½½½
½½
½
½½
½½½
½½½½½
½½½½½½½½½½½½½½½
½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½
½½½½½½½½
½
½½½½½½½½½½½½
½½½½½½
½½½½
½½½½½
½½
½½½½½½½
½
½½½½½
½½½½
½
½½
½½½
½½½
½
½½½½½½½
½½½½½½
½½
½
½½
½½½
½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½½½½½½½½½½½
½½½½½½½½½½½½½½½
½½½½½½½½
Note: LQN-0.8/50-D12 is not trimmable.
Note: Resistor values are in kΩ. Accuracy of adjustment is subject to
tolerances of resistors and factory-adjusted, initial output accuracy.
V
O
= desired output voltage. V
ONOM
= nominal output voltage.
5
Microcontroller MCU
京公网安备 11010802033920号
EEWORLD
