ETC 48D12.1700XT

40 Watt XT Dual Series DC/DC Converters
Features
!
Fully Shielded/Filtered Design
!
Lowest Noise Outputs, 70 mV P-P
!
Very Low and Specified Reflected Ripple Current
!
Very Low I/O Capacitance, 500 pF Typical
!
Water Washable Shielded Copper Case
!
5 Year Warranty
Description
Selection Chart
These dual output converters are designed for ultra wide input
range low noise telecommunications, industrial, and instrument
applications. The very wide input range (4:1) is ideal for
battery or unregulated input applications while the low noise
complements even the most sensitive analog circuitry.
Model
These converters are state of the art 220 kHz MOSFET
based designs that provide outstanding regulation and
conversion efficiencies of over 85%.
Remote ON/OFF and output voltage trim functions are also
included.
Input Range
VDC
Output
Min
Max
VDC
mA
24D5.3000XT
9
36
±5
±3000
Power
W
30
24D12.1500XT
9
36
±12
±1500
36
24D15.1200XT
9
36
±15
±1200
36
48D5.3500XT
20
72
±5
±3500
35
48D12.1700XT
20
72
±12
±1700
41
48D15.1300XT
20
72
±15
±1300
39
The converters are protected from output shorts to common
by a high speed pulse by pulse digital current limit circuit and
a self resetting thermal overload protection circuit.
As with all CALEX converters the 40 Watt XT Dual series
is covered by our 5 Year Warranty.
40 Watt XT Dual Series Block Diagram
A
2401 Stanwell Drive • Concord, California 94520 • Ph: 925/687-4411 or 800/542-3355 • Fax: 925/687-3333 • www.calex.com • Email: [email protected]
1
3/2001
40 Watt XT Dual Series DC/DC Converters
Input Parameters*
Model
24D5.3000XT
Voltage Range
Input Current Full Load
No Load
Efficiency
Reflected Ripple (1)
Switching Frequency
Maximum Input
Overvoltage,
100ms Maximum
Turn-on Time,
1% Output Error
Recommended Fuse
MIN
MAX
TYP
TYP
TYP
TYP
TYP
1550
15
81
80
8.5
24D12.1500XT 24D15.1200XT
9
36
1820
20
82
50
10
1835
20
82
50
10
TYP
885
15
82
40
6.5
48D12.1700XT 48D15.1300XT
20
72
1010
15
85
55
7.0
80
30
mA
%
mA P-P
mA RMS
kHz
45
40
Units
VDC
960
15
85
55
7.0
220
MAX
TYP
48D5.3500XT
30
40
VDC
30
30
(2)
ms
AMPS
Output Parameters*
Model
24D5.3000XT
Output Voltage
24D12.1500XT 24D15.1200XT
48D5.3500XT
48D12.1700XT 48D15.1300XT
Units
±5
±12
±15
±5
±12
±15
MIN
TYP
MAX
MIN
MAX
4.950
5.000
5.050
0
±3000
11.900
12.000
12.100
0
±1500
14.900
15.000
15.100
0
±1200
4.950
5.000
5.050
0
±3500
11.900
12.000
12.100
0
±1700
14.900
15.000
15.100
0
±1300
TYP
MAX
0.4
1.0
0.1
0.5
Cross Regulation (5)
TYP
2.5
0.8
Line Regulation
Vin = Min-Max VDC
TYP
MAX
0.1
0.2
%
%/24Hrs
Output Voltage Accuracy
Rated Load Range (3)
Load Regulation:
25% Max Load to
Max Load (4)
Short Term Stability (6)
TYP
< 0.05
Long Term Stability
TYP
< 0.1
Noise, Peak - Peak (1)
RMS Noise
TYP
TYP
TYP
MAX
Temperature Coefficient
130
40
70
15
Short Circuit Protection
70
30
(1)
(2)
(3)
(4)
(5)
(6)
VDC
mA
0.4
1.0
0.1
0.5
%
2.5
0.8
%
%/kHrs
120
35
130
35
50
250
100
30
mV P-P
mV RMS
ppm/°C
Output to Common and Thermal Protection
NOTES
*
VDC
All parameters measured at Tc = 25°C, nominal input voltage
and full rated load unless otherwise noted. Refer to the
CALEX Application Notes for the definition of terms,
measurement circuits and other information.
Noise is measured per CALEX application notes. Measurement
bandwidth is 0-20 MHz. RMS noise is measured over a 0.01-1
MHz bandwidth. To simulate standard PCB decoupling practices,
output noise is measured with a 10µf, tantalum and 0.01µF,
ceramic capacitor located 1 inch away from the converter. Input
ripple is measured into a 10µH source impedance.
See our application note for picking the correct fuse size.
The converter may be safely operated at any load from zero to
the full rating. Dynamic response of the converter will degrade
if the converter is operated with less than 25% output load.
Load regulation is defined for loading/unloading both outputs
simultaneously. Load range is 25 to 100%.
Cross regulation is defined for loading/unloading one output
while the other output is kept at full load. Load range is
25 to 100%.
Short term stability is specified after a 30 minute warmup
at full load, constant line and recording the drift over a 24
hour period.
(7)
(8)
A
Case is tied to the CMN output pin.
The functional temperature range is intended to give an additional
data point for use in evaluating this power supply. At the
low functional temperature the power supply will function with
no side effects, however sustained operation at the high
functional temperature may reduce the expected operational
life. The data sheet specifications are not guaranteed over
the functional temperature range.
(9) The case thermal impedance is specified as the case temperature
rise over ambient per package watt dissipated.
(10) Specifications subject to change without notice.
2401 Stanwell Drive • Concord, California 94520 • Ph: 925/687-4411 or 800/542-3355 • Fax: 925/687-3333 • www.calex.com • Email: [email protected]
2
3/2001
40 Watt XT Dual Series DC/DC Converters
General Specifications*
All Models
ON/OFF Function
ON Logic Level
or Leave Pin Open
OFF Logic Level
or Tie Pin to -Input
Open Circuit Voltage
Input Resistance
Converter Idle Current
ON/OFF Pin Low
Isolation (7)
Isolation Voltage
Input to Output, 24D
Input to Output, 48D
10µA Leakage
Input to Output
Capacitance
Output Trim Function
Trim Range
Input Resistance
Units
MIN
4
VDC
MAX
1.0
VDC
TYP
TYP
5
6
VDC
kohms
TYP
7
mA
MIN
MIN
700
1544
VDC
TYP
500
pF
MIN
MIN
±10
10
%
kohms
MIN
MAX
MIN
MAX
MIN
MAX
-40
85
-55
90
-55
105
°C
TYP
100
°C
TYP
TYP
4.4
7
°C/Watt
oz
BOTTOM VIEW
SIDE VIEW
Mechanical tolerances unless otherwise noted:
X.XX dimensions: ±0.020 inches
X.XXX dimensions: ±0.005 inches
Environmental
Case Operating Range
Case Functional Range (8)
Storage Range
Thermal Shutdown
Case Temperature
Thermal Impedance (9)
Unit Weight
°C
Pin
1
2
3
4
5
6
8
°C
Function
+INPUT
-INPUT
+OUTPUT
CMN
-OUTPUT
TRIM
ON/OFF
Mounting Options
Chassis Mounting Kit
-I Suffix on Part Number
-HS Suffix on Part Number
MS9
Inserts In Case
Heat Sink Option
Applications Information
Noise has also achieved new lows in this design, while the
industry standard is to specify output noise as 1 to 5% peak
to peak typical with no mention of measurement bandwidth.
The XT converters are fully specified and tested to a wide
bandwidth of 0-20 MHz.
You truly get what you pay for in a CALEX converter, a
complete system oriented and specified DC/DC converter no surprises, no external noise filtering circuits needed, no
heatsinking problems, just “plug and play”.
A
Input filtering reduces reflected ripple noise and is similarly
low and also fully specified for typical values (exact value
depends on input voltage range). Typical RMS noise over a 10
kHz to 1 MHz bandwidth is specified for both the input and
output.
The 40 Watt XT Dual series like all CALEX converters
carries the full 5 year CALEX no hassle warranty. We can offer
a five year warranty where others can’t because with CALEX
it’s rarely needed.
Keep reading, you’ll find out why.
Full overload protection is provided by independent pulseby-pulse current limiting and an over-temperature shutdown
circuit. These protection features assure you that our XT Dual
will provide you with zero failure rate operation.
General Information
The XT Dual series is mindful of battery operation for industrial,
medical control and remote data collection applications. The
remote ON/OFF pin places the converter in a very low power
mode that draws typically less than 10 mA from the input
source.
Five sided shielding is standard along with specified
operation over the full industrial temperature range of -40 to
+85°C case temperature.
2401 Stanwell Drive • Concord, California 94520 • Ph: 925/687-4411 or 800/542-3355 • Fax: 925/687-3333 • www.calex.com • Email: [email protected]
3
3/2001
40 Watt XT Dual Series DC/DC Converters
Applying The Input
Remote ON/OFF Pin Operation
Figure 1 shows the recommended input connections for the
XT Dual DC/DC converter. A fuse is recommended to protect
the input circuit and should not be omitted. The fuse serves to
prevent unlimited current from flowing in the case of a
catastrophic system failure.
The remote ON/OFF pin may be left floating if this function is
not used. The equivalent input circuit for the ON/OFF pin is
shown in figure 3. The best way to drive this pin is with an open
collector/drain or relay contact. See our application note titled
“Understanding the remote ON/OFF function” for more
information about using the remote ON/OFF pin.
No external capacitance on the input is required for normal
operation, in fact it can degrade the converters performance.
Normal RF bypass capacitors in the 1000 pF to 0.01µF range
may be used without harm.
When the ON/OFF pin is pulled low with respect to the Input, the converter is placed in a low power drain state. The
ON/OFF pin turns the converter off while keeping the input
bulk capacitor fully charged, this prevents the large inrush
current spike that occurs when the +input pin is opened and
closed.
Figure 1.
Standard connections for the XT Dual. The ON/OFF and TRIM pins
may be left floating if they are not used. The input protection fuse
should not be omitted. If desired, external transient protection
diodes can be used. See the text below for suggestions regarding
input and output capacitance. The load may also be operated in
“Single ended” mode as shown.
Figure 3.
The simplified schematic of the XT Dual series ON/OFF pin. The
input impedance is approximately 6 k ohms. By leaving this pin
floating the converter will be in the ON state. When the pin is pulled
below 1.0 volts (with respect to the -Input pin) the converter is placed
in the power down or OFF state. See our application note on the
remote ON/OFF function for more information.
Ultra Low Noise Input Circuit
The circuit shown in figure 2 can be used to reduce the input
noise to below 20 mA p-p over a 20 MHz bandwidth. It is
important to size inductor L1 appropriately for the maximum
expected load current and input voltage. Capacitor C1 should
be the moderate ESR type specified. The use of a very low
ESR capacitor should be avoided as this will make a high-Q
filter when we really want a low-Q, controlled cutoff filter.
Applying The Output
Figure 1 shows typical output connections for the XT Dual. In
most applications no external output capacitance will be
necessary. Only your normal 1 to 10 µF and 0.001 to 0.1 µF
bypass capacitors sprinkled around your circuit as needed
locally are required. Do not add extra output capacitance and
cost to your circuit “Just Because”.
A
If you feel you must add external output capacitance, do
not use the lowest ESR, biggest value capacitor that you can
find! This can only lead to reduced system performance or
oscillation. See our application note “Understanding Output
Impedance For Optimum Decoupling” for more information or
use the ultra low noise output circuit below.
Output Trimming
The trim pin may be used to adjust the outputs from the
nominal factory setting. The trim may be used to adjust for
system wiring voltage drops. Figure 4 shows the proper
connections to use the trim pin. If output trimming is not
desired the trim pin may be safely left floating.
Figure 2.
This circuit may be used to reduce the input reflected ripple to less
than 20 mA p-p. Capacitor C1 should be the moderate ESR type
shown to prevent input filter response peaking. Size the current
carrying capability of L1 for the maximum expected load and
minimum input operating voltage.
Trimming the output up reduces the output current
proportionally to keep the maximum power constant. Output
current is not increased over the listed maximum when
trimming the output voltage down.
2401 Stanwell Drive • Concord, California 94520 • Ph: 925/687-4411 or 800/542-3355 • Fax: 925/687-3333 • www.calex.com • Email: [email protected]
4
3/2001
40 Watt XT Dual Series DC/DC Converters
Operation With Very Light Loads
Down trim can actually reduce the minimum input voltage in
some circuits. Full up trim may not be achievable at minimum
input voltage and full rated load.
The dynamic response of the XT Dual will degrade when the
unit is operated with less than about 25% of full rated power.
Grounding
The input and output sections are fully floating from each
other. They may be operated fully floating or with a common
ground. If the input and output sections are connected either
directly at the converter or at some remote location from the
converter it is suggested that a 3.3 to 10 µF, 0.5 to 5 Ohm ESR
capacitor bypass be used directly at the converter output pins.
This capacitor prevents any common mode switching currents
from showing up at the converters output as normal mode
output noise. See “Applying the Output” for more information.
Another “Trick” that can be used when operating with a
common ground is to use a 10 to 100 µH choke between the
grounds. This gives you a solid low frequency ground
connection, but looks like a high impedance to the switching
current effects and prevents them from flowing in the
connection. This will have the effect of preventing the common
mode currents from showing up as normal mode components
in your input or output circuits.
FIGURE 4.
The output can be trimmed by either a trimpot or fixed resistors. If
fixed resistors are used their values may range from 0 to infinite
ohms. The trimpot should be typically 20 k ohms.
Non Standard Output Voltages
The XT Duals will typically trim much lower than the -10%
specified. This allows the XT’s to be trimmed lower than
specified for RF or other special applications.
Be sure that the inductor has a self resonant frequency of
greater than 200 kHz and that the Q of the inductor is quite low.
If necessary to keep the inductor Q under control, parallel it
with a 200 to 1 k ohm resistor.
The 5 volt XT’s can be typically trimmed over a range of 3.9
to 5.6 volts. The 12 volt XT’s can be typically trimmed over a
range of 6.4 to 13.3 volts. The 15 volt XT’s can be typically
trimmed over a range of 6.7 to 16.9 volts.
Case Grounding
The copper case serves not only as a heat sink but also as a
EMI shield. The 0.25 inch thick case provides >30 dB of
absorption loss to both electric and magnetic fields at 220
kHz, while at the same time providing 20 to 40 % better heat
sinking over competitive thin steel, aluminum or plastic designs.
Single Ended 10, 24 or 30 V Outputs
The dual outputs may also be used in a single ended mode as
shown in figure 1 to get 10, 24 or 30 volts of output at the full
rated power levels. To use the single ended mode just
connect your load to the + and - Output pins and leave the
CMN pin floating. Trimming of the outputs may also be done
while using the single ended mode.
The case shield is tied to the output CMN pin. This
connection is shown on the block diagram. The case is
floating from the input sections. The input is coupled to the
outputs only by the low 500 pF of isolation capacitance. This
low I/O capacitance insures that any AC common mode noise
on the inputs is not coupled to your output circuits.
Ultra Low Noise Output Circuit
A
The circuit shown in figure 5 can be used to reduce the output
noise to below 20 mV p-p over a 20 MHz bandwidth. Size the
inductors appropriately for the maximum expected load current.
Compare this isolation to the more usual 1000 - 2000 pF
found on competitive designs and you will see that CALEX
provides the very best DC and AC isolation available. After all,
you are buying an isolated DC/DC to cut ground loops. Don’t
let the isolation capacitance add them back in.
Temperature Derating
The XT Dual series can operate up to 85°C case temperature
without derating. Case temperature may be roughly calculated
from ambient by knowing that the XT Duals case temperature
rise is approximately 4.4°C per package watt dissipated.
For example: If an XT converter is outputting 35 Watts, at
what ambient could it expect to run with no moving air and no
extra heatsinking?
Figure 5.
For very low noise applications this circuit will reduce the output
noise to less than 20 mV p-p over a 0-20 MHz bandwidth. Be sure
to size the inductor appropriately for the maximum expected load
current.
2401 Stanwell Drive • Concord, California 94520 • Ph: 925/687-4411 or 800/542-3355 • Fax: 925/687-3333 • www.calex.com • Email: [email protected]
5
3/2001
40 Watt XT Dual Series DC/DC Converters
Efficiency is approximately 80%, this leads to an input
power of 44 Watts. The case temperature rise would be 9
Watts x 4.4 = 40°C. This number is subtracted from the
maximum case temperature of 85°C to get: 45°C.
below 3.3° C per watt with natural convection and less with
moving air. It also increases the heat removing efficiency of
any cooling air flow.
When the XT Dual is ordered with a HS option, CALEX will
ship the converter and heatsink attached. One heat sink is
needed for each converter ordered.
This example calculation is for an XT Dual without any
extra heat sinking or appreciable air flow. Both of these factors
can greatly effect the maximum ambient temperature (see
below). Exact efficiency depends on input line and load
conditions, check the efficiency curves for exact information.
Customer installed heat sinks may also be used. It is
recommended that either liquid heatsink compound or nothing
be used on the heatsink interface. Stay away from the so
called “Dry” pad heat sink materials, in our experience these
materials are actually worse than no compound at all. Test
them thoroughly before committing to production.
This is a rough approximation to the maximum ambient
temperature. Because of the difficulty of defining ambient
temperature and the possibility that the loads dissipation may
actually increase the local ambient temperature significantly,
these calculations should be verified by actual measurement
before committing to a production design.
Additional heatsinking will lower internal temperatures and
increase the expected operational life.
Mounting Kit
Heat Sinking
The MS9 chassis mounting kit allows for direct wire connection
to the XT Dual series pins. The mounting kit includes two
barrier strips for wire attachment. The MS9 may be conveniently
attached to a chassis by use of the 4 - 0.156 inch diameter
mounting holes provided at each corner.
The XT Dual can be ordered in a “-I” configuration which
provides a case with 3 X M3 inserts located on the top surface
of the case for attaching a heat sink or mounting the converter
on it’s back using the inserts provided. The mounting surface
should be flat to within ±0.01 inches to prevent warping the XT
Dual’s case.
Although the MS9 comes with solderless sockets, for
improved reliability in severe environmental or vibration
environments it is recommended that the XT Dual be soldered
to the mounting kit.
The CALEX HS heat sink was specially developed for this
model and can reduce the case temperature rise to typically
Typical Performance (Tc=25°C, Vin=Nom VDC, Rated Load).
24 VOLT EFFICIENCY Vs. LOAD
24 VOLT EFFICIENCY Vs. LINE INPUT VOLTAGE
90
24 VOLT INPUT CURRENT Vs. LINE INPUT VOLTAGE
6
90
LINE = 9VDC
75
70
65
60
20W LOAD
85
LINE =
24VDC
EFFICIENCY(%)
EFFICIENCY (%)
80
INPUT CURRENT (AMPS)
85
35W LOAD
80
75
LINE = 36VDC
5
A
4
3
35W LOAD
2
1
55
20W LOAD
50
70
0
10
20
30
40
50
60
70
80
90
100
0
8
12
LOAD (%)
20
24
28
32
36
0
48 VOLT EFFICIENCY Vs. LOAD
48 VOLT EFFICIENCY Vs. LINE INPUT VOLTAGE
INPUT CURRENT (AMPS)
40W LOAD
EFFICIENCY(%)
LINE =
48VDC
65
60
20
20W LOAD
80
75
70
30
40
1.5
40W LOAD
1.0
0.5
20W LOAD
50
20
35
2.0
LINE = 72VDC
10
30
2.5
55
0
25
48 VOLT INPUT CURRENT Vs. LINE INPUT VOLTAGE
85
75
15
3.0
LINE = 20VDC
80
70
10
LINE INPUT (VOLTS)
90
85
5
LINE INPUT(VOLTS)
90
EFFICIENCY (%)
16
40
50
60
LOAD (%)
70
80
90
100
0.0
20
30
40
50
60
LINE INPUT(VOLTS)
70
80
0
10
20
30
40
50
60
70
80
LINE INPUT (VOLTS)
2401 Stanwell Drive • Concord, California 94520 • Ph: 925/687-4411 or 800/542-3355 • Fax: 925/687-3333 • www.calex.com • Email: [email protected]
6
3/2001