25 to 30 Watt XC Triple Series DC/DC Converters
Features
Single and Dual Output Sections Isolated
from each Other and Independently Regulated
Overall Output Accuracy up to 10:1 Better than
Competitive Products
Standby Current Less than 0.5 mA for Low Power
Pulsed Battery Operation
Fully Filtered and Specified; Very Low Noise Inputs
and Outputs
PCB Mounting with Optional Heat Sink and Chassis
Mounting Kit
Industrial Operating Temperature Range Standard,
-40 to 85°C
Five Year Warranty
Description
The 25-30 Watt Triple Series opens up new application areas
in high efficiency DC/DC conversion. The unique dual control
loop output design allows for independent regulation of both
the single and dual outputs. This increases the total output
accuracy by up to 10:1 over competitive designs. The design
also eliminates cross regulation from the +5 section to the
dual outputs. The 25-30 Watt Triple Series runs at 80-85%
efficiency.
Model
12T5.12XC
12T5.15XC
24T5.12XC
24T5.15XC
48T5.12XC
48T5.15XC
Selection Chart
Input Range
VDC
Min
10.0
10.0
18.0
18.0
36.0
36.0
Max
20.0
20.0
36.0
36.0
72.0
72.0
Outputs
VDC
5, ±12
5, ±15
5, ±12
5, ±15
5, ±12
5, ±15
Outputs
mA
2500, ±500
2500, ±400
3000, ±625
3000, ±500
3000, ±625
3000, ±500
25-30 Watt Triple Series Block Diagram
SHIELDED
ISOLATION TRANSFORMERS
THERMAL SHUTDOWN
48T MODELS
ONLY
+ INPUT 1
SINGLE SECTION
6 +5
A
7 + 5 CMN
9 + 5 TRIM
- INPUT
2
DIFFERENTIAL
MODE
INPUT
FILTER
ANTI-PHASE
DUAL PWM
CONTROLLER
ISOLATION BARRIER
3 + 12/15
12T AND 24T
MODELS
4
± CMN
ON/OFF 8
5 - 12/15
SHIELDED, LOW THERMAL GRADIENT COPPER CASE
DUAL SECTION
2401 Stanwell Drive • Concord, California 94520 • Ph: 925/687-4411 or 800/542-3355 • Fax: 925/687-3333 • www.calex.com • Email: sales@calex.com
1
3/2001, eco# 041007-1
25 to 30 Watt XC Triple Series DC/DC Converters
Input Parameters*
Model
Voltage Range
Reflected Ripple (2), 0-20MHz bw
Input Current Full Load
No Load
Efficiency
Switching Frequency
Maximum Input Overvoltage,
100ms No Damage
Turn-on Time, 1% Output Error
Recommended Fuse
MIN
MAX
TYP
MAX
TYP
TYP
TYP
TYP
MAX
TYP
25
12T5.12XC
12T5.15XC
24T5.12XC
24T5.15XC
48T5.12XC
48T5.15XC
Units
VDC
mA P-P
mA
%
kHz
85
VDC
ms
Amps
10.0
20.0
350
500
2550
30
80
18.0
36.0
150
300
1465
20
85
120
45
35
(3)
36.0
72.0
150
350
735
15
85
Output Parameters*
Model
Output Voltage
Rated Current (4)
Voltage Range
100% Load
Output Balance
(Plus to Minus Output, Full Load)
Load Regulation 25-100% Load
(5)
0-100%
Cross regulation (6)
Line Regulation
Vin = Min-Max VDC
Short Term Stability (7)
Long Term Stability
Transient Response (8)
Dynamic Response (9)
Input Ripple Rejection (10)
Noise, 0-20MHz bw (2)
Temperature Coefficient
Overvoltage Clamp (11)
Short Circuit Protection to
Common for all Outputs
NOTES
MIN
MAX
MIN
TYP
MAX
TYP
MAX
TYP
MAX
TYP
MAX
TYP
MAX
TYP
MAX
TYP
TYP
TYP
TYP
TYP
TYP
MAX
TYP
MAX
TYP
12T5.12XC
12T5.15XC
24T5.12XC
24T5.15XC
48T5.12XC
48T5.15XC
+5
+5
0
0
2500
3000
4.950
5.000
5.050
N/A
N/A
0.4
0.7
0.5
0.75
N/A
N/A
12T5.12XC
±12
160
500
24T5.12XC
48T5.12XC
±12
160
625
12T5.15XC
±15
125
400
24T5.15XC
48T5.15XC
±15
125
500
Units
VDC
mA
11.925
14.925
12.000
15.000
VDC
12.075
15.075
0.5
0.5
%
0.7
0.7
0.05
0.05
0.1
0.1
%
0.1
0.1
0.2
0.2
0.6
0.5
%
0.8
0.75
0.0
%
0.1
0.02
%
0.1
%/kHrs
100
200
200
µs
270
250
200
mV peak
>70
dB
30
mV P-P
65
50
50
50
ppm/°C
100
200
200
6.8
15
18
VDC
Provides minimum of 8 hours continuous protection with current limiting and
thermal overload techniques
A
*
(2)
(3)
(4)
(5)
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 found in the
CALEX Power Conversion Design Guide and Catalog.
Measurement bandwidth is 0 - 20 MHz. See the applications
section of this note for more information.
Determine the correct fuse size by calculating the maximum DC
current drain at low line input, maximum load and then adding 20
to 25% to get the desired fuse size. A slow blow type fuse is
recommended.
Minimum load is required for proper regulation only. No module
damage is sustained if run less than minimum load. Regulation
of the dual output degrades with substantial load unbalance.
The dual section load regulation is defined as the voltage
change in either output as the loads on both outputs are changed
from minimum load to maximum load at the same time.
(6) Cross regulation is defined as the change in one output when the
other output is changed from minimum to maximum load.
(7) Short term stability is specified after a 30 minute warmup at full
load, constant line, load and ambient conditions.
(8) Transient response is defined as the time for the output to settle
from a 25 to 75 % step load change to a 1% error band (rise time
of step = 2µ Sec).
(9) Dynamic response is defined as the peak overshoot during a
transient as defined in note 8 above.
(10) The input ripple rejection is specified for DC to 120 Hz ripple with
a modulation amplitude of 1% of Vin.
(11) For module protection only, see also note 3.
(12) The ON/OFF pin is Open Collector TTL, CMOS, and relay
compatible. The input to this pin is referenced to the -input.
2401 Stanwell Drive • Concord, California 94520 • Ph: 925/687-4411 or 800/542-3355 • Fax: 925/687-3333 • www.calex.com • Email: sales@calex.com
2
3/2001, eco# 041007-1
25 to 30 Watt XC Triple Series DC/DC Converters
General Specifications*
All Models
ON/OFF Function (12)
ON Logic Level
or Leave Pin Open
OFF Logic Level
Input Resistance
Converter Idle Current,
Shut Down Pin Low
Isolation
Isolation Voltage
Input to Either Output
Single to Dual Output
10µA Leakage
Input to Output
Capacitance
Input to Single Output
Input to Dual Output
Single to Dual Output
Environmental
Case Operating Range
No Derating
Case Funtional Range (13)
Storage Range
Thermal Impedance
Pin Mount Version
Thermal Shutdown
Case Temperature
General
Unit Weight
Mounting Kit
Agency Aprovals
Units
MIN
MAX
TYP
TYP
2.4
1.5
2
12
VDC
VDC
kohms
mA
MIN
MIN
1544
500
VDC
TYP
TYP
TYP
MIN
MAX
MIN
MAX
MIN
MAX
TYP
TYP
95
90
45
-40
85
-40
90
-55
105
4.4
100
pF
BOTTOM VIEW
SIDE VIEW
Mechanical tolerances unless otherwise noted:
°C
°C
°C
°C/Watt
°C
X.XX dimensions: ±0.020 inches
X.XXX dimensions: ±0.005 inches
Seal around terminals is not hermetic. Do not immerse units in any
liquid.
6.2
MS12
UL 1459
oz.
Pin
1
2
3
4
5
Function
+INPUT
-INPUT
+12/15V
CMN
-12/15V
Pin
6
7
8
9
Function
+5V
CMN
ON/OFF
+5V TRIM
(13) 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 will reduce expected operational life. The data
sheet specifications are not guaranteed over the functional
temperature range.
(14) Specifications subject to change without notice.
(15) Water Washability - Calex DC/DC converters are designed to
withstand most solder/wash processes. Careful attention should
be used when assessing the applicability in your specific
manufacturing process. Converters are not hermetically sealed.
A
Chassis Mounting Kit - MS12
The MS12 chassis mounting kit allows for direct wire connection
to the 25-30 Watt Triple Series. The mounting kit includes two
barrier strips for wire attachment, an input fuse and an output
trim pot for trimming the +5 volt output. Provisions are also
made for additional output bypassing and grounding.
If the MS12 is ordered at the same time as a 25-30 Watt
Triple the mounting kit will be shipped with the correct fuse
size.
The MS12 may be conveniently attached to a chassis by
using the 4 - 0.156 inch diameter mounting holes provided at
each corner.
Although the MS12 comes with solderless sockets for the
25-30 Watt Triple, it is recommended that the converter be
soldered to the mounting kit for improved reliability under
severe environmental or vibration conditions.
Heat Sink Option
The 25-30 Watt Triple can be ordered with a “-I” configuration
which provides a case with 3 by M3 inserts located on the top
surface of the case for attaching a heat sink. When an “-HS”
is ordered CALEX will ship the converter with a heat sink
attached. The CALEX HS heat sink was specially developed
for this model and can reduce the case temperature rise to
below 3.3°C per watt with natural convection and less with
moving air. One heat sink is needed for each 25-30 Watt
Triple ordered.
Customer installed heat sinks may also be used. It is
recommended that only liquid heat sink compound be used on
the heat sink interface. Avoid the so called “Dry” pad heat sink
materials. In our experience these materials are actually
worse than using no compound at all.
2401 Stanwell Drive • Concord, California 94520 • Ph: 925/687-4411 or 800/542-3355 • Fax: 925/687-3333 • www.calex.com • Email: sales@calex.com
3
3/2001, eco# 041007-1
25 to 30 Watt XC Triple Series DC/DC Converters
Application Information
The dual control loops are locked together in time by a
proprietary “Anti-Phase Dual PWM Controller” subassembly.
The synchronization reduces beat frequency problems that
occur when two switching supplies run at slightly different
frequencies. The “Anti-Phase” operation also evens out the
current pulses on the input bulk capacitor allowing for
conservative derating and hence longer life.
The dual loop design allows both the single and dual
outputs to be fully isolated from each other. This helps the
system design by allowing the common analog and digital
ground point to be elsewhere in the system. The dual outputs
can also be used as single ended 24 or 30 volt outputs.
The 25-30 Watt Triple Series is also mindful of battery
operation for industrial/medical control and remote data
collection. The remote ON/OFF control pin places the converter
in a very low power mode that draws only 0.5 mA maximum
from the input source. This is at least a 10:1 improvement over
industry standard specifications of 5 to 30 mA standby current
drain.
These converters achieve an output noise of 30 mV peak
to peak typical and are fully specified and tested to a maximum
specification of 65 mV peak to peak over a wide bandwidth of
0-20 MHz. Input filtering reduces reflected ripple noise and is
similarly low and also fully specified for typical and maximum
values (exact value depends on input voltage range).
All inputs and outputs are protected from transient
overvoltage conditions by 500 watt transient overvoltage
suppressors. Full overload protection is provided by
independent pulse-by-pulse current limiting and
overtemperature shutdown. These protection features assure
you that our 25-30 Watt Triple will provide zero failure rate
operation.
Six-sided shielding is standard along with specified
operation over the full industrial temperature range of -40° to
+85°C.
The 25-30 Watt Triple 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.
General Operation
Figure 1 shows the recommended connections for the 25-30
Watt Triple DC/DC converter. A fuse is recommended to
protect the input circuit and should not be omitted. The fuse
serves two purposes:
1)
2)
It prevents unlimited current from flowing in the case of
a catastrophic system failure.
UL regulations for telecom equipment require the use of
a fuse.
Figure 1.
Standard connections for the 25-30 Watt Triple. The ON/OFF and
Trim pins can be left floating if they are not used. The input fuse
should not be omitted.
+ INPUT
FUSE
+5 6
1 + INPUT
+ 5 CMN 7
+ 5 TRIM 9
- INPUT
2 - INPUT
+ 5 TRIM
+ 5 LOAD
+ 12/15 3
± CMN 4
- 12/15 5
+ LOAD
- LOAD
ON/OFF
8 ON/OFF
The ON/OFF and +5 trim pins may be left floating if they are
not used. No external capacitance on either the input or
outputs is required for normal use which can, in fact, degrade
the converter’s operation. See our application note
“Understanding Power Supply Output Impedance for Optimum
Decoupling” for more information. The usual 0.1 to 0.01µF
bypasses may be used around your PCB as required for local
bypassing without harm. Extremely low ESR capacitors ( <0.2
ohms) should not be used at the input. This will cause peaking
of the input filters’ transfer function and actually degrade the
filters’ performance.
Single Output
The single output is independently regulated and isolated
from the dual outputs and can be operated independently or
with a common ground with the dual output.
The +5 TRIM pin may be used to adjust the +5 volt output
by up to ±5 % from the nominal factory setting of +5.000 volts.
The trim may be used to adjust for system wiring voltage drops
or to adjust the +5 output up to 5.2 volts for ECL applications.
Since the 5 volt output is completely isolated from the dual
section the output can be grounded to generate -5.2 volts or
+5.2 volts. Figure 2 shows the proper connections for the trim
pin.
A
+5 6
+ 5 TRIM
+ 5 CMN
9
7
TRIM DOWN
+ 5 LOAD
TRIM UP
10K TRIMPOT
Figure 2.
The 5 volt output can be trimmed by using either a trimpot or fixed
resistors. If fixed resistors are used their values may range from
zero to infinite ohms the trimpot should be 10K ohms nominal.
2401 Stanwell Drive • Concord, California 94520 • Ph: 925/687-4411 or 800/542-3355 • Fax: 925/687-3333 • www.calex.com • Email: sales@calex.com
4
3/2001, eco# 041007-1
25 to 30 Watt XC Triple Series DC/DC Converters
+5 6
R1
Q1
IC1
R2
+ 5 CMN 7
R3
C1
+ 5 TRIM 9
R4
REMOTE
+ 5 VOLT
LOAD
R5
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 Power Supply
Output Impedance for Optimum Decoupling” in the CALEX
Power Conversion Design Guide and Catalog for more
information.
+ INPUT
1
100K
C1
R1
R2
R3
Parts List
R4
0.1µF, 50V, Ceramic
R5
470 ohm, 5%
Q1
1.0K, 5%
2.4K, 5%
I
C1
4.99K, 1%
4.99K, 1%
2N3906
TL431
ON/OFF
8
100
W
15V
- INPUT
2
Figure 3.
This simple circuit allows for remote sensing with the 5 volt output.
The circuit can correct for up to 0.25 volts of total drop in the power
leads. At 3 amps of output this is approximately 0.08 ohms of line
resistance. A trimpot may be added to R5 to allow for exact
adjustment of the 5 volt output.
Figure 5.
The simplified schematic of the ON/OFF pin shows a 100K resistor
connected between the +Input and the ON/OFF pin. The maximum
open circuit voltage is clamped by the 15 volt zener diode. The 100
ohm resistor prevents large ground currents from flowing out the
ON/OFF pin instead of the -Input pin during power up transients.
Figure 3 shows how to implement remote sense with the
trim pin and a TL431 adjustable voltage reference. This circuit
allows automatic correction of the output voltage up to 0.25
volts total.
Dual Output
The dual output is independently regulated and isolated from
the single output and can be operated separately or with a
common ground with the single output. The dual outputs can
also be connected for single-ended load applications of either
24 or 30 volts as shown in Figure 4. This configuration allows
for full output current operation up to the full 25 or 30 watt
rating.
+ 12/15 3
+ LOAD
± CMN 4
- LOAD
- 12/15 5
24 or 30V
LOAD
Case Grounding
The case serves not only as a heat sink but also as an EMI
shield. The case/header shield is tied to the +Input pin for the
48T models. The 12T and 24T models have the case tied to
the -Input pin. These connections are shown on the 25-30
Watt Triple block diagram.
For all models the case is floating from the output sections.
Remote ON/OFF Pin Operation
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 5. 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.
When the ON/OFF pin is pulled low with respect to the -
Input, the converter is placed in a low power drain state. This
low power state typically draws less than 200 mA from the
input source. When the ON/OFF pin is released the converter
powers up in typically 35 mSec. 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.
Temperature Derating / Mounting Options
The XC Triple Series can operate up to 85°C case temperature
without derating. Case temperature may be roughly calculated
from ambient by knowing that the XC Triples’ case temperature
rise is 4.4°C per package watt dissipated. For example, if the
converter was functioning at an output of 30 Watts, at what
ambient could it expect to run with no moving air and no
additional heatsinks?
A
Figure 4.
The dual output may be used either as a dual polarity or single-
ended source. If the output is used as a single-ended source, pin 4
should be left unconnected.
Grounding
The +5 and ± dual sections are floating independently from
each other. They may be operated this way or with a common
ground.
If the single and dual sections are connected either directly
at the converter or at some remote location it is suggested that
1 µF, 35 volt Tantalum capacitor bypasses be used directly at
the converter output pins. These capacitors prevent any
common mode switching currents from showing up on the
converter’s outputs as normal mode output noise.
2401 Stanwell Drive • Concord, California 94520 • Ph: 925/687-4411 or 800/542-3355 • Fax: 925/687-3333 • www.calex.com • Email: sales@calex.com
5
3/2001, eco# 041007-1
DIY/Open Source Hardware
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