Installation Data Sheet
PXF Series (single output) DC-DC Converters
The PXF is a DC-DC converter which provides a regulated output at power levels up to 40 watts. It accepts a wide range DC input. The
converter may be operated with or without the input and output pins grounded.
Table of Contents
General Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Fusing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Installation Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Soldering and Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
EMI Filter (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Minimum Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Remote On-Off Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Thermal Consideration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
External Trim (output voltage adjustment) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Trim Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
General Safety Instructions
These products are designed to be PCB mounted and for use
within other equipment or enclosures. For safe installation and
operation, carefully follow the instructions below:
1. Do not install, test, or operate the products near water or
spill liquid on them.
2. Do not operate these products unless they are securely
fastened.
3. These products must be installed in a restricted access
location accessible to authorized personnel only.
4. These products must be professionally installed in
accordance with the prevailing electrical wiring regulations
and safety standards.
5. The output power taken from the unit must not exceed the
ratings stated in the catalog datasheet.
6. Ensure adequate ventilation is provided to allow air to
circulate.
7. This product has functional insulation between input and
output and therefore the DC source to this product must
be reinforced or double insulated to the AC input in
accordance with IEC/EN 60950-1 to achieve SELV output.
Soldering and Cleaning
Flow soldering : 260±10°C less than 15 seconds
Soldering iron : 370±10°C less than 5 seconds
Note: The pins of this module are coated with Tin. To assure the
solder-ability, modules should be kept in their original shipping
containers to provide adequate protection. Also, the storage
environment should be controlled to prevent oxidation of the pins.
Following wave solder, the converters should be given an
opportunity to cool to within 10°C of the cleaning solution
temperature. Cleaning while at a higher temperature may
increase the risk of vacuum absorption of the solution into the
converter between the pins and potting material during cooling.
It is recommended that during the wash process, the date code
screening is protected to avoid erasure.
Fusing
An external ceramic sand-filled fuse is needed for protection.
12V input ~ 250V, F8A, HBC
24V input ~ 250V, F5A, HBC
48V input ~ 250V, F5A, HBC
Installation Method
The unit can be mounted in any direction. Position single or
multiple units with proper spacing to allow for adequate air
ventilation. The case temperature of each unit should not exceed
the temperature range as noted in the data sheet.
Avoid placing PCB traces for the DC input and DC output directly
under the unit to limit the possibility of unwanted conducted noise.
3055 Del Sol Blvd • San Diego, CA 92154 • 1-800-LAMBDA-4
Installation Data Sheet
Block Diagram
Appropriate hook-up location for
test equipment to monitor output.
L1
DVM
0.1uf
DC
+
Source
-
Fuse
C1
Optional
EMI
Filter
+Vin
PXF
+Vo
1uf
Coax cable
Oscilloscope
C2
-Vin
-Vo
50Ω
Remote On / Off
Load
System Ground
Trim
EMI Filter (Optional)
Input filter components (C1, C2, L1) are used to help meet special
conducted emissions requirements for the PXF product. These
components should be mounted as close as possible to the DC-
DC converter; and all leads should be minimized to decrease
radiated noise.
C1
L1
C2
PXF40
1µF, MLC
5.5µH
39µF 100V
Electrolytic
Outline Drawing
Minimum Load
A 10% (of full load) minimum load is required to meet the
performance specifications. The unit does not maintain regulation
and operate properly under a no-load condition.
Pin Assignments
Pin
1
2
3
4
5
6
7
8
9
Connection
+ Input
- Input
Remote On / Off
No Pin
- Sense (*)
+ Sense (*)
+ Output
- Output
Trim
*
If remote sense is not being used, the
+Sense and - Sense should be
connected to their corresponding
outputs; + output, -output.
Pin Diameter: 1mm (0.04")
3055 Del Sol Blvd • San Diego, CA 92154 • 1-800-LAMBDA-4
Installation Data Sheet
Positive Logic
To turn the module on and off, the user must supply a switch (or
equivalent circuit below) to control the voltage between the on/off
terminal V
on/off
and the V
i(-)
input terminal. With an open circuit
the module is normally on. To turn the module off the voltage on
the Von/off poin needs to be 0V-1.2V. The maximum current
I
on/off
should be limited to less than 100µA
Below are five possible circuits for driving the ON/OFF Pin:
On/Off Control
On/Off Control
measured at the position indicated in figure to the right.
When operating the module, adequate cooling must be provided
to maintain the case temperature at or below 100°C. Maintaining
a lower temperature will yield higher reliability of the device.
Optimum cooling is obtained with forced convection.
Flow Rate
Convection*
100LFM
200LFM
300LFM
400LFM
500LFM
Heatsink**
Θ
9.2
°C/W
-
6.5
5.3
4.0
3.5
8.5 Convection
2.8 500LFM
Vin (-)
Opto Isolated Remote On/Off
Vin (-)
Positive Logic
(Permanently Disabled)
* Mounted vertically
** Optional heatsink 7G0026A (includes adhesive pad)
5V
On/Off Control
On/Off Control
Vin (-)
TTL/
CMOS
External Trim (output voltage
adjustment)
Output voltage set point adjustment allows the user to increase or
decrease the output voltage set point of a module. This is
accomplished by connecting an external resistor between the TRIM
pin and either the (+)Vout or (-)Vout pins. With an external resistor
between the TRIM and (+)Vout pin, the output voltage set point
decreases. With an external resistor between the TRIM and (-)Vout
pin, the output voltage set point increases.
See the following pages for values.
Vin (-)
Positive Logic
(Permanently Enabled)
On/Off Control
Vin (-)
Open Collector Remote On/Off
Thermal Consideration
The power module operates in a
variety of thermal environments;
however, sufficient cooling
should be provided to help
ensure reliable operation of the
unit. Heat is removed by
conduction, convention, and
radiation to the surrounding
environment. Proper cooling can
be verified by measuring the
case temperature. The case
temperature (Tc) should be
- Sense
+ Sense
(+) Vout
(-)Vout
TRIM
Top View
(+) Vin
(-) Vin
CTRL
Trim Tables
PXF40 1.5V
Trim down
Vout=
RD=
Trim up
Vout=
RU=
1
1.485
5.704
1
1.515
4.578
2
1.470
2.571
2
1.530
2.065
3
1.455
1.527
3
1.545
1.227
4
1.440
1.005
4
1.560
0.808
5
1.425
0.692
5
1.575
0.557
6
1.410
0.483
6
1.590
0.389
7
1.395
0.334
7
1.605
0.270
8
1.380
0.222
8
1.620
0.180
9
1.365
0.135
9
1.635
0.110
10
1.350
0.065
10
1.650
0.054
%
Volts
KOhms
%
Volts
KOhms
3055 Del Sol Blvd • San Diego, CA 92154 • 1-800-LAMBDA-4
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