TDK-Lambda PAH300 Series User manual

PAH300･350S24-SERIES
TDK-Lambda C175-04-11B
PAH300･350S24 SERIES
Instruction Manual
■Before using this product
Be sure to take note of precautions and warnings indicated in this manual when using this product. Improper usage may
lead to electric shock or fire. Be sure to read this instruction manual thoroughly before using this product.
■Precautions
● Avoid touching the baseplate and the case of this product because they get hot.
● There are high voltage and high temperature components within this product. Refrain from disassembling this product
or touching its internal components as this may lead to electric shock or burn.
● To avoid unexpected accident from placing hands or face near the unit during operation.
● Verify that connection to input, output and signal terminals are correct as indicated in this instruction manual.
● For acquisition of various Safety Standards and safety improvement, be sure to use an external fuse.
● This product is designed for installation on electronic equipment.
● For input terminals of 24 V input models, apply a voltage from a primary source with reinforced or double insulation.
● Output voltage of this product is considered to have hazardous energy level (voltage of 2V and above with power of
240W and above) and must not have physical contact with operator. Protection must be provided on this module when
installed on equipment to prevent physical contact with service technician himself or accidentally dropped tools during
repair. Before repair, be sure to turn off the input source and confirm that input and output voltage have drop down to a
safe level.
● Application circuit or component values described in this instruction manual are for reference only. When designing
circuit, be sure to verify actual circuit operation before determining final application circuit or component values.
● Contents of this instruction manual are subject to change without notice. When using this product, please refer to latest
data sheet to satisfy this product specification.
● No part of this document may be copied or reproduced in any for, or by any mean without prior written consent of
TDK-Lambda.

PAH300･350S24-SERIES
1
TDK-Lambda
Table of Contents
■ Block Diagram
■ Sequence Time Chart
■ Terminal Explanation
■ Explanation on Specifications
1. Input Voltage Range
2. Output Voltage Adjust Range
3. Maximum Output Ripple and Noise
4. Maximum Line Regulation
5. Maximum Load Regulation
6. Over Current Protection (OCP)
7. Over Voltage Protection (OVP)
8. Over Temperature Protection (OTP)
9. Remote Sensing (+S, -S terminal)
10. ON/OFF Control (CNT terminal)
11. Parallel Operation
12. Series Operation
13. Operating Ambient Temperature
14. Operating Ambient Humidity
15. Storage Ambient Temperature
16. Storage Ambient Humidity
17. Cooling Method
18. Baseplate temperature vs. output voltage drift
19. Withstand Voltage
20. Insulation Resistance
21. Vibration
22. Shock
23. CE MARKING / UKCA MARKING
■ Installation
1. Mounting Method
2. Heatsink Installation
3. Regarding Vibration
4. Recommended Soldering Condition
5. Recommended Cleaning Condition
■ Before concluding module damage

PAH300･350S24-SERIES
2
TDK-Lambda
■ Block Diagram
+Vin
-Vin
CNT
OCP
Input Voltage
Detector
OTP
OVP
Detector
TRM
+S
-S
Control Circuit
Input Filter
-V
+V
Bias
Power Supply
ON/OFF Control
Switching
Rectifier
Output Filter
Baseplate
CASE
Switching Frequency (fixed) : 330kHz (typ.)
■ Sequence Time Chart
(For Standard Model with Negative logic for ON/OFF control.)
Input V oltage
Ou tput V olta ge
*1
ON/O FF Control
L
H
0V
Vin
0V
Vo
ut
Reset
More than
100ms
O VP S et P oint
O C
P Set P oint
Input ON
Control ON
Control OFF
OCP ON
OVP Trip
Input OFF
Input ON
OCP OFF
Control OFF
Control ON
OTP ON
OTP OFF
*1 level : 4≦H≦35(V) or Open
0≦L≦0.8(V) or Short

PAH300･350S24-SERIES
3
TDK-Lambda
■Terminal Explanation
[Input Side Terminals] [Output Side Terminals]
-Vin : -Input Terminal -V : -Output Terminal
CASE : Baseplate Terminal -S : -Remote Sensing Terminal
CNT : ON/OFF Control Terminal TRM : Output Voltage Trimming Terminal
+Vin : +Input Terminal +S : +Remote Sensing Terminal
+V : +Output Terminal
Baseplate can be connected to FG (frame ground) M3 threaded holes. (standard model)
Connect +Vin, -Vin, +V, -V with consideration of contacting resistance.

PAH300･350S24-SERIES
4
TDK-Lambda
■ Explanations on Specifications
1. Input Voltage Range
Input voltage range for PAH300 ･350S24 Series is
indicated below.
Input Voltage Range : 18～36VDC
Basically ，ripple voltage (Vrpl) which results from
rectification and filtering of commercial AC line is
included within the input voltage as shown in fig. 1-1.
Ripple voltage must be limited within the voltage
described below.
Allowable input ripple voltage : 2Vp-p
When this value is exceeded, the output ripple voltage
becomes large.
Note that sudden input voltage change may cause
variation of output voltage transitionally.
Also, input voltage waveform peak value must not
exceed above input voltage range.
Fig.1-1 Input Ripple Voltage
● Basic Connection
-Vin
+
Vin
CNT
CASE
C1
C4
C3
C2
C5
+
-
Load
50mm
+
Fuse
+
+
V
+S
-S
-
V
POWER
MODULE
TRM
M3 threaded hole
M3 threaded hole
Fig.1-2 Basic Connection
Input Fuse
This power module has no built-in fuse. Use external
fuse to acquire various Safety Standards and to improve
safety. Also, use fast-blow type for every module.
Furthermore, fuse must be connected to the +Vin side
if –Vin side is used as ground, or fuse must be
connected to –Vin side if +Vin side is used as a ground.
Input Fuse recommended current rating:
PAH300S24 : 30A
PAH350S24 : 40A
C1:
To prevent the effect of input line inductance to the
power module, connect electrolytic capacitor or
ceramic capacitor between +Vin and –Vin terminals.
Furthermore, use electrolytic capacitor with small
ESR value. Especially take note that during line turn
off at low ambient temperature, power module output
will not normally shut down due to unstable C1 voltage.
Also, ripple current flows across this capacitor.
Therefore, verify maximum allowable ripple current
this capacitor when selecting component. Verify actual
ripple current value by actual measurement.
Recommended capacitor value : 220μF ×2pcs and
above (Parallel connect)
(Voltage Rating 50V and above)
Notes
1. Use low impedance electrolytic capacitor with
excellent temperature characteristics.
(Nippon Chemi-con LXY Series or equivalent)
2. When input line inductance becomes excessively
high due to insertion of choke coil, operation of the
power module could become unstable. For this case,
increase C1 value more than the value indicated above.
3. When ambient temperature becomes lower than
–20℃, connect 4 more and above capacitors indicated
above in parallel to reduce ESR.
C2, C3 : 0.022μF
To reduce spike noise voltage at the output, connect
film capacitors or ceramic capacitors between +V and
the nearest M3 threaded hole and between –V and the
nearest M3 threaded hole.
Also, take note that output spike noise voltage could
vary according to PCB (printed circuit board) wiring
design.
However, for cases where baseplate is connected to +V
or –V, use the nearest M3 threaded hole. (M3 threaded
t
Time
Input Voltage
Vrpl
below 2V
Input Voltage
Range

PAH300･350S24-SERIES
TDK-Lambda
5
holes is internally connected to baseplate inside the
Power Module.) For this type of connection, C2 and C3
can be omitted.
C4 :
For stable operation, connect an electrolytic capacitor
between +V and –V at 50mm distance from the output
terminals.
Take note that output ripple and output shutdown
could be affected by electrolytic capacitor, equivalent
impedance and inductance characteristics of wiring.
Take note that output ripple voltage could vary
according to PCB wiring design.
For cases of abrupt changes in load current or input
voltage, increasing capacitance value of the external
capacitors could reduce the voltage fluctuation.
Vout C4
12V 25V 470μF
28V 50V 220μF
Table1-1 C4:Recommended Values of External
Output Capacitor
Notes
1. Use low impedance electrolytic capacitor with
excellent temperature characteristics.
(Nippon Chemi-con LXY Series or equivalent)
2. Use three capacitors indicated above in parallel when
ambient temperature becomes lower than –20℃ to
reduce ESR.
3. Take note of the allowable ripple current of the
capacitor to be used. Especially, when load adding
capacitors for abrupt current changes, be sure to verify
that ripple current does not exceed allowable ripple
current before use.
C5 : 0.1μF
To reduce spike noise voltage at the output, connect a
ceramic capacitor between +V and –V within 50mm
distance from the output terminals.
Also, take note that output spike noise voltage could
vary according to PCB wiring design.
C6：
When switches or connectors are used between input
source and PAH300･350S24 Series input terminals,
impulse surge voltage is generated due to input throw-
in by switch on/off or due to inserting/ removing of
power module from the active line. For this case,
connect an additional electrolytic capacitor C6 as
shown in fig.1-3 and fig. 1-4.
Recommended Capacitance Value : 220μF and above
(Voltage Rating 50V and above)
Also, in-rush current flows at line throw-in. Therefore,
be sure to verify capability of switch or fuse to
withstand I2t at line throw-in.
Fuse
-Vin
+Vin
C1
+
C6
+
Switch
Fig.1-3 Input Filter with Input Switch
Fuse
-Vin
+Vin
C1
+
C6
+
Swtch
Fuse
C1
+
-Vin
+Vin
Fig.1-4 Input Filter when Plural Power Modules
Reverse input connection
Reverse input polarity would cause module damage.
For cases where reverse connections are possible, connect
a protective diode and fuse. Use protective diode with
higher voltage rating than the input voltage, and with
higher surge current rating than the fuse.
Fuse
-Vin
+Vin
C1
+
Fig.1-5 Protection for Reversed Connection of Input

PAH300･350S24-SERIES
TDK-Lambda
6
● Recommended input filter as EMI countermeasure
(conforms to VCCI Class 1, FCC class A)
(1) Recommended input filter
as EMI countermeasure
CNT
+Vin
CASE
-Vin
C1
+
C7
C8
C9
Fuse
L1
POWER
MODULE
Fig.1-6 Recommended input filter
as EMI countermeasure
Recommended Values:
C1 : 680μF (Electrolytic Capacitor)
3 pcs in parallel
C7 : 10μF (Ceramic Capacitor)
C8,C9 : 0.47μF (Film Capacitor)
L1 : 1mH (Common-mode choke coil)
Notes
1. For the power module output, connect output capacitors
described in the basic circuit connection.
2. C1 (Electrolytic Capacitor) value can be reduced if
impedance of input line is lower and operation of
power module is stable.
3. VCCI Class 1, FCC Class A limits can be satisfied
with the above recommended filter at Densei-Lambda
measuring conditions. However, there are cases where
above limits might not be satisfied due to input and
output wiring method, as well as, peripheral circuits.
When selecting input filter, be sure to verify actual
EMI characteristics (CE and RE) before finalizing the
filter. Refer to PAH300･350S24-* Evaluation Data for
details.
2. Output Voltage Adjustment Range
Output voltage could be adjusted within the range
described below by external resister or variable resistor.
However, take note that OVP might trigger when
output voltage adjustment exceeds the ranges indicated
below.
Output Voltage Adjustment Range
12V : -40%~+10% of nominal output Voltage
28V : -40%~+18% of nominal output Voltage
When increasing the output voltage, reduce the output
current accordingly so as not to exceed the maximum
output power.
Take note that input voltage range is limited as shown
in fig.2-1 when output voltage is increased.
Remote sensing is possible even when output voltage is
varied. For details on remote sensing function, please
refer to “9.Remote Sensing”.
Fig.2-1 Limit of Input Voltage
Output Voltage (%)
3618 18.5 19 19.5
110
100
90
Input Voltage (VD C)
120
28V
M odel
12V Model
118
60
0

PAH300･350S24-SERIES
TDK-Lambda
7
● Output Voltage Adjustment by external resistor
or by variable resistor
‘(1) In case of adjusting output voltage lower
(1-1) Available maximum output current = rated
output current
(1-2) Connect an external resistor Radj(down)
between the TRM terminal and –S terminal.
Fig.2-2 Connection for output voltage trim down
(1-3) Equation of external resistor and output
voltage.
[ ]
W
÷
ø
ö
ç
è
æ-
D
=kdownRadj 2
%
%100
)(
Radj(down) :Value of external resistor
Δ(%) :Output voltage change rate against
nominal output voltage
Below graph is relation Δ(%) and value of
external resistor.
Fig.2-3 Δ(%) vs. Radj(down) (1)
(2) In case of adjusting output voltage higher
(2-1) Allowable maximum output current =
maximum output power ÷ output voltage
(reduce maximum output current in
specification.)
(2-2) Connect an external resistor Radj(up) between
TRM terminal and +S terminal.
Fig.2-4 Connection for output voltage trim up
(2-3) Equation of external resistor and output voltage
[ ] W
÷
ø
ö
ç
è
æ
D
D´+
-
D´
D+
=k
Vo
upRadj %
%2%100
%225.1
%)%100(
)(
Vo :nominal output value of module
Radj(up) :external adjustment resistor
Δ (%) :Output voltage change rate against
nominal output voltage
Below graph is relation Δ(%) and value of
external resistor.
Fig.2-5 Δ% vs.Radj(up) (2)
0.1
1
10
100
1000
0 10 20 30 40
Change in Output Voltage Δ（%)
Radj (down) (kΩ)
10
100
1000
10000
0 10 20
Change in Output Voltage Δ（%)
Radj (up) (kΩ)
12V
28V
+V
+S
TRM
-S
-V
Radj(up)
+
-
PAH200H
Series
Load
Power
module
+V
+S
TRM
-S
-V
Radj(down)
+
-
PAH200H
Series
Load
Power
module

PAH300･350S24-SERIES
TDK-Lambda
8
3. Maximum Ripple and Noise
Measured value according to the specified methods
based on JEITA-9141 (Clause 7.12 and clause 7.13)
which is described in the following.
Connect according to fig.3-1 and measure. Connect
capacitors (C2, C3: film capacitor or ceramic capacitor
0.022μF) between output terminals and the nearest
M3 threaded hole. Connect capacitors (C4: refer to
table 1-1 for electrolytic capacitor values, C5: ceramic
capacitor 0.1μF) at 50mm distance from the output
terminals. Measure at ceramic capacitor (C5) terminals
as shown in fig. 3-1 using coaxial cable with JEITA
attachment. Use oscilloscope with 100MHz frequency
bandwidth or equivalent.
Take note that output ripple voltage and output spike
noise may vary depending on PCB wiring design.
Generally, output ripple voltage and output spike
noise can be reduced by increasing capacitance value
of external capacitor.
JEITA Attachment
R:50Ω
C:4700pF
+
50mm
+V
-V
As short as possible
Coaxial Cable
1.5m 50Ω
C5
C4
R
C
C2
C3
Load
-S
+S
Oscilloscope
Fig.3-1 Measurement of Maximum Output Ripple &
Noise
4. Maximum Line Regulation
Maximum value of output voltage change when input
voltage is gradually varied (steady state) within
specified input voltage range.
5. Maximum Load Regulation
Maximum value of output voltage change when
output current is gradually varied (steady state) within
specified output current range.
When using at dynamic load mode, audible noise
could be heard from the power module and output
voltage fluctuation might increase. A thorough pre-
evaluation must be performed before using this power
module.
6. Over Current Protection (OCP)
This power module has built-in OCP function.
Output will recover when short circuit or overload
conditions are released. OCP setting value is fixed and
therefore, cannot be externally adjusted.
Also, take note that power module might be damaged
continuing output short circuit or over load conditions
depending on thermal conditions.
7. Over Voltage Protection (OVP)
This power module has built-in OVP function.
OVP set point is relative to the rated output voltage
value. OVP setting value is fixed and therefore, can not
be externally adjusted.
When OVP is triggered, output can be recovered by
turning input line off and then turning it on again after
lowering the input voltage below the voltage value
indicated below, or by manual reset of the CNT
terminal. Reset time for CNT terminal is 100ms or
longer.
OVP release input voltage value : 3VDC and below
When verifying OVP function by applying external
voltage at the output terminals, applied voltage value
should not exceed specified OVP maximum value.
Refer to specification table for OVP maximum value.
Avoid applying external voltage that exceeds OVP
maximum value because this will cause power module
damage.
8. Over Temperature Protection (OTP)
This power module has built-in OTP function.
This function operates and shuts down the output when
ambient temperature or internal temperature of power
module abnormally rises. OTP operates at 105℃ to
130℃ baseplate temperature. OTP can be released when
baseplate temperature drops down approximately to
within 80℃ to 95℃. However, take note that OTP will
operate again unless the cause of abnormal heat of the
power module is eliminated.
9. Remote Sensing (+S, -S terminal)
Remote sensing terminal is provided to compensate for
voltage drop across the wirings from the power module
output terminal to the load input terminal.
When remote sensing function is not used (local sensing),
short +S terminal to +V terminal and, –S terminal to –V
terminal.
Take note that voltage compensation range for line
drop (voltage drop due to wiring) is determined such
that output voltage at the output terminals is within
output voltage range and that voltage between –V and –
S terminals is within 2V or less. Even for remote
sensing case, use power module such that output power

PAH300･350S24-SERIES
TDK-Lambda
9
is within specified maximumoutput power.
Furthermore, reduce noise effect by using shield wire,
twist pair, or parallel pattern.
Load
Stabilize the output voltage
+
-
+V
-V
-S
+S
+
+
ＴＲＭ
at load terminals
Fig.9-1 Remote Sensing is in Use
Load
Stabilize the output voltage
+
-
+V
-V
-S
+S
+
ＴＲＭ
at output terminals
Fig.9-2 Remote Sensing is Not in Use
10. ON/OFF Control (CNT terminal)
Without turning the input supply on and off, the
output can be enabled and disabled using this
function. This function also can be used for output
sequence of plural power modules.
There are two kinds of logic control, Negative logic
control and Positive logic control, depend on the
option selected.
ON/OFF control circuit is on the primary side (the
input side). For secondary control, isolation can be
achieved through the use of an opto-coupler or relay.
Notes
1. When ON/OFF control function is not used for
the Standard and /T option, CNT terminal should
be shorted to –Vin terminal.
2. When ON/OFF control function is not used for
the /P option and /PT option, CNT terminal
should be opened.
3. When using long wiring, for prevention of noise,
attach a 0.1µF capacitor between CNT terminal
and –Vin terminal.
4. At L level, maximum source current from CNT
terminal to –Vin terminal is 0.5mA
5. The maximum CNT terminal voltage is 35V.
(1) Output ON/OFF control
Fig.10-1 CNT Connection (1)
(2) Secondary (output side) control
Fig.10-2 CNT Connection (2)
11. Parallel Operation
Parallel Operation can not be used.
12. Series Operation
Series operation is possible for PAH300 ･350S24
series. Connections shown fig. 12-1 and fig. 12-2 are
possible.
+
+
+
-
Load
+V
+S
-S
-
V
TRM
+
V
+S
-S
-V
TRM
Fig.12-1 Series Operation due to High Output
Voltage
Logic CNT Terminal Level to -Vin Terminal Output status
Standard H Level (4V≦H≦35V) or Open OFF
/T option L Level (0V≦L≦0.8V) or Short ON
/P option H Level (4V≦H≦35V) or Open ON
/PT option L Level (0V≦L≦0.8V) or Short OFF
Negative Logic
Positive Logic
+Vin
CNT
-Vin
Transistor, Relay
or Equivalent
PAH200H
series
Power
module
+Vin
CNT
-Vin
Secondary
(output side)
PAH200H
series
Power
module

PAH300･350S24-SERIES
TDK-Lambda
10
+
+
+
-
Load
Load
+
-
+
V
+S
-S
-
V
TRM
+
V
+S
-S
-V
TRM
Fig.12-2 Series Operation due to ±Output
13. Operating ambient Temperature
There is no restriction on mounting direction but there
should be enough consideration for airflow so that heat
does not accumulate around the power module vicinity.
Determine external components configuration and
mounting direction on PCB such that air could flow
through the heatsink at forced cooling and conventional
cooling.
By maintaining actual baseplate temperature below
100℃, operation is possible.
For details on thermal design, refer to Application
Notes “Thermal Design”.
Note :
Maximum baseplate temperature is 100℃. For worst
case operating condition, verify baseplate temperature at
measurement point indicated in fig. 13-1.
Measurement Point
of Baseplate
Temperature
21mm
Input Side Output Side
CL
Fig.13-1 Measurement Point of
Baseplate Temperature
For better improvement of power module reliability,
derating of baseplate temperature when using is
recommended.
14. Operating Ambient Humidity
Take note that moisture could lead to power module
abnormal operation or damage.
15. Storage Ambient Temperature
Abrupt temperature change would cause moisture
formation that leads to poor solderabilty of each
terminal of the power module.
16. Storage Ambient Humidity
Take enough care when storing the power module
because rust which causes poor solderability would form
in each terminal when stored in high temperature, high
humidity environment.
17. Cooling Method
Operating temperature range is specified by the
baseplate temperature. Therefore, several methods of
heat dissipation are possible.
For details on thermal design, refer to Application Notes
“Thermal Design”.
18. Baseplate Temperature vs. Output
Voltage Drift
Output voltage drift is defined as the rate of voltage
change when baseplate temperature only is changed during
operation.
19. Withstand Voltage
This power module is designed to have a withstand
voltage of 1.5kVDC between input and baseplate,
1.5kVDC between input and output and 500VDC
between output and baseplate for 1 minute. When
conducting withstand voltage test during incoming
inspection, be sure to apply DC voltage. Also, set the
current limit value of the withstand voltage testing
equipment to 10mA.
Be sure to avoid conducting test with AC voltage
because this would cause power module damage.
Furthermore, avoid throw in or shut off of the testing
equipment when applying or when shutting down the
test voltage. Instead, gradually increase or decrease the
applied voltage. Take note especially not to use the
timer of the test equipment because when the timer
switches the applied voltage off, impulse voltage which
has several times the magnitude of the applied voltage
is generated causing damage to the power module.
Connect the terminals as shown in the diagram below.

PAH300･350S24-SERIES
TDK-Lambda
11
Withstand voltage Tester
+Vin
CASE
CNT
-Vin
+V
+S
TRM
-S
-V
1.5kVDC 1 minute (10mA)
Fig.19-1 Withstand Voltage Test for Input-Output
and Input-Baseplate
Withstand voltage Tester
+Vin
CASE
CNT
-Vin
+V
+S
TRM
-S
-V
500VDC 1minute (10mA)
Fig.19-2 Withstand Voltage Test for Output-Baseplate
20. Isolation Resistance
Use DC isolation tester (MAX 500V) between output
and baseplate. Isolation resistance value is 100MΩ and
above at 500VDC applied voltage. Also take note that
depending on the isolation tester used, some testers
generate high voltage pulse. Discharge the power module
after test using a resistor, etc.
DC Isolation Tester
+Vin
CASE
CNT
-Vin
+V
+S
TRM
-S
-V
Over 100MΩ at 500VDC
Fig.20-1 Isolation Test
21. Vibration
Vibration of power module is defined in case of
mounting on printed circuit board.
22. Shock
Withstand shock value is defined to be the value at
Densei -Lambda shipment and packaging conditions.
23. CE MARKING / UKCA MARKING
CE MARKING
CE Marking, when applied to a product or packing
material for a product covered by this handbook,
indicates compliance with the Low Voltage
Directive and RoHS Directive.
UKCA MARKING
UKCA Marking, when applied to a product or
packing material for a product covered by this
handbook, indicates compliance with the Electrical
Equipment (Safety) Regulations and Restriction of
the Use of Certain Hazardous Substances in
Electrical & Electronic Equipment Regulations.

PAH300･350S24-SERIES
TDK-Lambda
12
■ Installation
1. Mounting Method
By the following instruction shown in Fig.1-1 and Fig.1-2,
mount power module onto printed circuit board.
Fig.1-1 Mounting method
for standard model and /P option model
Fig.1-2 Mounting method
for /T option model and /PT option model
(1) Method to Fix
(1-1) Standard model and /P option model
To fix a power module onto printed circuit board, use
M3 screws and mount it to the M3 threaded holes
(4 places) of the power module. Recommended torque is
0.54N∙m.
(1-2) /T option model and /PT option model
To fix a power module onto printed circuit board, use
M3 screws and mount it to the M3 threaded holes of the
heatsink (4 places) through the φ3.4 non-threaded holes
(4 places) of the power module. Recommended torque is
0.54N∙m
(2) Mounting Holes
Mounting holes of the power module are connected to
baseplate. Connect baseplate to FG (Frame Ground) by
using this mounting holes.
(3) Mounting Holes on Printed Circuit Board
Refer to the following sizes when determining diameter of
hole and land diameter of printed circuit board.
Input / Signal terminals (φ1.0 mm )
Hole diameter : φ1.5 mm
Land diameter : φ3.0 mm
Output terminals (φ2.0 mm )
Hole diameter : φ2.5 mm
Land diameter : φ4.5 mm
Mounting Holes (FG)
Hole diameter : φ3.5 mm
Land diameter : φ5.5 mm
For position of the holes, see outline drawing of the
power module.
(4) Recommended Material of PCB
Recommended materials of the printed circuit board is
double sided glass epoxy with through holes.
(thickness t:1.6mm , copper 35μm).
(5) Input/ Output terminal pin
Connect +Vin, -Vin, +V, -V terminals such that
contact resistance is minimal. Note that if contact
resistance is high, efficiency will drop and power
module will be damaged by abnormal heat.
(6) Input / Output Pattern Width
Large current flows through input and output pattern.
If pattern width is too narrow, heat on pattern will
increase because of voltage drop of pattern.
Relationship between allowable current and pattern
width varies depending on materials of printed circuit
board, thickness of conductor. It is definitely necessary
to confirm on manufacturers of printed circuit board for
designing pattern.
M3 Threaded
Mounting Hole
Heatsink
Silicone grease
φ3.4 Non-threaded
Mounting Hole
Power Module
Printed Circuit Board
Plain Washer
Spring Washer
M3 Screw
M3 Screw
Spring Washer
Plain Washer
Heatsink
Silicone grease
M3 Threaded
Mounting Hole
Power Module
Printed Circuit Board
Plain Washer
Spring Washer
M3 Screw

PAH300･350S24-SERIES
TDK-Lambda
13
2. Heatsink Installation Method
(1) Method to Fix
(1-1) Standard model and /P option model
To fix the heatsink onto power module, use M3
screws and mount it to the M3 threaded holes
(4 places) at the baseplate side. Recommended
torque is 0.54 N∙m.
(1-2) /T option model and /PT option model
To fix the heatsink onto power module, use M3
screws those are the same screws for mounting power
module onto printed circuit board.
Use silicone grease or thermal conductive sheet in
between heatsink and baseplate to minimize the contact
thermal resistance and to enhance the heat conductivity.
Also use the no-warped heatsink and make sure good
contact between baseplate and heatsink.
(2) Mounting Hole of Heatsink
Recommended mounting hole is as follows.
(2-1) Standard model and /P option model
φ3.5 Non-threaded hole
(2-2) Standard model and /P option model
M3 Threaded hole
3. Regarding Vibration
The vibration specification of the module is
determined assuming that only the power module is
mounted on printed circuit board. To prevent excessive
force to the module and the printed circuit board, fix
the heatsink to the chassis as well as to the module
when a large size of heastsink is used.
4. Recommended Soldering Method
Recommended soldering conditions are as follows.
(1) Soldering dip
Dip condition : 260ºC within 10 seconds
Pre-heat condition : 110ºC during 30~40 seconds
(2) Soldering iron
φ1.0 mm : 350ºC (60W) within 3 seconds
φ2.0 mm : 350ºC (150W) within 20 seconds
※Soldering time changes according to heat capacity of
soldering iron, pattern on printed circuit board, etc.
Please confirm actual performance.
5. Recommended Cleaning Condition
Recommended cleaning condition after soldering is
as follows.
(1) Cleaning solvent
IPA (isopropyl alcohol )
(2) Cleaning Procedure
Use brush and dry the solvent completely.

PAH300･350S24-SERIES
TDK-Lambda
14
■ Before concluding power module damage
Verify following items before concluding power
module damage.
1) No output voltage
・Is specified input voltage applied?
・ Are the ON/OFF control terminal (CNT), remote
sensing terminal (+S, -S), output voltage trimming
terminal (TRM) correctly connected?
・ For cases where output voltage adjustment is used, is
the resistor or variable resistor setting, connections
correctly done?
・ Are there no abnormalities in the output load used?
・ Is the baseplate temperature within the specified
temperature range?
2) Output voltage is high
・ Are the remote sensing terminals (+S, -S) correctly
connected?
・ Is the measurement done at the sensing points?
・ For cases where output voltage adjustment is used, is
the resistor or volume setting, connections correctly
done?
3) Output voltage is low
・Is specified input voltage applied?
・ Are the remote sensing terminals (+S, -S) correctly
connected?
・ Is the measurement done at the sensing points?
・ For cases where output voltage adjustment is used, is
the resistor or variable resistor setting, connections
correctly done?
・ Are there no abnormalities in the output load used?
4) Load regulation and line regulation is large
・Is specified input voltage applied?
・ Are the input terminals and the output terminals
firmly connected?
・Is the measurement done at the sensing points?
・Is the input or output wire too thin?
5) Output ripple voltage is large
・ Is the measuring method used the same or equivalent
with the specified method in the Application Notes?
・Is the input ripple voltage value within the specified
value?