PAH-28 Vout, 350-Watt Series
www.murata-ps.com
Isolated, 350-Watt, Half-Brick DC-DC Converters
Output (V)
Current (A)
Input Voltage (V)
28
12.5
18-36 or 36-75
Typical unit
FEATURES
PRODUCT OVERVIEW
28Vout @ 12.5A (350W)
For applications requiring improved electrical and
thermal performance, consider Murata’s new PAH
series “Half Brick” DC-DC power converters. These
compact modules measure 2.3" X 2.4" X 0.5" (58
X 61 X 12.7mm) and offer the industry-standard
Half Brick footprint.
Trimmable 16.8 Vout to 32.2 Vout @ 350W
with Vin = 18-36V (D24) or 36-75V (D48)
Industry Standard “Half Brick” package
High Efficiency: up to 93%
Outstanding thermal performance
Standard baseplate for conduction cooled
applications
No output reverse conduction
Input to Output Isolation, 2250Vdc (Basic)
The PAH Series is ideal for power amplifier
applications, wireless networks, and telecom
applications. The baseplate provides a means for
conduction cooling in demanding thermal environment conditions.
Input under-voltage lockout
The module provides a 28Vdc output at 12.5 Amps
and accepts a wide input voltage range of 18-36 or
36-75 Vdc. The PAH topology offers high efficiency
(up to 93%), tight line and load regulation, low ripple/
noise, and a fast dynamic load response. A singleboard, highly optimized thermal design contributes to
the superior thermal performance.
These half-bricks provide output trim, sense
pins, and primary side on/off control. Standard features also include input under-voltage shutdown,
output over-voltage protection, output short-circuit/
current limiting protection, and thermal shutdown.
On/Off Control (Positive or Negative Logic)
Output over-voltage protection
Thermal shutdown
Output short circuit protection (hiccup
technique)
Certified to UL/EN 60950-1, CSA-C22.2 No.
60950-1, 2nd edition safety approvals
F1
+Vin
+Vout
Barrier
Case ground
External
DC
Power
Source
NOTE: A minimum of 470μF
of capacitance is required
on the output to ensure
Cout stable operation. An ESR
equal to or less than 0.02Ω
is also required.
Controller
and Power
On/Off
Control
Open = On
Reference and
Error Amplifier
Trim
logic)
-Vin
-Vout
Figure 1. Simplified Schematic
Typical topology is shown. Some models may vary slightly.
For full details go to
www.murata-ps.com/rohs
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MDC_PAH-28Vout-350W.B03 Page 1 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
PERFORMANCE SPECIFICATIONS SUMMARY AND ORDERING GUIDE
Output
Input
Efficiency
VOUT
(Volts)
IOUT
(Amps,
Max.)
(Watts)
Typ.
Max.
Line
PAH-28/12.5-D24
28
12.5
350
75
200
PAH-28/12.5-D48
28
12.5
350
100
300
Root Model ➀
Power
R/N (mV pk-pk)
Load
VIN Nom.
(Volts)
Range
(Volts)
IIN, no
load
(mA)
IIN, full
load
(Amps)
Min. ➃
Typ.
Dimensions
(inches)
±0.125%
±0.25%
24
18-36
80
15.7
91.5%
92.5%
2.3 x 2.4 x 0.5
±0.25%
±0.25%
48
36-75
80
7.84
92%
93%
2.3 x 2.4 x 0.5
Regulation (Max.)
➀ Please refer to the part number structure for additional ordering part numbers and options.
➁ All specifications are at nominal line voltage and full load, +25°C. unless otherwise noted. See
➂ Full power continuous output requires baseplate installation. Please refer to the derating curves.
➃ Minimum efficiency applies to all input voltages and working temperatures.
detailed specifications.
PART NUMBER STRUCTURE
PAH - 28 / 12.5 - D48 N Bx H Lx - C
Power Amplifier
Half-Brick
RoHS Hazardous Materials compliance
C = RoHS-6 (no lead), standard, does not claim EU exemption 7b – lead in solder
Nominal Output Voltage
Maximum Output Current
in Amps
Pin length option
Blank = standard pin length 0.180 in. (4.57 mm)
L1 = 0.110 in. (2.79 mm)*
L2 = 0.145 in. (3.68 mm)*
Input Voltage Range:
D24 = 18-36 Volts (24V nominal)
D48 = 36-75 Volts (48V nominal)
On/Off Control Logic
N = Negative logic
P = Positive logic
Conformal coating (optional)
Blank = no coating, standard
H = Coating added*
Baseplate (installed on all models)
B = Baseplate installed with standard M3-12.7 threaded rivet (typ. 4)
B1 = Baseplate installed with unthreaded insert
(see Mechanical section for details).
*Minimum order quantity is required.
Samples available with standard pin
length only.
Note:
Some model number combinations may
not be available. See website or contact
your local Murata sales representative.
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MDC_PAH-28Vout-350W.B03 Page 2 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
FUNCTIONAL SPECIFICATIONS, PAH-28/12.5-D24
ABSOLUTE MAXIMUM RATINGS
Input Voltage, Continuous
Input Voltage, Transient
Isolation Voltage
On/Off Remote Control
Output Power
Conditions
Minimum
Typical/Nominal
0
100 mS max. duration
Input to output
Power on, referred to -Vin
0
0
Maximum
Units
36
50
2250
13.5
357
Vdc
Vdc
Vdc
Vdc
W
Current-limited, no damage, short-circuit
0
12.5
A
protected
Storage Temperature Range
Vin = Zero (no power)
-55
125
˚C
Absolute maximums are stress ratings. Exposure of devices to greater than 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.
Output Current
INPUT
Operating voltage range
Start-up threshold
Undervoltage shutdown
Internal Filter Type
External Input fuse
Input current
Full Load Conditions
Low Line input current
Inrush Transient
Short Circuit input current
No Load input current
Shut-Down input currrent(Off, UV, OT)
Back Ripple Current
18
14.5
11.5
24
36
16.5
14
Pi
35
Vin = nominal
Vin = minimum
Vin = 24V.
15.77
1
0.03
80
5
80
Iout = minimum, unit=ON
16.26
22
0.10
100
15
120
Vdc
Vdc
Vdc
Vdc
A
A
A
A2-Sec.
A
mA
mA
mA, pk-pk
GENERAL and SAFETY
Efficiency
Isolation
Isolation Voltage
Vin=24V, full load
91.5
Input to output
Input to Baseplate
Output to Baseplate
Calculated MTBF
%
2250
1500
1500
Insulation Safety Rating
Isolation Resistance
Isolation Capacitance
Safety
92.5
Basic
10
1500
Certified to UL-60950-1, CSA-C22.2 No.609501, IEC/EN60950-1, 2nd edition (pending)
Per Telcordia SR-332, Issue 2, Method 1, Class
1, Ground Fixed, Tcase=+25°C
Vdc
Vdc
Vdc
MΩ
pF
Pending
1200
Hours x 103
300
KHz
DYNAMIC CHARACTERISTICS
Fixed Switching Frequency
Turn On Time
Startup Delay
Rise Time
Vout Rise Time
From 0%~100%
Dynamic Load Response
Dynamic Load Peak Deviation
Vin On to 10% Vout or Remote On to 10% Vout
10% Vout to 90% Vout
50-75-50%, 1A/μs,within 1% of Vout
same as above
25
28
35
35
mS
mS
28
±200
35
100
±400
mS
μSec
mV
1
13.5
1
2
V
V
mA
1
0.8
13.5
2
V
V
mA
2
% of Vout
FEATURES and OPTIONS
Remote On/Off Control
“P” suffix:
Positive Logic, ON state
Positive Logic, OFF state
Control Current
“N” suffix:
Negative Logic, ON state
Negative Logic, OFF state
Control Current
Remote Sense Compliance
ON = pin open or external voltage
OFF = ground pin or external voltage
open collector/drain
3.5
0
ON = ground pin or external voltage
OFF = pin open or external voltage
open collector/drain
Sense pins connected externally to respective
Vout pins
-0.1
2.5
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MDC_PAH-28Vout-350W.B03 Page 3 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
FUNCTIONAL SPECIFICATIONS, PAH-28/12.5-D24 (CONT.)
OUTPUT
Total Output Power
Voltage
Setting Accuracy
Output Adjust Range
Overvoltage Protection
Current
Output Current Range
Minimum Load
Current Limit Inception ➃
Short Circuit
Short Circuit Current
Short Circuit Duration
(remove short for recovery)
Short circuit protection method
Regulation ➄
Line Regulation
Load Regulation
Ripple and Noise
Temperature Coefficient
Maximum Output Capacitance
Conditions
At 100% load, no trim, all conditions
Minimum
Typical/Nominal
Maximum
Units
0
350
357
W
27.44
16.8
34
28
28.56
32.2
37
Vdc
Vdc
Vdc
12.5
A
19
A
0
98% of Vnom., cold
14
Hiccup technique,
autorecovery within ±1% of Vout
34.6
12.5
No minimum load
16
0.03
A
Output shorted to ground, no damage
Continuous
Hiccup current limiting
Non-latching
Vin = 18-36, Vout = nom., full load
Iout = min. to max., Vin = nom.
20 MHz BW, Cout = 1μF paralleled with 10μF
At all outputs
(Loads : CR mode)
(Loads : CC mode)
±0.125
±0.25
200
75
0.02
470
470
3,300
2,200
%
%
mV pk-pk
% of Vnom./°C
μF
μF
MECHANICAL
Outline Dimensions
with baseplate; see mechanical drawings
2.3 x 2.4 x 0.5
58.4 x 60.96 x 12.7
3.42
97
0.04/0.08
1.016/2.032
Copper alloy
100-299
10.31
Weight
Through Hole Pin Diameter
Through Hole Pin Material
TH Pin Plating Metal and Thickness
Pins 1–4, 6–8/5,9
Nickel subplate
Gold overplate
Inches
mm
Ounces
Grams
Inches
mm
μ-inches
μ-inches
ENVIRONMENTAL
Operating Ambient Temperature Range
Operating Baseplate Temperature
Storage Temperature
Thermal Protection/Shutdown
(with "B" Suffix)
Electromagnetic Interference
Conducted, EN55022/CISPR22
RoHS rating
with derating
Vin = Zero (no power)
-40
-40
-55
115
External filter required;
see emissions performance test.
125
B
85
115
125
˚C
˚C
˚C
130
˚C
Class
RoHS-6
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MDC_PAH-28Vout-350W.B03 Page 4 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
TYPICAL PERFORMANCE DATA, PAH-28/12.5-D24
Efficiency and Power Dissipation
96
32
92
28
24
VIN = 36V
VIN = 24V
VIN = 18V
84
20
80
16
76
12
Power Dissipation
VIN = 24V
72
Dissipation (Watts)
Efficiency (%)
88
8
68
4
64
0.5
1.7
2.9
4.1
5.3
6.5
7.7
Iout (Amps)
8.9
10.1
11.3
0
12.5
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MDC_PAH-28Vout-350W.B03 Page 5 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
TYPICAL PERFORMANCE DATA, PAH-28/12.5-D24
Transverse
Longitudinal
Maximum Current Temperature Derating at sea level
(Vin=18V, airflow from Vin to Vout, open frame)
14
14
12
12
10
10
Output Current (Amps)
Output Current (Amps)
Maximum Current Temperature Derating at sea level
(Vin=18V, airflow from Vin- to Vout+, open frame)
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
8
6
4
2
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
8
6
4
2
0
0
30
35
40
45
50
55
60
65
70
75
80
85
30
35
40
45
Ambient Temperature (°C)
12
12
10
Output Current (Amps)
Output Current (Amps)
14
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
4
2
65
70
75
80
85
10
75
80
85
75
80
85
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
8
6
4
2
0
0
30
35
40
45
50
55
60
65
70
75
80
85
30
35
40
45
Ambient Temperature (°C)
12
12
10
10
Output Current (Amps)
14
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
6
55
60
65
70
Maximum Current Temperature Derating at sea level
(Vin=36V, airflow from Vin to Vout, open frame)
14
8
50
Ambient Temperature (°C)
Maximum Current Temperature Derating at sea level
(Vin=36V, airflow from Vin- to Vout+, open frame)
Output Current (Amps)
60
Maximum Current Temperature Derating at sea level
(Vin=24V, airflow from Vin to Vout, open frame)
14
6
55
Ambient Temperature (°C)
Maximum Current Temperature Derating at sea level
(Vin=24V, airflow from Vin- to Vout+, open frame)
8
50
4
2
8
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
6
4
2
0
0
30
35
40
45
50
55
60
65
Ambient Temperature (°C)
70
75
80
85
30
35
40
45
50
55
60
65
70
Ambient Temperature (°C)
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MDC_PAH-28Vout-350W.B03 Page 6 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
TYPICAL PERFORMANCE DATA, PAH-28/12.5-D24
Transverse
Longitudinal
Maximum Current Temperature Derating at sea level
(Vin=18V, airflow from Vin to Vout, with baseplate)
14
14
12
12
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
10
8
Output Current (Amps)
Output Current (Amps)
Maximum Current Temperature Derating at sea level
(Vin=18V, airflow from Vin- to Vout+, with baseplate)
6
4
2
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
10
8
6
4
2
0
0
30
35
40
45
50
55
60
65
70
75
80
85
30
35
40
45
Ambient Temperature (°C)
12
12
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
Output Current (Amps)
Output Current (Amps)
14
6
4
2
65
70
75
80
85
10
75
80
85
75
80
85
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
8
6
4
2
0
0
30
35
40
45
50
55
60
65
70
75
80
85
30
35
40
45
Ambient Temperature (°C)
12
12
10
10
Output Current (Amps)
14
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
6
55
60
65
70
Maximum Current Temperature Derating at sea level
(Vin=36V, airflow from Vin to Vout, with baseplate)
14
8
50
Ambient Temperature (°C)
Maximum Current Temperature Derating at sea level
(Vin=36V, airflow from Vin- to Vout+, with baseplate)
Output Current (Amps)
60
Maximum Current Temperature Derating at sea level
(Vin=24V, airflow from Vin to Vout, with baseplate)
14
8
55
Ambient Temperature (°C)
Maximum Current Temperature Derating at sea level
(Vin=24V, airflow from Vin- to Vout+, with baseplate)
10
50
4
2
8
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
6
4
2
0
0
30
35
40
45
50
55
60
65
Ambient Temperature (°C)
70
75
80
85
30
35
40
45
50
55
60
65
70
Ambient Temperature (°C)
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MDC_PAH-28Vout-350W.B03 Page 7 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
FUNCTIONAL SPECIFICATIONS, PAH-28/12.5-D48
ABSOLUTE MAXIMUM RATINGS
Input Voltage, Continuous
Input Voltage, Transient
Isolation Voltage
Input Reverse Polarity
On/Off Remote Control
Output Power
Conditions ➀
Minimum
Full power operation
Operating or non-operating, tested:
100 mS max. duration
Input to output
None, install external fuse
Power on or off, referred to -Vin
0
Typical/Nominal
0
Maximum
Units
80
Vdc
100
Vdc
2250
Vdc
Vdc
Vdc
W
None
0
0
350
15
355.25
Current-limited, no damage,
0
12.5
A
short-circuit protected
Storage Temperature Range
Vin = Zero (no power)
-55
125
˚C
Absolute maximums are stress ratings. Exposure of devices to greater than 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.
Output Current
INPUT
Operating voltage range
Recommended External Fuse
Turn On/Start-up threshold tested at 1/2 load
Turn Off/Undervoltage lockout tested at 1/2 load
Reverse Polarity Protection
Internal Filter Type
Input current
Full Load Conditions
Low Line
Inrush Transient
Output in Short Circuit
No Load Input Current
Shut-Down Mode Input Current
Reflected (back) ripple current ➁
Fast blow
Rising input voltage
Falling input voltage
None, install external fuse
36
48
33
31
34
32
None
Pi
Vin = nominal
Vin = minimum
7.84
10.57
2.5
60
80
5
40
Iout = minimum, unit=ON
Measured at input with specified filter
75
20
35
33
Vdc
A
Vdc
Vdc
Vdc
8.04
10.84
5
100
100
10
80
A
A
A2-Sec.
mA
mA
mA
mA, pk-pk
GENERAL and SAFETY
Efficiency
Vin=48V, full load, +25˚C.
@ Vin=Max
92
91.0
93
92.0
%
%
2250
1500
1500
basic
10
1,000
Vdc
Isolation
Isolation Voltage
Input to output, continuous
Input to Baseplate, continuous
Output to Baseplate, continuous
Insulation Safety Rating
Isolation Resistance
Isolation Capacitance
Safety
Calculated MTBF
Certified to UL-60950-1, CSA-C22.2 No.609501, IEC/EN60950-1, 2nd edition
Per Telcordia SR332, issue 1 class 3, ground
fixed, Tambient=+25˚C
Mohm
pF
Yes
Hours x 106
1.2
DYNAMIC CHARACTERISTICS
Fixed Switching Frequency
Startup Time
Startup Time
Dynamic Load Response
Dynamic Load Peak Deviation
380
Power On to Vout regulated
(100% resistive load)
Remote ON to 10% Vout (50% resistive load)
50-75-50% load step, settling time to within
±1% of Vout di/dt = 1 A/μSec
same as above
420
460
KHz
25
50
mS
25
50
mS
2500
3500
μSec
±500
±1000
mV
1
0.8
15
2
V
V
mA
15
1
2
10
V
V
mA
% of Vout
FEATURES and OPTIONS
Remote On/Off Control ➂
“N” suffix:
Negative Logic, ON state
Negative Logic, OFF state
Control Current
“P” suffix:
Positive Logic, ON state
Positive Logic, OFF state
Control Current
Remote Sense Compliance
Pin open=ON
–0.1
2.5
open collector/drain
Pin open=ON
open collector/drain
Vsense=Vout–Vload, Sense connected at load
3.5
0
1
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MDC_PAH-28Vout-350W.B03 Page 8 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
FUNCTIONAL SPECIFICATIONS, PAH-28/12.5-D48 (CONT.)
OUTPUT
Conditions
Minimum
Typical/Nominal
Maximum
Units
Total Output Power
Voltage
Nominal Output Voltage
Setting Accuracy
Output Voltage Range
Overvoltage Protection
Current
Output Current Range
Minimum Load
Current Limit Inception ➃
Short Circuit
See Derating
0.0
350
355.25
W
No trim
At 50% load
User-adjustable
Via magnetic feedback
27.58
-1.5
16.8(-40%)
34
28
28.42
1.5
32.2(+15%)
50
Vdc
% of Vnom.
Vdc
Vdc
Short Circuit Current
Short Circuit Duration
(remove short for recovery)
Short circuit protection method
Regulation ➄
Line Regulation
Load Regulation
Ripple and Noise
Temperature Coefficient
External output capacitance required ➅
36
0
98% of Vnom., after warmup
16
Hiccup technique,
autorecovery within ±1% of Vout
Output shorted to ground, no damage
12.5
A
No minimum load
19
25
A
0.01
0.1
A
±0.25
±0.25
300
%
%
mV pk-pk
% of Vnom./°C
μF
Continuous
Current limiting
Vin=min. to max. Vout=nom.
Iout=min. to max. Vin=48V.
5 Hz- 20 MHz BW
At all outputs
Cap. ESR=<0.02Ω, Full resistive load
100
±0.015
470
4700
MECHANICAL (Through Hole Models)
Outline Dimensions
with baseplate; see mechanical drawings
2.3 x 2.4 x 0.5
58.4 x 60.96 x 12.7
3.67
104
0.04/0.08
1.016/2.032
Copper alloy
100-299
10.31
Aluminum
Weight
Through Hole Pin Diameter
Through Hole Pin Material
TH Pin Plating Metal and Thickness
Pins 1–4, 6–8/5,9
Nickel subplate
Gold overplate
Case or Baseplate Material
Inches
mm
Ounces
Grams
Inches
mm
μ-inches
μ-inches
ENVIRONMENTAL
Operating Ambient Temperature Range
Operating Case Temperature
Storage Temperature
Thermal Protection/Shutdown
Electromagnetic Interference
Conducted, EN55022/CISPR22
Radiated, EN55022/CISPR22
Relative humidity, non-condensing
Altitude
(must derate -1%/1000 feet)
RoHS rating
Notes
With derating, full power, measured at Tref
Vin = Zero (no power)
Measured in center
-40
-40
-55
115
External filter required
125
85
120
125
130
B
Class
B
To +85°C
➀ Unless otherwise noted, all specifications are at nominal input voltage, nominal output voltage
and full load. General conditions are +25˚ Celsius ambient temperature, near sea level altitude,
natural convection airflow. All models are tested and specified with external parallel 1 μF and 470
μF output capacitors. A 220μF external input capacitors is required. All capacitors are low-ESR
types wired close to the converter.
➁ Input (back) ripple current is tested and specified over 5 Hz to 20 MHz bandwidth. Input filtering
is Cbus=220 μF/100V, Cin=470 μF/100V and Lbus=12 μH.
10
-500
-152
˚C
˚C
˚C
˚C
90
10,000
3048
Class
%RH
feet
meters
RoHS-6
➂ The Remote On/Off Control is referred to -Vin.
➃ Over-current protection is non-latching with auto reovery (Hiccup)
➄ Regulation specifications describe the output voltage changes as the line voltage or load current
is varied from its nominal or midpoint value to either extreme.
➅ Required minimum output capacitance is 470 μF, low ESR.
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MDC_PAH-28Vout-350W.B03 Page 9 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
TYPICAL PERFORMANCE DATA, PAH-28/12.5-D48
Efficiency and Power Dissipation, Ambient Temperature = +25°C
Output Power Derating in Conduction Cooling (Cold Baseplate) Applications
(Vin=48V, Ambient Temperature <70°C)
96
36
92
32
80
24
20
76
16
Power Dissipation
VIN = 48V
72
12
68
8
64
4
60
1.25
2.5
3.75
5
6.25
7.5
Iout (Amps)
8.75
10
11.25
Output Power (Watts)
84
Efficiency (%)
350
28
VIN = 75V
VIN = 48V
VIN = 36V
Dissipation (Watts)
88
375
325
300
275
0
12.5
250
20
30
40
50
60
70
80
90
100
Cold Baseplate (Interior) Temperature (°C)
Maximum Current Temperature Derating at sea level
(Vin=48V, longitudinal airflow, from Vin to Vout, with baseplate)
14
14
12
12
10
Output Current (Amps)
Output Current (Amps)
Maximum Current Temperature Derating at sea level
(Vin=48V, transverse airflow, from Vin- to Vout+, with baseplate)
0.25 m/s (50 LFM)
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
2.5 m/s (500 LFM)
3.0 m/s (600 LFM)
8
6
4
2
10
0.25 m/s (50 LFM)
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
2.5 m/s (500 LFM)
3.0 m/s (600 LFM)
8
6
4
2
0
0
30
35
40
45
50
55
60
65
70
75
80
85
30
35
40
45
50
Ambient Temperature (°C)
340
320
320
300
300
Output Power (Watts)
Output Power (Watts)
360
340
0.25 m/s (50 LFM)
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
2.5 m/s (500 LFM)
3.0 m/s (600 LFM)
240
220
200
280
70
75
80
85
80
85
0.25 m/s (50 LFM)
0.5 m/s (100 LFM)
1.0 m/s (200 LFM)
1.5 m/s (300 LFM)
2.0 m/s (400 LFM)
2.5 m/s (500 LFM)
3.0 m/s (600 LFM)
260
240
220
200
180
160
30
65
Maximum Current Temperature Derating at sea level
(Vin=48V, longitudinal airflow, from Vin to Vout, with baseplate)
360
260
60
Ambient Temperature (°C)
Maximum Current Temperature Derating at sea level
(Vin=48V, transverse airflow, from Vin- to Vout+, with baseplate)
280
55
180
35
40
45
50
55
60
65
Ambient Temperature (°C)
70
75
80
85
160
30
35
40
45
50
55
60
65
70
75
Ambient Temperature (°C)
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MDC_PAH-28Vout-350W.B03 Page 10 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
TYPICAL PERFORMANCE DATA, PAH-28/12.5-D48
On/Off Enable Startup (Vin=48V, Vout=nom, Iout=12.5A, Cload=470μF, Ta=+25°C)
Ch2=Vout, Ch4=Enable
Startup Delay (Vin=48V, Vout=nom, Iout=12.5A, Cload=470μF, Ta=+25°C)Ch1=Vin,
Ch2=Vout
Output Ripple and Noise (Vin=48V, Vout=nom, Iout=0A, Cload=470μF, Ta=+25°C)
Output Ripple and Noise (Vin=48V, Vout=nom, Iout=12.5A, Cload=470μF, Ta=+25°C)
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MDC_PAH-28Vout-350W.B03 Page 11 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
TYPICAL PERFORMANCE DATA, PAH-28/12.5-D48
Step Load Transient Response (Vin=48V, Vout=nom, Cload=470μF,
Iout=75 % to 50% of full load, Ta=+25°C)
Step Load Transient Response (Vin=48V, Vout=nom, Cload=470μF,
Iout=50% to 75% of full load, Ta=+25°C)
Step Load Transient Response (Vin=48V, Vout=nom, Cload=470μF,
Iout=50-75-50% of full load, Ta=+25°C)
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MDC_PAH-28Vout-350W.B03 Page 12 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
MECHANICAL SPECIFICATIONS
0.50 (12.7)
0.008 (0.20) Min
8
7
3
6
4
5
2.30 (58.42)
PINS 1-4,6-8:
ij 0.040±0.001(1.016±0.025)
PINS 5,9:
ij 0.082±0.001(2.083±0.025)
1.900 (48.26)
0.010 (0.254) Min
SECTION A-A
Dimensions are in inches (mm shown for ref. only).
Third Angle Projection
L
0.50 (12.7)
Bottom Pin Side View
0.335 (8.51) TYP 4PL
2
0.126 (3.2) THREADED TYP 4PL
9
1.400 (35.56)
1
0.600
(15.24)
2.40 (60.96)
1.400 (35.56)
0.600 (15.24)
PIN STANDOFF IS LOWER THAN DIA
3.2mm THROUGH HOLE RIVET STANDOFF
SEE NOTE 8
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25)
Angles ± 2˚
Components are shown for reference only.
2.00 (50.8)
MOUNTING INSERT OPTIONAL
B: M3 THREAD TYP 4PL
B1: ij 3.2 THRU HOLE TYP 4PL
NOTES:
UNLESS OTHERWISE SPECIFIED:
1:FOR OPTIONAL M3, THE M3 SCREW USED TO BOLT UNIT'S BASEPLATE TO OTHER
SURFACES (SUCH AS HEATSINK) MUST NOT OUT OF THE RANGE FROM 0.138''(3.5mm) TO
0.236''(6mm)DEPTH BELOW THE SURFACE OF BASEPLATE
2:APPLIED TORQUE PER SCREW SHOULD NOT EXCEED 5.3In-lb(0.6Nm);
3:ALL DIMENSION ARE IN INCHES[MILIMETER];
4:ALL TOLERANCES: ×.××in ,±0.02in(×.×mm,±0.5mm)
×.×××in ,±0.01in(×.××mm,±0.25mm)
5:COMPONENTS WILL VARY BETWEEN MODELS
6:OVERALL DIMENSIONS:2.30(58.42)×2.4(60.96)×0.50(12.7)
BEFORE REMOVAL OF PROTECTIVE HEAT SHIELD;
7:*The Remote On/Off Can Be Provided With Either Positive Or Negative ("N"Suffix) Logic
8:STANDARD PIN LENGTH: 0.180 Inch
FOR L2 PIN LENGTH OPTION IN MODEL NAME, USE STANDARD L2 PIN WITH PIN LENGTH TO 0.145 Inch
Top View
INPUT/OUTPUT CONNECTIONS
Pin
Function
1
−Vin
2
Case ground
3
On/Off Control
4
+Vin
5
+Vout
6
+Sense
7
Trim
8
−Sense
9
−Vout
Since there is some pinout inconsistency between manufacturers of half brick converters, be
sure to follow the pin function, not the pin number, when laying out your board.
Standard pin length is shown. Please refer to the Part Number Structure for special order pin
lengths.
* Note that the “case” connects to the baseplate (when installed). This case connection is
isolated from the rest of the converter. Pin 2 may be deleted under special order. Please contact
Murata Power Solutions for information.
The Trim connection may be left open and the converter will achieve its rated output voltage.
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MDC_PAH-28Vout-350W.B03 Page 13 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
BASEPLATE WITH STANDARD M3-12.7 THREADED RIVET
BASEPLATE WITH UNTHREADED INSERT
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MDC_PAH-28Vout-350W.B03 Page 14 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
SHIPPING TRAYS: LOW DENSITY CLOSED CELL POLYETHYLENE STATIC DISSIPATIVE FOAM
+.000
2.300
(58.42)
TYP
9.920 -.062
(251.97)
0.625
(15.86) TYP
0.50
(12.7)
9.920 +.000
-.062
(251.97)
0.625 (15.86) TYP
2.400 (60.96)
TYP
1.150
(29.21)
TYP
.25 (6.35) R TYP
.25 (6.35) CHAMFER TYP (4-PL)
SHIPPING BOXES
Anti-static foam
Label top side
Dimensions are in inches (mm shown for ref. only).
Third Angle Projection
Components are shown for reference only.
4.25
(107.95)
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25)
Angles ± 2˚
10
(25
4)
10 )
4
(25
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MDC_PAH-28Vout-350W.B03 Page 15 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
TECHNICAL NOTES
Input Fusing
Certain applications and/or safety agencies may require fuses at the inputs of
power conversion components. Fuses should also be used when there is the
possibility of sustained input voltage reversal which is not current-limited. For
greatest safety, we recommend a fast blow fuse installed in the ungrounded
input supply line.
The installer must observe all relevant safety standards and regulations. For
safety agency approvals, install the converter in compliance with the end-user
safety standard.
Input Reverse-Polarity Protection
If the input voltage polarity is 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 appropriately fused, it could cause permanent damage to the converter.
Input Under-Voltage Shutdown and Start-Up Threshold
Under normal start-up conditions, converters will not begin to regulate properly
until the ramping-up input voltage exceeds and remains at the Start-Up
Threshold Voltage (see Specifications). Once operating, converters will not
turn off until the input voltage drops below the Under-Voltage Shutdown Limit.
Subsequent restart will not occur until the input voltage rises again above the
Start-Up Threshold. This built-in hysteresis prevents any unstable on/off operation at a single input voltage.
Users should be aware however of input sources near the Under-Voltage
Shutdown whose voltage decays as input current is consumed (such as capacitor inputs), the converter shuts off and then restarts as the external capacitor
recharges. Such situations could oscillate. To prevent this, make sure the
operating input voltage is well above the UV Shutdown voltage AT ALL TIMES.
impedance, performance is improved by adding external filter components.
Sometimes only a small ceramic capacitor is sufficient. Since it is difficult to
totally characterize all applications, some experimentation may be needed.
Note that external input capacitors must accept high speed switching currents.
Because of the switching nature of DC-DC converters, the input of these
converters must be driven from a source with both low AC impedance and
adequate DC input regulation. Performance will degrade with increasing input
inductance. Excessive input inductance may inhibit operation. The DC input
regulation specifies that the input voltage, once operating, must never degrade
below the Shut-Down Threshold under all load conditions. Be sure to use
adequate trace sizes and mount components close to the converter.
I/O Filtering, Input Ripple Current and Output Noise
All models in this converter series are tested and specified for input reflected
ripple current and output noise using designated external input/output components, circuits and layout as shown in the figures below. External input capacitors
(Cin in the figure) serve primarily as energy storage elements, minimizing line
voltage variations caused by transient IR drops in the input conductors. Users
should select input capacitors for bulk capacitance (at appropriate frequencies), low ESR and high RMS ripple current ratings. In the figure below, the Cbus
and Lbus components simulate a typical DC voltage bus. Your specific system
configuration may require additional considerations. Please note that the values
of Cin, Lbus and Cbus will vary according to the specific converter model.
TO
OSCILLOSCOPE
+VIN
VIN
Start-Up Time
Assuming that the output current is set at the rated maximum, the Vin to Vout
Start-Up Time (see Specifications) is the time interval between the point when
the ramping input voltage crosses the Start-Up Threshold and the fully loaded
regulated output voltage enters and remains within its specified accuracy band.
Actual measured times will vary with input source impedance, external input
capacitance, input voltage slew rate and final value of the input voltage as it
appears at the converter.
These converters include a soft start circuit to moderate the duty cycle of its
PWM controller at power up, thereby limiting the input inrush current.
The On/Off Remote Control interval from On command to Vout regulated
assumes that the converter already has its input voltage stabilized above the
Start-Up Threshold before the On command. The interval is measured from the
On command until the output enters and remains within its specified accuracy
band. The specification assumes that the output is fully loaded at maximum
rated current. Similar conditions apply to the On to Vout regulated specification
such as external load capacitance and soft start circuitry.
Input Source Impedance
These converters will operate to specifications without external components,
assuming that the source voltage has very low impedance and reasonable input voltage regulation. Since real-world voltage sources have finite
CURRENT
PROBE
+
–
+
–
LBUS
CBUS
CIN
–VIN
CIN = 33μF, ESR < 700mΩ @ 100kHz
CBUS = 220μF, ESR < 100mΩ @ 100kHz
LBUS = 12μH
Figure 2. Measuring Input Ripple Current
In critical applications, output ripple and noise (also referred to as periodic
and random deviations or PARD) may be reduced by adding filter elements
such as multiple external capacitors. Be sure to calculate component temperature rise from reflected AC current dissipated inside capacitor ESR. Our
Application Engineers can recommend potential solutions.
Floating Outputs
Since these are isolated DC-DC converters, their outputs are “floating” with
respect to their input. The essential feature of such isolation is ideal ZERO
CURRENT FLOW between input and output. Real-world converters however do
exhibit tiny leakage currents between input and output (see Specifications).
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MDC_PAH-28Vout-350W.B03 Page 16 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
Note that the temperatures are of the ambient airflow, not the converter
itself which is obviously running at higher temperature than the outside air.
Also note that very low flow rates (below about 25 LFM) are similar to “natural
convection”, that is, not using fan-forced airflow.
+SENSE
+VOUT
C1
C2
SCOPE
RLOAD
–VOUT
–SENSE
C1 = 1μF
C2 = 470μF
LOAD 2-3 INCHES (51-76mm) FROM MODULE
Figure 3. Measuring Output Ripple and Noise (PARD)
These leakages consist of both an AC stray capacitance coupling component
and a DC leakage resistance. When using the isolation feature, do not allow
the isolation voltage to exceed specifications. Otherwise the converter may
be damaged. Designers will normally use the negative output (-Output) as
the ground return of the load circuit. You can however use the positive output
(+Output) as the ground return to effectively reverse the output polarity.
Minimum Output Loading Requirements
These converters employ a synchronous rectifier design topology. All models
regulate within specification and are stable under no load to full load conditions. Operation under no load might however slightly increase output ripple
and noise.
Thermal Shutdown
To prevent many over temperature problems and damage, these converters
include thermal shutdown circuitry. If environmental conditions cause the
temperature of the DC-DC’s to rise above the Operating Temperature Range
up to the shutdown temperature, an on-board electronic temperature sensor
will power down the unit. When the temperature decreases below the turn-on
threshold, the converter will automatically restart. There is a small amount of
hysteresis to prevent rapid on/off cycling. The temperature sensor is typically
located adjacent to the switching controller, approximately in the center of the
unit. See the Performance and Functional Specifications.
CAUTION: If you operate too close to the thermal limits, the converter may
shut down suddenly without warning. Be sure to thoroughly test your application to avoid unplanned thermal shutdown.
Temperature Derating Curves
The graphs in this data sheet illustrate typical operation under a variety of
conditions. The Derating curves show the maximum continuous ambient air
temperature and decreasing maximum output current which is acceptable
under increasing forced airflow measured in Linear Feet per Minute (“LFM”).
Note that these are AVERAGE measurements. The converter will accept brief
increases in temperature and/or current or reduced airflow as long as the average is not exceeded.
MPS makes Characterization measurements in a closed cycle wind
tunnel with calibrated airflow. We use both thermocouples and an infrared
camera system to observe thermal performance. As a practical matter, it is
quite difficult to insert an anemometer to precisely measure airflow in most
applications. Sometimes it is possible to estimate the effective airflow if you
thoroughly understand the enclosure geometry, entry/exit orifice areas and the
fan flowrate specifications. If in doubt, contact MPS to discuss placement and
measurement techniques of suggested temperature sensors.
CAUTION: If you routinely or accidentally exceed these Derating guidelines,
the converter may have an unplanned Over Temperature shut down. Also, these
graphs are all collected at slightly above Sea Level altitude. Be sure to reduce
the derating for higher density altitude.
Output Overvoltage Protection
This converter monitors its output voltage for an over-voltage condition using
an on-board electronic comparator. The signal is optically coupled to the primary side PWM controller. If the output exceeds OVP limits, the sensing circuit
will power down the unit, and the output voltage will decrease. After a time-out
period, the PWM will automatically attempt to restart, causing the output voltage to ramp up to its rated value. It is not necessary to power down and reset
the converter for this automatic OVP-recovery restart.
If the fault condition persists and the output voltage climbs to excessive
levels, the OVP circuitry will initiate another shutdown cycle. This on/off cycling
is referred to as “hiccup” mode. It safely tests full current rated output voltage
without damaging the converter.
Output Current Limiting
As soon as the output current increases to its maximum rated value, the DC-DC
converter will enter a current-limiting mode. The output voltage will decrease
proportionally with increases in output current, thereby maintaining a somewhat constant power output. This is commonly referred to as power limiting.
Current limiting inception is defined as the point at which full power falls
below the rated tolerance. See the Performance/Functional Specifications. Note
particularly that the output current may briefly rise above its rated value. This
enhances reliability and continued operation of your application. If the output
current is too high, the converter will enter the short circuit condition.
Output Short Circuit Condition
When a converter is in current-limit mode, the output voltage will drop as the
output current demand increases. If the output voltage drops too low, the magnetically coupled voltage used to develop primary side voltages will also drop,
thereby shutting down the PWM controller. Following a time-out period, the
PWM will restart, causing the output voltage to begin ramping up to its appropriate value. If the short-circuit condition persists, another shutdown cycle will
initiate. This on/off cycling is called “hiccup mode”. The hiccup cycling reduces
the average output current, thereby preventing excessive internal temperatures. A short circuit can be tolerated indefinitely.
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MDC_PAH-28Vout-350W.B03 Page 17 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
Remote Sense Input
Sense inputs compensate for output voltage inaccuracy delivered at the load.
This is done by correcting voltage drops along the output wiring such as moderate IR drops and the current carrying capacity of PC board etch. Sense inputs
also improve the stability of the converter and load system by optimizing the
control loop phase margin.
Note: The Sense input and power Vout lines are internally connected through
low value resistors to their respective polarities so that the converter can
operate without external connection to the Sense. Nevertheless, if the Sense
function is not used for remote regulation, the user should connect +Sense to
+Vout and –Sense to –Vout at the converter pins.
The remote Sense lines carry very little current. They are also capacitively
coupled to the output lines and therefore are in the feedback control loop to
regulate and stabilize the output. As such, they are not low impedance inputs
and must be treated with care in PC board layouts. Sense lines on the PCB
should run adjacent to DC signals, preferably Ground. In cables and discrete
wiring, use twisted pair, shielded tubing or similar techniques.
DC voltage may also be used for trimming). Trimming resistors should have a
low temperature coefficient (±100 ppm/deg.C or less) and be mounted close
to the converter. Keep leads short. If the trim function is not used, leave the
trim unconnected. With no trim, the converter will exhibit its specified output
voltage accuracy.
There are two CAUTIONs to be aware for the Trim input:
CAUTION: To avoid unplanned power down cycles, do not exceed EITHER the
maximum output voltage OR the maximum output power when setting the trim.
Be particularly careful with a trimpot. If the output voltage is excessive, the
OVP circuit may inadvertantly shut down the converter. If the maximum power
is exceeded, the converter may enter current limiting. If the power is exceeded
for an extended period, the converter may overheat and encounter overtemperature shut down.
CAUTION: Be careful of external electrical noise. The Trim input is a senstive
input to the converter’s feedback control loop. Excessive electrical noise may
cause instability or oscillation. Keep external connections short to the Trim
input. Use shielding if needed.
Please observe Sense inputs tolerance to avoid improper operation:
[Vout(+) –Vout(-)] – [ Sense(+) – Sense(-)] ≤ 10% of Vout
Contact and PCB resistance
losses due to IR drops
+VIN
+VOUT
+VOUT
+VIN
I OUT
+SENSE
+SENSE
Sense Current
ON/OFF
CONTROL
TRIM
LOAD
ON/OFF
CONTROL
TRIM
7 5-22
TURNS
LOAD
Sense Return
–SENSE
–SENSE
I OUT Return
–VIN
–VIN
–VOUT
–VOUT
Contact and PCB resistance
losses due to IR drops
Figure 4. Remote Sense Circuit Configuration
Output overvoltage protection is monitored at the output voltage pin, not the
Sense pin. Therefore excessive voltage differences between Vout and Sense
together with trim adjustment of the output can cause the overvoltage protection circuit to activate and shut down the output.
Figure 5. Trim adjustments using a trimpot
+VOUT
+VIN
+SENSE
Power derating of the converter is based on the combination of maximum
output current and the highest output voltage. Therefore the designer must ensure:
(Vout at pins) x (Iout) ≤ (Max. rated output power)
Trimming the Output Voltage
The Trim input to the converter allows the user to adjust the output voltage
over the rated trim range (please refer to the Specifications). In the trim equations and circuit diagrams that follow, trim adjustments use either a trimpot or
a single fixed resistor connected between the Trim input and either the +Sense
or –Sense terminals. (On some converters, an external user-supplied precision
ON/OFF
CONTROL
TRIM
LOAD
R TRIM UP
–SENSE
–VIN
–VOUT
Figure 6. Trim adjustments to Increase Output Voltage using a Fixed Resistor
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MDC_PAH-28Vout-350W.B03 Page 18 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
Negative-logic devices are on (enabled) when the On/Off is grounded or
brought to within a low voltage (see Specifications) with respect to –Vin. The
device is off (disabled) when the On/Off is pulled high to +15V with respect
to –Vin.
+VOUT
+VIN
+SENSE
ON/OFF
CONTROL
TRIM
LOAD
+VIN
R TRIM DOWN
+VCC
–SENSE
–VIN
ON/OFF
CONTROL
–VOUT
Figure 7. Trim adjustments to Decrease Output Voltage using a Fixed Resistor
–VIN
Trim Equations
Radj_up (in kΩ) = Vnominal x (1+Δ) - 1 - 2
1.225 x Δ
Δ
where Δ =
Figure 9. Driving the Negative Logic On/Off Control Pin
Vout -Vnominal
Vnominal
Dynamic control of the On/Off function should be able to sink appropriate
signal current when brought low and withstand appropriate voltage when
brought high. Be aware too that there is a finite time in milliseconds (see
Specifications) between the time of On/Off Control activation and stable,
regulated output. This time will vary slightly with output load type and current
and input conditions.
1
-2
Δ
Vnominal -Vout
Vnominal
Radj_down (in kΩ) =
where Δ =
Where Vref = +1.225 Volts and Δ is the desired output voltage change. Note
that "Δ" is given as a small fraction, not a percentage.
A single resistor connected between Trim and +Sense will increase the output
voltage. A resistor connected between Trim and –Sense will decrease the output.
Remote On/Off Control
On the input side, a remote On/Off Control can be ordered with either logic type.
Positive models are enabled when the On/Off pin is left open or is pulled
high to +15V with respect to –Vin. Some models will also turn on at lower
intermediate voltages (see Specifications). Positive-logic devices are disabled
when the On/Off is grounded or brought to within a low voltage (see Specifications) with respect to –Vin.
There are two CAUTIONs for the On/Off Control:
CAUTION: While it is possible to control the On/Off with external logic if you
carefully observe the voltage levels, the preferred circuit is either an open
drain/open collector transistor or a relay (which can thereupon be controlled by
logic).
CAUTION: Do not apply voltages to the On/Off pin when there is no input
power voltage. Otherwise the converter may be permanently damaged.
Soldering Guidelines
Murata Power Solutions recommends the specifications below when installing these
converters. These specifications vary depending on the solder type. Exceeding these
specifications may cause damage to the product. Your production environment may
differ; therefore please thoroughly review these guidelines with your process engineers.
Wave Solder Operations for through-hole mounted products (THMT)
For Sn/Ag/Cu based solders:
+ Vcc
ON/OFF CONTROL
CONTROL
Maximum Preheat Temperature
For Sn/Pb based solders:
115° C.
Maximum Preheat Temperature
105° C.
Maximum Pot Temperature
270° C.
Maximum Pot Temperature
250° C.
Maximum Solder Dwell Time
7 seconds
Maximum Solder Dwell Time
6 seconds
–VIN
Figure 8. Driving the Positive Logic On/Off Control Pin
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MDC_PAH-28Vout-350W.B03 Page 19 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
Emissions Performance
Murata Power Solutions measures its products for radio frequency emissions
against the EN 55022 and CISPR 22 standards. Passive resistance loads are
employed and the output is set to the maximum voltage. If you set up your
own emissions testing, make sure the output load is rated at continuous power
while doing the tests.
[3] Conducted Emissions Test Results
The recommended external input and output capacitors (if required) are
included. Please refer to the fundamental switching frequency. All of this
information is listed in the Product Specifications. An external discrete filter is
installed and the circuit diagram is shown below.
L1
C2
L2
C6
C5
C3
C7
UNIT UNDER TEST
C1
C8
C4
Graph 1. Conducted emissions performance, Positive Line,
CISPR 22, Class B, 48 Vin, full load
Figure 10. Conducted Emissions Test Circuit
[1] Conducted Emissions Parts List
Reference
Part Number
Description
Vendor
CAP SMT NON POL CERAMIC
C1, C2, C7
GRM32ER72A225KA35L
X7R 2.2μF 100V 20%
Murata
1210
COMMON MODE-809uHL1, L2
LB22H1463
±25%-9.7A-R5KHaiguang
28*26*12.7mm
SMD CERAMIC 630V-0.22μFC3, C4, C5, C6 GRM55DR72J224KW01L
Murata
±10%-X7R-2220
Aluminum 100V-33μFC8
UVK2A330MPD
Nichicon
±10%-long lead
[2] Conducted Emissions Test Equipment Used
Hewlett Packard HP8594L Spectrum Analyzer – S/N 3827A00153
2Line V-networks LS1-15V 50Ω/50Uh Line Impedance Stabilization Network
Graph 2. Conducted emissions performance, Negative Line,
CISPR 22, Class B, 48 Vin, full load
[4] Layout Recommendations
Most applications can use the filtering which is already installed inside the
converter or with the addition of the recommended external capacitors. For
greater emissions suppression, consider additional filter components and/or
shielding. Emissions performance will depend on the user’s PC board layout,
the chassis shielding environment and choice of external components. Please
refer to Application Note GEAN02 for further discussion.
Since many factors affect both the amplitude and spectra of emissions, we
recommend using an engineer who is experienced at emissions suppression.
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MDC_PAH-28Vout-350W.B03 Page 20 of 21
PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
Vertical Wind Tunnel
IR Transparent
optical window
Unit under
test (UUT)
Variable
speed fan
IR Video
Camera
Murata Power Solutions employs a computer controlled custom-designed
closed loop vertical wind tunnel, infrared video camera system, and test instrumentation for accurate airflow and heat dissipation analysis of power products.
The system includes a precision low flow-rate anemometer, variable speed
fan, power supply input and load controls, temperature gauges, and adjustable
heating element.
The IR camera monitors the thermal performance of the Unit Under Test
(UUT) under static steady-state conditions. A special optical port is used which
is transparent to infrared wavelengths.
Heating
element
Precision
low-rate
anemometer
3” below UUT
Both through-hole and surface mount converters are soldered down to a
10" x 10" host carrier board for realistic heat absorption and spreading. Both
longitudinal and transverse airflow studies are possible by rotation of this carrier board since there are often significant differences in the heat dissipation
in the two airflow directions. The combination of adjustable airflow, adjustable
ambient heat, and adjustable Input/Output currents and voltages mean that a
very wide range of measurement conditions can be studied.
The collimator reduces the amount of turbulence adjacent to the UUT by
minimizing airflow turbulence. Such turbulence influences the effective heat
transfer characteristics and gives false readings. Excess turbulence removes
more heat from some surfaces and less heat from others, possibly causing
uneven overheating.
Ambient
temperature
sensor
Airflow
collimator
Figure 11. Vertical Wind Tunnel
Both sides of the UUT are studied since there are different thermal gradients
on each side. The adjustable heating element and fan, built-in temperature
gauges, and no-contact IR camera mean that power supplies are tested in
real-world conditions.
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
This product is subject to the following operating requirements
and the Life and Safety Critical Application Sales Policy:
Refer to: http://www.murata-ps.com/requirements/
ISO 9001 and 14001 REGISTERED
Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other
technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply
the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without
notice.
© 2015 Murata Power Solutions, Inc.
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MDC_PAH-28Vout-350W.B03 Page 21 of 21