OKR-T/50-W12-C
www.murata-ps.com
Adjustable Output 50-Amp SIP-mount DC-DC Converters
Typical unit
FEATURES
PRODUCT OVERVIEW
Wide input range: 6.5V to 13.8V
The OKR-T/50-W12-C series are miniature SIP non-isolated Point-of-Load (PoL) DC-DC power converters measuring only 1.45 x 0.64 x 1.1 inches (36.8 x 16.2 x 27.9 mm). The wide input range is 6.5 to
13.8 Volts DC. Based on 450 KHz synchronous buck topology, the high power conversion efficient Point
of Load (PoL) module features programmable output voltage and On/Off control, under voltage lock out
(UVLO), overcurrent and over temperature protections. This unit is designed to meet all standard UL/EN/IEC
60950-1 safety certifications and RoHS-6 hazardous substance compliance.
Wide trim range: 0.6V to 2.5V
High power density design means reduced
board space requirement
Power good output signal (open collector)
Operating ambient temperature up to +70°C
with suitable derating and forced air cooling
Remote ON/OFF (active high)
Input undervoltage lockout
RoHS-6 hazardous substance compliance
Figure 1. Connection Diagram
+Vin
F1
+Vout
• Switching
On/Off
Control
Controller
• Filters
• Current Sense
External
DC
Power
Source
Trim
Open = On
Closed = Off
(Positive
On/Off)
Common
Reference and
Error Amplifier
(-)Trim
Common
For full details go to
www.murata-ps.com/rohs
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MDC_OKR-T/50-W12-C.A03 Page 1 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
PERFORMANCE SPECIFICATIONS SUMMARY AND ORDERING GUIDE
Output
Root Model
VOUT
(Volts)
R/N (mVp-p) ➁ Regulation (Max.)
IOUT
(Amps
max)
OKR-T/50-W12-C 0.6-2.5
Input
Power
(Watts)
50
125
Max.
25
Line
±0.25%
VIN Nom.
(Volts)
Load
±0.25%
12
Range
(Volts)
IIN,
no load
(mA)
6.5-13.8
150
IIN,
full load
(Amps) ➂
8.5
Efficiency ➂
Typ.
Dimensions ➀
88.5%
1.45 x 0.64 x 1.1
(36.8 x 16.2 x 27.9)
➀ Dimensions (L x W x H) are in inches (mm).
➁ Ripple and Noise is shown at Vout = 1.8V. See specs for details.
➂ All specifications are at nominal line voltage, Vout = 1.8V and full load, +25°C. unless otherwise noted. Output capacitors are 10μF and two ceramic in parallel. Input cap is 22 μF. See detailed
specifications. I/O caps are necessary for our test equipment and may not be needed for your application.
PART NUMBER STRUCTURE
OK R - T / 50 - W12 - C
Okami Non-isolated PoL
SIP-Mount
Output Voltage Range
T = Trimmable, 0.6-2.5 Volts
RoHS Hazardous
Substance Compliance
C = RoHS-6 (does not claim EU RoHS exemption 7b–lead in solder)
Wide Input Voltage Range
W12 = 6.5-13.8 Volts
Maximum Rated Output
Current in Amps
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MDC_OKR-T/50-W12-C.A03 Page 2 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
FUNCTIONAL SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Input Voltage, Continuous
Output Power
Output Current
Conditions
Full power operation
Current-limited, no damage,
short-circuit protected
Minimum
6.5
0
Typical/Nominal
12
Maximum
15
127
50
Units
Vdc
W
A
On/Off Control
Vin
Vdc
Power Good Pin
7
Vdc
Storage Temperature Range
Vin = Zero (no power)
-40
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 or recommended.
INPUT
Operating voltage range
6.5
12
13.8
Vdc
Recommended External Fuse
Fast blow
40
A
Turn On/Start-up threshold
Rising input voltage
5.8
6.1
6.4
Vdc
Undervoltage Shutdown
4.8
5.3
5.8
Internal Filter Type
C-Type
Input current
Full Load Conditions
Vin = nominal (1.8Vset)
8.5
A
Low Line
Vin @ min, 1.8Vset
15.6
A
Inrush Transient
2
A2-Sec.
Short Circuit Input Current
300
mA
No Load Input Current
1.8V
150
mA
Shut-Down Mode Input Current
20
mA
Measured at input with specified filter
Reflected (back) ripple current
12
mA, pk-pk
Cin = 100μF, Cbus = 1000μF, Lbus = 1μH
GENERAL and SAFETY
Efficiency
12Vin, 1.8Vout, 50A
87
88.5
%
Certified to UL-60950-1, CSA-C22.2
Safety
Yes
No.60950-1, IEC/60950-1, 2nd edition
Per Telcordia SR332, issue 1 class 3, ground
Calculated MTBF
7,476,403
Hours
fixed, Tambient = +25˚C
Calculated MTBF
Per Mil-HDBK-217N2 Method
11,076,048
Hours
DYNAMIC CHARACTERISTICS
Fixed Switching Frequency
450
KHz
Startup Time
6
9
mS
1.8Vout (50% Load Step within 2% of Vset @
Dynamic Load Response
25
50
μSec
1A/μS; Cext = 10μF POSCAP)
Dynamic Load Peak Deviation
150
200
mV
Capacitive Loading
Peak Deviation
Settling Time
330μF Ceramic
180mV
30 μsec
830μF Cermaic, 1410μF Poscap
120mV
45 μsec
FEATURES and OPTIONS
Remote On/Off Control
Positive Logic, ON state
Pin pulled high
1.2
5
V
Control Current, ON state
0.04
1.3
mA
Positive Logic, OFF state
Pin open or pulled low
0
0.7
V
Control Current, OFF state
open collector/drain
0
6
μA
Remote Sense
mV
Power Good Option
PGOOD, Open Drain Configuration, Sinking:
Vout window for PGOOD: Upper limit
+8.3
+12.5
+16.2
%
Vout window for PGOOD: Lower limit
-15
-12.5
-9.2
%
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MDC_OKR-T/50-W12-C.A03 Page 3 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
FUNCTIONAL SPECIFICATIONS (CONT.)
OUTPUT
Total Output Power
Voltage
Nominal Output Voltage Range
Setting Accuracy
Output Voltage Overshoot-Startup
Current
Output Current Range
Current Limit Inception
Short Circuit
Short Circuit Current
Short Circuit Duration (remove short for
recovery)
Regulation
Total Regulation Band
Line Regulation
Load Regulation
Ripple and Noise
Temperature Coefficient
Maximum Capacitive Loading
MECHANICAL
Outline Dimensions
Conditions
Minimum
0
See trim formula
At 50% load
0.6
Continuous
98% of Vnom., after warmup
0
55
Hiccup technique, autorecovery within ±1%
of Vout
Typical/Nominal
70
Maximum
125
Units
W
2.5
±1
0.5
Vdc
% of Vnom.
% Vo set
50
85
A
A
10
A
Output shorted to ground, no damage
-3
Vin = min to max, output @ nominal load
Min load to max load
1.8Vo, 12Vin
3
±0.25
±0.25
25
15
0.02
1.8Vo
15000
LxWxH
1.45 x 0.64 x 1.1
36.8 x 16.2 x 27.9
0.70
20
Weight
% Vo set
%
%
mV pk-pk
% of Vnom./°C
μF
Inches
mm
Ounces
Grams
ENVIRONMENTAL
Operating Ambient Temperature Range
Storage Temperature
RoHS rating
full power, all output voltages, see derating
curves
Vin = Zero (no power)
0
-40
70
°C
125
°C
RoHS-6
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MDC_OKR-T/50-W12-C.A03 Page 4 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
OKR-T/50-W12-C PERFORMANCE DATA
Efficiency vs. Line Voltage and Load Current @ 25°C
Vout = 1.8V
Maximum Current Temperature Derating @ Sea Level
(VIN = 12V, VOUT = 1.8V)
93
91
89
85
VIN = 6.5V
83
VIN = 12V
81
VIN = 13.8V
Output Current (Amps)
Efficiency (%)
87
79
77
75
73
71
69
2
4
6
8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
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)
30
Load Curre nt (Amps)
35
40
45
50
55
60
65
70
75
80
85
Ambient Temperature (°C)
Thermal reference point
120°C max.
Start-up from ENABLE: 1 Vin, 1.5 Vout, 0 A Iout 2100 μF (external Cout: [10 x 22uF]+[4 x
47uF]). Trace 1 = Vin, Trace 2 = ENABLE, Trace 3 = Vout, Trace 4 =Power Good
Output Ripple and Noise (Vin = 12V, Vout = 1.8V, Iout = 50A, Cout = 10μ, Ta = +25°C)
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MDC_OKR-T/50-W12-C.A03 Page 5 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
OSCILLOGRAMS – Vout = 1.8V
Step Load Transient Response (Vin = 6.5V, Vout = 1.8V, Cload = 10μF
POSCAP, Iout = 0A to 25A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 6.5V, Vout = 1.8V, Cload = 10μF
POSCAP, Iout = 25A to 50A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 12V, Vout = 1.8V, Cload = 10μF
POSCAP, Iout = 0A to 25A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 12V, Vout = 1.8V, Cload = 10μF
POSCAP, Iout = 25A to 50A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 13.8V, Vout = 1.8V, Cload = 10μF
POSCAP, Iout = 0A to 25A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 13.8V, Vout = 1.8V, Cload = 10μF
POSCAP, Iout = 25A to 50A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
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MDC_OKR-T/50-W12-C.A03 Page 6 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
OSCILLOGRAMS – Vout = 1.5V
Step Load Transient Response (Vin = 6.5V, Vout = 1.5V, Cload = 2240μF
15 x 22μF = 330μF ceramic; 5 x 100μF = 500μF ceramic; 3 x 470μF = 1410μF POSCAP,
Iout = 0A to 25A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 6.5V, Vout = 1.5V, Cload = 2240μF
15 x 22μF = 330uF ceramic; 5 x 100μF = 500μF ceramic; 3 x 470μF = 1410μF POSCAP,
Iout = 25A to 50A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 12V, Vout = 1.5V, Cload = 2240μF,
15 x 22μF = 330μF ceramic; 5 x 100μF = 500μF ceramic; 3 x 470μF = 1410μF POSCAP,
Iout = 0A to 25A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 12V, Vout = 1.5V, Cload = 2240μF,
15 x 22μF = 330μF ceramic; 5 x 100μF = 500μF ceramic; 3 x 470μF = 1410μF POSCAP,
Iout = 25A to 50A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 13.8V, Vout = 1.5V, Cload = 2240μF,
15 x 22μF = 330μF ceramic; 5 x 100μF = 500μF ceramic; 3 x 470μF = 1410μF POSCAP,
Iout = 0A to 25A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 13.8V, Vout = 1.5V, Cload = 2240μF,
15 x 22μF = 330μF ceramic; 5 x 100μF = 500μF ceramic; 3 x 470μF = 1410μF POSCAP,
Iout = 25A to 50A [5A/μSec]) Top trace = Vout, Bottom trace = Iout
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MDC_OKR-T/50-W12-C.A03 Page 7 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
OSCILLOGRAMS – Vout = 1.2V
Step Load Transient Response (Vin = 6.5V, Vout = 1.2V, Cload = 15 x 22μF/6.3V 1206
ceramic caps for a total of 330μF, Iout = 0A to 25A [5A/μSec])
Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 6.5V, Vout = 1.2V, Cload = 15 x 22μF/6.3V 1206
ceramic caps for a total of 330μF, Iout = 25A to 50A [5A/μSec])
Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 12V, Vout = 1.2V, Cload = 15 x 22μF/6.3V 1206 ceramic Step Load Transient Response (Vin = 12V, Vout = 1.2V, Cload = 15 x 22μF/6.3V 1206 ceramic
caps for a total of 330μF, Iout = 0A to 25A [5A/μSec])
caps for a total of 330μF, Iout = 25A to 50A [5A/μSec])
Top trace = Vout, Bottom trace = Iout
Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 13.8V, Vout = 1.2V, Cload = 15 x 22μF/6.3V 1206
ceramic caps for a total of 330μF, Iout = 0A to 25A [5A/μSec])
Top trace = Vout, Bottom trace = Iout
Step Load Transient Response (Vin = 13.8V, Vout = 1.2V, Cload = 15 x 22μF/6.3V 1206
ceramic caps for a total of 330μF, Iout = 25A to 50A [5A/μSec])
Top trace = Vout, Bottom trace = Iout
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MDC_OKR-T/50-W12-C.A03 Page 8 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
MECHANICAL SPECIFICATIONS
TOP VIEW
END VIEW
16.2
0.64
FRONT VIEW
36.8
1.45
11.6
0.46
INPUT/OUTPUT CONNECTIONS
Pin
Function
J1
Vout+1
J2
Vout+1
J3
Vout+1
J4
PGND
J5
PGND
J6
Enable
J7
(-) Trim
J8
Trim
J9
PGood
J10
-Sense
J11
+Sense
J12
Vin+
J13
VinJ14
Mechanical Support
J15
Mechanical Support
27.9
1.10
1 2 3 4 5
6 7 8
9 10
14
1.27
2x 0.050
11
12
2.92±0.25
2x 0.115±0.010
13
2.06
0.081
15
2.00
0.079 TYP
20.00
0.787
4.39
0.173
13x
2.85±0.25
13x 0.112±0.010
26.00
1.024
34.29
1.350
0.76±0.05
0.030±0.002
6.7
0.27
1.35
0.053
10.3
0.41
DIMENSIONS ARE IN INCHES [mm]
TOLERANCES:
2 PLACE 0.02
3 PLACE 0.010
ANGLES:
1
COMPONENTS SHOWN ARE FOR REFERENCE ONLY
MATERIAL:
0.030 HEADER PINS: COPPER ALLOY
SUPPORT PINS: TIN PLATED BRASS
FINISH: (ALL HEADER PINS)
200μ" MIN MATTE TIN OVER NICKEL (40μ" MIN)
Dimensions are in inches (mm shown for ref. only).
Third Angle Projection
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25)
Angles ± 2˚
Components are shown for reference only.
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MDC_OKR-T/50-W12-C.A03 Page 9 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
MECHANICAL SPECIFICATIONS
37.34
1.470
1.52
0.060
34.29
1.350
2.06
0.081
17.96
0.707
13x
0.89±0.08
0.035±0.003
1.98±0.08
2x 0.078±0.003
2.06
0.081
5.92
0.233
12.12
0.477
2.00
0.079
TYP
4.39
0.173
26.00
1.024
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MDC_OKR-T/50-W12-C.A03 Page 10 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
STANDARD PACKAGING
)2$03$'6
($&+67$7,&',66,3$7,9(
32/<(7+</(1()2$075$<
$&&2002'$7(6
&219(57(56
,1$;$55$<
&2558*$7('
&$5721
&/26('+(,*+7
67$1'$5'3$&.$*,1*
Dimensions are in inches (mm shown for ref. only).
Third Angle Projection
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25)
Angles ± 2˚
Components are shown for reference only.
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MDC_OKR-T/50-W12-C.A03 Page 11 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount 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 safely, 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, i.e. IEC/EN/UL 60950-1.
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.
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.
For best performance, we recommend installing a low-ESR capacitor
immediately adjacent to the converter’s input terminals. The capacitor should
be a ceramic type such as the Murata GRM32 series or a polymer type. Initial
suggested capacitor values are 10 to 22 μF, rated at twice the expected maximum input voltage. Make sure that the input terminals do not go below the
undervoltage shutdown voltage at all times. More input bulk capacitance may
be added in parallel (either electrolytic or tantalum) if needed.
Recommended Output Filtering
The converter will achieve its rated output ripple and noise with no additional
external capacitor. However, the user may install more external output capacitance to reduce the ripple even further or for improved dynamic response.
Again, use low-ESR ceramic (Murata GRM32 series) or polymer capacitors.
Initial values of 10 to 47 μF may be tried, either single or multiple capacitors in
parallel. Mount these close to the converter. Measure the output ripple under
your load conditions.
Use only as much capacitance as required to achieve your ripple and noise
objectives. Excessive capacitance can make step load recovery sluggish or
possibly introduce instability. Do not exceed the maximum rated output capacitance listed in the specifications.
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. In the figure below,
the Cbus and Lbus components simulate a typical DC voltage bus. Please
note that the values of Cin, Lbus and Cbus will vary according to the specific
converter model.
TO
OSCILLOSCOPE
CURRENT
PROBE
+VIN
VIN
+
–
+
–
LBUS
CBUS
CIN
-VIN
CIN = 100μF, ESR < 700mΩ @ 100kHz
CBUS = 1000μF, ESR < 100mΩ @ 100kHz
LBUS = 1μH
Figure 3. Measuring Input Ripple Current
Recommended Input Filtering
The user must assure that the input source has low AC impedance to provide
dynamic stability and that the input supply has little or no inductive content,
including long distributed wiring to a remote power supply. The converter will
operate with no additional external capacitance if these conditions are met.
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MDC_OKR-T/50-W12-C.A03 Page 12 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
+VOUT
C1
SCOPE
RLOAD
-VOUT
C1 = 10μF TANTALUM
LOAD 2-3 INCHES (51-76mm) FROM MODULE
Figure 4. Measuring Output Ripple and Noise (PARD)
Minimum Output Loading Requirements
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 current or reduced airflow as long as the average is not exceeded.
Output Current 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 in normal
operation as long as the average output power is not exceeded. 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 (approximately 98% of nominal output voltage for most models), 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
rapid on/off cycling is called “hiccup mode”. The hiccup cycling reduces the
average output current, thereby preventing excessive internal temperatures
and/or component damage. A short circuit can be tolerated indefinitely.
The “hiccup” system differs from older latching short circuit systems
because you do not have to power down the converter to make it restart. The
system will automatically restore operation as soon as the short circuit condition is removed.
External Enable On/Off Control (see figure 5)
The forced On/Off enable option uses positive logic for the external control. The
converter may be powered ON by applying a positive voltage (logic HI) between
the On/Off pin and the negative power input (-Vin). This positive voltage is
referred to –Vin and must be in the range of at least +2.0V and not to exceed
the power supply input voltage (+Vin). The current drain is 12 mA max. when
turned on.
If the On/Off pin is left open, an internal 100 Kilohm pulldown resistor will
turn the converter OFF. The OFF condition may also be commanded by grounding the pin or from an external logic LO voltage not to exceed +0.4 Volts. All
voltages are referred to the –Vin negative power input.
If you wish to control the On/Off circuit by external logic rather than a switch,
carefully compare your logic threshold voltages with that of the On/Off input.
The circuit below indicates the equivalent input. Please avoid false signals
from ground bounce errors on the On/Off control.
Vin
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.
Murata Power Solutions 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.
10K
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.
Figure 5. On/Off Control Circuit
www.murata-ps.com/support
MDC_OKR-T/50-W12-C.A03 Page 13 of 14
OKR-T/50-W12-C
Adjustable Output 50-Amp SIP-mount DC-DC Converters
Trim Connections
Output Voltage Adustment
The output voltage may be adjusted over a limited range by connecting an
external trim resistor (Rtrim) between the Trim pin and (-)Trim. The Rtrim
resistor must be a 1/10 Watt precision metal film type, ±0.5% accuracy or
better with low temperature coefficient, ±100 ppm/oC. or better. Mount the
resistor close to the converter with very short leads or use a surface mount
trim resistor.
In the tables below, the calculated resistance is given. Do not exceed the
specified limits of the output voltage or the converter’s maximum power
rating when applying these resistors. Also, avoid high noise at the Trim
input. However, to prevent instability, you should never connect any capacitors to Trim.
OKR-T/50-W12-C
Output Voltage
+VOUT
RTRIM
Trim
(-)Trim
RLOAD
Ground
Resistor Trim Equation, OKR-T/50-W12-C models:
1.2
RTRIM (kΩ) = ___________
(VOUT – 0.6)
Calculated Rtrim (Ω)
2.5 V
632
1.8 V
1000
1.2 V
2000
0.6 V
∞ (open)
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:
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
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
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/
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.
© 2016 Murata Power Solutions, Inc.
www.murata-ps.com/support
MDC_OKR-T/50-W12-C.A03 Page 14 of 14