MURATA-PS OKX-T3-W5

OKX T/3-W5 Series
www.murata-ps.com
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
FEATURES
„
Non-isolated SIP PoL DC/DC power module
„
2.4-5.5Vdc input voltage range
„
Programmable output voltage from 0.75253.366Vdc
„
Under Voltage shutdown (Vin)
Typical unit
„
Drives 1000 μF ceramic capacitive loads
„
High power conversion efficiency 94.5% at 3.3
Vout (typical)
„
Outstanding thermal derating performance
„
Over temperature and over current protection
„
On/Off control
„
UL60950, CSA-C22.2 No.60950 IEC/EN60950
(pending)
„
Industry-standard (DOSA) SIP format
„
RoHS-6 hazardous substance compliance
PRODUCT OVERVIEW
The OKX-T/3-W5 series are miniature SIP nonisolated Point-of-Load (PoL) DC/DC power converters for embedded applications. The module is fully
compatible with Distributed-power Open Standards
Alliance industry-standard specifications.
Applications include powering CPU’s, datacom/
telecom systems, programmable logic and mixed
voltage systems. The wide input range is 2.4 to 5.5
Volts DC at 3 amps. Based on fixed-frequency syn-
chronous buck converter switching topology, the
high power conversion efficient Point of Load (PoL)
module features programmable output voltage
and On/Off control. These converters also include
under voltage lock out (UVLO), output short circuit
protection, over-current and over temperature
protections. These units are designed to meet all
standard UL/EN/IEC 60950-1 safety certifications
and RoHS-6 hazardous substance compliance.
Connection Diagram
+Vin
F1
+Vout
t4XJUDIJOH
On/Off
Control
Controller
t'JMUFST
t$VSSFOU4FOTF
External
DC
Power
Source
Trim
Open = On
Closed = Off
(Positive
On/Off)
Reference and
Error Amplifier
Common
Common
Figure 1. OKX-T/3-W5
Note: Murata Power Solutions strongly recommends an external input fuse, F1.
See specifications.
For full details go to
www.murata-ps.com/rohs
(pending)
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MDC_OKX_T/3-W5 Series.A01 Page 1 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
PERFORMANCE SPECIFICATIONS SUMMARY AND ORDERING GUIDE
Output
Model Number ➀
OKX-T/3-W5-C
IOUT
(Amps,
max) ➀
VOUT
(Volts) ➀
.7525-3.6
3
Input
R/N
Power (mVp-p)
(Watts) Max. d
9.9
40
Regulation (Max.)
Line
±0.2%
Load
±0.5%
➀ All specifications are typical at nominal line voltage, Vout=nominal (3.3V for W5 models) and full load, +25°C.
Vin Nom. Range
(Volts) (Volts) e
5
2.4-5.5
Iin,
no load
(mA)
40
Iin,
full load
(Amps)
2.095
Efficiency
Min.
Typ.
92.5% 94.5%
Dimensions
in inches (mm)
0.40x0.90x0.282
(10.16x 22.86x 7.163)
e The input voltage range must be 0.5V greater than the output voltage.
d Ripple and Noise (R/N) is shown at Vout=1V. See specs for details.
PART NUMBER STRUCTURE
OK X - T / 3 - W5 N - C
Okami Non-isolated PoL
RoHS Hazardous Substance Compliance
C = RoHS-6 (does not claim EU RoHS
exemption 7b–lead in solder)
SIP Mount
Trimmable Output
Voltage Range
W5 Models = 0.7525-3.63V
Maximum Rated Output
Current in Amps
On/Off Logic
P = Positive Logic
N = Negative Logic
Input Voltage Range
W5 = 2.4-5.5V
Note: Some model number combinations
may not be available. See Ordering Guide
above. Contact Murata Power Solutions for
availability.
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MDC_OKX_T/3-W5 Series.A01 Page 2 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
FUNCTIONAL SPECIFICATIONS, OKX-T/3-W5-C
Conditions ➀
Full power operation
None, install external fuse
Power on or off, referred to -Vin
ABSOLUTE MAXIMUM RATINGS
Input Voltage, Continuous
Input Reverse Polarity
On/Off Remote Control
Output Power
Minimum
0
Typical/Nominal
Maximum
5.8
None
0
0
9.9
5.5
10.1
Units
Vdc
Vdc
Vdc
W
Current-limited, no damage,
0
3
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 or recommended.
INPUT
Conditions ➀ ➂
Operating voltage range
Vo < Vin-0.5
2.4
5
5.5
Vdc
Recommended External Fuse
Fast blow
6
A
Turn On/Start-up threshold
Rising input voltage
1.95
2.15
Vdc
Falling input voltage
1.73
2.07
Vdc
Turn Off/Undervoltage lockout 15
Reverse Polarity Protection
None, install external fuse
None
Vdc
Internal Filter Type
C-TYPE
Output Current
Input current
Full Load Conditions
Low Line
Inrush Transient
Short Circuit Input Current
No Load Input Current
No Load Input Current
Shut-Down Mode Input Current
Reflected (back) ripple current ➁
Vin = nominal (3.3Vo set)
Vin @ min, 3.3 Vout
2.095
2.672
0.04
60
40
20
5
20
3.3Vout, Iout @ 0
0.75V, Iout @ 0
Measured at input with specified filter
2.183
2.784
50
30
A
A
A2-Sec.
mA
mA
mA
mA, pk-pk
GENERAL and SAFETY
Efficiency
Safety (certified to the following
requirements)
Calculated MTBF ➃
@ Vin nom, 3.3Vout
@ Vin min, 3.3Vout
@ Vin nom, 2.5Vout
@Vin nom, 1.8Vout
@Vin nom, 1.5Vout
@Vin nom, 1.2Vout
@Vin nom, 1Vout
@Vin nom, 0.7525Vout
UL-60950-1, CSA-C22.2 No.60950-1, IEC/
EN60950-1, 2nd edition (pending)
Class 3, ground fixed, Tambient=+25°C
92.5
93
91
88
87
84
82
78
94.5
95
92.5
90
89
86
84
79
%
%
%
%
%
%
%
%
Yes
Hours x 106
TBD
DYNAMIC CHARACTERISTICS
250
Fixed Switching Frequency
Startup Time
Startup Time
Dynamic Load Response
Dynamic Load Peak Deviation
Power On, to Vout regulation band,
100% resistive load
Remote ON to 10% Vout (50% resistive load)
50-100-50% load step, settling time to within
±2% of Vout di/dt = 2.5 A/μSec
same as above
300
350
8
10
6
KHz
mS
mS
90
μSec
±200
mV
0.4
+Vin
V
V
mA
+Vin
0.4
V
V
mA
FEATURES and OPTIONS
Remote On/Off Control 15
“N” suffix:
Negative Logic, ON state
Negative Logic, OFF state
Control Current
“P” suffix:
Positive Logic, ON state
Positive Logic, OFF state
Control Current
Pin open=ON
0
1.5
open collector/drain
Pin open=ON
open collector/drain
1
+Vin-0.4
0
1
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MDC_OKX_T/3-W5 Series.A01 Page 3 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
FUNCTIONAL SPECIFICATIONS, OKX-T/3-W5-C (CONT.)
OUTPUT
Total Output Power
Voltage
Nominal Output Voltage Range 13
Setting Accuracy
Output Voltage Overshoot - Startup:
Current
Output Current Range
Minimum Load
Current Limit Inception ➅
Short Circuit
Short Circuit Current ➆
Short Circuit Duration
(remove short for recovery)
Short circuit protection method
Regulation ➉
Total Regulation Band
Line Regulation
Load Regulation
Ripple and Noise ➇
Ripple and Noise
Temperature Coefficient
Maximum Capacitive Loading
Maximum Capacitive Loading
14
Conditions ➀
Minimum
0
See trim formula
At 50% load
0.7525
-2
0
Typical/Nominal
9.9
Maximum
10.1
Units
W
3.6
2
1
Vdc
% of Vnom.
%Vo nom
3
No minimum load
5
3
A
8
A
Hiccup technique, autorecovery within ±1%
of Vout
0.5
1
A
Output shorted to ground, no damage
Continuous
4
±0.2
±0.5
60
40
±0.02
1000
3000
% Vo set
%
%
mV pk-pk
mV pk-pk
% of Vnom./°C
uF
μF
0.40x0.90x0.282
10.2x22.9x8.85
0.064
1.81
Inches
mm
Ounces
Grams
98% of Vnom., after warmup @3.3Vout
3.75
Current limiting
Over all line, load and temp conditions
Vin=min. to max. Vout=nom.
Iout=min. to max. Vin=48V.
3.3Vo, 5Vin
1Vo, 5Vin
At all outputs
low ESR
0.01 ohm
-4
Vo set
MECHANICAL (Through Hole Models)
Outline Dimensions
Weight
ENVIRONMENTAL
Operating Ambient Temperature Range ➈
Operating PCB Temperature
Storage Temperature
Thermal Protection/Shutdown
Electromagnetic Interference
Conducted, EN55022/CISPR22
Radiated, EN55022/CISPR22
12
Full power, all output voltages,
see derating curves
No derating
Vin = Zero (no power)
Measured in center
External filter is required
-40
85
°C
-40
-55
130
100
125
135
°C
°C
°C
130
B
B
Class
Class
Notes
➀ Specifications are typical at +25 deg.C, Vin=nominal (+5V.), Vout=nominal (+3.3V), full load, external caps and natural
convection unless otherwise indicated. Extended tests at higher power must supply substantial forced airflow. All models
are tested and specified with external 1 μF paralleled with 10 μF ceramic output capacitors and a 22 μF external input
capacitor. All capacitors are low ESR types. These capacitors are necessary to accommodate our test equipment and
may not be required to achieve specified performance in your applications. However, Murata Power Solutions recommends installation of these capacitors. All models are stable and regulate within spec under no-load conditions.
➁ Input Back Ripple Current is tested and specified over a 5 Hz to 20 MHz bandwidth. Input filtering is Cin=2 x 100 μF
tantalum, Cbus=1000 μF electrolytic, Lbus=1 μH.
➂ Note that Maximum Power Derating curves indicate an average current at nominal input voltage. At higher temperatures
and/or lower airflow, the DC/DC converter will tolerate brief full current outputs if the total RMS current over time does
not exceed the Derating curve.
➇ Output noise may be further reduced by adding an external filter. At zero output current, the output may contain low
frequency components which exceed the ripple specification. The output may be operated indefinitely with no load.
➈ All models are fully operational and meet published specifications, including “cold start” at –40°C.
➉ Regulation specifications describe the deviation as the line input voltage or output load current is varied from a nominal
midpoint value to either extreme.
11
Other input or output voltage ranges will be reviewed under scheduled quantity special order.
12
Maximum PC board temperature is measured with the sensor in the center of the converter.
13
Do not exceed maximum power specifications when adjusting the output trim.
14
➃ Mean Time Before Failure is calculated using the Telcordia (Belcore) SR-332 Method 1, Case 3, ISSUE 2, ground fixed
controlled conditions, Tambient=+25 deg.C, full output load, natural air convection. (
➄ The On/Off Control Input should use either a switch or an open collector/open drain transistor referenced to -Input
Common. A logic gate may also be used by applying appropriate external voltages which not exceed +Vin.
➅ Short circuit shutdown begins when the output voltage degrades approximately 1% from the selected setting.
➆ “Hiccup” overcurrent operation repeatedly attempts to restart the converter with a brief, full-current output. If the
overcurrent condition still exists, the restart current will be removed and then tried again. This short current pulse
prevents overheating and damaging the converter. Once the fault is removed, the converter immediately recovers normal
operation.
15
16
The maximum output capacitive loads depend on the the Equivalent Series Resistance (ESR) of the external output
capacitor and, to a lesser extent, the distance and series impedance to the load. Larger caps will reduce output noise but
may change the transient response. Newer ceramic caps with very low ESR may require lower capacitor values to avoid
instability. Thoroughly test your capacitors in the application. Please refer to the Output Capacitive Load Application Note.
Do not allow the input voltage to degrade lower than the input undervoltage shutdown voltage at all times. Otherwise,
you risk having the converter turn off. The undervoltage shutdown is not latching and will attempt to recover when the
input is brought back into normal operating range.
The outputs are not intended to sink appreciable reverse current.
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MDC_OKX_T/3-W5 Series.A01 Page 4 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
PERFORMANCE DATA, OKX-T/3-W5-C
Efficiency vs. Line Voltage and Load Current @ +25°C
(VOUT = 3.3V)
100
100
95
95
VIN = 3.8V
VIN = 5V
VIN = 5.5V
90
Efficiency (%)
90
Efficiency (%)
Efficiency vs. Line Voltage and Load Current @ +25°C
(VIN = 3.3V)
85
80
80
75
75
70
70
65
0
0.5
1
1.5
2
2.5
3
65
3.5
Vout = 2.5V
Vout = 1.5V
Vout = 1.0V
85
0
0.5
1
Load Curre nt (Amps)
2
2.5
3
3.5
3
3.5
3
3.5
Efficiency vs. Line Voltage and Load Current @ +25°C
(VOUT = 1.8V)
Efficiency vs. Line Voltage and Load Current @ +25°C
(VOUT = 2.5V)
100
120
95
100
VIN = 3V
VIN = 5V
VIN = 5.5V
VIN = 2.4V
VIN = 5V
VIN = 5.5V
80
Efficiency (%)
90
Efficiency (%)
1.5
Load Curre nt (Amps)
85
80
60
40
75
20
70
65
0
0.5
1
1.5
2
2.5
3
0
3.5
0
0.5
1
Load Curre nt (Amps)
Efficiency vs. Line Voltage and Load Current @ +25°C
(VOUT = 1.5V)
1.5
2
Load Curre nt (Amps)
2.5
Efficiency vs. Line Voltage and Load Current @ +25°C
(VOUT = 1.2V)
120
100
90
100
80
Efficiency (%)
Efficiency (%)
VIN = 2.4V
VIN = 5V
VIN = 5.5V
70
VIN = 2.4V
VIN = 5V
VIN = 5.5V
80
60
60
50
40
40
30
20
20
10
0
0
0
0.5
1
1.5
2
Load Curre nt (Amps)
2.5
3
3.5
0
0.5
1
1.5
2
2.5
Load Curre nt (Amps)
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MDC_OKX_T/3-W5 Series.A01 Page 5 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
PERFORMANCE DATA, OKX-T/3-W5-C
Step Load Transient Response (Vin=3.3V, Cload=1uF || 10uF) Top trace=Vout, Bottom trace=Iout
1.5A-3.0A (2.5A/us)
3.0A-1.5A (2.5A/us)
2.5Vout
1.5Vout
1.0Vout
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MDC_OKX_T/3-W5 Series.A01 Page 6 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
PERFORMANCE DATA, OKX-T/3-W5-C
Step Load Transient Response (Vin=5V, Cload= 1uF || 10uF, Ta=+25°C)
3.0A 1.5A ( di/dt=2.5A/uSec )
1.5A 3.0A ( di/dt=2.5A/uSec )
3.3Vout
1.8Vout
1.0Vout
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MDC_OKX_T/3-W5 Series.A01 Page 7 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
PERFORMANCE DATA, OKX-T/3-W5-C
Output Ripple and Noise (Vin=5V, Cin=22uF, Cout= 1uF || 10uF, Ta=+25°C)
0A
3.0A
3.3Vout
1.8Vout
1.0Vout
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MDC_OKX_T/3-W5 Series.A01 Page 8 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
PERFORMANCE DATA, OKX-T/3-W5-C
Start-up Delay ( 5Vin, Cload=1uF || 10uF, Cin=22uF, Ta=+25°C.)
0A
3.0A
3.3Vout
0.75Vout
Maximum Current Temperature Derating at Sea Level
(For Vin = 5.0V, Vout = 0.75 to 3.3V. For Vin = 5.5V or 4.13V, Vout = 3.63V.
For Vin = 3.3V, Vout = 0.75 to 2.5V. Airflow is from pin 3 to pin 2.)
3.5
3.0
Output Current (Amps)
Natural convection
2.5
2.0
1.5
1.0
0.5
0.0
20
25
30
35
40
45
50
55
60
65
Ambient Temperature (ºC)
70
75
80
85
90
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MDC_OKX_T/3-W5 Series.A01 Page 9 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
PERFORMANCE DATA, OKX-T/3-W5-C
On/Off Enable delay (Vin=5V, Cload=1uF || 10uF, Cin=22uF, Ta=+25°C)
0A
3.0A
3.3Vout
1.8Vout
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MDC_OKX_T/3-W5 Series.A01 Page 10 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
MECHANICAL SPECIFICATIONS
TOP VIEW
7.1
0.28
22.9
0.90
END VIEW
FRONT VIEW
10.2
0.40
1.45
0.057
REF
1.3
0.05
0.34
REF
3.8
0.15
5
4
3
0.55
REF
2
2.54
0.100
TYP
0.025 TYP
20.32
0.800
1.3
0.05
5.8
0.23
0.64
0.025
Dimensions are in mm [inches] shown for ref. only.
RECOMMENDED FOOTPRINT
(VIEWED FROM TOP)
[23.37]
0.92
[20.32]
0.800
[7.62]
0.30
5
4
Third Angle Projection
[1.52]
0.06
3
2
1
[2.54] 0.100
[5.08] 0.200
[1.52]
0.06
[17.78]
0.700
[0.94] 0.037
(5 OR 6 PLS)
ISOMETRIC VIEW
(REF ONLY)
Tolerances (unless otherwise specified):
.XX ± 0.02 (0.5)
.XXX ± 0.010 (0.25)
Angles ± 1˚
Components are shown for reference only.
I/O CONNECTIONS
Pin
Function
1
+Vout
2
Trim
3
Gnd (Common)
4
+Vin
5
Remote On/Off
*The Remote On/Off can be provided with either positive (P)
or negative (N) logic.
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MDC_OKX_T/3-W5 Series.A01 Page 11 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
STANDARD PACKAGING
Each static dissipative polyethylene foam tray
accommodates 75 converters
2.75±.25 (69.85)
Closed height
11.00 ±.25
(279.4)
10.50±.25
(266.7)
Carton accommodates four (4) trays of 75 yielding 300 converters per carton.
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 ± 1˚
Components are shown for reference only.
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MDC_OKX_T/3-W5 Series.A01 Page 12 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated 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, 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 poorly
regulated 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 regulation
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.
mum 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. The Cbus and Lbus
components simulate a typical DC voltage bus. Please note that the values of
Cin, Lbus and Cbus may vary according to the specific converter model.
TO
OSCILLOSCOPE
CURRENT
PROBE
+INPUT
VIN
+
–
+
–
LBUS
CBUS
CIN
-INPUT
CIN = 2 x 100μF, ESR < 700mΩ @ 100kHz
CBUS = 1000μF, ESR < 100mΩ @ 100kHz
LBUS = 1μH
Figure 2. Measuring Input Ripple Current
+SENSE
+OUTPUT
C1
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.
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 maxi-
C2
SCOPE
RLOAD
-OUTPUT
C1 = 1μF
C2 = 10μF
LOAD 2-3 INCHES (51-76mm) FROM MODULE
Figure 3. Measuring Output Ripple and Noise (PARD)
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MDC_OKX_T/3-W5 Series.A01 Page 13 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
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
temperature hysteresis to prevent rapid on/off cycling.
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.
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.
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 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.
Remote On/Off Control
The remote On/Off Control can be ordered with either logic type. Please refer to
the Connection Diagram on page 1 for On/Off connections.
Positive logic models are enabled when the On/Off pin is left open or is
pulled high to +Vin with respect to –Vin. Therefore, the On/Off control can be
disconnected if the converter should always be on. Positive-logic devices are
disabled when the On/Off is grounded or brought to within a low voltage (see
Specifications) with respect to –Vin.
Negative logic devices are on (enabled) when the On/Off pin is left open 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 (see Specifications) with
respect to –Vin.
Dynamic control of the On/Off function must 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.
Output Capacitive Load
These converters do not require external capacitance added to achieve rated
specifications. Users should only consider adding capacitance to reduce
switching noise and/or to handle spike current load steps. Install only enough
capacitance to achieve your noise and surge response objectives. Excess external
capacitance may cause regulation problems and possible oscillation or instability.
Proper wiring of the Sense inputs will improve these factors under capacitive load.
The maximum rated output capacitance and ESR specification is given for a
capacitor installed immediately adjacent to the converter. Any extended output
wiring, smaller wire gauge or less ground plane may tolerate somewhat higher
capacitance. Also, capacitors with higher ESR may use a larger capacitance.
Pre-Biased Startup
Some sections have external power already partially applied (possibly because
of earlier power sequencing) before POL power up. Or leakage power is present so that the DC/DC converter must power up into an existing output voltage.
This power may either be stored in an external bypass capacitor or supplied by
an active source. These converters include a pre-bias startup mode to prevent
initialization problems.
This “pre-biased” condition can also occur with some types of programmable logic or because of blocking diode leakage or small currents passed
through forward biased ESD diodes. This feature is variously called “monotonic” because the voltage does not decay or produce a negative transient
once the input power is applied and startup begins.
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 PWM controller
will shut down. 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.
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MDC_OKX_T/3-W5 Series.A01 Page 14 of 15
OKX T/3-W5 Series
Adjustable 3-Amp SIP Non-Isolated DC/DC Converters
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 Ground. The Rtrim resistor
is recommended to have a ±0.5% accuracy (or better) with low temperature
coefficient, ±100 ppm/°C 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.
OKX-T/3-W5
Output Voltage
Calculated Rtrim (KΩ)
3.3 V.
3.160
2.5 V.
6.947
1.8 V.
15.004
1.5 V.
23.077
1.2 V.
41.973
1.0 V.
80.021
0.7525 V.
∞ (open)
Resistor Trim Equation:
21070
RTRIM (:) = ____________
VOUT – 0.7525V
–5110
Soldering Guidelines
Product Label
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.
Because of the small size of these products, the product label contains a
character-reduced code to indicate the model number and manufacturing
date code. Not all items on the label are always used. Please note that the label
differs from the product photograph on page 1. Here is the layout of the label:
Wave Solder Operations for through-hole mounted products (THMT)
For Sn/Ag/Cu based solders:
Maximum Preheat Temperature
115° C.
Maximum Pot Temperature
270° C.
Maximum Solder Dwell Time
7 seconds
For Sn/Pb based solders:
Maximum Preheat Temperature
105° C.
Maximum Pot Temperature
250° C.
Maximum Solder Dwell Time
6 seconds
Mfg.
date
code
X00016
Product code
YMDX Rev.
Revision level
Figure 4. Label Artwork Layout
The label contains three rows of information:
First row – Murata Power Solutions logo
Second row – Model number product code (see table)
Third row – Manufacturing date code and revision level
Model Number
Product Code
OKX-T/3-W5N-C
X00003
OKX-T/3-W5P-C
X01003
The manufacturing date code is four characters:
First character – Last digit of manufacturing year, example 2009
Second character – Month code (1 through 9 and O through D)
Third character – Day code (1 through 9 = 1 to 9, 10 = O and
11 through 31 = A through Z)
Fourth character – Manufacturing information
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.
© 2012 Murata Power Solutions, Inc.
www.murata-ps.com/support
MDC_OKX_T/3-W5 Series.A01 Page 15 of 15