MYMGK1R806FRSR/MYMGK00506ERSR
Mono Block Type Small & High Power Density 6A DC-DC Converter Series
TECHNICAL NOTES
Input Fuse
The capacitor should be a ceramic type such as the Murata GRM32
Certain applications and/or safety agencies may require fuses at series and a electrolytic type such as Panasonic OS-CON series.
the inputs of power conversion components. Fuses should also Initial suggested capacitor values are 22 uF x 2 or 47uF x 2 ceramic
be used when there is the possibility of sustained input voltage type and 1000uF x 1 electrolytic type , rated at twice the expected
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.
maximum input voltage. Make sure that the input terminals do not go
below the under voltage shutdown voltage at all times. More input bulk
capacitance may be added in parallel (either electrolytic or tantalum) if
needed.
Recommended Output Filtering
For safety agency approvals, install the converter in compliance The converter will achieve its rated output ripple and noise with
with the end-user safety standard.
Input Under-Voltage Shutdown and Start-Up Threshold
Under normal start-up conditions, converters will not begin to
additional external capacitor. The user may install more external
output capacitance reduce the ripple even further or for improved
dynamic response. Again, use low-ESR ceramic (Murata GRM32
regulate properly until the ramping-up input voltage exceeds and series). Initial values of 220 uF x 2 or 100 uF x 4 ceramic type may be
remains at the Start-Up Threshold Voltage (see Specifications). tried,either single or multiple capacitors in parallel. Mount these close
Once operating, converters will not turn off until the input voltage to the converter. Measure the output ripple under your load conditions.
drops below the Under-Voltage Shutdown Limit. Subsequent
Use only as much capacitance as required to achieve your ripple and
restart will not occur until the input voltage rises again above the noise objectives. Excessive capacitance can make step load recovery
Start-Up Threshold. This built-in hysteresis prevents any unstable sluggish or possibly introduce instability. Do not exceed the maximum
on/off operation at a single input voltage.
rated output capacitance listed in the specifications.
Users should be aware however of input sources near the Under- Input Ripple Current and Output Noise
Voltage Shutdown whose voltage decays as input current is
All models in this converter series are tested and specified for input
consumed (such as capacitor inputs), the converter shuts off and reflected ripple current and output noise using designated external
then restarts as the external capacitor recharges. Such situations input/output components, circuits and layout as shown in the figures
could oscillate. To prevent this, make sure the operating input
voltage is well above the UV Shutdown voltage AT ALL TIMES. In the figure below, the two copper strips simulate real-world printed
Start-Up Time
circuit impedances between the power supply and its load. In order to
below.
Assuming that the output current is set at the rated maximum, the minimize circuit errors and standardize tests between units, scope
Vin to Vout Start-Up Time (see Specifications) is the time interval measurements should be made using BNC connectors or the probe
between the point when the ramping input voltage crosses the
ground should not exceed one half inch and soldered directly to the
Start-Up Threshold and the fully loaded regulated output voltage test circuit.
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.
COPPER STRIP
VOUT
GND
SCOPE
C1
C2
RLOA
COPPER
STRIP
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.
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. For best performance, we recommend
installing a low-ESR capacitor immediately adjacent to the
converter’s input terminals.
3-7mm
C1=220uF x 2 or 100uF x 4 CERAMIC
C2=OPEN
Figure: Measuring Output Ripple and Noise
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.
http://www.murata.com/ja-jp/products/power
MYMGK1R806FRSR/MYMGK00506ERSR A04 Page 19 of 22
