(1) See SOA curves or consult factory for appropriate derating.
(2) The set-point voltage tolerance is affected by the tolerance of RSET. The stated limit is unconditionally met if RSET has a tolerance of 1% with 100ppm/°C or better
temperature stability.
(3) When the set-point voltage is adjusted higher than 3.6 V, a 10-V minimum input voltage is recommended.
(4) A small, low-leakage (<100 nA) MOSFET is recommended to control this pin. The open-circuit voltage is less than 1 Vdc.
(5) This control pin has an internal pull-up to 6.7 V. If left open-circuit, the module operates when input power is applied. A small, low leakage (<100 nA) MOSFET or
open-drain/collector voltage supervisor IC is recommended for control. See the
Application Information
section for further guidance.
(6) Default voltages may be adjusted using the
UVLO Prog
control input. See the
Application Information
section for further guidance.
(7) This control pin has an internal pull-up to 5 V nominal. If it is left open-circuit, the module operates when input power is applied. A small,
(8) Low-leakage (<100 nA) MOSFET is recommended for control. For further information, see the related application note. A minimum capacitance of 560-µF is required
at the input for proper operation. For best results, 1000µF is recommended. The capacitance must be rated for a minimum of 300 mArms of ripple current.
(9) A minimum value of output capacitance is required for proper operation. Adding additional capacitance at the load further improves transient response.
(10) This is the calculated maximum. The minimum ESR requirement often results in a lower value. See the
Application Information
section for further guidance.
(11) This is the typical ESR for all the electrolytic (non-ceramic) output capacitance. Use 4 mΩ as the minimum when using max-ESR values to calculate.
Note:
1. This datasheet is downloaded from the website of Murata Manufacturing co., ltd. Therefore, it’ s specifications are subject to change or our
products in it may be discontinued without advance notice. Please check with our sales representatives or product engineers before ordering.
2. This datasheet has only typical specifications because there is no space for detailed specifications. Therefore, please approve our product
specifications or transact the approval sheet for product specifications before ordering.
2008.1.21
MPDTH12040WA*Application
4
Characteristic Data; Vin =12 V
Figure 1
Figure 2
Figure 3
(1)
(2)
Figure 4
The electrical characteristic data has been developed from actual products tested at 25°C. This data is considered typical for the converter.
Applies to
Figure 1
and
Figure 2.
The temperature derating curves represent the conditions at which internal components are at or below the manufacturer's maximum
operating temperatures. Derating limits apply to modules soldered directly to a 4-mm x 4-mm, double-sided PCB with 1-oz. copper. For
surface mount packages (AS and AZ suffix), multiple vias (plated through holes) are required to add thermal paths around the power pins.
Please refer to the mechanical specification for more information. Applies to
Figure 3
and
Figure 4.
Characteristic Data; Vin =8 V
Figure 5
(3)
Figure 6
The electrical characteristic data has been developed from actual products tested at 25°C. This data is considered typical for the converter.
Applies to
Figure 5
, and
Figure 6.
Note:
1. This datasheet is downloaded from the website of Murata Manufacturing co., ltd. Therefore, it’ s specifications are subject to change or our
products in it may be discontinued without advance notice. Please check with our sales representatives or product engineers before ordering.
2. This datasheet has only typical specifications because there is no space for detailed specifications. Therefore, please approve our product
specifications or transact the approval sheet for product specifications before ordering.
2008.1.21
MPDTH12040WA*Application
5
Capacitor Recommendations for the MPDTH12040W Power Modules
Ceramic Capacitors
The MPDTH12040W is a state-of-the-art multi-phase power
Above 150 kHz the performance of aluminum electrolytic
converter topology that uses three parallel switching and filter
capacitors is less effective. Multilayer ceramic capacitors
inductor paths between the common input and output filter
have very low ESR and a resonant frequency higher than the
capacitors. The three paths share the load current, operate at
bandwidth of the regulator. They can be used to reduce the
the same frequency, and are evenly displaced in phase.
reflected ripple current at the input as well as improve the
With multiple switching paths the transient output current
transient response of the output.
capability is significantly increased. This reduces the amount of
When used on the output their combined ESR is not critical
external output capacitance required to support a load
as long as the total value of ceramic capacitors, with values
transient. As a further benefit, the ripple current, as seen by the
between 10 µF and 100 µF, does not exceed 400 µF. Also, to
input and output capacitors, is reduced in magnitude and
prevent the formation of local resonances, do not place more
effectively tripled in frequency.
than five identical ceramic capacitors in parallel with values of
10 µF or greater.
Input Capacitor
The improved transient response of a multi-phase converter
Tantalum Capacitors
places a bigger burden on the transient capability of the input
Tantalum type capacitors are only used on the output bus,
source. The size and value of the input capacitor is therefore
and are recommended for applications where the ambient
determined by this converter’s transient performance
operating temperature is less than 0°C. The AVX TPS,
capability. The minimum amount of input capacitance required
Sprague 593D/594/595 and Kemet T495/T510 capacitor
is 560 µF, with an RMS ripple current rating of 300 mA. This
series are suggested over many other tantalum types due to
minimum value assumes that the converter is supplied with a
their higher rated surge, power dissipation, and ripple current
responsive, low inductance input source. This source should
capability. As a caution, many general purpose tantalum
have ample capacitive decoupling, and be distributed to the
capacitors have higher ESR, reduced power dissipation,
converter via PCB power and ground planes. For
and lower ripple current capability. These capacitors are also
high-performance applications, or wherever the transient
less reliable due to their reduced power dissipation and surge
performance of the input source is limited, 1000 µF of input
current ratings. Tantalum capacitors that have no stated ESR
capacitance is recommended. Ripple current, less than 100
or surge current rating are not recommended for power
mΩ of equivalent series resistance (ESR), and temperature are
applications.
the main considerations when selecting input capacitors. The
When specifying Os-con and polymer-tantalum capacitors for
ripple current reflected from the input of the MPDTH12040W
the output, the minimum ESR limit is encountered well before
module is moderate to low. Therefore any good quality,
the maximum capacitance value is reached.
computer-grade electrolytic capacitor, of either value
suggested, has an adequate ripple current rating.
Capacitor Table
Regular tantalum capacitors are not recommended for the
Table 1
identifies the characteristics of capacitors from a
input bus. These capacitors require a recommended minimum
number of vendors with acceptable ESR and ripple current
voltage rating of 2 × (maximum dc voltage + ac ripple). This is
(rms) ratings. The recommended number of capacitors
standard practice to ensure reliability. No tantalum capacitors
required at both the input and output buses is identified for
were found with a sufficient voltage rating to meet this
each capacitor type.
requirement. When the operating temperature is below 0°C,
the ESR of aluminum electrolytic capacitors increases. For
Note: This is not an extensive capacitor list. Capacitors from
these applications, Os-Con, poly-aluminum, and
other vendors are available with comparable specifications.
polymer-tantalum types should be considered. Adding one or
Those listed are for guidance. The RMS ripple current rating
two ceramic capacitors to the input reduces high-frequency
and ESR
reflected ripple current.
(at 100 kHz) are critical parameters necessary to insure both
optimum regulator performance and long capacitor life.
Output Capacitors
The MPDTH12040W requires a minimum output capacitance
Designing for Very Fast Load Transients
of 660 µF (or 2 × 330 µF), with an ESR of 15 mΩ to 40 mΩ.
The transient response of the dc/dc converter has been
This is necessary for the stable operation of the regulator.
characterized using a load transient with a di/dt of 1 A/µs. The
Additional capacitance can be added to improve the module's
typical voltage deviation for this load transient is given in the
performance to load transients. High quality computer-grade
data sheet specification table using the mnimum required
electrolytic capacitors are recommended.
value of output capacitance. As the di/dt of a transient is
Aluminum electrolytic capacitors provide adequate decoupling
increased, the response of a converter’s regulation circuit
over the frequency range, 2 kHz to 150 kHz, and are suitable
ultimately depends on its output capacitor decoupling
when ambient temperatures are above 0°C. For operation
network. This is an inherent limitation with any dc/dc
below 0°C, tantalum, ceramic, or Os-Con type capacitors are
converter once the speed of the transient exceeds its
necessary. When using a combination of one or more
bandwidth capability. If the target application specifies a
non-ceramic capacitors, the calculated equivalent ESR should
higher di/dt or lower voltage deviation, the requirement can
be no lower than 2 mΩ (4 mΩ when calculating using the
only be met with additional output capacitor decoupling. In
manufacturer’s maximum ESR values). A list of preferred
these cases special attention must be paid to the type, value
low-ESR type capacitors are identified in
Table 1.
and ESR of the capacitors selected.
Note:
1. This datasheet is downloaded from the website of Murata Manufacturing co., ltd. Therefore, it’ s specifications are subject to change or our
products in it may be discontinued without advance notice. Please check with our sales representatives or product engineers before ordering.
2. This datasheet has only typical specifications because there is no space for detailed specifications. Therefore, please approve our product
specifications or transact the approval sheet for product specifications before ordering.
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