NMT Series
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Triple Output 3W DC-DC Converters
SELECTION GUIDE
Order Code
FEATURES
RoHS compliant
Triple outputs (-24V, -48V & -72V)
Input/output isolation 1kVDC
Power sharing on outputs
Industrial temperature range
Nominal
Nominal Output Current1
Input
Output
Min.
Full
Voltage Output Voltage Load
Load
V
V
mA
mA
NMT0572SC
5
NMT1272SC
12
Toroidal magnetics
-24
-48
-72
-24
-48
-72
1.4
0.7
0.5
1.4
0.7
0.5
42
21
14
42
21
14
4.2
2.1
1.4
4.2
2.1
1.4
126
63
42
126
63
42
MTTF3
Recommended
Alternative
kHrs
145
Contact Murata
145
Contact Murata
When operated with additional external load capacitance the rise time of the input voltage will determine the maximum external
capacitance value for guaranteed start up. The slower the rise time of the input voltage the greater the maximum value of the
additional external capacitance for reliable start up.
INPUT CHARACTERISTICS
Parameter
Voltage range
UL 94V-0 package material
Internal SMD construction
-VOUT1
-VOUT2
-VOUT3
-VOUT1
-VOUT2
-VOUT3
Output Current2
Min.
Full
Load
Load
mA
mA
Ripple current (IRIPPLE)
Zero load input current
(ICCZL)
Conditions
Min.
Typ.
Max.
Units
NMT0572SC
NMT1272SC
NMT0572SC
NMT1272SC
NMT0572SC, 0% output load
NMT1272SC, 0% output load
4.5
10.8
5.0
12
85
66
50
27.5
5.5
13.2
V
80
50
mA
Typ.
Max.
Units
W
1.01
8
220
3.0
10
2.5
26.4
24.6
52.8
49.2
79.2
73.8
1.2
15
400
mV
Typ.
Max.
Units
mA
No external components required
Power density 1.65W/cm3
DESCRIPTION
The NMT series is a range of DC-DC converters offering three output voltages of -24V, -48V
and -72V from a single isolated 5V or 12V input
voltage. The product is designed for use with
telecommunications circuits requiring an on board
supply for the -72V RING-TIP connection service
generated from a nominal 5V or 12V DC input
supply rail. The device also offers battery level
voltages of -24V and -48V for access control and
data pump IC’s. The product is packaged in an
8 pin SIP case for minimum PCB footprint. The
rated power may be shared or drawn from any
one output providing the total output load does not
exceed 3W.
OUTPUT CHARACTERISTICS
Parameter
Conditions
Min.
Total Rated Power (POUT)
Total of all outputs or any single output
POUT = 100mW
POUT = 3W
POUT = 100mW
POUT = 3W
POUT = 100mW
POUT = 3W
POUT = 100mW
POUT = 3W
VIN = 90% to 110% of nominal
POUT = 100mW to 3W
DC to 20MHz single channel (24V)
0.1
0
-7.5
24
22.2
48
44.4
72
66.6
Single Channel Voltage Set
Point Accuracy
Output Voltage - VOUT1
Output Voltage - VOUT2
Output Voltage - VOUT3
Line regulation
Load regulation
Ripple & Noise
V
%
ISOLATION CHARACTERISTICS
Parameter
Conditions
Min.
Isolation test voltage
Flash tested for 1 second
NMT0572SC, 1MHz, 1V
NMT1272SC, 1MHz, 1V
1000VDC
1000
Isolation Capacitance
Insulation Resistance
For full details go to
https://www.murata.com/englobal/products/power/rohs
%
1
VDC
65
130
10
pF
GΩ
1. Assuming all 3 channels are equally loaded.
2. Assuming only 1 channel is loaded.
3. Calculated using MIL-HDBK-217F with nominal input voltage at full load.
All specifications typical at TA=25°C, nominal input voltage and rated output current unless otherwise specified.
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KDC_NMT.H01 Page 1 of 6
NMT Series
Triple Output 3W DC-DC Converters
ABSOLUTE MAXIMUM RATINGS
Short-circuit protection4
1 second
Wave Solder profile not to exceed the profile recommended in IEC 61760-1 Section 6.1.3.
Please refer to application notes for further information.
Wave Solder
Lead temperature 1.5mm from case for 10 seconds
Input Voltage VIN, NMT0572SC
Input voltage VIN, NMT1272SC
260°C
7V
15V
GENERAL CHARACTERISTICS
Parameter
Conditions
Efficiency
Switching frequency
All channels or any single channel
Min.
Typ.
75
85
85
Min.
Typ.
Max.
Units
%
kHz
TEMPERATURE CHARACTERISTICS
Parameter
Conditions
Operating temperature
Storage
Case temperature rise above
ambient
-40
-50
1 litre static air chamber
Max.
85
125
Units
°C
27
OUTPUT VOLTAGE CONFIGURATION
Although the output is described for negative rails, the input and output circuits are iternally isolated hence positive rails can also be generated, or a mixture of positive
and negative. The output +VOUT rail reference can be taken from any of the output terminals to give the range of outputs as described in the Output Voltage Configurations
table below.
Channel Name
Standard Ref
Option 1
Option 2
Option 3
OV
+24V
+48V
+72V
+VOUT
-VOUT1
-VOUT2
-VOUT3
-24V
-48V
-72V
OV
-24V
-48V
+24V
OV
-24V
+48V
+24V
OV
POWER SHARING
The 3W total power delivery can be taken from either a single channel, or from any combination of all three channels. This allows an enormous amount of flexibility,
especially when combined with the selectable output OV reference. For example, using the option 2 output configuration; -24V at 0.5W, +24V at 1W and +48V at 1.5W
power supplies are available from a single NMT device.
4. Supply voltage must be disconnected at the end of the short circuit duration.
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KDC_NMT.H01 Page 2 of 6
NMT Series
Triple Output 3W DC-DC Converters
PERFORMANCE CHARACTERISTICS
NMT1272SC - Channel -VOUT1 (24V NOM)
0VUQVU7PMUBHF 7
&GmDJFODZ
0VUQVU7PMUBHF 7
&GmDJFODZ
NMT0572SC - Channel -VOUT1 (24V NOM)
0VUQVU1PXFS 8
0VUQVU1PXFS 8
0VUQVU7PMUBHF 7
&GmDJFODZ
0VUQVU1PXFS 8
0VUQVU7PMUBHF 7
&GmDJFODZ
0VUQVU7PMUBHF 7
NMT1272SC - Channel -VOUT3 (72V NOM)
0VUQVU1PXFS 8
0VUQVU1PXFS 8
0VUQVU1PXFS 8
NMT0572SC - Channel -VOUT3 (72V NOM)
0VUQVU1PXFS 8
0VUQVU1PXFS 8
NMT1272SC - Channel -VOUT2 (48V NOM)
0VUQVU1PXFS 8
0VUQVU7PMUBHF 7
&GmDJFODZ
0VUQVU1PXFS 8
NMT0572SC - Channel -VOUT2 (48V NOM)
&GmDJFODZ
0VUQVU1PXFS 8
0VUQVU1PXFS 8
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KDC_NMT.H01 Page 3 of 6
NMT Series
Triple Output 3W DC-DC Converters
APPLICATION NOTES
RIPPLE SPECIFICATION
The output ripple for the NMT series is higher than standard for a Murata Power Solutions DC-DC converter.
This is due to using low value ceramic capacitors internally for longer life perfomance of the component and
the superimposition of ripples between each output channel. Consequently with a maximum 400mV ripple per
output channel, at -72V the ripple is potentially three times this value (1.2V). The ripple will always be additively
superimposed since the output windings are synchronised.
To reduce ripple, external capacitors are recommended with a value of 1μF per channel (see Figure 1). This
typically reduces the ripple to 50mV per channel. Further ripple reduction can be achieved by use of series
inductors on each output channel plus additional external capacitors to form a pi-filter with the internal capacitors of the device.
SLIC CIRCUITS
Figure 1. VOUT3 Output Ripple
Top: No external capacitors
Bottom: 1μF per channel external capacitors
The primary application for the NMT series is in subscriber line interface circuits (SLIC’s), particularly for the
Integrated Services Digital Network (ISDN). The NMT can also be used in standard telecommunications circuits
where a local power source is preferred to the telephone system power due to either the power quality of the
telecommunications system power supply or to avoid potential power line disturbances, such as lightening
strikes and access switching, which will effect the target circuit function.
Another application area is in fibre-in-the-loop (FITL) or radio-in-the-loop (RITL) interfacing via a standard telecommunication SLIC, where the usual telecommunication battery voltage is not available due to the transmission media in use (fibre or radio). In particular, FITL/RITL interfaces directly on PC cards, in local monitor and
boost circuits and at exchanges between the fibre/radio and wire media.
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The supply rails can be used for ringing generators as well as SLIC circuits or where both are combined, such as
in the AMD AM79R79 Ringing SLIC device (see Figure 2). The -72V rail is used primarily for the generation of the
ringing signal (VBAT1), the -48V rail is used to supply in line access circuitry (VBAT2) and the -24V supply for the
on-chip regulator for the logic interface (VNEG). Alternative devices from other manufacturers could use the -24V
output for their internal circuit supply and -72V for ringing.
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7
7#"5
7065 7
7065 7
7/&(
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5*1
7#"5
07
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Figure 2. Supply for Ringing SLIC Device
TECHNICAL NOTES
ISOLATION VOLTAGE
‘Hi Pot Test’, ‘Flash Tested’, ‘Withstand Voltage’, ‘Proof Voltage’, ‘Dielectric Withstand Voltage’ & ‘Isolation Test Voltage’ are all terms that relate to the same thing, a test voltage,
applied for a specified time, across a component designed to provide electrical isolation, to verify the integrity of that isolation.
Murata Power Solutions NMT series of DC-DC converters are all 100% production tested at their stated isolation voltage. This is 1kVDC for 1 second.
A question commonly asked is, “What is the continuous voltage that can be applied across the part in normal operation?”
For a part holding no specific agency approvals, such as the NMT series, both input and output should normally be maintained within SELV limits i.e. less than 42.4V peak, or
60VDC. The isolation test voltage represents a measure of immunity to transient voltages and the part should never be used as an element of a safety isolation system. The part
could be expected to function correctly with several hundred volts offset applied continuously across the isolation barrier; but then the circuitry on both sides of the barrier must be
regarded as operating at an unsafe voltage and further isolation/insulation systems must form a barrier between these circuits and any user-accessible circuitry according to safety
standard requirements.
REPEATED HIGH-VOLTAGE ISOLATION TESTING
It is well known that repeated high-voltage isolation testing of a barrier component can actually degrade isolation capability, to a lesser or greater degree depending on materials,
construction and environment. The NMT series has toroidal isolation transformers, with no additional insulation between primary and secondary windings of enamelled wire. While
parts can be expected to withstand several times the stated test voltage, the isolation capability does depend on the wire insulation. Any material, including this enamel (typically
polyurethane) is susceptible to eventual chemical degradation when subject to very high applied voltages thus implying that the number of tests should be strictly limited. We
therefore strongly advise against repeated high voltage isolation testing, but if it is absolutely required, that the voltage be reduced by 20% from specified test voltage.
This consideration equally applies to agency recognised parts rated for better than functional isolation where the wire enamel insulation is always supplemented by a further
insulation system of physical spacing or barriers.
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KDC_NMT.H01 Page 4 of 6
NMT Series
Triple Output 3W DC-DC Converters
PACKAGE SPECIFICATIONS
MECHANICAL DIMENSIONS
PIN CONNECTIONS - 8 PIN SIP
Pin
Function
1
2
5
6
7
8
+VIN
-VIN
+VOUT
-VOUT1
-VOUT2
-VOUT3
TUBE OUTLINE DIMENSIONS
All dimensions in mm ±0.25mm. All pins on a 2.54 pitch and within ±0.25 of true position.
Weight: 3.85g
Unless otherwise stated all dimensions in inches ±0.02 (mm ±0.5mm).
Tube length : 20.47±0.079 (520mm±2mm).
Tube Quantity : 23
RECOMMENDED FOOTPRINT DETAILS`
RoHS COMPLIANT INFORMATION
This series is compatible with RoHS soldering
systems with a peak wave solder temperature
of 260ºC for 10 seconds. Please refer to
application notes for further information.
The pin termination finish on this product
series is Tin Plate, Hot Dipped over Matte Tin
with Nickel Preplate. The series is backward
compatible with Sn/Pb soldering systems.
For further information, please visit www.murata-ps.com/rohs
Unless otherwise stated all dimensions in mm ±0.5mm.
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KDC_NMT.H01 Page 5 of 6
NMT Series
Triple Output 3W DC-DC Converters
DISCLAIMER
Unless otherwise stated in the datasheet, all products are designed for standard commercial and industrial applications and NOT for safety-critical and/or life-critical
applications.
Particularly for safety-critical and/or life-critical applications, i.e. applications that may directly endanger or cause the loss of life, inflict bodily harm and/or loss or severe
damage to equipment/property, and severely harm the environment, a prior explicit written approval from Murata is strictly required. Any use of Murata standard products for any safety-critical, life-critical or any related applications without any prior explicit written approval from Murata shall be deemed unauthorised use.
These applications include but are not limited to:
•
Aircraft equipment
•
Aerospace equipment
•
Undersea equipment
•
Power plant control equipment
•
Medical equipment
•
Transportation equipment (automobiles, trains, ships, etc.)
•
Traffic signal equipment
•
Disaster prevention / crime prevention equipment
•
Data Processing equipment
Murata makes no express or implied warranty, representation, or guarantee of suitability, fitness for any particular use/purpose and/or compatibility with any application or device of the buyer, nor does Murata assume any liability whatsoever arising out of unauthorised use of any Murata product for the application of the buyer. The
suitability, fitness for any particular use/purpose and/or compatibility of Murata product with any application or device of the buyer remain to be the responsibility and
liability of the buyer.
Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards that anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause harm, and take appropriate remedial actions. Buyer will fully indemnify and hold
Murata, its affiliated companies, and its representatives harmless against any damages arising out of unauthorised use of any Murata products in any safety-critical and/
or life-critical applications.
Remark: Murata in this section refers to Murata Manufacturing Company and its affiliated companies worldwide including, but not limited to, Murata Power Solutions.
This product is subject to the following operating requirements
and the Life and Safety Critical Application Sales Policy:
Refer to: https://www.murata.com/en-eu/products/power/requirements
Murata Power Solutions (Milton Keynes) Ltd. 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.
© 2022 Murata Power Solutions (Milton Keynes) Ltd.
www.murata.com
KDC_NMT.H01 Page 6 of 6
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