SELECTION GUIDE
ISOLATION CHARACTERISTICS
GENERAL CHARACTERISTICS
FEATURES
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Triple Outputs (–24V, –48V & –72V)
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Toroidal Magnetics
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Input/Output Isolation 1kVDC
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Power Sharing on Outputs
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Internal SMD Construction
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Industrial Temperature Range
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No External Components Required
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Power Density 1.41W/cm3
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UL 94V-0 Package Material
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.
Nominal
Rated
Output Current2
Output Current3
Input
Output
MIN
Full
MIN
Full
Voltage
Output
Voltage
Load
MTTF1
Order Code
(V)
V
(mA)
kHrs
VO1
–24
1.4
42
4.2
126
NMT0572S
5
VO2
–48
0.7
21
2.1
63
145
VO3
–72
0.5
14
1.4
42
VO1
–24
1.4
42
4.2
126
NMT1272S
12
VO2
–48
0.7
21
2.1
63
145
VO3
–72
0.5
14
1.4
42
i When operated without additional external load capacitance, the output voltage of the devices is guaranteed
to be within 95% of its steady state value within 100ms after the input voltage has reached 95% of its steady
state value, irrespective of the rise time of the input voltage.
ii 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.
Parameter
Conditions
MIN
TYP
MAX
Units
Voltage Range
NMT0572S
4.5
5.0
5.5
(VIN)
NMT1272S
10.8
12
13.2
V
Ripple Current
NMT0572S
85
(IRIPPLE)
NMT1272S
66
mA
Zero Load Input NMT0572S, 0% output load
50
80
Current (ICCZL)
NMT1272S, 0% output load
27.5
50
mA
Parameter
Conditions
MIN
TYP
MAX
Units
Total Rated Power (P OUT)
Total of all outputs or any
0.1
3.0
W
single output
Single Channel Voltage
POUT = 100mW
0
10
%
Setpoint Accuracy
POUT = 3W
–7.5
2.5
Output Voltage - VO1 (VOUT)
POUT = 100mW
24.0
26.4
V
POUT = 3W
22.2
24.6
Output Voltage - VO2 (VOUT)
POUT = 100mW
48.0
52.8
V
POUT = 3W
44.4
49.2
Output Voltage - VO3 (VOUT)
POUT = 100mW
72.0
79.2
V
POUT = 3W
66.6
73.8
Line Regulation
VIN = 90% to 110%
1.01
1.2
%
of nominal
Load Regulation
POUT = 100mW to 3W
8
15
%
Ripple & Noise
DC to 20MHz single
0
220
400
mV
channel (24V)
Parameter
Conditions
MIN
TYP
MAX
Units
Isolation Voltage (VISOL)
Flash tested for 1 second
1000
VDC
Isolation Capacitance (CISOL)
NMT0572S, 1MHz, 1V
65
pF
NMT1272S, 1MHz, 1V
130
Insulation Resistance
1000VDC test
1
10
G
Parameter
Conditions
MIN
TYP
MAX
Units
Efficiency
All channels or any single channel
75
85
%
Switching Frequency (fOSC)
85
kHz
Short-circuit duration4
1 second
Lead temperature 1.5mm from case for 10 seconds
300°C
Input voltage VIN, NMT0572S
7V
Input voltage VIN, NMT1272S
15V
INPUT CHARACTERISTICS
OUTPUT CHARACTERISTICS
ABSOLUTE MAXIMUM RATINGS
1 Calculated using MIL-HDBK-217F with nominal input voltage at full load.
2 Assuming all 3 channels are equally loaded.
3 Assuming only 1 channel is loaded.
4 Supply voltage must be discontinued at the end of the short circuit duration.
All specifications typical at TA=25°C, nominal input voltage and rated output current unless otherwise specified.
NMT SERIES
Triple Output 3W DC-DC Converters
www.dc-dc.com