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Q48T30025-NDB0

P1-P3P4-P6P7-P9P10-P12P13-P14
JUN 09, 2003 revised to NOV 20, 2006 Page 7 of 14 www.power-one.com
Q48T30025 DC-DC Converter Data Sheet
3
6
-75 VDC In
p
ut; 2.5 VDC
@
30A O
u
t
p
ut
Protection Features
Input Undervoltage Lockout
Input undervoltage lockout is standard with this converter.
The converter will shut down when the input voltage drops
below a pre-determined voltage.
The input voltage must be at least 35 V for the converter to
turn on. Once the converter has been turned on, it will shut
off when the input voltage drops below 31 V. This feature is
beneficial in preventing deep discharging of batteries used in
telecom applications.
Output Overcurrent Protection (OCP)
The converter is protected against overcurrent or short cir-
cuit conditions. Upon sensing an overcurrent condition, the
converter will switch to constant current operation and
thereby begin to reduce output voltage. When the output
voltage drops below 1 Vdc, the converter will shut down (Fig.
26).
Once the converter has shut down, it will attempt to restart
nominally every 100 ms with a 3% duty cycle (Fig 27). The
attempted restart will continue indefinitely until the overload
or short circuit conditions are removed or the output voltage
rises above 1 Vdc.
Output Overvoltage Protection (OVP)
The converter will shut down if the output voltage across
Vout(+) (Pin 8) and Vout(-) (Pin 4) exceeds the threshold of
the OVP circuitry. The OVP circuitry contains its own refer-
ence, independent of the output voltage regulation loop.
Once the converter has shut down, it will attempt to restart
every 100 ms until the OVP condition is removed.
Overtemperature Protection (OTP)
The converter will shut down under an overtemperature con-
dition to protect itself from overheating caused by operation
outside the thermal derating curves, or operation in abnor-
mal conditions such as system fan failure. After the con-
verter has cooled to a safe operating temperature, it will
automatically restart.
Safety Requirements
The converters meet North American and International
safety regulatory requirements per UL60950 and EN60950.
Basic Insulation is provided between input and output.
To comply with safety agencies requirements, an input line
fuse must be used external to the converter. A 4-A fuse is
recommended for use with this product.
Electromagnetic Compatibility (EMC)
EMC requirements must be met at the end-product system
level, as no specific standards dedicated to EMC character-
istics of board mounted component dc-dc converters exist.
However, Power-One tests its converters to several system
level standards, primary of which is the more stringent
EN55022, Information technology equipment - Radio distur-
bance characteristics - Limits and methods of measurement.
With the addition of a simple external filter (see application
notes), all versions of the Q48T30 converters pass the re-
quirements of Class B conducted emissions per EN55022
and FCC, and meet at a minimum, Class A radiated emis-
sions per EN 55022 and Class B per FCC Title 47CFR, Part
15-J. Please contact Power-One Applications Engineering
for details of this testing.
Input Transient Withstand
This family of converters meets the input transient withstand
requirements of Bellcore GR-513 (Section 13, Table 4.2) as
shown in Fig. 6, and also withstands 100 V input transient for
100 ms.
Transient Duration Vdc
5 seconds -65
10 ms -75
10 µs
-100
1µs
-200
Fig. 6: Input transient withstand capability per Bellcore GR-513.
(Negative signs imply telecom transients relative to Vin(+) terminal)
JUN 09, 2003 revised to NOV 20, 2006 Page 8 of 14 www.power-one.com
Q48T30025 DC-DC Converter Data Sheet
3
6
-75 VDC In
p
ut; 2.5 VDC
@
30A O
u
t
p
ut
Characterization
General Information
The converter has been characterized for many operational
aspects, to include thermal derating (maximum load current
as a function of ambient temperature and airflow) for vertical
and horizontal mounting, efficiency, start-up and shutdown
parameters, output ripple and noise, transient response to
load step-change, overload and short circuit.
The following pages contain specific plots or waveforms as-
sociated with the converter. Additional comments for specific
data are provided below.
Test Conditions
All data presented were taken with the converter soldered to
a test board, specifically a 0.060” thick printed wiring board
(PWB) with four layers. The top and bottom layers were not
metalized. The two inner layers, comprising two-ounce cop-
per, were used to provide traces for connectivity to the con-
verter.
The lack of metalization on the outer layers as well as the
limited thermal connection ensured that heat transfer from
the converter to the PWB was minimized. This provides a
worst-case but consistent scenario for thermal derating pur-
poses.
All measurements requiring airflow were made in Power-
One’s vertical and horizontal wind tunnel facilities using In-
frared (IR) thermography and thermocouples for thermome-
try.
Ensuring components on the converter do not exceed their
ratings is important to maintaining high reliability. If one an-
ticipates operating the converter at or close to the maximum
loads specified in the derating curves, it is prudent to check
actual operating temperatures in the application. Thermo-
graphic imaging is preferable; if this capability is not avail-
able, then thermocouples may be used. Power-One recom-
mends the use of AWG #40 gauge thermocouples to ensure
measurement accuracy. Careful routing of the thermocouple
leads will further minimize measurement error. Refer to Fig-
ure 28 for optimum measuring thermocouple location.
Thermal Derating
Load current vs. ambient temperature and airflow rates are
given in Figs. 10-13. Ambient temperature was varied be-
tween 25°C and 85°C, with airflow rates from 30 to 500 LFM
(0.15 to 2.5 m/s), and vertical and horizontal converter
mounting.
For each set of conditions, the maximum load current was
defined as the lowest of:
(i) The output current at which either any FET junction tem-
perature reached a maximum specified (either 105°C or
120°C) as indicated by the thermographic image, or
(ii) The nominal rating of the converter (30 A)
During normal operation, derating curves with maximum FET
temperature less than or equal to 120°C should not be ex-
ceeded. Temperature on the PCB at the thermocouple loca-
tion shown in Fig. 28 should not exceed 118°C in order to
operate inside the derating curves..
Efficiency
Efficiency vs. load current plots are shown in Figs. 14 and 16
for ambient temperature of 25ºC, airflow rate of 300 LFM
(1.5 m/s), both vertical and horizontal orientations, and input
voltages of 36 V, 54 V and 72 V. Also, plots of efficiency vs.
load current, as a function of ambient temperature with Vin =
54 V, airflow rate of 200 LFM (1 m/s) are shown for both a
vertically and horizontally mounted converter in Figs. 15 and
17, respectively.
Start-up
Output voltage waveforms, during the turn-on transient using
the ON/OFF pin for full rated load currents (resistive load)
are shown without and with 10,000
µF load capacitance in
Figs. 18 and 19, respectively.
Ripple and Noise
Figure 22 shows the output voltage ripple waveform, meas-
ured at full rated load current with a 10 µF tantalum and 1 µF
ceramic capacitor across the output. Note that all output
voltage waveforms are measured across a 1
µF ceramic ca-
pacitor.
The input reflected ripple current waveforms are obtained
using the test setup shown in Fig 23. The corresponding
waveforms are shown in Figs. 24 and 25.
JUN 09, 2003 revised to NOV 20, 2006 Page 9 of 14 www.power-one.com
Q48T30025 DC-DC Converter Data Sheet
3
6
-75 VDC In
p
ut; 2.5 VDC
@
30A O
u
t
p
ut
Start-up Information (using negative ON/OFF)
Scenario #1: Initial Start-up From Bulk Supply
ON/OFF function enabled, converter started via application of V
IN
.
See Figure 7.
Time Comments
t
0
ON/OFF pin is ON; system front end power is toggled
on, V
IN
to converter begins to rise.
t
1
V
IN
crosses Under-Voltage Lockout protection circuit
threshold; converter enabled.
t
2
Converter begins to respond to turn-on command (con-
verter turn-on delay).
t
3
Converter V
OUT
reaches 100% of nominal value.
For this example, the total converter start-up time (t
3
- t
1
) is typically
2.5 ms.
Scenario #2: Initial Start-up Using ON/OFF Pin
With V
IN
previously powered, converter started via ON/OFF pin.
See Figure 8.
Time Comments
t
0
V
INPUT
at nominal value.
t
1
Arbitrary time when ON/OFF pin is enabled (converter
enabled).
t
2
End of converter turn-on delay.
t
3
Converter V
OUT
reaches 100% of nominal value.
For this example, the total converter start-up time (t
3
- t
1
) is typically
2.5 ms.
Scenario #3: Turn-off and Restart Using ON/OFF Pin
With V
IN
previously powered, converter is disabled and then en-
abled via ON/OFF pin. See Figure 9.
Time Comments
t
0
V
IN
and V
OUT
are at nominal values; ON/OFF pin ON.
t
1
ON/OFF pin arbitrarily disabled; converter output falls
to zero; turn-on inhibit delay period (100 ms typical) is
initiated, and ON/OFF pin action is internally inhibited.
t
2
ON/OFF pin is externally re-enabled.
If (t
2
- t
1
) ≤ 100 ms, external action of ON/OFF pin
is locked out by start-up inhibit timer.
If (t
2
- t
1
) > 100 ms, ON/OFF pin action is internally
enabled.
t
3
Turn-on inhibit delay period ends. If ON/OFF pin is ON,
converter begins turn-on; if off, converter awaits
ON/OFF pin ON signal; see Figure 8.
t
4
End of converter turn-on delay.
t
5
Converter V
OUT
reaches 100% of nominal value.
For the condition, (t
2
- t
1
) ≤ 100 ms, the total converter start-up
time (t
5
- t
2
) is typically 102.5 ms. For (t
2
- t
1
) > 100 ms, start-up will
be typically 2.5 ms after release of ON/OFF pin.
Fig. 7: Start-up scenario #1.
ON/OFF
STATE
VOUT
t0 t1 t2 t3
ON
OFF
VIN
t
Fig. 8: Start-up scenario #2.
ON/OFF
STATE
OFF
ON
V
OUT
t0 t2t1 t5
VIN
t
t4t3
100 ms
Fig. 9: Start-up scenario #3.
VIN
ON/OFF
STATE
V
OUT
t
t
0 t1 t2 t3
ON
OFF
P1-P3P4-P6P7-P9P10-P12P13-P14

Q48T30025-NDB0

Mfr. #:
Buy Q48T30025-NDB0
Manufacturer:
Bel Power Solutions
Description:
Isolated DC/DC Converters
Lifecycle:
New from this manufacturer.
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