SQE48T20050 DC-DC Converter Data Sheet
36-75 VDC Input; 5.0 VDC @ 20 A Output
Features
•
RoHS lead free solder and lead solder exempted
products are available
•
Delivers up to 20 A
•
Industry-standard quarter-brick pinout
•
On-board input differential LC-filter
•
Start-up into pre-biased load
•
No minimum load required
•
Weight: 0.72 oz [20.6 g]
•
Meets Basic Insulation requirements of EN60950
•
Withstands 100 V input transient for 100 ms
•
Fixed-frequency operation
•
Fully protected
•
Latching and non-latching protection available
•
Positive or negative logic ON/OFF option
•
Remote output sense
•
Output voltage trim range: +10%/−20% with
industry-standard trim equations
•
High reliability: MTBF = 13.19 million hours,
calculated per Telcordia TR-332, Method
I
Case 1
•
UL60950 recognized in US and Canada and
DEMKO certified per IEC/EN60950
•
Designed to meet Class B conducted emissions per
FCC and EN55022 when used with external filter
•
All materials meet UL94, V-0 flammability rating
Applications
•
•
•
•
Telecommunications
Data communications
Wireless communications
Servers
Benefits
•
High efficiency – no heat sink required
•
Higher current capability at elevated temperatures
than most competitors' 20 A quarter-bricks
•
Extremely small footprint: 0.896” x 2.30” (2.06 in
2
),
38% smaller than conventional quarter-bricks
Description
The new high temperature SQE48-Series of dc-dc converter provides a high efficiency single output in a physical
package that is only 62% the size of the industry-standard quarter-brick. Specifically designed for operation in
systems that have limited airflow and increased ambient temperatures, the SQE48-Series of converters utilizes the
same pinout and functionality of the industry-standard quarter-bricks.
The SQE48-Series of converters provides thermal performance in high temperature environments that exceeds
most competitors' 20 A quarter-bricks. This performance is accomplished through the use of patented/
patent-pending circuits, packaging, and processing techniques to achieve ultra-high efficiency, excellent thermal
management, and a low-body profile.
Low-body profile and the preclusion of heat sinks minimize airflow shadowing, thus enhancing cooling for
downstream devices. The use of 100% automation for assembly, coupled with advanced electronic circuits, and
thermal design, results in a product with extremely high reliability.
The SQE48T20050 operates over an input voltage range of 36 to 75 VDC, and provides an output current up to
20 A with a standard output voltage of 5.0 VDC. The output can be trimmed from –20% to +10% of the nominal
output voltage, thus providing outstanding design flexibility.
With standard pinout and trim equations, the SQE48 converters are perfect drop-in replacements for the
competing quarter-brick designs. Inclusion of this converter in new designs can result in significant board space
and cost savings. The designer can expect reliability improvement over other available converters because of the
SQE48-Series’ optimized thermal efficiency.
JUL 07, 2006 revised to APR 12, 2007
Page 1 of 16
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SQE48T20050 DC-DC Converter Data Sheet
36-75 VDC Input; 5.0 VDC @ 20 A Output
Electrical Specifications
Conditions: T
A
= 25 ºC, Airflow=300 LFM (1.5 m/s), Vin = 48 VDC, unless otherwise specified.
Parameter
Absolute Maximum Ratings
Input Voltage
Operating Ambient Temperature
Storage Temperature
Input Characteristics
Operating Input Voltage Range
Input Under Voltage Lockout
Turn-on Threshold
Turn-off Threshold
Input Voltage Transient
Isolation Characteristics
I/O Isolation
See note *
Isolation Capacitance
See note *
Isolation Resistance
Feature Characteristics
Switching Frequency
Output Voltage Trim Range
1
Remote Sense Compensation
1
Notes
Continuous
Min
0
-40
-55
36
Typ
Max
80
85
125
Units
VDC
°C
°C
VDC
VDC
VDC
VDC
VDC
VDC
48
34
32
75
35
33
100
Non-latching
33
31
100 ms
2250
1500
190
1200
10
460
Industry-std. equations
Percent of V
OUT
(
NOM
)
Latching or Non-latching
Non-latching*
Non-latching
Peak amplitude
Peak duration
Converter Off;
external voltage 5 VDC
Applies to all protection features
-20
117
120
122
125
125
1
50
10
200
4
-20
2.4
2.4
-20
0.8
20
20
0.8
30
+10
+10
127
130
pF
pF
MΩ
kHz
%
%
%
%
°C
ADC
µs
mADC
ms
ms
VDC
VDC
VDC
VDC
Output Overvoltage Protection
Overtemperature Shutdown (PCB)
Peak Back-drive Output Current
(Sinking current from external source)
during startup into pre-biased output
Back-drive Output Current (Sinking Current
from external source)
Auto-Restart Period (For non-latching option)
Turn-On Time
ON/OFF Control (Positive Logic)
Converter Off (logic low)
Converter On (logic high)
ON/OFF Control (Negative Logic)
Converter Off (logic high)
Converter On (logic low)
Additional Notes:
1.
Vout can be increased up to 10% via the sense leads or up to 10% via the trim function. However, the total output voltage trim from all
sources should not exceed 10% of V
OUT
(
NOM
), in order to ensure specified operation of overvoltage protection circuitry.
For models with the special feature “K”.
*
JUL 07, 2006 revised to APR 12, 2007
Page 2 of 16
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SQE48T20050 DC-DC Converter Data Sheet
36-75 VDC Input; 5.0 VDC @ 20 A Output
Electrical Specifications (continued)
Conditions: T
A
= 2 5ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, unless otherwise specified.
Parameter
Input Characteristics
Maximum Input Current
Input Stand-by Current
Input No Load Current (0 load on the output)
Input Reflected-Ripple Current
Input Voltage Ripple Rejection
Output Characteristics
Output Voltage Set Point (no load)
Output Regulation
Over Line
Over Load
Output Voltage Range
Output Ripple and Noise - 20MHz
bandwidth
External Load Capacitance
Output Current Range
Current Limit Inception
Peak Short-Circuit Current
RMS Short-Circuit Current
Notes
20 ADC, 5.0 VDC Out @ 36 VDC In
Vin = 48 V, converter disabled
Vin = 48 V, converter enabled
20 MHz bandwidth
120Hz
Min
Typ
Max
3.1
Units
ADC
mADC
mADC
mA
PK-PK
dB
VDC
mV
mV
VDC
mV
PK-PK
μF
ADC
ADC
A
Arms
mV
mV
µs
mV
%
%
2
40
8
75
4.950
5.000
±2
±2
5.050
±5
±5
5.075
100
10,000
20
29
8
Over line, load and temperature
2
Full load + 10
μF
tantalum + 1
μF
ceramic
Plus full load (resistive)
Non-latching
For non-latching option, Short = 10 mΩ
For non-latching option
4.925
50
0
22
25
25
4
40
180
20
100*
91
92.5
Dynamic Response
Load Change 50%-100%-50%, di/dt = 0.1 A/µs Co = 1
μF
ceramic
di/dt = 5 A/µs
Co = 470
μF
POS + 1
μF
ceramic
Settling Time to 1%
Load Change 50%-75%-50%, di/dt = 2.5 A/µs Co = 2x100
μF
TA + 1
μF
ceramic
Efficiency
100% Load
50% Load
Additional Notes:
.
-40 ºC to 85 ºC.
*
For models with the special feature “K”.
2
JUL 07, 2006 revised to APR 12, 2007
Page 3 of 16
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SQE48T20050 DC-DC Converter Data Sheet
36-75 VDC Input; 5.0 VDC @ 20 A Output
Operations
Input and Output Impedance
These power converters have been designed to be
stable with no external capacitors when used in low
inductance input and output circuits.
In many applications, the inductance associated with
the distribution from the power source to the input of
the converter can affect the stability of the converter.
The addition of a 33 µF electrolytic capacitor with an
ESR < 1
Ω
across the input helps ensure stability of
the converter. In many applications, the user has to
use decoupling capacitance at the load. The power
converter will exhibit stable operation with external
load capacitance up to 10,000 µF on 5.0 V output.
Additionally, see the EMC section of this data sheet
for discussion of other external components which
may be required for control of conducted emissions
ON/OFF (Pin 2)
The device must be capable of sinking up to 0.2 mA
at a low level voltage of
≤
0.8 V. An external voltage
source (±20 V maximum) may be connected directly
to the ON/OFF input, in which case it must be
capable of sourcing or sinking up to 1 mA depending
on the signal polarity. See the Startup Information
section for system timing waveforms associated with
use of the ON/OFF pin.
Remote Sense (Pins 5 and 7)
The remote sense feature of the converter
compensates for voltage drops occurring between
the output pins of the converter and the load. The
SENSE(-) (Pin 5) and SENSE(+) (Pin 7) pins should
be connected at the load or at the point where
regulation is required (see Fig. B).
SQE48 Converter
(Top View)
ON/OFF
Rw
Vin (+)
Vout (+)
100
SENSE (+)
Vin
TRIM
SENSE (-)
10
Rload
The ON/OFF pin is used to turn the power converter
on or off remotely via a system signal. There are two
remote control options available, positive and
negative logic. with both referenced to Vin(-). A
typical connection is shown in Fig. A.
Vin (-)
Vout (-)
Rw
Fig. B: Remote sense circuit configuration.
CAUTION
Vin (+)
SQE48 Converter
(Top View)
Vout (+)
SENSE (+)
TRIM
SENSE (-)
Rload
Vin
ON/OFF
Vin (-)
CONTROL
INPUT
Vout (-)
If remote sensing is not utilized, the SENSE(-) pin must be
connected to the Vout(-) pin (Pin 4), and the SENSE(+) pin
must be connected to the Vout(+) pin (Pin 8) to ensure the
converter will regulate at the specified output voltage. If these
connections are not made, the converter will deliver an
output voltage that is slightly higher than the specified data
sheet value.
Fig. A: Circuit configuration for ON/OFF function.
The positive logic version turns on when the ON/OFF
pin is at a logic high and turns off when at a logic
low. The converter is on when the ON/OFF pin is left
open. See the Electrical Specifications for logic
high/low definitions.
The negative logic version turns on when the pin is
at a logic low and turns off when the pin is at a logic
high. The ON/OFF pin can be hard wired directly to
Vin(-) to enable automatic power up of the converter
without the need of an external control signal.
The ON/OFF pin is internally pulled up to 5 V
through a resistor. A properly de-bounced
mechanical switch, open-collector transistor, or FET
can be used to drive the input of the ON/OFF pin.
JUL 07, 2006 revised to APR 12, 2007
Because the sense leads carry minimal current,
large traces on the end-user board are not required.
However, sense traces should be run side by side
and located close to a ground plane to minimize
system noise and ensure optimum performance.
The converter’s output overvoltage protection (OVP)
senses the voltage across Vout(+) and Vout(-), and
not across the sense lines, so the resistance (and
resulting voltage drop) between the output pins of
the converter and the load should be minimized to
prevent unwanted triggering of the OVP.
When utilizing the remote sense feature, care must
be taken not to exceed the maximum allowable
output power capability of the converter, which is
equal to the product of the nominal output voltage
and the allowable output current for the given
conditions.
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Page 4 of 16
SQE48T20050 DC-DC Converter Data Sheet
36-75 VDC Input; 5.0 VDC @ 20 A Output
When using remote sense, the output voltage at the
converter can be increased by as much as 10%
above the nominal rating in order to maintain the
required voltage across the load. Therefore, the
designer must, if necessary, decrease the maximum
current (originally obtained from the derating curves)
by the same percentage to ensure the converter’s
actual output power remains at or below the
maximum allowable output power.
Output Voltage Adjust /TRIM (Pin 6)
The output voltage can be adjusted up 10% or down
20% relative to the rated output voltage by the
addition of an externally connected resistor.
The TRIM pin should be left open if trimming is not
being used. To minimize noise pickup, a 0.1 µF
capacitor is connected internally between the TRIM
and SENSE(-) pins.
To increase the output voltage, refer to Fig. C. A trim
resistor, R
T-INCR
, should be connected between the
TRIM (Pin 6) and SENSE(+) (Pin 7), with a value of:
R
T
−
INCR
=
5.11(100
+
Δ)V
O
−
NOM
−
626
−
10.22
1.225Δ
R
T
−
DECR
=
511
−
10.22
Δ
[kΩ]
where,
R
T
−DECR
=
Required value of trim-down resistor [kΩ]
and
Δ
is defined above.
Note:
The above equations for calculation of trim resistor values
match those typically used in conventional industry-standard
quarter-bricks and one-eighth bricks.
Vin (+)
SQE48 Converter
(Top View)
Vout (+)
SENSE (+)
TRIM
SENSE (-)
Rload
R
T-DECR
Vin
ON/OFF
Vin (-)
Vout (-)
Fig. D: Configuration for decreasing output voltage.
[kΩ]
where,
R
T
−INCR
=
Required value of trim-up resistor kΩ]
V
O
−NOM
=
Nominal value of output voltage [V]
Δ
=
(V
O-REQ
−
V
O-NOM
)
X 100
[%]
V
O -NOM
Trimming/sensing beyond 110% of the rated output
voltage is not an acceptable design practice, as this
condition could cause unwanted triggering of the
output overvoltage protection (OVP) circuit. The
designer should ensure that the difference between
the voltages across the converter’s output pins and
its sense pins does not exceed 10% of V
OUT
(
NOM
),
or:
[V
OUT
(
+
)
−
V
OUT
(
−
)]
−
[V
SENSE
+
)
−
V
SENSE
−
)]
≤
V
O - NOM X
10%
[V]
(
(
V
O
−REQ
=
Desired (trimmed) output voltage [V].
SQE48 Converter
(Top View)
SENSE (+)
Vin
ON/OFF
TRIM
SENSE (-)
Vin (-)
Vout (-)
R
T-INCR
Rload
This equation is applicable for any condition of
output sensing and/or output trim.
Vin (+)
Vout (+)
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 typically 34 V for the
converter to turn on. Once the converter has been
turned on, it will shut off when the input voltage
drops typically below 32 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 circuit conditions. Upon sensing an over-
current condition, the converter will switch to
constant current operation and thereby begin to
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Fig. C: Configuration for increasing output voltage.
When trimming up, care must be taken not to exceed
the converter‘s maximum allowable output power.
See the previous section for a complete discussion
of this requirement.
To decrease the output voltage (Fig. D), a trim
resistor, R
T-DECR
, should be connected between the
TRIM (Pin 6) and SENSE(-) (Pin 5), with a value of:
JUL 07, 2006 revised to APR 12, 2007
Page 5 of 16
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