SQE48T20033 DC-DC Converter Data sheet
36-75 VDC Input; 3.3 VDC @ 20A Output
Features
•
RoHS lead-free solder and lead-solder-exempted
products are available
•
Delivers 20A with no derating up to 70
°C
•
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
•
Remote output sense
•
Positive or negative logic ON/OFF option
•
Output voltage trim range: +10%/−20% with Industry
Standard trim equations
•
High reliability: MTBF approx. 15.75 million hours,
calculated per Telcordia TR-332, Method
I
Case 1
•
UL 60950 recognized in US and Canada and TUV
certified per IEC/EN 60950
•
Designed to meet Class B conducted emissions per
FCC and EN 55022 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 many competitors’ 25A and 30A 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
20A SemiQ™ Family
of dc-dc converters provides a high efficiency single output in a
size that is only 60% of industry-standard quarter-bricks. Specifically designed for operation in systems that have
limited airflow and increased ambient temperatures, the
SQE48T20033
eighth-brick converters utilize the same
pinout and functionality of the industry-standard quarter-bricks.
The
20A SQE48T Series
converters of the
SemiQ™ Family
provide thermal performance in high temperature
environments that exceeds many competitors’ 25A and 30A quarter-bricks. This is accomplished through the use
of 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.
Operating from a 36-75V input, the
20A SQE48T Series
converters provides a standard output voltage 3.3V. The
outputs can be trimmed from –20% to +10% of the nominal output voltage, thus providing outstanding design
flexibility.
With standard pinout and trim equations, the
SQE48T Series
converters are perfect drop-in replacements for
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
SQE48T Series’
optimized thermal efficiency.
SQE48T20033 Rev. 1.0
Page 1 of 13
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SQE48T20033 DC-DC Converter Data sheet
36-75 VDC Input; 3.3 VDC @ 20A 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
Isolation Capacitance
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
48
34
32
75
35
33
100
Non-latching
33
31
100 ms
2000
160
10
480
Industry-std. equations
Percent of V
OUT
(
NOM
)
Non-latching
Non-latching
Applies to all protection features
-20
117
122
125
200
4
-20
2.4
2.4
-20
0.8
20
20
0.8
+10
+10
127
pF
MΩ
kHz
%
%
%
°C
ms
ms
VDC
VDC
VDC
VDC
Output Over-Voltage Protection
Over-Temperature Shutdown (PCB)
Auto-Restart Period
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 insure specified operation of overvoltage protection circuitry.
SQE48T20033 Rev. 1.0
Page 2 of 13
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SQE48T20033 DC-DC Converter Data sheet
36-75 VDC Input; 3.3 VDC @ 20A Output
Electrical Specifications (continued)
Conditions: T
A
=25 ºC, 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 - 25 MHz
bandwidth
External Load Capacitance
Output Current Range
Current Limit Inception
Peak Short-Circuit Current
RMS Short-Circuit Current
Notes
20 ADC, 3.3 VDC Out @ 36 VDC In
Vin = 48 V, converter disabled
Vin = 48 V, converter enabled
20 MHz bandwidth
120 Hz
Min
Typ
Max
2
Units
ADC
mADC
mADC
mA
PK-PK
dB
VDC
mV
mV
VDC
mV
PK-PK
μF
ADC
ADC
A
Arms
mV
mV
µs
%
%
2
38
6
75
3.275
3.300
±2
±2
3.325
±5
±5
3.350
70
20,000
20
29
8
Over line, load and temperature
2
Full load + 10
μF
tantalum + 1
μF
ceramic
Plus full load (resistive)
Non-latching
Non-latching. Short=10mΩ.
Non-latching. Short=10mΩ.
3.250
35
0
21
25
25
4
20
110
15
92
92
Dynamic Response
Load Change 10A-15A-10A, di/dt = 0.1A/μs Co = 1
μF
ceramic
di/dt = 5A/μs
Co = 470
μF
POS + 1
μF
ceramic
Settling Time to 1%
Efficiency
100% Load
50% Load
Additional Notes: 2. -40ºC to 85ºC.
SQE48T20033 Rev. 1.0
Page 3 of 13
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SQE48T20033 DC-DC Converter Data sheet
36-75 VDC Input; 3.3 VDC @ 20A 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 < 1Ω 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 20,000 µF on 3.3V outputs.
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 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 logic and
negative logic and both are referenced to Vin(-). A
typical connection is shown in Fig. A.
of
≤
0.8V. An external voltage source (±20V
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 Start-up 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).
Semi
Q
Family
TM
Rw
Vin (+)
Converter
Vout (+)
100
(Top View)
Vin
ON/OFF
SENSE (+)
TRIM
SENSE (-)
10
Rload
Vin (-)
Vout (+)
Rw
Fig. B:
Remote sense circuit configuration.
Vin (+)
Semi
Q
Family
TM
Converter
Vout (+)
SENSE (+)
TRIM
SENSE (-)
Rload
(Top View)
Vin
ON/OFF
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.
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 insure optimum performance.
When using the remote sense function, the
converter’s output over-voltage 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, equal to the
product of the nominal output voltage and the
allowable output current for the given conditions.
When using remote sense, the output voltage at the
converter can be increased by as much as 10%
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Vin (-)
CONTROL
INPUT
Vout (-)
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 table, page 2 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 5V through
a resistor. A properly debounced mechanical switch,
open collector transistor, or FET can be used to drive
the input of the ON/OFF pin. The device must be
capable of sinking up to 0.2mA at a low level voltage
SQE48T20033 Rev. 1.0
Page 4 of 13
SQE48T20033 DC-DC Converter Data sheet
36-75 VDC Input; 3.3 VDC @ 20A Output
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. For
output voltage 3.3V, trim up to 10% is guaranteed
only at Vin
≥
40V, and it is marginal (8% to 10%) at
Vin = 36V.
The TRIM pin should be left open if trimming is not
being used. To minimize noise pickup, a 0.1µF
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
−
DECR
=
511
−
10.22
Δ
[k
Ω
]
where,
R
T
−DECR
=
Required value of trim-down resistor [k
Ω
]
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.
Semi
Q
Family
TM
Vin (+)
Converter
Vout (+)
SENSE (+)
TRIM
SENSE (-)
R
T-DECR
Rload
(Top View)
Vin
ON/OFF
Vin (-)
Vout (-)
Fig. D:
Configuration for decreasing output voltage.
R
T
−
INCR
=
5.11(100
+
Δ)V
O
−
NOM
−
626
−
10.22
1.225Δ
[k
Ω
]
where,
R
T
−INCR
=
Required value of trim-up resistor k
Ω
]
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 over-voltage 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]
(
(
This equation is applicable for any condition of
output sensing and/or output trim.
V
O
−REQ
=
Desired (trimmed) output voltage [V].
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 34V for the
converter to turn on. Once the converter has been
turned on, it will shut off when the input voltage
drops typically below 32V. This feature is beneficial
in preventing deep discharging of batteries used in
telecom applications.
Vin (+)
Semi
Q
Family
TM
Converter
Vout (+)
SENSE (+)
R
T-INCR
(Top View)
Vin
ON/OFF
TRIM
SENSE (-)
Rload
Vin (-)
Vout (-)
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 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:
Output Protections
All output circuit protection features are non-latching
and operate in a “hiccup” mode. After an output
protection event occurs, the converter will be turned
off, and held off for approximately 200 ms after
which, the protection circuit will reset and the
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SQE48T20033 Rev. 1.0
Page 5 of 13
