The new iPWER™ high performance 20 A SSQL48T20033 DC-DC converter
provides a high efficiency single output, in a 1/16th brick package that is only
56% the size of the industry-standard eighth-brick. Specifically designed for
operation in systems that have limited airflow and increased ambient
temperatures, the SSQL48T20033 converter utilizes the same pin-out and
Input / Output functionality of the industry-standard sixteenth-bricks. In
addition, a heat spreader feature is available (-xxxBx suffix) that provides an
effective thermal interface for coldplate and heat sinking options.
The SSQL48T20033 converter thermal performance 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 impedance to
system airflow, thus enhancing cooling for both upstream and 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 wide-range 36-75 V input, the SSQL48T20033 converter
provides a fully regulated 3.3 V output voltage. The outputs can be trimmed
from –20% to +10% of the nominal output voltage, thus providing outstanding
design flexibility. Employing a standard power pin-out, the SSQL48T20033
converter is an ideal drop-in replacement for existing high current eighth-brick
designs. Inclusion of this converter in a new design can result in significant
board space and cost savings. The designer can expect reliability
improvement over other available converters because of the SSQL48T20033’s
optimized thermal efficiency.
36-75 VDC Input; 3.3 VDC @ 20 A
Industry-standard eighth-brick pin-out
Withstands 100 V input transient for 100 ms
Fixed-frequency operation
On-board input differential LC-filter
Start-up into pre-biased load
No minimum load required
Hiccup overcurrent protection
Fully protected (OTP, OCP, OVP, UVLO)
Remote sense
High efficiency – no heat sink required (Baseplate/heat spreader option
(suffix ‘-xxxBx’) facilitates heatsink mounting to further enhance the unit’s
thermal capability.)
Remote ON/OFF positive or negative logic option
Output voltage trim range: +10%/−20% with industry-standard trim equations
Designed to meet Class B conducted emissions per FCC and EN55022 when
used with external filter
All materials meet UL94, V-0 flammability rating
Approved to the latest edition and amendment of ITE Safety standards, UL/CSA
60950-1 and IEC60950-1
RoHS lead free solder and lead-solder-exempted products are available
2
SSQL48T20033
Conditions: T
A
= 25ºC, Airflow = 300 LFM (1.5 m/s), Vin = 48 VDC, unless otherwise specified.
PARAMETER
Absolute Maximum Ratings
Input Voltage
Operating Temperature
1
(See Derating Curves)
Storage Temperature
CONDITIONS / DESCRIPTION
MIN
TYP
MAX
UNITS
Continuous
Transient (100ms)
Ambient (T
A
)
Component (T
C
)
Baseplate (T
B
)
-0.3
-40
-40
-40
-55
80
100
85
120
105
125
VDC
VDC
°C
°C
°C
°C
Isolation Characteristics
I/O Isolation
Isolation Capacitance
Isolation Resistance
Input to Baseplate
Output to Baseplate
10
1,500
1,500
2,250
150
VDC
pF
MΩ
VDC
VDC
Feature Characteristics
Switching Frequency
Output Voltage Trim Range
2
Remote Sense Compensation
2, 4
Output Overvoltage Protection
Over Temperature Shutdown
Auto-Restart Period
Turn-On Time from Vin
Turn-On Time from ON/OFF Control
ON/OFF Control (Positive Logic option)
Converter On (logic high)
Converter Off (logic high)
ON/OFF Control (Negative Logic option)
Converter On (logic low)
-20
0.8
VDC
2.4
2.4
20
20
VDC
VDC
Industry-std. equations
3
Percent of V
OUT
(NOM)
Non-latching
Non-latching
Applies to all protection features
Time from UVLO to Vo = 90%V
OUT
(NOM)
Resistive Load
Time from ON to Vo = 90%V
OUT
(NOM)
Resistive Load
Converter Off (logic low)
-20
115
125
200
4
4
20
20
0.8
-20
500
+10
+10
140
kHz
%
%
%
°C
ms
ms
ms
VDC
Input Characteristics
Operating Input Voltage Range
Input Undervoltage Lockout
Lockout Hysteresis Voltage
Maximum Input Current
Input Standby Current
3.3 Vout, Full Load @ 36 VDC In
Vin = 48 V, converter disabled
5
Turn-on Threshold
Turn-off Threshold
36
31.5
30
1.0
48
33.5
32
75
35.5
34
2.0
2.1
VDC
VDC
VDC
VDC
ADC
mADC
1
2
Reference Figure H for component (T
C
and T
B
) locations.
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-up
should not exceed 10% of V
OUT
(NOM).
3
Trim equations are defined within this document’s “Operations” section.
4
When using remote sense a minimum of 100uF ceramic capacitance should be mounted between Vout(+) and Vout(-) close to pin 8
and pin 4.
tech.support@psbel.com
SSQL48T20033
Input No Load Current
(No load on the output)
Input Reflected-Ripple Current,
ic
Vin = 48 V, 20 MHz bandwidth,
Full Load (resistive) (See Fig. J)
Input Reflected-Ripple Current,
i
S
Input Voltage Ripple Rejection
@ 120 Hz
60
Vin = 48 V, converter enabled
45
100
65
200
150
30
5
3
mADC
mA
PK-PK
mA
RMS
mA
PK-PK
mA
RMS
dB
Output Characteristics
Output Voltage Setpoint
Output Regulation
Output Voltage Range
Output Ripple and Noise – 20 MHz
bandwidth
External Load Capacitance
5
Output Current Range
Current Limit Inception
Short-Circuit Current
Pk:
RMS:
Non-latching Short = 10 mΩ
Non-latching
Over Line
Over Load
V
IN
= 48 V, I
OUT
= 0 Amps, T
A
= 25°C
I
OUT
= 20 Amps, T
A
= 25°C
V
IN
= 48 V, , T
A
= 25°C
Over line, load and temperature
I
OUT
= 20 Amps,
C
EXT
=10 µF tantalum + 1 µF ceramic
Plus Full Load (resistive)
C
EXT
ESR
0
1
0
22
26
35
8
3.2
30
15
3.25
3.3
±2
±2
3.35
±17
±17
3.4
100
30
10,000
20
30
VDC
mV
mV
VDC
mV
PK-PK
V
RMS
µF
mOhm
ADC
ADC
Amps
A
RMS
Dynamic Response
Load Change 50%-75%-50% of I
OUT
Max
di/dt = 0.1 A/μs
C
EXT
= 10µF tantalum + 1µF ceramic
di/dt = 1.0 A/μs
C
EXT
= 470µF POS + 1µF ceramic
±50
±100
50
mV
mV
µs
Settling Time to 1% of V
OUT
Efficiency
@ 100% Load
@ 50% Load
48 V
IN
, T
A
= 25°C, 300 LFM (1.5 m/s)
89
90
90.5
91.0
%
%
Environmental Characteristics
Operating Humidity
Storage Humidity
RH (Non-condensing)
RH (Non-condensing)
95
95
%
%
Mechanical Characteristics
Dimensions
Weight
No Baseplate
With Baseplate
Telcordia SR-332, Method I Case 1 50%
electrical stress, 40°C components
14.1
23 ± 1
g
g
Reliability
MTBF
23
MHrs
EMI and Regulatory Compliance
Conducted Emissions
Safely Agency Approvals
CISPR 22 B with external EMI filter network
UL60950-1/CSA60950-1, EN60950-1 and
IEC60950-1
5
See
“Input Output Impedance”
, Page 4.
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+86 755 298 85888
Europe, Middle East
+353 61 225 977
North America
+1 408 785 5200
BCD.00780_AB
© 2016 Bel Power Solutions & Protection
4
SSQL48T20033
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 to
ensure stability of the converter. In applications where decoupling capacitance is distributed at the load, the power converter
will exhibit stable operation with up to the maximum admissible external load capacitance up to 10,000
μF
and ESR > 1mΩ.
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 (+)
SSQL 48 Converter
(Top View )
Vout (+)
SENSE (+)
TRIM
SENSE (-)
Rload
Vin
ON /OFF
Vin ( -)
CONTROL
INPUT
Vout (-)
Figure A. Circuit configuration for ON/OFF function.
The positive logic version turns on when the ON/OFF pin is at logic high and turns off when at 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 logic low and turns off when the pin is at 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 VDC 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. 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.
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). When using remote sense a minimum of 100uF ceramic capacitance should be
mounted between Vout(+) and Vout(-) close to the pin 8 and pin 4.
SSQL 48 Converter
(Top View )
ON /OFF
Vin (+)
Vout (+)
100
Rw
SENSE (+)
Vin
TRIM
SENSE
Vin (- )
(-)
10
Rw
Vout ( -)
Figure B. Remote sense circuit configuration.
CAUTION
If remote sensing is not utilized, the SENSE(-) pin must be connected to the Vout(-) pin, and the SENSE(+) pin must be
connected to the Vout(+) pin 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.
tech.support@psbel.com
SSQL48T20033
5
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) circuitry 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.
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.
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 3.3 V, trim up to 10% is guaranteed only at Vin
≥
40V, and it is marginal (8% to 10%)
at Vin = 36 V.
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 (Fig. C) a trim resistor, RT-INCR, should be connected between the TRIM (Pin 6) and SENSE(+)
(Pin 7), with a value of:
R
T
INCR
½
where,
5.11(100
Δ)V
O
NOM
626
10.22
1.225Δ
, [kΩ],
R
T
INCR
½
Required value of trim-up resistor [kΩ]
V
O
NOM
½
Nominal value of output voltage [V]
Δ
½
(V
O-REQ
V
O-NOM
)
X 100
V
O -NOM
, [%]
V
O
REQ
½
Desired (trimmed) output voltage [V].
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.
Vin (+)
SSQL 48 Converter
(Top View )
Vout (+)
SENSE (+)
R
T - INCR
Rload
Vin
ON /OFF
TRIM
SENSE (-)
Vin (-)
Vout (-)
Figure C. Configuration for increasing output voltage.
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:
R
T
DECR
½
where,
511
10.22
|Δ|
[kΩ]
R
T
DECR
½
Required value of trim-down resistor [kΩ]
Asia-Pacific
+86 755 298 85888
Europe, Middle East
+353 61 225 977
North America
+1 408 785 5200
BCD.00780_AB
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