SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
Features
Applications
Telecommunications
Data communications
Wireless
Servers
RoHS lead-free solder and lead-solder-exempted
products are available
Delivers up to 3.3 A @ 15 V
Higher current capability at elevated temperatures
than most competitors' quarter-bricks
Onboard input differential LC-filter
High reliability: MTBF of 3.4 million hours,
calculated per Telcordia TR-332, Method I Case 1
Positive or negative logic ON/OFF option
Industry-standard quarter-brick pinout
Extremely small footprint: 0.896” x 2.30” (2.06 in2),
40% smaller than conventional quarter-bricks
High efficiency – no heat sink required
Start-up into pre-biased output
No minimum load required
Available in through-hole and SM packages
Low profile: 0.274” (6.96 mm)
Low weight: 0.53 oz (15 g)
Meets Basic insulation requirements
Fixed-frequency operation
Fully protected
Remote output sense
Output voltage trim range: +10%/−20% with
Industry-standard trim equations
CAN/CSA C22.2, No. 60950-1/UL 60950-1
Second Edition, IEC/EN 60950-1 Second Edition
safety approved
Meets conducted emissions requirements of FCC
Class B and EN55022 Class B with external filter
All materials meet 94, V-0 flammability rating
Description
The SemiQ™ Family of DC-DC converters provide a high-efficiency single output in a size that is only 60% of
industry-standard quarter-bricks, while preserving the same pinout and functionality.
In high-temperature environments, the thermal performance of SemiQ™ converters exceeds that of most
competitors' quarter-bricks. This is accomplished through the use of patent pending circuit, packaging and
processing techniques to achieve ultra-high efficiency, excellent thermal management, and a very 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 electrical and thermal
design results in a product with extremely high reliability.
With a standard pinout and trim equations, the SQ24 Series converters are perfect drop-in replacements for
existing quarter-brick designs. Inclusion of this converter in new designs can result in significant board space and
cost savings. The device is also available in a surface mount package.
In both cases the designer can expect reliability improvement over other available converters because of the
SQ24 Series’ optimized thermal efficiency.
MCD10160 Rev.1.0, 01-Jun-10
Page 1 of 16
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SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
Electrical Specifications
Conditions: TA=25 ºC, Airflow=300 LFM (1.5 m/s), Vin=24 VDC, All output voltages, unless otherwise specified.
PARAMETER
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Operating Ambient Temperature
Storage Temperature
NOTES
Continuous
MIN
TYP
0
-40
-55
MAX
UNITS
40
85
125
VDC
°C
°C
INPUT CHARACTERISTICS
Operating Input Voltage Range
Input Under Voltage Lockout
Turn-on Threshold
Turn-off Threshold
19
24
36
VDC
16
15
17
16
17.5
16.5
VDC
VDC
Non-latching
ISOLATION CHARACTERISTICS
I/O Isolation
Isolation Capacitance:
Isolation Resistance
2000
VDC
pF
MΩ
230
10
FEATURE CHARACTERISTICS
Switching Frequency
1
Output Voltage Trim Range
1
Remote Sense Compensation
Output Over-Voltage Protection
Auto-Restart Period
Turn-On Time
ON/OFF Control (Positive Logic)
Converter Off
Converter On
ON/OFF Control (Negative Logic)
Converter Off
Converter On
415
Industry-std. equations
Percent of VOUT(NOM)
Non-latching
Applies to all protection features
-20
117
125
100
4
+10
+10
140
kHz
%
%
%
ms
ms
-20
2.4
0.8
20
VDC
VDC
2.4
-20
20
0.8
VDC
VDC
Additional Notes:
1.
Vout can be increased up to 10% via the sense leads or up to 10% via the trim function for Vin > 21 V; however total output voltage trim
from all sources should not exceed 10% of VOUT(NOM), in order to insure specified operation of overvoltage protection circuitry. Vout can be
increased up to 5% for Vin > 20V.
MCD10160 Rev.1.0, 01-Jun-10
Page 2 of 16
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SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
Electrical Specifications (continued)
Conditions: TA=25 ºC, Airflow=300 LFM (1.5 m/s), Vin=24 VDC, Vout=15 VDC unless otherwise specified.
PARAMETER
NOTES
MIN
TYP
MAX
UNITS
3.2
ADC
mADC
mADC
mAPK-PK
dB
15.000
15.150
VDC
±4
±4
±10
±10
15.225
140
1000
3.3
4.5
15
mV
mV
VDC
mVPK-PK
μF
ADC
ADC
A
Arms
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
3.3 ADC, 15 VDC Out @ 19 VDC In
Vin = 24 V, converter disabled
Vin = 24 V, converter enabled
25MHz bandwidth
120Hz
3
105
7
TBD
OUTPUT CHARACTERISTICS
Output Voltage Set Point (no load)
Output Regulation
Over Line
Over Load
Output Voltage Range
Output Ripple and Noise - 25MHz bandwidth
External Load Capacitance
Output Current Range
Current Limit Inception
Peak Short-Circuit Current
RMS Short-Circuit Current
14.850
2
Over line, load and temperature
Full load + 10 μF tantalum + 1 μF ceramic
Plus full load (resistive)
14.775
110
0
Non-latching
Non-latching. Short=10mΩ
Non-latching
4
12
0.75
Co = 1 μF ceramic
Co = 47 μF tant. + 1 μF ceramic
200
150
mV
mV
Co = 47 μF tant. + 1 μF ceramic
150
µs
89
88
%
%
DYNAMIC RESPONSE
Load Change 25% of Iout Max, di/dt = 0.1 A/μS
di/dt = 5 A/μS
Setting Time to 1%
Load Change (25%-75%-25%), di/dt = 5 A/μS
EFFICIENCY
100% Load
50% Load
Additional Notes: 2. -40 ºC to 85 ºC.
MCD10160 Rev.1.0, 01-Jun-10
Page 3 of 16
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SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
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.
Operation
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.
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).
However, 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 100 µF
electrolytic capacitor with an ESR < 1 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 1000 µF.
SemiQ Family
TM
Vin (+)
Converter
(Top View)
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(-).
Typical connections are shown in Fig. A.
Vin
ON/OFF
Vout (+)
Rw
100
SENSE (+)
TRIM
Rload
SENSE (-)
10
Vin (-)
Vout (-)
Rw
Fig. B: Remote sense circuit configuration.
SemiQ Family
TM
Vin (+)
Converter
(Top View)
ON/OFF
Vin
Vout (+)
SENSE (+)
TRIM
Rload
SENSE (-)
Vin (-)
Vout (-)
CONTROL
INPUT
Fig. 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.
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 V
through a resistor. A 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 of ±20 V max.
may be connected directly to the ON/OFF input, in
which case it should be capable of sourcing or
MCD10160 Rev.1.0, 01-Jun-10
If remote sensing is not required, 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 value.
Because the sense leads carry minimal current,
large traces on the end-user board are not required.
However, sense traces should be located close to a
ground plane to minimize system noise and insure
optimum performance. When wiring discretely,
twisted pair wires should be used to connect the
sense lines to the load to reduce susceptibility to
noise.
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.
Page 4 of 16
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SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
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.
To decrease the output voltage (Fig. D), a trim
resistor, RT-DECR, should be connected between the
TRIM (Pin 6) and SENSE(-) (Pin 5), with a value of:
RTDECR
where,
RTDECR Required value of trim-down resistor [k]
and Δ is as defined above.
Output Voltage Adjust /TRIM (Pin 6)
The converter’s output voltage can be adjusted up
10% or down 20% relative to the rated output voltage
by the addition of an externally connected resistor.
Trim up to 10% is guaranteed only at Vin ≥ 21 V, and
to 5% is guaranteed only at Vin ≥ 20 V.
Note: The above equations for
resistor values match those
conventional industry-standard,
one-eighth brick. For more
Application Note 103.
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.
Vin
ON/OFF
Vout (+)
SENSE (+)
TRIM
SENSE (-)
Vin (-)
Rload
R T-DECR
Vout (-)
5.11(100 Δ)VONOM 626
10.22 [k]
1.225Δ
Fig. D: Configuration for decreasing output voltage.
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 VOUT(NOM), or:
RTINCR Required value of trim-up resistor k]
VONOM Nominal value of output voltage [V]
(VO-REQ VO -NOM)
X 100 [%]
VO -NOM
VOREQ Desired (trimmed) output voltage [V].
[VOUT() VOUT()] [VSENSE() VSENSE()] VO - NOMX10% [V]
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.
Vin (+)
SemiQ Family
TM
Converter
(Top View)
Vin
Converter
(Top View)
where,
Δ
SemiQ Family
calculation of trim
typically used in
quarter-bricks and
information, see
TM
Vin (+)
To increase the output voltage, refer to Fig. C. A trim
resistor, RT-INCR, should be connected between the
TRIM (Pin 6) and SENSE(+) (Pin 7), with a value of:
RTINCR
511
10.22 [k]
|Δ|
ON/OFF
Protection Features
Vout (+)
Input Undervoltage Lockout
SENSE (+)
R T-INCR
TRIM
SENSE (-)
Vin (-)
Vout (-)
Fig. C: Configuration for increasing output voltage.
MCD10160 Rev.1.0, 01-Jun-10
This equation is applicable for any condition of
output sensing and/or output trim.
Rload
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 17.5 V for the
converter to turn on. Once the converter has been
turned on, it will shut off when the input voltage
drops below 15 V. This feature is beneficial in
Page 5 of 16
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SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
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 overcurrent
condition, the converter will switch to constant
current operation and thereby begin to reduce output
voltage. When the output voltage drops below 50%
of the nominal value of output voltage, the converter
will shut down.
Once the converter has shut down, it will attempt to
restart nominally every 100 ms with a typical 1-2%
duty cycle The attempted restart will continue
indefinitely until the overload or short circuit
conditions are removed or the output voltage rises
above 50% of its nominal value.
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 reference, 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.
Electromagnetic Compatibility (EMC)
EMC requirements must be met at the end-product
system level, as no specific standards dedicated to
EMC characteristics 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
disturbance characteristics - Limits and methods of
measurement.
With the addition of a simple external filter (see
application notes), all versions of the SQ Series of
converters pass the requirements of Class B
conducted emissions per EN55022 and FCC, and
meet at a minimum, Class A radiated emissions per
EN 55022 and Class B per FCC Title 47CFR, Part
15-J. Please contact Power-One Applications
Engineering for details of this testing.
Overtemperature Protection (OTP)
The converter will shut down under an
overtemperature condition to protect itself from
overheating caused by operation outside the thermal
derating curves, or operation in abnormal conditions
such as system fan failure. After the converter has
cooled to a safe operating temperature, it will
automatically restart.
Safety Requirements
The converters meet North American and
International safety regulatory requirements per
CAN/CSA C22.2, No. 60950-1/UL 60950-1 Second
Edition, IEC/EN 60950-1 Second Edition safety
approved. 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 6 A fuse is recommended for use with
this product.
If one input fuse is used for a group of modules, the
maximum fuse rating should not exceed 15 A.
SQ converters are UL approved with up to a 15 A
fuse.
MCD10160 Rev.1.0, 01-Jun-10
Page 6 of 16
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SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
Load current vs. ambient temperature and airflow
rates are given in Fig. 1 to Fig. 4 for through-hole
and surface mount version. Ambient temperature
was varied between 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.
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.
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 temperature did not exceed a maximum
specified temperature (120 °C) as indicated by the
thermographic image, or
The following pages contain specific plots or
waveforms associated with the converter. Additional
comments for specific data are provided below.
(ii) The nominal rating of the converter (3.3 A).
During normal operation, derating curves with
maximum FET temperature less than or equal to
120 °C should not be exceeded. Temperature on the
PCB at the thermocouple location shown in Fig. H
should not exceed 118 °C in order to operate inside
the derating curves.
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 copper, were used to
provide traces for connectivity to the converter.
Efficiency
Fig. 5 shows the efficiency vs. load current plot for
ambient temperature of 25 ºC, airflow rate of 300
LFM (1.5 m/s) with vertical mounting and input
voltages of 18 V, 24 V, and 36 V. Also, a plot of
efficiency vs. load current, as a function of ambient
temperature with Vin = 24 V, airflow rate of 200 LFM
(1 m/s) with vertical mounting is shown in Fig. 6.
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 purposes.
All measurements requiring airflow were made in
vertical and horizontal wind tunnels using Infrared
(IR)
thermography
and
thermocouples
for
thermometry.
Ensuring components on the converter do not
exceed their ratings is important to maintaining high
reliability. If one anticipates 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.
Thermographic imaging is preferable; if this
capability is not available, then thermocouples may
be used. Power-One recommends the use of AWG
#40 gauge thermocouples to ensure measurement
accuracy. Careful routing of the thermocouple leads
will further minimize measurement error. Refer to
Figure H for optimum measuring thermocouple
location.
Power Dissipation
Fig. 7 shows the power dissipation vs. load current
plot for Ta = 25 ºC, airflow rate of 300 LFM (1.5 m/s)
with vertical mounting and input voltages of 18 V,
24 V, and 36 V. Also, a plot of power dissipation vs.
load current, as a function of ambient temperature
with Vin = 24 V, airflow rate of 200 LFM (1 m/s) with
vertical mounting is shown in Fig. 8.
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
external load capacitance in
Fig. 9 and Fig. 10,
respectively.
Ripple and Noise
Fig. 13 shows the output voltage ripple waveform,
measured 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 F ceramic capacitor.
The input reflected ripple current waveforms are
obtained using the test setup shown in Fig 14. The
Thermal Derating
MCD10160 Rev.1.0, 01-Jun-10
Page 7 of 16
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SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
corresponding waveforms are shown in Fig. 15 and
Fig. 16.
For the condition, (t2- t1) ≤ 100 ms, the total converter
start-up time (t5- t2) is typically 104 ms. For (t2- t1) > 100
ms, start-up will be typically 4 ms after release of ON/OFF
pin.
Start-up Information (using negative ON/OFF)
Scenario #1: Initial Start-up From Bulk Supply
ON/OFF function enabled, converter started via application
of VIN. See Figure E.
Time
Comments
t0
ON/OFF pin is ON; system front end power is
toggled on, VIN to converter begins to rise.
t1
VIN crosses Under-Voltage Lockout protection
circuit threshold; converter enabled.
t2
Converter begins to respond to turn-on
command (converter turn-on delay).
t3
Converter VOUT reaches 100% of nominal value.
For this example, the total converter start-up time (t3- t1) is
typically 4 ms.
Scenario #2: Initial Start-up Using ON/OFF Pin
With VIN previously powered, converter started via
ON/OFF pin. See Figure F.
Time
Comments
t0
VINPUT at nominal value.
t1
Arbitrary time when ON/OFF pin is enabled
(converter enabled).
t2
End of converter turn-on delay.
t3
Converter VOUT reaches 100% of nominal value.
For this example, the total converter start-up time (t3- t1) is
typically 4 ms.
Scenario #3: Turn-off and Restart Using ON/OFF Pin
With VIN previously powered, converter is disabled and
then enabled via ON/OFF pin. See Figure G.
Time
Comments
t0
VIN and VOUT are at nominal values; ON/OFF pin
ON.
t1
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.
t2
ON/OFF pin is externally re-enabled.
If (t2- t1) ≤ 100 ms, external action of
ON/OFF pin is locked out by start-up inhibit
timer.
If (t2- t1) > 100 ms, ON/OFF pin action is
internally enabled.
t3
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 F.
t4
End of converter turn-on delay.
t5
Converter VOUT reaches 100% of nominal value.
MCD10160 Rev.1.0, 01-Jun-10
Page 8 of 16
V IN
ON/OFF
STATE
OFF
ON
V OUT
t0
t1 t2
t
t3
Fig. E: Start-up scenario #1
VIN
ON/OFF
STATE OFF
ON
VOUT
t0
t1 t2
t
t3
Fig. F: Start-up scenario #2.
www.power-one.com
SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
V IN
100 ms
ON/OFF
STATE OFF
ON
V OUT
t0
t1
t2
t3 t4
t5
t
Fig. G: Start-up scenario #3.
MCD10160 Rev.1.0, 01-Jun-10
Page 9 of 16
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4
4
3
3
Load Current [Adc]
Load Current [Adc]
SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
2
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
30 LFM (0.15 m/s)
1
2
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
30 LFM (0.15 m/s)
1
0
0
20
30
40
50
60
70
80
20
90
30
Fig. 1: Available load current vs. ambient air
temperature and airflow rates for SQ24T03150 converter
with B height pins mounted vertically with Vin = 24 V, air
flowing from pin 3 to pin 1 and maximum FET
temperature 120 C.
60
70
80
90
Fig. 2: Available load current vs. ambient air
temperature and airflow rates for SQ24T03150 converter
with B height pins mounted horizontally with Vin = 24 V,
air flowing from pin 3 to pin 1 and maximum FET
temperature 120 C.
4
4
3
3
Load Current [Adc]
Load Current [Adc]
50
Ambient Temperature [°C]
Ambient Temperature [°C]
2
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
30 LFM (0.15 m/s)
1
40
2
500 LFM (2.5 m/s)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
30 LFM (0.15 m/s)
1
0
0
20
30
40
50
60
70
80
20
90
40
50
60
70
80
90
Ambient Temperature [°C]
Ambient Temperature [°C]
Fig. 3: Available load current vs. ambient temperature
and airflow rates for SQ24S03150 converter mounted
vertically with Vin = 24 V, air flowing from pin 3 to pin 1
and maximum FET temperature 120 C.
MCD10160 Rev.1.0, 01-Jun-10
30
Fig. 4: Available load current vs. ambient temperature
and airflow rates for SQ24S03150 converter mounted
horizontally with Vin = 24 V, air flowing from pin 3 to pin
1 and maximum FET temperature 120 C.
Page 10 of 16
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0.95
0.95
0.90
0.90
0.85
0.85
Efficiency
Efficiency
SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
0.80
0.75
0.80
0.75
36 V
24 V
18 V
70 C
55 C
40 C
0.70
0.70
0.65
0.65
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0.0
3.5
0.5
1.0
Load Current [Adc]
2.0
2.5
3.0
3.5
Fig. 6: Efficiency vs. load current and ambient
temperature for SQ24T/S03150 converter mounted
vertically with Vin = 24 V and air flowing from pin 3 to pin
1 at a rate of 200 LFM (1.0 m/s).
Fig. 5: Efficiency vs. load current and input voltage for
SQ24T/S03150 converter mounted vertically with air
flowing from pin 3 to pin 1 at a rate of 300 LFM
(1.5 m/s) and Ta = 25 C.
8.00
8.00
6.00
6.00
Power Dissipation [W]
Power Dissipation [W]
1.5
Load Current [Adc]
4.00
36 V
24 V
18 V
2.00
4.00
70 C
55 C
40 C
2.00
0.00
0.00
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0.0
3.5
1.0
1.5
2.0
2.5
3.0
3.5
Load Current [Adc]
Load Current [Adc]
Fig. 7: Power dissipation vs. load current and input
voltage for SQ24T/S03150 converter mounted vertically
with air flowing from pin 3 to pin 1 at a rate of 300 LFM
(1.5 m/s) and Ta = 25 C.
MCD10160 Rev.1.0, 01-Jun-10
0.5
Fig. 8: Power dissipation vs. load current and ambient
temperature for SQ24T/S03150 converter mounted
vertically with Vin = 24 V and air flowing from pin 3 to pin
1 at a rate of 200 LFM (1.0 m/s).
Page 11 of 16
www.power-one.com
SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
Fig. 9: Turn-on transient at full rated load current
(resistive) with no output capacitor at Vin = 24 V,
triggered via ON/OFF pin. Top trace: ON/OFF signal
(5 V/div.). Bottom trace: output voltage (5 V/div.). Time
scale: 1 ms/div.
Fig. 10: Turn-on transient at full rated load current
(resistive) plus 1,000 F at Vin = 24 V, triggered via
ON/OFF pin. Top trace: ON/OFF signal (5 V/div.).
Bottom trace: output voltage (5 V/div.). Time scale:
5 ms/div.
Fig. 11: Output voltage response to load current
step-change (0.825 A – 1.65 A – 0.825 A) at Vin = 24 V.
Top trace: output voltage (200 mV/div.). Bottom trace:
load current (1 A/div.). Current slew rate: 0.1 A/s. Co =
1 F ceramic. Time scale: 0.5 ms/div.
Fig. 12: Output voltage response to load current
step-change (0.825 A – 1.65 A – 0.825 A) at Vin = 24 V.
Top trace: output voltage (200 mV/div.). Bottom trace:
load current (1 A/div.). Current slew rate: 5 A/s. Co =
47 F tantalum + 1 F ceramic. Time scale: 0.5 ms/div.
MCD10160 Rev.1.0, 01-Jun-10
Page 12 of 16
www.power-one.com
SQ24T/S03150 DC-DC Converter Data Sheet
19-36 VDC Input; 15 VDC Output @ 3.3 A
iS
10 H
source
inductance
Vsource
Fig. 13: Output voltage ripple (100 mV/div.) at full rated
load current into a resistive load with Co = 10 F
tantalum + 1uF ceramic and Vin = 24 V. Time scale:
1 s/div.
Fig. 15: Input reflected ripple current, ic (100 mA/div.),
measured at input terminals at full rated load current and
Vin = 24 V. Refer to Fig. 14 for test setup. Time scale:
1 s/div.
MCD10160 Rev.1.0, 01-Jun-10
iC
33 F
ESR
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