Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
Description
The Q24S25033 surface mounted DC-DC converter offers
unprecedented performance in an industry-standard
quarter-brick format. This is accomplished through the use of
patent pending circuit and packaging techniques to achieve
ultra-high efficiency, excellent thermal performance and a
very low body profile.
Family 25 A conIn telecommunications applications the Q
verters provide thermal performance that far exceeds all
quarter bricks and is comparable even to existing half-bricks.
Low body profile and the preclusion of heat sinks minimize
airflow shadowing, thus enhancing cooling for downstream
devices. The use of 100% surface-mount technologies for
assembly, coupled with Power-One’s advanced electric and
thermal circuitry and packaging, results in a product with
extremely high quality and reliability.
30
Load Current [Adc]
Features
25
20
15
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)
10
5
0
20
30
40
50
60
70
80
90
Ambient Temperature [°C]
Fig. 1: Available load current vs. ambient air temperature and airflow rates for Q24S25033 converter mounted vertically with air flowing from pin 3 to pin 1, MOSFET temperature 120C, Vin = 27 V.
Applications
Q24S25033 Converter
Telecommunications
Data communications
Wireless
Servers
MCD10216 Rev. 1.0, 23-Aug-10
Page 1 of 14
RoHS lead-free solder and lead-solder-exempted
products are available
Delivers up to 25 A
Higher current capability at 70 ºC than existing
quarter-brick and half-brick converters
High efficiency: 88.5% @ 25 A, 88.5% @ 12.5 A
Start-up into pre-biased output
No minimum load required
No heat sink required
Low profile: 0.26” [6.6 mm]
Low weight: 1 oz [28 g] typical
Industry-standard footprint: 1.45” x 2.30”
Meets Basic Insulation Requirements of EN60950
On-board LC input filter
Fixed-frequency operation
Fully protected
Remote output sense
Output voltage trim range: +10%/-20%
Trim resistor via industry-standard equations
High reliability: MTBF 2.6 million hours, calculated per
Telcordia TR-332, Method I Case 1
Positive or negative logic ON/OFF option
UL 60950 recognized in U.S. & Canada, and DEMKO
certified per IEC/EN 60950
Meets conducted emissions requirements of FCC
Class B and EN55022 Class B with external filter
All materials meet UL94, V-0 flammability rating
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Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
Electrical Specifications
Conditions: TA=25 ºC, Airflow=300 LFM (1.5 m/s), Vin=24 VDC, 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
18
24
36
VDC
16
15
17
16
17.5
16.5
VDC
VDC
30,000
25
33
46
6.7
μF
ADC
ADC
A
Arms
Non-latching
OUTPUT CHARACTERISTICS
External Load Capacitance
Output Current Range
Current Limit Inception
Peak Short-Circuit Current
RMS Short-Circuit Current
Plus full load (resistive)
Non-latching
Non-latching. Short=10mΩ.
Non-latching
0
27.5
30
35
ISOLATION CHARACTERISTICS
I/O Isolation
Isolation Capacitance
Isolation Resistance
2000
VDC
ρF
MΩ
230
10
FEATURE CHARACTERISTICS
Switching Frequency
1
Output Voltage Trim Range
Remote Sense Compensation
435
Use trim equations on Page 6
1
Output Over-Voltage Protection
Over-Temperature Shutdown (PCB)
Auto-Restart Period
Turn-On Time
ON/OFF Control (Positive Logic)
Converter Off
Converter On
ON/OFF Control (Negative Logic)
Converter Off
Converter On
+10
kHz
%
+10
%
127
%
°C
ms
ms
-20
2.4
0.8
20
VDC
VDC
2.4
-20
20
0.8
VDC
VDC
-20
Percent of VOUT(NOM)
Non-latching
Non-latching
Applies to all protection features
117
122
118
100
2.5
Additional Notes:
1. Vout can be increased up to 10% via the sense leads or up to 10% via the trim function, however total output voltage trim from all sources
should not exceed 10% of VOUT(NOM), in order to insure specified operation of over-voltage protection circuitry. See further discussion at end of
Output Voltage Adjust /TRIM section.
MCD10216 Rev. 1.0, 23-Aug-10
Page 2 of 14
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Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
Electrical Specifications (continued)
Conditions: TA=25 ºC, Airflow=300 LFM (1.5 m/s), Vin=24 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
NOTES
MIN
25 ADC, 3.3 VDC Out @ 18 VDC In
Vin = 24 V, converter disabled
Vin = 24 V, converter enabled
See Figure 25 - 25MHz bandwidth
120Hz
TYP
MAX
UNITS
5.2
ADC
mADC
mADC
mAPK-PK
dB
3.300
3.333
VDC
±2
±2
±5
±5
3.350
50
mV
mV
VDC
mVPK-PK
3.5
140
6
TBD
OUTPUT CHARACTERISTICS
Output Voltage Set Point (no load)
Output Regulation
Over Line
Over Load
Output Voltage Range
Output Ripple and Noise - 25MHz bandwidth
-40ºC to 85ºC
Over line, load and temperature
Full load + 10 μF tantalum + 1 μF ceramic
3.267
3.250
30
DYNAMIC RESPONSE
Load Change 25% of Iout Max, di/dt = 0.1 A/μS
di/dt = 5 A/μS
Setting Time to 1%
Co = 1 μF ceramic (Fig.20)
Co = 450 μF tant. + 1 μF ceramic (Fig.21)
50
140
100
mV
mV
µs
88.5
88.5
%
%
EFFICIENCY
100% Load
50% Load
MCD10216 Rev. 1.0, 23-Aug-10
Page 3 of 14
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Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
Physical Information
1
8
Pin Connections
7
2
TOP VIEW
Pin #
1
2
3
4
5
6
7
8
6
5
3
4
SIDE VIEW
Function
Vin (+)
ON/OFF
Vin (-)
Vout (-)
SENSE(-)
TRIM
SENSE(+)
Vout (+)
All dimensions are in inches [mm]
Connector Material: Copper
Connector Finish: Gold over Nickel
Converter Weight: 1 oz [28 g] typical
Recommended Surface-Mount Pads:
Min. 0.080” x 0.112” [2.03 x 2.84]
Max. 0.092” x 0.124” [2.34 x 3.15]
Converter Part Numbering Scheme
Product
Series
Input
Voltage
Mounting
Scheme
Rated
Load
Current
Output
Voltage
Q
24
S
25
033
Quarter-Brick
Format
18-36 V
Surface
Mount
25 ADC
033 3.3 V
ON/OFF Logic
Maximum
Height
Pin
Length
Special
Features
N
S
0
0
N Negative
P Positive
S 0.273”
0 0.00”
0 STD
-
The example above describes P/N Q24S25033-NS00: 18-36 V input, surface mounting, 25 A @ 3.3 V output, negative ON/OFF logic. Please
consult factory regarding availability of a specific version.
Models highlighted in yellow or shaded are not recommended for new designs.
RoHS Ordering Information:
No RoHS suffix character is required for lead-solder-exemption compliance.
For RoHS compliance to all six substances, add the letter "G" as the last letter of the part number.
MCD10216 Rev. 1.0, 23-Aug-10
Page 4 of 14
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Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
case it should 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.
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.
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 33 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 30,000 µF.
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. 3).
Q
TM
Vin (+)
Family
Converter
(Top View)
ON/OFF (Pin 2)
Vin
Q
TM
Family
Converter
(Top View)
ON/OFF
Vin
Rw
100
SENSE (+)
TRIM
Rload
SENSE (-)
10
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. 2.
Vin (+)
ON/OFF
Vout (+)
Vout (+)
SENSE (+)
TRIM
Rload
SENSE (-)
Vin (-)
Vout (-)
CONTROL
INPUT
Fig. 2: 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.
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
MCD10216 Rev. 1.0, 23-Aug-10
Vin (-)
Vout (-)
Rw
Fig. 3: Remote sense circuit configuration.
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 5 of 14
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Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A 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.
Family
Converter
Vout (+)
(Top View)
SENSE (+)
Vin
ON/OFF
R T-INCR
TRIM
Rload
SENSE (-)
Vin (-)
Vout (-)
Fig. 4: Configuration for increasing output voltage.
Output Voltage Adjust /TRIM (Pin 6)
where,
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 ≥ 20 V, and it is marginal (8% to 10%) at
Vin = 18 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.
RTDECR Required value of trim-down resistor [k]
and Δ is as defined above.
Note: The above equations for calculation of trim resistor
values match those typically used in conventional industrystandard quarter bricks.
To increase the output voltage, refer to Fig. 4. A trim resistor,
RT-INCR, should be connected between the TRIM (Pin 6) and
SENSE(+) (Pin 7), with a value of:
Q Family
Converter
Vout (+)
(Top View)
SENSE (+)
TM
Vin (+)
Vin
ON/OFF
TRIM
SENSE (-)
5.11(100 Δ)VONOM 626
RTINCR
10.22 [k]
1.225Δ
where,
Vin (-)
RTINCR Required value of trim-up resistor k]
VONOM Nominal value of output voltage [V]
Δ
Q
TM
Vin (+)
Rload
R T-DECR
Vout (-)
Fig. 5: 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 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 0.33 V, or:
(VO-REQ VO-NOM)
X 100 [%]
VO -NOM
VOREQ Desired (trimmed) output voltage [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.
[VOUT() VOUT()] [VSENSE() VSENSE()] 0.33 [V]
This equation is applicable for any condition of output sensing and/or output trim.
To decrease the output voltage (Fig. 5), a trim resistor,
RT-DECR, should be connected between the TRIM (Pin 6) and
SENSE(-) (Pin 5), with a value of:
RTDECR
511
10.22 [k]
Δ
MCD10216 Rev. 1.0, 23-Aug-10
Page 6 of 14
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Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
Protection Features
Safety Requirements
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 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 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 1.2 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 1.2 VDC.
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 10-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 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 Q24S25 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.
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.
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.
MCD10216 Rev. 1.0, 23-Aug-10
Page 7 of 14
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Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
(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.
The following pages contain specific plots or waveforms associated 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 copper, were used to provide traces for connectivity to the converter.
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 PowerOne’s vertical and horizontal wind tunnel facilities using
Infrared (IR) thermography and thermocouples for thermometry.
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
(either 105°C or 120°C) as indicated by the thermographic
image, or
(ii) The nominal rating of the converter (25 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. 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 18 V, 27 V and 36 V. Also, plots of efficiency vs.
load current, as a function of ambient temperature with Vin =
27 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 F load capacitance in
Figs. 18 and 19, respectively.
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 28 for optimum measuring thermocouple location.
Figure 22 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.
Thermal Derating
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.
Ripple and Noise
Load current vs. ambient temperature and airflow rates are
given in Figs. 10-13. Ambient temperature was varied between 25°C and 85°C, with airflow rates from 30 to 500 LFM
MCD10216 Rev. 1.0, 23-Aug-10
Page 8 of 14
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Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
V IN
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 7.
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
2.5 ms.
ON/OFF
STATE
OFF
ON
V OUT
t0
t1 t2
t
t3
Fig. 7: Start-up scenario #1.
Scenario #2: Initial Start-up Using ON/OFF Pin
With VIN previously powered, converter started via ON/OFF pin.
See Figure 8.
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
2.5 ms.
VIN
ON/OFF
STATE OFF
ON
VOUT
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 9.
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 8.
t4
End of converter turn-on delay.
t5
Converter VOUT reaches 100% of nominal value.
For the condition, (t2- t1) ≤ 100 ms, the total converter start-up
time (t5- t2) is typically 102.5 ms. For (t2- t1) > 100 ms, start-up will
be typically 2.5 ms after release of ON/OFF pin.
t0
t1 t2
t
t3
Fig. 8: Start-up scenario #2.
VIN
100 ms
ON/OFF
STATE OFF
ON
VOUT
t0
t1
t2
t3 t4
t5
t
Fig. 9: Start-up scenario #3.
MCD10216 Rev. 1.0, 23-Aug-10
Page 9 of 14
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30
30
25
25
Load Current [Adc]
Load Current [Adc]
Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
20
15
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)
10
5
20
15
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)
10
5
0
0
20
30
40
50
60
70
80
90
20
30
Ambient Temperature [°C]
30
25
25
Load Current [Adc]
Load Current [Adc]
60
70
80
90
Fig. 11: Available load current vs. ambient air temperature and
airflow rates for converter mounted vertically with Vin = 27 V,
air flowing from pin 3 to pin 1 and maximum FET temperature
105C.
30
20
15
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)
5
50
Ambient Temperature [°C]
Fig. 10: Available load current vs. ambient air temperature and
airflow rates for converter mounted vertically with Vin = 27 V,
air flowing from pin 3 to pin 1 and maximum FET temperature
120C.
10
40
20
15
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)
10
5
0
0
20
30
40
50
60
70
80
20
90
40
50
60
70
80
90
Ambient Temperature [°C]
Ambient Temperature [°C]
Fig. 12: Available load current vs. ambient temperature and
airflow rates for converter mounted horizontally with Vin = 27
V, air flowing from pin 3 to pin 4 and maximum FET temperature 120C.
MCD10216 Rev. 1.0, 23-Aug-10
30
Fig. 13: Available load current vs. ambient temperature and
airflow rates for converter mounted horizontally with Vin = 27
V, air flowing from pin 3 to pin 4 and maximum FET temperature 105C.
Page 10 of 14
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0.95
0.95
0.90
0.90
0.85
0.85
Efficiency
Efficiency
Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
0.80
0.75
36 V
27 V
18 V
0.80
0.75
0.70
70 C
55 C
40 C
0.70
0.65
0.65
0
5
10
15
20
25
30
0
5
10
Load Current [Adc]
20
25
30
Load Current [Adc]
Fig. 14: Efficiency vs. load current and input voltage for converter mounted vertically with air flowing from pin 3 to pin 1 at a
rate of 300 LFM (1.5 m/s) and Ta = 25C.
Fig. 15: Efficiency vs. load current and ambient temperature
for converter mounted vertically with Vin = 27 V and air flowing
from pin 3 to pin 1 at a rate of 200 LFM (1.0 m/s).
0.95
0.95
0.90
0.90
0.85
0.85
Efficiency
Efficiency
15
0.80
0.75
0.80
0.75
36 V
27 V
18 V
70 C
55 C
40 C
0.70
0.70
0.65
0.65
0
5
10
15
20
25
0
30
10
15
20
25
30
Load Current [Adc]
Load Current [Adc]
Fig. 16: Efficiency vs. load current and input voltage for converter mounted horizontally with air flowing from pin 3 to pin 4
at a rate of 300 LFM (1.5 m/s) and Ta = 25C.
MCD10216 Rev. 1.0, 23-Aug-10
5
Fig. 17: Efficiency vs. load current and ambient temperature
for converter mounted horizontally with Vin = 27 V and air flowing from pin 3 to pin 4 at a rate of 200 LFM (1.0 m/s).
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Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
Fig. 18: 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 (1 V/div.) Time scale: 1 ms/div.
Fig. 19: Turn-on transient at full rated load current (resistive)
plus 10,000 F at Vin = 24 V, triggered via ON/OFF pin. Top
trace: ON/OFF signal (5 V/div.). Bottom trace: output voltage
(1 V/div.). Time scale: 1 ms/div.
Fig. 20: Output voltage response to load current step-change
(7.5 A – 15 A – 7.5 A) at Vin = 24 V. Top trace: output voltage
(100 mV/div). Bottom trace: load current (5 A/div.). Current
slew rate: 0.1 A/s. Co = 1 F ceramic. Time scale: 0.2 ms/div.
Fig. 21: Output voltage response to load current step-change
(7.5 A – 15 A – 7.5 A) at Vin = 24 V. Top trace: output voltage
(100 mV/div.). Bottom trace: load current (5 A/div). Current
slew rate: 5 A/s. Co = 450 F tantalum + 1 F ceramic. Time
scale: 0.2 ms/div.
MCD10216 Rev. 1.0, 23-Aug-10
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Q24S25033 DC-DC Converter Data Sheet
18-36 VDC Input; 3.3 VDC @ 25A Output
iS
10 H
source
inductance
Vsource
iC
33 F
ESR
工商网监
湘ICP备2023018690号
