Q24T25033
18-36 Vdc Input, 25 A, 3.3 Vdc Output
The
Q24T25033
through-hole mounted DC/DC converter
offers unprecedented performance in the 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.
Data Sheet
&&
In telecommunications applications the
Q
Family
25 A con-
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 heatsinks minimize
airflow shadowing, thus enhancing cooling for downstream
devices. The use of 100% surface-mount technologies for
assembly, coupled with di/dt’s advanced electric and thermal
circuitry and packaging, results in a product with extremely
high quality and reliability.
30
25
Q24T25033 Converter
Features
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•
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•
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•
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Delivers up to 25 A
Higher current capability at 70ºC than existing
quarter brick and half brick converters
High efficiency: 88.5% @ 25 A, 88.5% @ 12.5 A
Starts-up into pre-biased output
No minimum load required
No heatsink required
Lowest profile in industry: 0.28” [7.2 mm]
Lowest weight in industry: 1 oz [28 g] typical
Industry-standard footprint: 1.45” x 2.30”
Industry-standard pinout
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
Load Current [Adc]
20
15
10
5
0
20
30
40
50
60
70
80
90
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)
Ambient Temperature [°C]
Fig. 1:
Available load current vs. ambient air temperature and air-
flow rates for Q24T25033 converter mounted vertically with air flow-
ing from pin 3 to pin 1, MOSFET temperature
≤
120°C, Vin = 27 V.
Applications
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Telecommunications
Datacommunications
Wireless
Servers
Q24T25033 FDS Ver 2 05-01-03
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Page 1 of 14
Q24T25033
18-36 Vdc Input, 25 A, 3.3 Vdc Output
Electrical Specifications
Conditions: T
A
=25ºC, Airflow=300 LFM (1.5 m/s), Vin=24 Vdc, unless otherwise specified.
Data Sheet
PARAMETER
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Operating Ambient Temperature
Storage Temperature
Continuous
NOTES
MIN
0
-40
-55
18
TYP
MAX
40
85
125
UNITS
Vdc
°C
°C
Vdc
Vdc
Vdc
µF
Adc
Adc
A
Arms
Vdc
ρF
MΩ
kHz
%
%
%
°C
ms
ms
Vdc
Vdc
Vdc
Vdc
INPUT CHARACTERISTICS
Operating Input Voltage Range
Input Under Voltage Lockout
Turn-on Threshold
Turn-off Threshold
24
17
16
36
17.5
16.5
30,000
25
33
46
6.7
Non-latching
16
15
Plus full load (resistive)
Non-latching
Non-latching. Short=10mΩ.
Non-latching
0
27.5
30
35
OUTPUT CHARACTERISTICS
External Load Capacitance
Output Current Range
Current Limit Inception
Peak Short-Circuit Current
RMS Short-Circuit Current
ISOLATION CHARACTERISTICS
I/O Isolation
Isolation Capacitance
Isolation Resistance
2000
230
10
435
Use trim equations on Page 6
1
FEATURE CHARACTERISTICS
Switching Frequency
1
Output Voltage Trim Range
Remote Sense Compensation
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
-20
117
122
118
100
2.5
+10
+10
127
Percent of V
OUT
(
NOM
)
Non-latching
Non-latching
Applies to all protection features
-20
2.4
2.4
-20
0.8
20
20
0.8
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 V
OUT
(
NOM
), in order to insure specified operation of over-voltage protection circuitry. See further discussion at end of
Output Voltage Adjust /TRIM
section.
Q24T25033 FDS Ver 2 05-01-03
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Page 2 of 14
Q24T25033
18-36 Vdc Input, 25 A, 3.3 Vdc Output
Electrical Specifications (continued)
Conditions: T
A
=25ºC, Airflow=300 LFM (1.5 m/s), Vin=24 Vdc, unless otherwise specified.
Data Sheet
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
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
-40ºC to 85ºC
MIN
TYP
MAX
5.2
UNITS
Adc
mAdc
mAdc
mA
PK-PK
dB
Vdc
mV
mV
Vdc
mV
PK-PK
mV
mV
µs
%
%
3.5
140
6
TBD
3.267
3.300
±2
±2
3.333
±5
±5
3.350
50
OUTPUT CHARACTERISTICS
Output Voltage Set Point (no load)
Output Regulation
Over Line
Over Load
Output Voltage Range
Output Ripple and Noise - 25MHz bandwidth
Over line, load and temperature
Full load + 10 µF tantalum + 1 µF ceramic
Co = 1 µF ceramic (Fig.20)
Co = 450 µF tant. + 1 µF ceramic (Fig.21)
3.250
30
50
140
100
88.5
88.5
DYNAMIC RESPONSE
Load Change 25% of Iout Max, di/dt = 0.1 A/µS
di/dt = 5 A/µS
Setting Time to 1%
EFFICIENCY
100% Load
50% Load
Q24T25033 FDS Ver 2 05-01-03
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Q24T25033
18-36 Vdc Input, 25 A, 3.3 Vdc Output
Physical Information
Data Sheet
Pin Connections
Pin #
1
2
3
4
5
6
7
8
Function
Vin (+)
ON/OFF
Vin (-)
Vout (-)
SENSE(-)
TRIM
SENSE(+)
Vout (+)
1
2
3
8
7
TOP VIEW
6
5
4
SIDE VIEW
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•
•
•
•
•
All dimensions are in inches [mm]
Pins 1-3 and 5-7 are Ø 0.040” [1.02]
with Ø 0.078” [1.98] shoulder
Pins 4 and 8 are Ø 0.062” [1.57]
without shoulder
Pin Material: Brass
Pin Finish: Tin/Lead over Nickel
Converter Weight: 1 oz [28 g] typical
Height
Option
A
B
C
D
HT
(Maximum Height)
+0.000 [+0.00]
-0.038 [-0.97]
0.303 [7.69]
0.336 [8.53]
0.500 [12.70]
0.400 [10.16]
CL
(Minimum Clearance)
+0.016 [+0.41]
-0.000 [-0.00]
0.030 [0.77]
0.063 [1.60]
0.227 [5.77]
0.127 [3.23]
Pin
Option
A
B
C
PL
(Pin Length)
±0.005 [±0.13]
0.188 [4.77]
0.145 [3.68]
0.110 [2.79]
Converter Part Numbering Scheme
Product
Series
Input
Voltage
Mounting
Scheme
Rated
Load
Current
Output
Voltage
ON/OFF
Logic
Maximum
Height (HT)
Pin
Length (PL)
Special
Features
Q
Quarter-Brick
Format
24
18-36 V
T
Through-
hole
25
25 Adc
033
033
⇒
3.3 V
-
N
N
⇒
Negative
P
⇒
Positive
B
A
⇒
0.303”
B
⇒
0.336”
C
⇒
0.500”
D
⇒
0.400”
A
A
⇒
0.188”
B
⇒
0.145”
C
⇒
0.110”
0
0
⇒
STD
The example above describes P/N Q24T25033-NBA0: 18-36 V input, through-hole mounting, 25 A @ 3.3 V output, negative ON/OFF logic, a
maximum height of 0.336”, and a through the board pin length of 0.188”. Please consult factory regarding availability of a specific version.
Q24T25033 FDS Ver 2 05-01-03
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Page 4 of 14
Q24T25033
18-36 Vdc Input, 25 A, 3.3 Vdc Output
Operation
Input and Output Impedance
These power converters have been designed to be stable
with no external capacitors when used in low inductance in-
put 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 addi-
tion 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 capaci-
tance at the load. The power converter will exhibit stable op-
eration with external load capacitance up to 30,000
µF.
Data Sheet
age 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 sinking up to 1 mA
depending on the signal polarity. See the Start-up Informa-
tion 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 con-
verter 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
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 con-
trol options available, positive logic and negative logic and
both are referenced to Vin(-). Typical connections are shown
in Fig. 2.
Vin (+)
Vin
Vin (+)
Family
Converter
(Top View)
Vout (+)
100
Rw
SENSE (+)
TRIM
SENSE (-)
10
Rload
ON/OFF
Vin (-)
Vout (-)
Rw
Fig. 3:
Remote sense circuit configuration.
Q
TM
Family
Converter
(Top View)
Vout (+)
SENSE (+)
TRIM
SENSE (-)
Rload
Vin
ON/OFF
Vin (-)
CONTROL
INPUT
Vout (-)
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 capabil-
ity of the converter, equal to the product of the nominal out-
put voltage and the allowable output current for the given
conditions.
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 volt-
Q24T25033 FDS Ver 2 05-01-03
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Page 5 of 14
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