Technical Reference Notes
ALQ25B50 Bus Converter
DC Transformer
ALQ25B50 Single Output Open-Frame DC Bus Converter
Industry Standard ¼ Brick: 300W DC Transformer
PRELIMINARY
The ALQ25B50 is among a series of Bus Converter solutions from Astec intended to drive multiple non-isolated POLs
employed on Distributed Power Architectures (DPA). It’s a DC transformer that accepts a narrow input range (48V nominal) to
ensure a stepped down output of 12V nominal with 10% line regulation. Such a DC conversion scheme allows the converters
to exhibit a purely resistive output characteristic that eases stability management when driving multiple POLs. It comes with
ON/OFF Enable pin, Input over voltage and under voltage protection, OTP and output pin length options.
Electrical Parameters
Input
Input Range
Efficiency
OVP
42-53 VDC
12V up to 96% Efficiency
60Vdc
Control
Enable
TTL compatible
(Positive and Negative Enable Options)
Output
Special Features
•
•
•
•
•
•
•
•
Load Current
Line Regulation
Load Regulation
Ripple and Noise
0A - 25A max
10.25V – 13.6V
±3%Vo (Typical)
80mV (Typical)
300W DC Transformer for DPA Front End
Industry Standard ¼ Brick Footprint
High Efficiency
Positive and Negative Enable Options
Regulation to Zero Load
Meets Basic Insulation
Input OVP and UVLO
Low profile / open-frame
Environmental Specifications
Safety
•
•
•
UL + cUL 60950, Recognized
EN60950 through TUV-PS
-40ºC to 85ºC Operating Temperature
-40ºC to 125ºC Storage Temperature
MTBF > 1 million hours
MODEL: ALQ25B50 SERIES
SEPTEMBER 11, 2003 - REVISION A (PRELIMINARY)
SHEET 1 OF 11
Technical Reference Notes
ALQ25B50 Bus Converter
DC Transformer
ALQ25B50 Series
MODEL
NUMBER
ALQ25B50
ALQ25B50-6
ALQ25B50N
ALQ25B50N-6
CONSTRUCTION
Open Frame; Low profile; Pos Enable; 5mm Pin Length
Open Frame; Low profile; Pos Enable; 3.7mm Pin length
Open Frame; Low profile; Neg Enable; 5mm Pin length
Open Frame; Low profile; Neg Enable; 3.7mm Pin Length
OPTIONS:
Negative Enable:
Positive Enable:
3.7mm nominal Pin Length
5mm nominal Pin Length
MODEL: ALQ25B50 SERIES
SEPTEMBER 11, 2003 - REVISION A (PRELIMINARY)
Vin range
42V - 53V
42V - 53V
42V - 53V
42V - 53V
Vout/Iout
12V / 25A
12V / 25A
12V / 25A
12V / 25A
SUFFIX
"N"
No suffix
“-6” suffix
No suffix
SHEET 2 OF 11
Technical Reference Notes
ALQ25B50 Bus Converter
DC Transformer
Electrical Specifications
STANDARD TEST CONDITION on a single module unless otherwise specified.
TA
Airflow
+VIN
Enable
-VIN
-VOUT
+ Vout
PIN 1
PIN 2
PIN 3
PIN 4
PIN 5
25°C (Ambient Air)
400LFM
Connected to +Input
Dependent on model series
Connected to -Input
Connected to Load return
Connected to Load
ABSOLUTE MAXIMUM RATINGS
Stresses in excess of the absolute maximum ratings can cause permanent damage to the converter. Functional
operation of the device is converter is not implied at these or any other conditions in excess of those given in the
operational section of the specs. Exposure to absolute maximum ratings for extended period can adversely affect
device reliability.
Parameter
Input Voltage1
Continuous
Transient (100ms)
Isolation Voltage
Input to Output
Operating Ambient Temperature
Storage Temperature
Operating Humidity
Maximum Enable Voltage
Max Output Power2
Note:
Device
Symbol
Min
Typ
Max
Unit
All
All
VIN
VI N, trans
42
-
-
56
60
Vdc
Vdc
TA
TSTG
-
-40
-55
-
-
PO
-
-
2000
85
125
85
5.5
300
Vdc
ºC
ºC
%
Vdc
W
All
All
All
All
All
All
1. The module is not internally fused. Type 3AB Littlefuse rated at 10A, 250V or equivalent is
recommended.
2. Output Derating applies. See Figure 9.
MODEL: ALQ25B50 SERIES
SEPTEMBER 11, 2003 - REVISION A (PRELIMINARY)
SHEET 3 OF 11
Technical Reference Notes
ALQ25B50 Bus Converter
DC Transformer
Electrical Specifications (continued)
INPUT SPECIFICATION
Parameter
Operating Input Voltage
Input Under-Voltage Lock-out
T_ON Threshold
T_OFF Threshold
Input Over Voltage Shutdown
Protection3
Maximum Input Current1
Conditions: VIN =VIN, MIN
IO = IO, MAX; TA = 25 ºC
Maximum Input Current
IO = 0A
Input Reflected Ripple Current4
Conditions: PO = PO, MAX; TA = 25 ºC
BW: 5Hz to 20MHz
Device
All
All
Symbol
VIN
All
All
Min
42
Typ
48
Max
53
Unit
VDC
41
39
-
60
43
41
-
Vdc
-
-
6.6
A
0.17
A
IIN,max
All
Vdc
All
II1/ II2
-
5
-
mARMS
Device
All
Symbol
VO,SET
Min
11.85
Typ
12.00
Max
12.15
Unit
Vdc
All
-
10.25
-
13.60
Vdc
All
-
-
-
± 5.5
%VO
All
-
-
-
±7.5
%VO
All
-
-
80
130
mVp-p
All
All
IO
0
-
200
25
mVp-p
A
All
-
All
IO
26.5
-
2,000
40
µF
mΩ
A
110
115
120
°C
800
820
KHz
OUTPUT SPECIFICATIONS
Parameter
Output Voltage Set point
VIN = VIN, NOM; IO =IO,MIN
Output Regulation Ta=25 ºC
Line: VIN = VIN, MIN to VIN, MAX
IO=IO, MIN = 0A
Load: IO = IO, MIN to IO, MAX
VIN=VIN, NOM = 48V
Temperature: Ta = 0 ºC to +85 ºC
Ripple and Noise5
Peak-to-Peak: (5Hz to 20MHz)
TA = 25°C, IO = IO, MAX
VIN=VIN, NOM = 48V
Other conditions
Output Current2
External Load Capacitance
Capacitor ESR
Output Current-limit Inception6
VOUT = 90% VO, SET
Over Temperature Range7
All
(Average PCM Temperature)
Switching Frequency
MODEL: ALQ25B50 SERIES
SEPTEMBER 11, 2003 - REVISION A (PRELIMINARY)
All
-
780
SHEET 4 OF 11
Technical Reference Notes
ALQ25B50 Bus Converter
DC Transformer
Electrical Specifications (continued)
OUTPUT SPECIFICATIONS
Parameter
Device
Symbol
Min
Typ
Max
Unit
Efficiency
All
94
96
%
η
VIN = VIN-MIN to VIN-MAX
IO = 13.5A Resistive load
TA = 25°C
Turn-On Response Time
from Active Enable to
All
4.0
ms
90% VO (TA = 25°C)
Output Overshoot at T-on / T-off
All
200
mV
Ta=25°C
Passive Resistive Full Load
Note: 3. The modules will shutdown once the input voltage OVP threshold is attained. Restart is possible once the
fault is removed and the input voltage is cycled.
4. See Figure 1 for the Input Reflected Ripple Current test measurement setup.
5. See Figure 2 for the Output Ripple test measurement setup.
6. In an event of an over current condition - the output will be in shutdown mode to prevent excessive heating
that could eventually damage the converter. Restart is possible once the input voltage or Enable is cycle
for a 10 second wait period.
7. Output of the module will be terminated once the average PCB temp reaches the OTP range. Normal
operation resumes once the temperature falls below the OTP range.
FEATURE SPECIFICATION
Parameter
Output Enable ON/OFF
Negative Enable ("N" suffix)
Enable Pin voltage for Module ON
Module OFF
Positive Enable (No suffix)
Enable Pin voltage for Module ON
Module OFF
Device
Symbol
Min
Typ
Max
Unit
N
suffix
-
0
2.00
-
0.8
5.0
V
V
No
suffix
-
2.00
0
-
5.0
0.8
V
SAFETY APPROVAL
The ALQ25B50 series have been certified through:
• UL + cUL 60950, Third Edition - Recognized
• EN 60950 through TUV-PS
• Basic Insulation
• UL94V-0 flammability rating
MODEL: ALQ25B50 SERIES
SEPTEMBER 11, 2003 - REVISION A (PRELIMINARY)
SHEET 5 OF 11
Technical Reference Notes
ALQ25B50 Bus Converter
DC Transformer
Electrical Specifications (continued)
TO OSCILLOSCOPE
Vi(+)
Ltest
12 uH
Cs 220 uF
ESR < 0.1 OHM
@ 20 ºC, 100 kHz
BATTERY
33 uF
220uF
ESR<<0.1
0.7 OHM
OHM
ESR
@ 20 ºC, 100 kHz
Vi(-)
Note: Measure the input reflected ripple current with a simulated source
inductance (Ltest) of 12uH. Capacitor Cs offsets possible battery/
source impedance. Measure current as shown above.
Figure 1. Input Reflected Ripple Current Measurement Setup.
COPPER STRIP
Vo(+)
0.1 uF
10 uF
SCOPE
RESISTIVE
LOAD
Vo(-)
Note: Use a 0.1µF 50V X7R ceramic capacitor and a 10µF 25V tantalum cap.
Scope measurement should be made using a BNC probe socket. Position
the load between 51 mm and 76 mm (2 in. and 3 in.) from module the
latter.
Figure 2. Peak to Peak Output Noise Measurement Setup.
MODEL: ALQ25B50 SERIES
SEPTEMBER 11, 2003 - REVISION A (PRELIMINARY)
SHEET 6 OF 11
Technical Reference Notes
ALQ25B50 Bus Converter
DC Transformer
Basic Operation and Features
INPUT UNDER VOLTAGE LOCKOUT
To prevent any instability to the converter, which may affect the end system, the ALQ25B50 series have been designed to turnon once VIN is in the voltage range of 41-43 VDC. Likewise, it has also been programmed to turn-off when VIN drops down to
39-41 VDC.
INPUT OVER VOLTAGE PROTECTION
The ALQ25B50 employs a DC Transformer conversion scheme where the input and output relationship is dictated by the turns
ratio of the windings. The OVP circuit senses the input line and shuts down the entire module once the sensed voltage reaches
the OVP threshold. Restart is possible once the fault is removed and the input power is recycled.
OUTPUT ENABLE
The ALQ25B50 series comes with an Enable pin (PIN 2), which is primarily used to turn ON/OFF the converter. Both a
Positive (no part number suffix required) and a Negative (suffix “N” required) Enable Logic options are being offered. Please
refer to Table 2 for the Part Numbering Scheme.
For Positive Enable, the converter is turned on when the Enable pin is at logic HIGH or left open. The unit turns off when the
Enable pin is at logic LOW or directly connected to -VIN. On the other hand, the Negative Enable version turns unit on when
the Enable pin is at logic LOW or directly connected to -VIN. The unit turns off when the Enable pin is at Logic HIGH.
OVER CURRENT PROTECTION (OCP)
The Over Current Protection circuit comes in latching mode. The converter is latched off if the load current on the output
reaches the OCP threshold limit. The OCP latch can be reset either by cycling the input voltage or toggling the Enable signal
for 100ms. Consult factory for Auto-restart option.
OVER TEMPERATURE PROTECTION (OTP)
The Over Temperature Protection circuit will shutdown the converter once the average PCB temperature reaches the OTP
range. This feature prevents the unit from overheating and consequently going into thermal runaway, which may further
damage the converter and the end system. Such overheating may be an effect of operation outside the given power thermal
derating conditions. Restart is possible once the temperature of the sensed location drops to less than 110°C.
MODEL: ALQ25B50 SERIES
SEPTEMBER 11, 2003 - REVISION A (PRELIMINARY)
SHEET 7 OF 11
Technical Reference Notes
ALQ25B50 Bus Converter
DC Transformer
Performance Curves
Efficiency Curves
Power Dissipation at TA=25ºC
Efficiency vs. Output Load, TA = 25ºC
98%
16
96%
14
Dissipation [W]
Efficiency [%]
94%
92%
90%
88%
48Vin
12
53Vin
10
8
6
86%
42V
84%
48V
4
82%
53V
2
80%
42Vin
0
0
5
10
15
Output Current [A]
20
25
Figure 3. Efficiency vs. Output current at TA = 25ºC with
400LFM airflow directed across pin 3 to 1.
0
18
96%
16
94%
14
92%
90%
88%
25
12
10
8
6
42Vin
48Vin
4
48Vin
53Vin
2
53Vin
42Vin
82%
20
Power Dissipation at TA=70ºC
Dissipation [W]
Efficiency [%]
Efficiency vs. Output Load, TA=70ºC
84%
10
15
Output Current [A]
Figure 4. Power dissipation curves at TA = 25ºC with
400LFM airflow directed across pin 3 to 1.
98%
86%
5
80%
0
0
5
10
15
Output Current [A]
20
25
Figure 5. Efficiency vs. Output current at TA = 70ºC with
400LFM airflow directed across pin 3 to 1.
MODEL: ALQ25B50 SERIES
SEPTEMBER 11, 2003 - REVISION A (PRELIMINARY)
0
5
10
15
Output Current [A]
20
25
Figure 6. Efficiency vs. Output current at TA=70ºC with
400LFM airflow directed across pin 3 to 1.
SHEET 8 OF 11
Technical Reference Notes
ALQ25B50 Bus Converter
DC Transformer
Performance Curves
Line Regulation, IO = IO,MAX, TA = 25ºC
14.75
12.50
12.40
12.30
12.20
12.10
12.00
11.90
11.80
11.70
11.60
11.50
11.40
11.30
11.20
11.10
11.00
14.00
Output Voltage [V]
Output Voltage [V]
Load Regulation, VIN = 48V, TA = 25ºC
13.25
12.50
11.75
11.00
10.25
9.50
0
5
10
15
Output Current [A]
20
25
42
43 44 45 46 47 48 49 50
51 52 53
Input Voltage [V]
Figure 7. Load Regulation at VIN = VIN, NOM = 48Vdc, TA
= 25ºC with 400LFM airflow directed across pin 3 to 1.
Figure 8. Line Regulation at IO = IO, MAX = 25A, TA = 25ºC
with 400LFM airflow directed across pin 3 to 1.
Output Derating Curves
Output Current [A]
25
20
15
10
0 LFM (0 m/ s)
100 LFM (0.5m/ s)
5
200 LFM (1 m/ s)
400 LFM (2 m/s)
0
25
40
55
70
Ambient Temperature [°C]
85
Figure 9. Output Derating curves at VIN = 48Vdc with
400LFM airflow directed across pin 3 to 1.
MODEL: ALQ25B50 SERIES
SEPTEMBER 11, 2003 - REVISION A (PRELIMINARY)
SHEET 9 OF 11
Technical Reference Notes
ALQ25B50 Bus Converter
DC Transformer
Mechanical Specifications
Parameter
Dimension
Device
All
Symbol
L
W
H
Weight
PIN ASSIGNMENT
1
2
3
Min
-
Typ
2.30 [58.42]
1.45 [36.83]
0.40 [10.16]
-
49.9 [1.76]
+VIN
ENABLE
-VIN
Max
-
Unit
in [ mm ]
in [ mm ]
in [ mm ]
gm [oz]
4
5
- VO
+ VO
0.22
[5.5]
2.30 [58.4]
0.38 [9.6]
0.06 Ø[1.5Ø]
1
1.48 [37.6]
0.04Ø [1.0Ø]
5
2
3
4
SIDE VIEW
PIN SIDE DOWN
0.15 [3.8]
2.00 [50.8]
0.44 [11.2]
0.44 [11.2]
0.74 [18.9]
1.04 [26.5]
0.60 [15.2]
PIN SIDE UP
Figure 10. ALQ25B50 Series Mechanical Outline Drawing
MODEL: ALQ25B50 SERIES
SEPTEMBER 11, 2003 - REVISION A (PRELIMINARY)
SHEET 10 OF 11
Technical Reference Notes
ALQ25B50 Bus Converter
DC Transformer
Mechanical Specifications (continued)
SOLDERING CONSIDERATIONS
The ALQ25B50 series converters are compatible with standard wave soldering techniques. When wave soldering, the
converter pins should be preheated for 20-30 seconds at 110°C and wave soldered at 260°C for less than 10 seconds.
When hand soldering, the iron temperature should be maintained at 425°C and applied to the converter pins for less
than 5 seconds. Longer exposure can cause internal damage to the converter. Cleaning can be performed with cleaning
solvent IPA or with water.
PART NUMBERING SCHEME FOR ORDERING
OUTPUT
VOLTAGE
ALQ25
x
ENABLE LOGIC
50
B = 12V
y
N
= Negative Enable
“Blank” = Positive Enable (Default)
Please call 1-888-41-ASTEC for further inquiries
or visit us at www.astecpower.com
MODEL: ALQ25B50 SERIES
SEPTEMBER 11, 2003 - REVISION A (PRELIMINARY)
SHEET 11 OF 11