25A/37.5W

Technical Specification
Quarter
Brick
48Vin 1.5Vout 25A
High Efficiency, No Heatsink, Isolated DC/DC Converter
The PQ48015QNA25 PowerQor™ quarter-brick
converter is a next-generation, board-mountable,
isolated, fixed switching frequency dc/dc
converter that uses synchronous rectification to
achieve extremely high conversion efficiency. The
power dissipated by the converter is so low that a
heatsink is not required, which saves cost, weight,
height, and application effort. All of the power and
control components are mounted to the multi-layer PCB
substrate with high-yield surface mount technology.
Since the PowerQor converter has no explicit
thermal connections, it is extremely reliable.
PQ48015QNA25 Module
Operational Features
• Ultra-high efficiency, 81% at full rated load current
• Delivers up to 25 amps of output current with minimal derating - no heatsink required
• Wide input voltage range: 35V – 75V meets or
exceeds all 48V bus standards
• Fixed frequency switching provides predictable EMI
performance
• No minimum load requirement means no preload
resistors required
Mechanical Features
• Industry standard pin-out configuration (pin for pin
compatible with Lucent QHW series)
• Industry standard size: 1.45” x 2.3”
• Total height less than 0.40”, permits better airflow
and smaller card pitch
• Total weight: 34 grams (1.2 oz.), lower mass greatly reduces vibration and shock problems
• Input under-voltage lockout disables converter at
low input voltage conditions
• Output current limit and short circuit protection
protects converter from excessive load current or
short circuits
• Output over-voltage protection protects load from
damaging voltages
• Thermal shutdown protects converter from abnormal environmental conditions
Control Features
• On/Off control referenced to input side (positive
and negative logic options are available)
• Remote sense for the output voltage compensates
for output distribution drops
• Output voltage trim: +10%/-20%, permits custom
voltages and voltage margining
Safety Features (cont.)
Safety Features
• 2000V, 10 MΩ input-to-output isolation provides
input/output ground separation
• UL 1950 recognized (US & Canada), basic insulation rating
• TUV certified to EN60950
Product # PQ48015QNA25
Protection Features
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• Meets 72/23/EEC and 93/68/EEC directives
which facilitates CE Marking in user’s end product
• Board and plastic components meet 94V-0 flammability requirements
Doc.# 005-2QN451D_C
9/4/01
Page 1
Technical Specification
Quarter
48Vin 1.5Vout 25A
Brick
2.30
(58.4)
0.14
(3.6)
2.00
(50.8)
0.300
0.150 (7.62)
(3.81)
0.43
(10.8)
1.45
(36.8)
0.450
0.600
0.600
(11.43)
Top View
(15.24)
(15.24)
0.300
(7.62)
0.110 *
(2.79)
0.40
(10.2)
Shown Actual Size
Side View
* Other pin lengths available
1) All dimensions in inches (mm)
2) Pins 1-3, 5-7 are 0.040” (1.02mm) dia. with
0.080” (2.03mm) dia. standoff shoulders.
3) Pins 4 and 8 are 0.062” (1.57 mm) dia. with 0.100”
(2.54mm) dia. standoff shoulders.
4) All pins are Brass with Tin/Lead plating over Nickel
5) Tolerances: x.xx in. +/-0.02 in. (0.5mm)
x.xxx in. +/-0.010 in. (0.25mm)
6) Weight: 1.20 oz. (34 g)
7) Workmanship: Meets or exceeds IPC-A-610B Class II
ABSOLUTE MAXIMUM RATINGS
Input Voltage:
Non-Operating: 100V continuous
Operating:
80V continuous
100V 10µs transients,1% duty cycyle
Input/Output Isolation Voltage: 2000V
Storage Temperature: -55°C to +125°C
Operating Temperature: -40°C to +115°C
Voltage at ON/OFF input pin: +18V / -2V
Pin No.
Name
Function
1
Vin(+)
Positive input voltage (35V - 75V)
2
ON/OFF
TTL input to turn converter
on and off, referenced to
Vin(-), with internal pull up.
3
Vin(-)
Negative input voltage
4
Vout(-)
Negative output voltage
5
SENSE(-)
Negative remote sense1
6
TRIM
Output voltage trim2
7
SENSE(+)
Positive remote sense3
8
Vout(+)
Positive output voltage
Notes:
1. Pin 5 must be connected to Vout(-) at load.
2. Leave Pin 6 open for nominal output voltage.
3. Pin 7 must be connected to Vout(+) at load.
OPTIONS
SAFETY
The PQ48015QNA25 comes in two versions that differ by
the sense of the logic used for the ON/OFF control signal.
The PQ48015QNA25P version uses positive logic; meaning that the converter is on when the ON/OFF signal (Pin
2) is high. The PQ48015QNA25N version uses negative
logic; the converter is on when the ON/OFF signal is low.
Logic input is TTL compatible with an internal pull up.
The PQ48015QNA25 series of converters are UL 1950
recognized (US & Canada) with basic insulation rating
and TUV certified to EN60950 requirements.
Patents: SynQor is protected under various patents,
including but not limited to U.S. Patent # 5,999,417.
Product # PQ48015QNA25
Phone 1-888-567-9596
The converters also meet 72/23/EEC and 93/68/EEC
directives as well as 94V-0 flammability requirements for
board and plastic components.
An external input fuse must always be used to meet these
safety requirements.
Doc.# 005-2QN451D_C
9/4/01
Page 2
Technical Specification
Quarter
Brick
48Vin 1.5Vout 25A
PQ48015QNA25 ELECTRICAL CHARACTERISTICS
(TA=25°C, airflow rate=300 LFM, Vin=48Vdc unless otherwise noted; full operating temperature range is -40°C to +115°C ambient
temperature with appropriate power derating.)
PARAMETER
NOTES and CONDITIONS
PQ48015QNA25
Min.
Typ.
Max.
Units
35
48
75
V
32
28.5
2.5
33
29.5
3.5
34
30.5
4.5
1.3
60
3
V
V
V
A
mA
mA
A 2s
mA
1.500
1.515
V
+2
+2
+6
+5
+5
+20
1.54
mV
mV
mV
V
50
10
100
20
25
34
60
mV
mV
A
A
A
INPUT CHARACTERISTICS
Operating Input Voltage Range
Input Under-Voltage Lockout
Turn-On Voltage Threshold
Turn-Off Voltage Threshold
Lockout Hysteresis Voltage
Maximum Input Current
No-Load Input Current
Off Converter Input Current
Inrush Current Transient Rating
Input Reflected-Ripple Current
100% Load, 35Vin
45
1.6
.01
3
P-P thru 10µH inductor; Figures 13 & 15
OUTPUT CHARACTERISTICS
Output Voltage Set Point
Output Voltage Regulation
Over Load
Over Line
Over Temperature
Total Output Voltage Range
Output Voltage Ripple and Noise
Peak-to-Peak
RMS
Operating Output Current Range
Output DC Current-Limit Inception
Short-Circuit Protection (redundant shutdown)
DYNAMIC CHARACTERISTICS
Input Voltage Ripple Rejection
Output Voltage Current Transient
Positive Step Change in Output Current
Negative Step Change in Output Current
Settling Time to 1%
Turn-On Transient
Turn-On Time
Start-Up Inhibit Period
Maximum Output Capacitance
1.485
over sample load, line and temperature
20MHz bandwidth; Figures 13 & 16
Full Load, 1µF ceramic, 10µF tantalum
Full Load, 1µF ceramic, 10µF tantalum
1.46
0
26
52
Output Voltage 10% Low; Figure 17
120 Hz; Figure 20
470µF load cap, 5A/µs; Figure 12
50% Io to 75% Io
75% Io to 50% Io
Figures 9 & 10
-40°C to +125°C; Figure F
Full load; 5% overshoot of Vout at startup
EFFICIENCY
100% Load
50% Load
180
Figure 1
TEMPERATURE LIMITS FOR POWER DERATING CURVES
Semiconductor Junction Temperature
Board Temperature
Transformer Temperature
82
dB
160
200
800
mV
mV
µs
4
200
Isolation Voltage
Isolation Resistance
Isolation Capacitance
190
See circuit diagram; Figure E
Pull up to Vin/6
Across Pins 8 & 4
Across Pins 7 & 5
Over full temp range; % of nominal Vout
Average PCB Temperature
°C
°C
°C
V
MΩ
pF
470
230
kHz
-2
2.4
0.8
18
V
V
2.4
-2
18
0.8
V
V
9.2
V
kΩ
%
%
%
°C
-20
124
210
ms
ms
µF
%
%
125
125
125
2000
10
FEATURE CHARACTERISTICS
8
215
40,000
81.0
84.0
Package rated to 150°C
Board rated to 165°C
Figures 5 & 7
ISOLATION CHARACTERISTICS
Switching Frequency
ON/OFF Control (Option P)
Off-State Voltage
On-State Voltage
ON/OFF Control (Option N)
Off-State Voltage
On-State Voltage
ON/OFF Control (Either Option)
Pull-Up Voltage
Pull-Up Resistance
Output Voltage Trim Range
Output Voltage Remote Sense Range
Output Over-Voltage Protection
Over-Temperature Shutdown
30
56
Vin/6.5
40
129
125
+10
+10
134
Specifications subject to change without notice.
Product # PQ48015QNA25
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Doc.# 005-2QN451D_C
9/4/01
Page 3
Performance Curves
Quarter
48Vin 1.5Vout 25A
Brick
90
88
87
85
Efficiency (%)
Efficiency (%)
86
80
75
70
48 Vin
75 Vin
3
5
8
10
13
15
18
20
23
83
25 C
40 C
81
55 C
80
60
0
84
82
36 Vin
65
85
0
25
100
200
Vin = 48V
Load Current (A)
Figure 1: Efficiency vs. load current for minimum, nominal, and
maximum input voltage at 25°C.
300
400
500
Air Flow (LFM)
Figure 2: Efficiency at 60% rated power vs. airflow rate for ambient
air temperatures of 25°C, 40°C, and 55°C and nominal input voltage.
10
6.0
5.5
8
Power Dissipation (W)
Power Dissipation (W)
9
7
6
5
4
3
36 Vin
2
4.5
4.0
25 C
40 C
3.5
48 Vin
1
5.0
75 Vin
0
55 C
3.0
0
3
5
8
10
13
15
18
20
23
25
0
100
200
Vin = 48V
Load Current (A)
Figure 3: Power dissipation vs. load current for minimum, nominal,
and maximum input voltage at 25°C.
300
400
500
Air Flow (LFM)
Figure 4: Power dissipation at 60% rated power vs. airflow rate for
ambient air temperatures of 25°C, 40°C, and 55°C and nominal input
voltage.
25
Iout (A)
20
15
10
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
5
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
0 LFM (0 m/s)
0
0
Vin = 48V
25
40
55
70
85
Semiconductor junction temperature is
within 2°C of surface temperature
Ambient Air Temperature (oC)
Figure 5: Maximum output power-derating curves vs. ambient air temperature for airflow rates of 0 LFM through 400 LFM with air flowing
across the converter from pin 3 to pin 1 (nominal input voltage).
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Figure 6: Thermal plot of converter at 25 amp load current with 55°C
air flowing at the rate of 200 LFM. Air is flowing across the converter
sideways from pin 3 to pin 1 (nominal input voltage).
Doc.# 005-2QN451D_C
9/4/01
Page 4
Performance Curves
Quarter
Brick
48Vin 1.5Vout 25A
25
Iout (A)
20
15
10
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
5
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
0 LFM (0 m/s)
0
0
Vin = 48V
25
40
55
70
85
Ambient Air Temperature (oC)
Semiconductor junction temperature is
within 2°C of surface temperature
Figure 7: Maximum output power-derating curves vs. ambient air temperature for airflow rates of 0 LFM through 400 LFM with air flowing
lengthwise from output to input (nominal input voltage).
Figure 8: Thermal plot of converter at 25 amp load current with 55°C
air flowing at the rate of 200 LFM. Air is flowing across the converter
in the long direction from output to input (nominal input voltage).
Figure 9: Turn-on transient at full rated load current (resistive load) (2
ms/div). Top Trace: Vout; 1V/div
Bottom Trace: ON/OFF input; 5V/div
Figure 10: Turn-on transient at zero load current (2 ms/div).
Top Trace: Vout; 1V/div
Bottom Trace: ON/OFF input; 5V/div
Figure 11: Output voltage response to step-change in load current (50%-75%-50%
of Imax; dI/dt = 0.1A/µs). Load cap: 10µF, 100 mΩ ESR tantalum capacitor and
Figure 12: Output voltage response to step-change in load current (50%-75%-50%
of Imax: dI/dt = 5A/µs). Load cap: 470µF, 30 mΩ ESR tantalum capacitor and 1µF
ceramic capacitor. Top trace: Vout (100mV/div), Bottom trace: Iout (5A/div).
1µF ceramic capacitor. Top trace: Vout (100mV/div), Bottom trace: Iout (5A/div).
Product # PQ48015QNA25
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Doc.# 005-2QN451D_C
9/4/01
Page 5
Performance Curves
Quarter
Brick
Figure 15
10 µH
Figure 14
source
impedance
Figure 16
iS
iC
VSOURCE
48Vin 1.5Vout 25A
DC/DC
Converter
VOUT
1 µF
47 µF,
<1Ω ESR
10 µF,
ceramic 100mΩ ESR
capacitor
tantalum
capacitor
electrolytic
capacitor
Figure 13: Test set-up diagram showing measurement points for Input
Terminal Ripple Current (Figure 14), Input Reflected Ripple Current
(Figure 15) and Output Voltage Ripple (Figure 16).
Figure 14: Input Terminal Ripple Current, ic, at full rated output current and nominal input voltage with 10µH source impedance and 47µF
electrolytic capacitor (100 mA/div). (See Figure 13)
Figure 15: Input reflected ripple current, is, through a 10 µH source
inductor at nominal input voltage and rated load current (10 mA/div).
(See Figure 13)
Figure 16: Output voltage ripple at nominal input voltage and rated
load current (20 mV/div). Load capacitance: 1µF ceramic capacitor
and 10µF tantalum capacitor. Bandwidth: 20 MHz. (See Figure 13).
3.0
Output Voltage (V)
2.5
2.0
1.5
1.0
36 V
48 V
75 V
0.5
0.0
0
5
10
15
20
25
30
Load Current (A)
Figure 17: Output voltage vs. load current showing typical current limit
curves and converter shutdown points.
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Figure 18: Load current (20A/div) as a function of time when the converter attempts to turn on into a 10 mΩ short circuit. Top trace is an
expansion of the on-time portion of the bottom trace.
Doc.# 005-2QN451D_C
9/4/01
Page 6
Performance Curves
Quarter
48Vin 1.5Vout 25A
Brick
0
1
0.1
36 Vin
48 Vin
0.01
75 Vin
0.001
Forward Transmission (dB)
Output Impedance ( )
-10
-20
-30
-40
-50
36 Vin
48 Vin
-60
75 Vin
-70
-80
-90
-100
0.0001
10
100
1,000
10,000
10
100,000
100
1,000
10,000
100,000
Hz
Hz
Figure 19: Output impedance (Zout = Vout/Iout) for minimum, nominal, and maximum input voltage at full rated power.
Figure 20: Forward Transmission (FT = Vout/Vin) for minimum, nominal, and maximum input voltage at full rated power.
0
1000
100
-20
-30
36 Vin
48 Vin
75 Vin
-40
-50
Input Impedance ( )
Reverse Transmission (dB)
-10
36 Vin
48 Vin
75 Vin
10
1
-60
-70
0.1
10
100
1,000
10,000
100,000
10
100
Hz
10,000
100,000
Hz
Figure 21: Reverse Transmission (RT = Iin/Iout) for minimum, nominal, and maximum input voltage at full rated power.
Product # PQ48015QNA25
1,000
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Figure 22: Input impedance (Zin = Vin/Iin) for minimum, nominal, and
maximum input voltage at full rated power.
Doc.# 005-2QN451D_C
9/4/01
Page 7
Technical Specification
Quarter
Brick
BASIC OPERATION AND
FEATURES
The PowerQor series converter uses a two-stage power circuit topology. The first stage is a buck-converter that keeps
the output voltage constant over variations in line, load, and
temperature. The second stage uses a transformer to provide
the functions of input/output isolation and voltage stepdown to achieve the low output voltage required.
Both the first stage and the second stage switch at a fixed
frequency for predictable EMI performance. Rectification of
the transformer’s output is accomplished with synchronous
rectifiers. These devices, which are MOSFETs with a very
low on-state resistance, dissipate far less energy than
Schottky diodes used in conventional dc/dc converters. This
is the primary reason that the PowerQor converter has such
high efficiency—even at very low output voltages and very
high output currents.
Dissipation throughout the converter is so low that the
PowerQor converter requires no heatsink to deliver
a greater level of power than can be delivered by a conventional, Schottky-diode-based dc/dc converter with a
0.5” high heatsink. At equivalent ambient air temperature,
airflow rate, and output power level, the hottest semiconductor junction temperature and the hottest PCB temperature
within the PowerQor converter are cooler than those found
in conventional dc/dc converters with a 0.5” high heatsink
attached.
Since a heatsink is not required, the PowerQor converter
does not need a metal baseplate or potting material to help
conduct the dissipated energy to the heatsink. The
PowerQor converter can thus be built more simply using
high yield surface mount techniques on a PCB substrate.
Unlike conventional dc/dc converters, which have critical
thermal connections between the power components and the
baseplate, and between the baseplate and the heatsink, the
PowerQor converter has no explicit, failure-prone thermal
connections.
Compared to a conventional Schottky-diode-based dc/dc
converter with a 0.5” high heatsink, the PowerQor converter is more efficient and therefore it dissipates less than half
the energy. Additionally, because the PowerQor converter is
thinner (0.4” vs. 1.0”), the board-to-board pitch in a rack
can be much smaller, and cooling airflow is less impeded by
Product # PQ48015QNA25
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48Vin 1.5Vout 25A
the converter. Because the PowerQor converter is much
lighter, vibration and shock-induced problems are greatly
reduced. Moreover, due to the lack of failure-prone explicit
thermal connections and the lack of potting material the
PowerQor converter is more reliable than conventional
dc/dc converters.
The PowerQor series converter uses the industry standard
pin-out configuration used by other vendors of comparably
sized and rated dc/dc converters. The unit is pin for pin
compatible with the Lucent QW series.
The PowerQor converter has many standard control and
protection features. All shutdown features are non-latching,
meaning that the converter shuts off for 200ms before
restarting. (see Figure F)
• An ON/OFF input permits the user to control when the
converter is on and off in order to properly sequence different power supplies and to reduce power consumption
during a standby condition.
• Remote sense inputs permit the user to maintain an
accurate voltage at the load despite distribution voltage
drops between the converter’s output and the load.
• An output voltage trim input permits the user to trim
the output voltage up or down to achieve a custom voltage level or to do voltage margining.
• An input under-voltage lockout avoids input system
instability problems while the input voltage is rising.
• The output current limit protects both the converter
and the board on which it is mounted against a short circuit condition.
• An output over-voltage limit circuit shuts the unit
down if the output voltage at the output pins gets too
high.
• A sensor located in a central spot of the PCB provides a
PCB temperature limit. If, due to an abnormal condition, this spot gets too hot, the converter will turn off.
Once the converter has cooled, it will automatically turn
on again without the need to recycle the input power.
CONTROL PIN DESCRIPTIONS
Pin 2 (ON/OFF): The ON/OFF input, Pin 2, permits the
user to control when the converter is on or off. This input is
Doc.# 005-2QN451D_C
9/4/01
Page 8
Technical Specification
Quarter
48Vin 1.5Vout 25A
Brick
referenced to the return terminal of the 48V input bus. There
are two versions of the PowerQor series converter that differ
by the sense of the logic used for the ON/OFF input. In the
PQxxyyyQNAzzPxx version, the ON/OFF input is active
high (meaning that a high turns the converter on). In the
PQxxyyyQNAzzNxx version, the ON/OFF signal is active
low (meaning that a low turns the converter on). Figure A
details five possible circuits for driving the ON/OFF pin.
it should trigger, not the voltage across the converter’s sense
pins (pins 7 and 5). Therefore, the resistive drop on the
board should be small enough so that output OVP does not
trigger, even during load transients.
Pin 6 (TRIM): The TRIM input permits the user to adjust the
output voltage across the sense leads up or down. To lower
the output voltage, the user should connect a resistor
between Pin 6 and Pin 5, which is the SENSE(-) input. To
raise the output voltage, the user should connect a resistor
between Pin 6 and Pin 7, which is the SENSE(+) input.
Pins 7 and 5 (SENSE(+)): The SENSE(+) inputs correct
for voltage drops along the conductors that connect the converter’s output pins to the load.
A resistor connected between Pin 6 and Pin 5 will decrease
the output voltage. For a desired decrease of ∆ percent of
the nominal output voltage, the value of this resistor should
be
Pin 7 should be connected to Vout(+) and Pin 5 should be
connected to Vout(-) at the point on the board where regulation is desired. That is,
[Vout(+) - Vout(-)] – [SENSE(+) - SENSE (-)]
< 10%Vout
Pins 7 and 5 must be connected for proper regulation of the
output voltage. However, if these connections are not made,
nothing catastrophic will happen to the converter under normal operating conditions—the converter will simply deliver
an output voltage that is slightly higher than its specified
value.
Rtrim-down =
(511
∆% ) - 10.22
(
)
where
∆=
and
VNOM – VDES
VNOM
ON/OFF
Vin(_)
Negative Logic
Vin(_)
Remote Enable Circuit
x 100%
VNOM = Nominal Voltage
VDES = Desired Voltage
Note: the output over-voltage protection circuit senses the
voltage across the output (pins 8 and 4) to determine when
ON/OFF
(kΩ)
(Permanently Enabled)
ON/OFF
Vin(_)
Positive Logic
(Permanently Enabled)
5V
ON/OFF
TTL/
CMOS
ON/OFF
Vin(_)
Vin(_)
Open Collector Enable Circuit
Direct Logic Drive
Figure A: Various circuits for driving the ON/OFF pin.
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Page 9
Technical Specification
Quarter
Brick
Figure B graphs this relationship between Rtrim-down and ∆.
The output voltage can be trimmed down as much as 20%.
Trim Resistance (kOhms)
10,000
48Vin 1.5Vout 25A
Note: the TRIM feature does not affect the voltage at which
the output over-voltage protection circuit is triggered.
Trimming the output voltage too high may cause the overvoltage protection circuit to engage, particularly during transients.
TOTAL DC VARIATION OF Vout: For the converter to
meet its full specifications, the maximum variation of the dc
value of Vout, due to both trimming and remote load voltage
drops, should not be greater than +10%/-20%
1,000
100
PROTECTION FEATURES
10
0
2
4
6
8
10
12
14
16
18
20
% Decrease in Output Voltage
Figure B: Trim Down Graph for 1.5Vout
A resistor connected between Pin 6 and Pin 7 will increase
the output voltage. For a desired increase of ∆ percent of the
nominal output voltage, the value of this resistor should be
Rtrim-up =
(
5.11VOUT(100+∆%) _ 511 _
10.22
1.225∆%
∆%
)
(kΩ)
where
VOUT = Nominal Output Voltage
Figure C graphs this relationship between Rtrim-up and ∆.
The output voltage can be trimmed up as much as 10%.
Output Current Limit: The current limit does not change
appreciably as the output voltage drops. However, once the
impedance of the short across the output is small enough to
make the output voltage drop below approximately 60% of
its nominal value, the converter turns off.
The converter then enters a mode where it repeatedly turns
on and off at a 5 Hz (nominal) frequency with a 5% duty
cycle until the short circuit condition is removed. This prevents excessive heating of the converter or the load board
(see Figure 18).
Output Over-Voltage Limit: If the voltage across the
output pins exceeds the O.V. threshold, the converter will
immediately stop switching. This prevents damage to the
load circuit due to 1) a sudden unloading of the converter,
2) a release of a short-circuit condition, or 3) a release of a
current limit condition. Load capacitance determines exactly
how high the output voltage will rise in response to these
conditions. After 200 ms the converter will automatically
restart.
1,000
Trim Resistance (kOhms)
Input Under-Voltage Lockout: The converter is
designed to turn off when the input voltage is too low, helping avoid an input system instability problem, described in
more detail below. The lockout circuitry is a comparator with
dc hysteresis. When the input voltage is rising, it must
exceed a typical value of 33V before the converter will turn
on. Once the converter is on, the input voltage must fall
below a typical value of 29.5V before the converter will turn
off.
100
10
1
0
1
2
3
4
5
6
7
8
9
10
% Increase in Output Voltage
Figure C: Trim Up Graph for 1.5Vout
Product # PQ48015QNA25
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Thermal Shutdown: The PowerQor series has a temperature sensor located such that it senses the average temperature of the converter. The thermal shutdown circuit is
designed to turn the converter off when the temperature at
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Technical Specification
Quarter
48Vin 1.5Vout 25A
Brick
the sensed location reaches 115°C. It will allow the converter to turn on again when the temperature of the sensed
location falls below 110°C.
APPLICATION CONSIDERATIONS
Input System Instability: This condition can occur
because a dc/dc converter appears incrementally as a
negative resistance load. A detailed application note titled
“Input System Instability” is available on the SynQor web
site (www.synqor.com) which provides an understanding
of why this instability arises, and shows the preferred solution for correcting it.
Application Circuits: Figure D below provides a typical
circuit diagram which is useful when using input filtering
and voltage trimming. Figure E is a detailed look of the internal ON/OFF circuitry that is shown in Figure A.
Input Filtering
Vin(+ )
Electrolytic
Capacitor
33µF
Vout(+ )
Vsense(+ )
ESR ≅1Ω
ON/OFF
35V < Vin < 75V
Vin(_)
Trim
Vsense(_)
Vout(_)
Rtrim-up
or
Rtrim-down
Cload
Iload
Figure D: Typical application circuit (negative logic unit, permanently enabled).
Vin(+ )
5V
274k
ON/OFF
50k
TTL
100pF
50k
Vin(_)
Figure E: Internal ON/OFF pin circuitry
Product # PQ48015QNA25
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9/4/01
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Technical Specification
Quarter
Brick
STARTUP INHIBIT PERIOD
The Startup Inhibit Period ensures that the converter will
remain off for at least 200ms when it is shut down for any
reason. When an output short is present, this generates a
5Hz "hiccup mode," which prevents the converter from overheating. In all, there are seven ways that the converter can
be shut down, initiating a Startup Inhibit Period:
• Input Under-Voltage Lockout
• Input Over-Voltage Shutdown (not present in Quarterbrick)
48Vin 1.5Vout 25A
Figure F shows three turn-on scenarios, where a Startup
Inhibit Period is initiated at t0, t1, and t2:
Before time t0, when the input voltage is below 34V (typ.),
the unit is disabled by the Input Under-Voltage Lockout feature. When the input voltage rises above 34V, the Input
Under-Voltage Lockout is released, and a Startup Inhibit
Period is initiated. At the end of this delay, the ON/OFF pin
is evaluated, and since it is active, the unit turns on.
At time t1, the unit is disabled by the ON/OFF pin, and it
cannot be enabled again until the Startup Inhibit Period has
elapsed.
• Output Over-Voltage Protection
• Over Temperature Shutdown
When the ON/OFF pin goes high after t2, the Startup Inhibit
Period has elapsed, and the output turns on within the 4ms
(typ.) "Turn On Time."
• Current Limit
• Short Circuit Protection
• Turned off by the ON/OFF input
Vin
Under-Voltage
Lockout Turn-On
Threshold
ON/OFF
(pos logic)
ON
OFF ON
OFF
ON
Vout
4ms (typical
turn on time)
200ms
(typical start-up
inhibit period)
t0
200ms
200ms
t1
t
t2
Figure F: Startup Inhibit Period (turn-on time not to scale)
Product # PQ48015QNA25
Phone 1-888-567-9596
Doc.# 005-2QN451D_C
9/4/01
Page 12
Technical Specification
Quarter
48Vin 1.5Vout 25A
Brick
PART NUMBERING SYSTEM
The part numbering system for SynQor’s PowerQor DC/DC
converters has the following format:
Quarter-Brick Product Family and Part Numbering Scheme
Product Family Input Voltage
PQ
48
PQ - PowerQor 48 - (35v-75v)
Output
Voltage
Package Size
Performance
Series
Thermal
Design
"Rated"
Output Current
033
Q
N
A
25
015 - 1.5V
018 - 1.8V
020 - 2.0V
025 - 2.5V
033 - 3.3V
050 - 5.0V
060 - 6.0V
120 - 12V
150 - 15V
25 - 25 Amps
Q - Quarter Brick
N - Normal
A - Open Frame
B - Baseplate
20 - 20 Amps
17 - 16.67 Amps
08 - 8.33 Amps
07 - 6.67 Amps
Base Part Number
Pos./Neg.
Logic
Pin Length
N
N
K - 0.110"
P - Positive N - 0.145"
N - Negative R - 0.180"
Y - 0.250"
Features
S
S - Standard
Options
Example part #: P Q 4 8 0 3 3 Q N A 2 5 N N S
This part number indicates a PowerQor converter with
48Vin, 3.3Vout, quarter-brick size, normal performance
level, open air design, 25 amps output current, negative
logic, 0.145” pins, and the standard feature set.
Although there are no default values for enable logic and
pin length, the most common options are negative logic and
0.145” pins. These part numbers are more likely to be
readily available in stock for evaluation and prototype quantities.
The Giga Quarter-brick (QGA) series is identical in form, fit
and function to the QNA 25A quarter-brick series. Only the
part number has changed. Please use the QGA part number sequence when ordering these modules.
When ordering SynQor converters, please ensure that you
use the complete 15 character part number.
Contact SynQor for further information:
Phone:
Toll Free:
Fax:
E-mail:
Web:
Address:
Product # PQ48015QNA25
978-567-9596
888-567-9596
978-567-9599
[email protected]
www.synqor.com
188 Central Street
Hudson, MA 01749
Phone 1-888-567-9596
Warranty
SynQor offers a three (3) year limited warranty. Complete warranty
information is listed on our web site or is available upon request from
SynQor.
Information furnished by SynQor is believed to be accurate and reliable.
However, no responsibility is assumed by SynQor for its use, nor for any
infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any
patent or patent rights of SynQor.
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Page 13
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