Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 1
Technical Specification
24Vin 12Vout 8.3A
Quarter
Quarter
Brick
Brick
The PQ24120QGA08 PowerQor™ Giga quarter-
brick converter is a next-generation, board-mount-
able, 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 technolo-
gy. Since the PowerQor converter has no explicit
thermal connections, it is extremely reliable.
PQ24120QGA08 Module
100 Watts, No Heatsink, Isolated DC/DC Converter
Mechanical Features
• Industry standard quarter-brick pin-out configuration
• 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 great-
ly reduces vibration and shock problems
Operational Features
• High efficiency, >88% at full rated load current
• Delivers up to 8.3 amps of output current (100W)
with minimal derating - no heatsink required
• Wide input voltage range: 18V – 36V meets or
exceeds all 24V bus standards
• Fixed frequency switching provides predictable EMI
performance
• No minimum load requirement means no preload
resistors required
Protection Features
• 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 abnor-
mal environmental conditions
Safety Features
• 2000V, 10 MΩinput-to-output isolation provides
input/output ground separation
• UL 1950 recognized (US & Canada), basic insula-
tion rating (pending)
• TUV certification to EN60950 (pending)
• 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 flamma-
bility requirements
• NEBS and ETSI compliant
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 permits custom voltages and
voltage margining
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 2
Technical Specification
24Vin 12Vout 8.3A
Quarter
Quarter
Brick
Brick
Shown Actual Size
Pin No. Name Function
1 Vin(+) Positive input voltage (18 - 36V)
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 should be connected to Vout(-) at load.
2. Leave Pin 6 open for nominal output voltage.
3. Pin 7 should be connected to Vout(+) at load.
OPTIONS
• Logic sense - Negative (N); converter is on when the
ON/OFF signal is low. Positive (P); converter is on
when the ON/OFF signal is high. Logic input is TTL
compatible with an internal pull up. Use N or P as
13th letter in part number to indicate logic.
• Pin Length - a variety of pin lengths are available for
all modules (see last page). The14th letter in the part
number indicates pin length.
• Feature Set - Quarter-bricks are available with
Standard (S) feature options only. Use S as 15th letter
in part number to indicate feature set.
SAFETY
• UL 1950 - All modules are UL 1950 recognized (US &
Canada) with basic insulation rating.
• EN60950 - All modules are TUV certified to EN60950
requirements.
• 72/23/EEC - All modules meet 72/23/EEC directives.
• 93/68/EEC - All modules meet 93/68/EEC directives.
• 94V-0 - All modules meet 94V-0 flammability require-
ments for board and plastic components.
• NEBS - All modules meet NEBS compatibility.
• An external input fuse must always be used to meet
these safety requirements.
1) Pins 1-3, 5-7 are 0.040” (1.02mm) dia. with
0.080” (2.03mm) dia. standoff shoulders.
2) Pins 4 and 8 are 0.062” (1.57 mm) dia. with 0.100”
(2.54mm) dia. standoff shoulders.
3) Other pin extension lengths available.
4) Undimensioned components are for visual reference only.
5) Weight: 1.2 oz. (34g) typical
6) All dimensions in inches (mm)
Tolerances: x.xx +/-0.02 in. (x.x +/-0.5mm)
x.xxx +/-0.010 in. (x.xx +/-0.25mm)
7) Workmanship: Meets or exceeds IPC-A-610B Class II
0.40
(10.2)
0.300
(7.62)
1.45
(36.8)
0.43
(10.9)
0.14
(3.6)
2.30
(58.4)
2.00
(50.8)
0.150
(3.81)
0.300
(7.62)
0.450
(11.43) 0.600
(15.24)
0.600
(15.24) Top View
Side View
0.145
(3.68)
See Note 3
ABSOLUTE MAXIMUM RATINGS
Input Voltage:
Non-Operating: 50V continuous
Operating: 40V continuous
50V 10
µ
s 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
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 3
Technical Specification
24Vin 12Vout 8.3A
Quarter
Quarter
Brick
Brick
PARAMETER NOTES and CONDITIONS PQ24120QGA08
Min. Typ. Max. Units
INPUT CHARACTERISTICS
Operating Input Voltage Range 18 24 36 V
Input Under-Voltage Lockout
Turn-On Voltage Threshold 15.5 16.0 16.5 V
Turn-Off Voltage Threshold 14.0 14.5 15.0 V
Lockout Hysteresis Voltage 1.0 1.5 2.0 V
Maximum Input Current 100% Load, 18Vin 6.3 A
No-Load Input Current 160 320 mA
Off Converter Input Current 1.6 3 mA
Input Reflected-Ripple Current P-P thru 3.3
µH inductor
; Figures 13 & 15 10 mA
OUTPUT CHARACTERISTICS
Output Voltage Set Point 11.82 12.00 12.18 V
Output Voltage Regulation
Over Line +0.05 (5) +0.2 (24) % (mV)
Over Load +0.05 (5) +0.2 (24) % (mV)
Over Temperature +90 +240 mV
Total Output Voltage Range over sample line, load and temperature 11.58 12.42 V
Output Voltage Ripple and Noise 20MHz bandwidth; Figures 13 & 16
Peak-to-Peak Full Load, 1
µF ceramic, 10µF tantalum
80 160 mV
RMS Full Load, 1
µF ceramic, 10µF tantalum
20 40 mV
Operating Output Current Range 0 8.33 A
Output DC Current-Limit Inception Output Voltage 10% Low; Fig. 17 & 18 9 9.6 11 A
Short-Circuit Protection (redundant shutdown) 16 18 20 A
DYNAMIC CHARACTERISTICS
Input Voltage Ripple Rejection 120 Hz; Figure 20 60 dB
Output Voltage Current Transient 470µF load cap, 5A/µs; Figure 12
Positive Step Change in Output Current 50% Io to 75% Io 500 mV
Negative Step Change in Output Current 75% Io to 50% Io 550 mV
Settling Time to within 1% Vout nominal 400 µs
Turn-On Transient
Turn-On Time Full load, Vout=90% nom.; Figs 9 & 10 4 8 12 ms
Start-Up Inhibit Period
-40°C to +125°C; Figure F 180 200 215 ms
Maximum Output Capacitance Full load; 5% overshoot of Vout at startup 2,000 µF
EFFICIENCY
100% Load Figure 1 88 %
50% Load 88 %
TEMPERATURE LIMITS FOR POWER DERATING CURVES
Semiconductor Junction Temperature Plastic Package rated to 150°C 125 °C
Board Temperature Board rated to 165°C 125 °C
Transformer Temperature Figures 5 - 8 125 °C
ISOLATION CHARACTERISTICS
Isolation Voltage 2000 V
Isolation Resistance 10 M
Ω
Isolation Capacitance 470 pF
FEATURE CHARACTERISTICS
Switching Frequency 280 300 320 kHz
ON/OFF Control (Option P)
Off-State Voltage -2 0.8 V
On-State Voltage 2.4 18 V
ON/OFF Control (Option N)
Off-State Voltage 2.4 18 V
On-State Voltage -2 0.8 V
ON/OFF Control (Either Option)
Pull-Up Voltage See circuit diagram; Figure B Vin/3 9.6 V
Pull-Up Resistance Pull up to Vin/3 33 k
Ω
Output Voltage Trim Range Across Pins 8 & 4; Figures C & D -20 +10 %
Output Over-Voltage Protection Over full temp range; % of nominal Vout 117 122 127 %
Over-Temperature Shutdown Average PCB Temperature 125 °C
PQ24120QGA08 ELECTRICAL CHARACTERISTICS
T
A
=25°C, airflow rate=300 LFM, V
in
=24Vdc, nominal Vout unless otherwise noted; full operating temperature range is -40°C to
+115°C ambient temperature with appropriate power derating.
Specifications subject to change without notice.
Patents: SynQor is protected under various patents, including but not limited to U.S. Patent # 5,999,417.
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 4
Performance Curves
24Vin 12Vout 8.3A
Quarter
Quarter
Brick
Brick
60
65
70
75
80
85
90
95
0.0 0.8 1.7 2.5 3.3 4.2 5.0 5.8 6.7 7.5 8.3
Load Current (A)
Efficiency (%)
18Vin
24Vin
36Vin
Figure 1: Efficiency at nominal output voltage vs. load current for min-
imum, nominal, and maximum input voltage at 25
°
C.
82
83
84
85
86
87
88
89
90
0 100 200 300 400 500
Air Flow (LFM)
Efficiency (%)
25 C
40 C
55 C
Figure 2: Efficiency at nominal output voltage and60% rated power vs.
airflow rate for ambient air temperatures of 25
°
C, 40
°
C, and 55
°
C
(nominal input voltage).
0
2
4
6
8
10
12
14
16
18
0.0 0.8 1.7 2.5 3.3 4.2 5.0 5.8 6.7 7.5 8.3
Load Current (A)
Power Dissipation (W)
18Vin
24Vin
36Vin
Figure 3: Power dissipation at nominal output voltage vs. load current
for minimum, nominal, and maximum input voltage at 25
°
C.
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
0 100 200 300 400 500
Air Flow (LFM)
Power Dissipation (W)
25 C
40 C
55 C
Figure 4: Power dissipation at nominal output voltage and 60% rated
power vs. airflow rate for ambient air temperatures of 25
°
C, 40
°
C, and
55
°
C (nominal input voltage).
0
1
2
3
4
5
6
7
8
0 2540557085
Ambient Air Temperature (oC)
Iout (A)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
0 LFM (0 m/s)
Figure 5: Maximum output power derating curves vs. ambient air tem-
perature for airflow rates of 0 LFM through 400 LFM with air flowing
from input to output (nominal input voltage).
Figure 6: Thermal plot of converter at 5.7 amp load current with 55
°
C
air flowing at the rate of 200 LFM. Air is flowing across the converter
from input to output (nominal input voltage).
Vin = 24V
Semiconductor junction temperature is
within 1
°
C of surface temperature
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 5
Performance Curves
24Vin 12Vout 8.3A
0
1
2
3
4
5
6
7
8
0 2540557085
Ambient Air Temperature (oC)
Iout (A)
400 LFM (2.0 m/s)
300 LFM (1.5 m/s)
200 LFM (1.0 m/s)
100 LFM (0.5 m/s)
0 LFM (0 m/s)
Quarter
Quarter
Brick
Brick
Figure 7: Maximum output power derating curves vs. ambient air tem-
perature for airflow rates of 0 LFM through 400 LFM with air flowing
from pin 1 to pin 3 (nominal input voltage).
Figure 8: Thermal plot of converter at 5.5 amp load current with 55
°
C
air flowing at the rate of 200 LFM. Air is flowing across the converter
from pin 1 to pin 3 (nominal input voltage).
Figure 9: Turn-on transient at full load (resistive load) (2 ms/div).
Ch1: Vout (5V/div)
Ch2: ON/OFF input (5V/div)
Figure 10: Turn-on transient at zero load (2 ms/div).
Ch1: Vout (5V/div)
Ch2: ON/OFF input (5V/div)
Figure 11: Output voltage response to step-change in load current (50%-75%-50%
of Iout(max); dI/dt = 0.1A/
µ
s). Load cap: 10
µ
F, 100 m
Ω
ESR tantalum capacitor and
1
µ
F ceramic capacitor. Ch1: Vout (500mV/div), Ch2: Iout (5A/div).
Figure 12:Output voltage response to step-change in load current (50%-75%-
50% of Iout(max): dI/dt = 5A/
µ
s). Load cap: 470
µ
F, 30 m
Ω
ESR tantalum capaci-
tor and 1
µ
F ceramic capacitor. Ch1: Vout (500mV/div), Ch2: Iout (5A/div).
Vin = 24V
Semiconductor junction temperature is
within 1
°
C of surface temperature
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 6
Performance Curves
24Vin 12Vout 8.3A
Quarter
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Figure 14: Input Terminal Ripple Current, ic, at full rated output cur-
rent and nominal input voltage with 3.3
µ
H source impedance and
100
µ
F electrolytic capacitor (500 mA/div). See Figure 13.
Figure 15: Input reflected ripple current, is, through a 3.3
µ
H source
inductor at nominal input voltage and rated load current (20 mA/div).
See Figure 13.
Figure 16: Output voltage ripple at nominal input voltage and rated
load current (50 mV/div). Load capacitance: 1
µ
F ceramic capacitor
and 10
µ
F tantalum capacitor. Bandwidth: 20 MHz. See Figure 13.
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 17: Output voltage vs. load current showing typical current limit
curves and converter shutdown points.
Figure 18: Load current (10A/div) as a function of time when the con-
verter attempts to turn on into a 10 m
Ω
short circuit. Top trace
(2.5ms/div) is an expansion of the on-time portion of the bottom trace.
3.3
µ
H
source
impedance
DC/DC
Converter
Figure 15
Figure 14
Figure 16
1
µ
F
ceramic
capacitor
10
µ
F,
100m
Ω
ESR
tantalum
capacitor
100
µ
F,
≅0.33
Ω
ESR
electrolytic
capacitor
VSOURCE
iSiCVOUT
To be provided in future revision
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 7
Performance Curves
24Vin 12Vout 8.3A
0.01
0.1
1
10
10 100 1,000 10,000 100,000
Hz
Output Impedance (
ΩΩ
)
18 Vin
24 Vin
36 Vin
Figure 19: Magnitude of incremental output impedance (Zout =
vout/iout) for minimum, nominal, and maximum input voltage at full
rated power.
-80
-70
-60
-50
-40
-30
-20
-10
0
10 100 1,000 10,000 100,000
Hz
Forward Transmission (dB)
18 Vin
24 Vin
36 Vin
Figure 20: Magnitude of incremental forward transmission (FT =
vout/vin) for minimum, nominal, and maximum input voltage at full
rated power.
-40
-30
-20
-10
0
10
20
10 100 1,000 10,000 100,000
Hz
Reverse Transmission (dB)
18 Vin
24 Vin
36 Vin
Figure 21: Magnitude of incremental reverse transmission (RT =
iin/iout) for minimum, nominal, and maximum input voltage at full rated
power.
0.1
1
10
100
10 100 1,000 10,000 100,000
Hz
Input Impedance (
ΩΩ
)
18 Vin
24 Vin
36 Vin
Figure 22: Magnitude of incremental input impedance (Zin = vin/iin)
for minimum, nominal, and maximum input
voltage at full rated power.
Quarter
Quarter
Brick
Brick
BASIC OPERATION AND
FEATURES
The
Power
Qor series converter uses a two-stage power cir-
cuit 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 step-
down 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
Power
Qor 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
Power
Qor converter requires no heatsink to deliver
a greater level of power than can be delivered by a con-
ventional, 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 semicon-
ductor junction temperature and the hottest PCB temperature
within the
Power
Qor 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
Power
Qor converter
does not need a metal baseplate or potting material to help
conduct the dissipated energy to the heatsink. The
Power
Qor 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
Power
Qor 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
Power
Qor convert-
er is more efficient and therefore it dissipates less than half
the energy. Additionally, because the
Power
Qor 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
the converter. Because the
Power
Qor 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
Power
Qor converter is more reliable than conventional
dc/dc converters.
The
Power
Qor 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
Power
Qor 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 dif-
ferent 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 volt-
age 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 cir-
cuit condition. (see
Figure 18
)
• 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 con-
dition, 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
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 8
Technical Specification
24Vin 12Vout 8.3A
Quarter
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referenced to the return terminal of the 24V input bus. There
are two versions of the
Power
Qor series converter that differ
by the sense of the logic used for the ON/OFF input. In the
PQxxyyyQGAzzPxx version, the ON/OFF input is active
high (meaning that a high turns the converter
on
). In the
PQxxyyyQGAzzNxx 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.
Figure B
shows detail of the internal ON/OFF circuitry.
Pins 7 and 5 (SENSE(+)): The SENSE(+) inputs correct
for voltage drops along the conductors that connect the con-
verter’s output pins to the load.
Pin 7 should be connected to Vout(+) and Pin 5 should be
connected to Vout(-) at the point on the board where regu-
lation 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 nor-
mal operating conditions—the converter will simply deliver
an output voltage that is slightly higher than its specified
value.
Note: the output over-voltage protection circuit senses the
voltage across the output (pins 8 and 4) to determine when
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.
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
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 9
Technical Specification
24Vin 12Vout 8.3A
Quarter
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Rtrim-down =
(
511
)
- 10.22
∆%
(k
Ω)
∆=
(
VNOM – VDES
)
x100%
VNOM
where
VNOM = Nominal Voltage
VDES = Desired Voltage
and
Open Collector Enable Circuit
Figure A: Various circuits for driving the ON/OFF pin.
Remote Enable Circuit
Direct Logic Drive
Negative Logic
(Permanently Enabled) Positive Logic
(Permanently Enabled)
ON/OFF
Vin(_)
ON/OFF
ON/OFF
Vin(_)
ON/OFF
5V
TTL/
CMOS
Vin(_)
ON/OFF
Vin(_)
Vin(_)
Figure B: Internal ON/OFF pin circuitry (detail)
TTL
5V
50k
100k
Vin(+)
ON/OFF
Vin(_)
50k 100pF
Figure C
graphs this relationship between Rtrim-down and ∆.
The output voltage can be trimmed down as much as 20%.
Figure C: Trim Down Graph for 12.0Vout
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
Figure D
graphs this relationship between Rtrim-up and ∆.
The output voltage can be trimmed up as much as 10%.
Figure D: Trim Up Graph for 12.0Vout
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 over-
voltage protection circuit to trip, particularly during tran-
sients.
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%
PROTECTION FEATURES
Input Under-Voltage Lockout: The converter is
designed to turn off when the input voltage is too low, help-
ing 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 16V before the converter will turn
on. Once the converter is on, the input voltage must fall
below a typical value of 14.5V before the converter will turn
off.
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 pre-
vents excessive heating of the converter or the load board.
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.
Thermal Shutdown: The
Power
Qor series has a temper-
ature sensor located such that it senses the average temper-
ature of the converter. The thermal shutdown circuit is
designed to turn the converter off when the temperature at
the sensed location reaches 125°C. It will allow the con-
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 10
Technical Specification
24Vin 12Vout 8.3A
Quarter
Quarter
Brick
Brick
10
100
1,000
10,000
0 2 4 6 8 10 12 14 16 18 20
% Decrease in Output Voltage
Trim Resistance (kOhms)
100
1,000
10,000
100,000
012345678910
% Increase in Output Voltage
Trim Resistance (kOhms)
Rtrim-up
(k
Ω)
)
where
VOUT = Nominal Output Voltage
= (
_511 _10.22
5.11VOUT(100+
∆%)
1.225∆%∆%
verter to turn on again when the temperature of the sensed
location falls below 115°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 solu-
tion for correcting it.
Application Circuits:
Figure E
below provides a typical
circuit diagram which is useful when using input filtering
and voltage trimming.
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 11
Technical Specification
24Vin 12Vout 8.3A
Quarter
Quarter
Brick
Brick
18V < Vin < 36V
Input Filtering
Trim
3.3µH Vin(+)
Iload
Cload
Vout(+)
Rtrim-up
or
Rtrim-down
Vsense(+)
ON/OFF
Vin(_)Vout(_)
Vsense(_)
Electrolytic
Capacitor
100µF
ESR
≅
0.33
Ω
Figure E: Typical application circuit (negative logic unit, permanently enabled).
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 over-
heating. 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 Quarter-
brick)
• Output Over-Voltage Protection
• Over Temperature Shutdown
• Current Limit
• Short Circuit Protection
• Turned off by the ON/OFF input
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 16V (typ.),
the unit is disabled by the Input Under-Voltage Lockout fea-
ture. When the input voltage rises above 16V, 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.
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."
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 12
Technical Specification
24Vin 12Vout 8.3A
Quarter
Quarter
Brick
Brick
Under-Voltage
Lockout Turn-On
Threshold
ON/OFF
(pos logic)
Figure F: Startup Inhibit Period (turn-on time not to scale)
Vout
Vin
200ms 200ms
200ms
(typical start-up
inhibit period)
t0t1t2
t
4ms (typical
turn on time)
ON ON ONOFF OFF
PART NUMBERING SYSTEM
The part numbering system for SynQor’s
Power
Qor DC/DC
converters follows the format shown in the example below.
The first 12 characters comprise the base part number and
the last 3 characters indicate available options. 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 avail-
able in stock for evaluation and prototype quantities.
ORDERING INFORMATION
The tables below show the valid model numbers and order-
ing options for converters in this product family. When
ordering SynQor converters, please ensure that you use the
complete 15 character part number consisting of the 12
character base part number and the additional 3 characters
for options.
The following option choices must be included in place of
the
x y z
spaces in the model numbers listed above.
Product # PQ24120QGA08 Phone 1-888-567-9596 Doc.# 005-2QG212D_A 3/1/02 Page 13
Technical Specification
24Vin 12Vout 8.3A
Quarter
Quarter
Brick
Brick
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.
Contact SynQor for further information:
Phone: 508-485-8434
Toll Free: 888-567-9596
Fax: 508-485-8414
E-mail: sales@synqor.com
Web: www.synqor.com
Address: 188 Central Street
Hudson, MA 01749
Application Notes Available
• Current Sharing for Full Feature Modules
• EMI Characteristics
• Thermal Relief Vias
• Input System Instability
All application notes and technical white papers can
be downloaded in pdf format at www.synqor.com.
Output Max Output Full Load
Voltage Current Efficiency
PQ24018QGA25xyz 18 - 36 V 1.8 V 25 A 84%
PQ24033QGA25xyz 18 - 36 V 3.3 V 25 A 87%
PQ24050QGA20xyz 18 - 36 V 5.0 V 20 A 87%
PQ24120QGA08xyz 18 - 36 V 12 V 8.3 A 88%
PQ24150QGA07xyz 18 - 36 V 15 V 6.7 A 87%
Model Number
Input Voltage
PQ 48 033 H T A 50 N K S
Product Family
Package Size
Performance Level
Thermal Design
Output Current
Options (see
Ordering Information)
Input Voltage
Output Voltage
Enable Pin Feature
Logic Length Set
P - Positive
N - Negative
K - 0.110"
N - 0.145"
R - 0.180"
Y - 0.250"
S - Standard
Options Description: x y z
