QKS48T21120 DC-DC Bus Converter Data Sheet
Quarter-Brick with 48VDC Input; 12VDC @ 21A Output
Benefits
•
Simplifies power system design; reduces design
time and technical risk
•
Compatible with all (12 Vin nom.) POLs available in
the market
Features
•
RoHS lead free solder and lead solder exempted
products are available
•
Loosely regulated output
•
High output power of 252 W
•
Efficiency to 94%
•
Wide-input voltage range from 36 to 75 VDC
•
100V/100ms input voltage surge withstand
•
Input-to-output isolation: 1500 VDC
•
Basic insulation
•
Backdrive protection
•
Start-up into pre-biased load
•
Output overcurrent protection
•
Output overvoltage protection
•
Overtemperature protection
•
Remote on/off (primary referenced), positive or
negative logic option
•
Designed to comply with NEBS GR-1089 and GR-63
•
Safety: UL60950-1, CSA C22.2 No. 60950-1,TUV
EN60950-1, IEC60950-1
Applications
•
Power systems utilizing Intermediate Bus
Architecture
•
Networking equipment
•
Data/voice processing
•
Wireless communications
•
Computing
•
ATCA
Description
The QKS is a high density and highly efficient, isolated DC-DC converter that operates over an input voltage range
of 36 VDC to 75VDC. It provides a 12 VDC nominal, loosely-regulated output voltage at up to 21 ADC of current.
The converter is an ideal choice for building a complete power system utilizing the Intermediate Bus Architecture
(IBA). The thermally-optimized construction of the QKS allows the converter to provide high output current over a
wide operating temperature range while maintaining a safe guardband for component electrical and thermal
ratings. The QKS employs 100% surface-mount components for consistency and reliability in the production
process.
Model Selection
Model
Input
Voltage
VDC
Input
Current,
Max ADC
Output
Voltage
VDC
Output Rated
Current I
rated
ADC
Output
Ripple/Noise,
mV p-p
Typical
Eff.@ 75%
I
rated
, 40C,
48Vi
%
94
QKS48T21120
35-75
7.5
12
(NOM.)
21
120
(NOM.)
Model numbers highlighted in yellow or shaded are not recommended for new designs.
The QKS48T21120 is not recommended for new designs. Please refer to the
QME48T20120 data sheet for a similar product.
.
MCD10089 Rev. 1.1, 8-Oct-08
Page 1 of 9
www.power-one.com
QKS48T21120 DC-DC Bus Converter Data Sheet
Quarter-Brick with 48VDC Input; 12VDC @ 21A Output
Absolute Maximum Ratings
Stresses in excess of the absolute maximum ratings may cause performance degradation, adversely effect long-
term reliability, and cause permanent damage to the converter.
Parameter
Input Voltage
Operating Temperature
Storage Temperature
Conditions/Description
Continuous
Transient, 100 ms
PC Board Temperature
Min
Max
75
100
100
125
Units
VDC
VDC
°C
°C
-40
-40
Environmental and Mechanical Specifications
All specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted.
Parameter
Operating Humidity
Storage Humidity
Shock
Sinusoidal Vibration
Weight
Water Washing
MTBF
Conditions/Description
Relative Humidity, Non-cond.
Relative Humidity, Non-cond.
(Half-sinewave, 6ms), 3 axes
GR-63-CORE, Section 5.4.2
Standard process
Per Bellcore TR-NWT-000332
Min
Nom
Max
95
95
Units
%
%
g
g
Oz/g
MHrs
50
1
1.2/35
Yes
1.8
Isolation Specifications
All specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted.
Parameter
Insulation Safety Rating
Isolation Voltage
Isolation Resistance
Isolation Capacitance
Conditions/Description
Input to Output
Min
1500
10
1000
Nom
Basic
Max
Units
VDC
MOhm
pF
Input Specifications
All specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted.
Parameter
Input Voltage
Input Undervoltage Lockout
Turn-on Voltage Threshold
Turn-off Voltage Threshold
Hysteresis
Power up Turn-on delay time
(Time from V
IN
@ UVLO to Vo @
10% of Vo nominal)
Enable Turn-on delay time
(Time from V
enable
@ 0.8V to Vo
@ 10% of Vo nominal)
Conditions/Description
Continuous
Vin
Min
36
33.5
32
1.5
0.5
0.5
Nom
48
34.5
33
Max
75
35.5
34
30
11
Units
VDC
V
All
All
ms
ms
MCD10089 Rev. 1.1, 8-Oct-08
Page 2 of 9
www.power-one.com
QKS48T21120 DC-DC Bus Converter Data Sheet
Quarter-Brick with 48VDC Input; 12VDC @ 21A Output
Parameter
Output Rise Time at Turn-on
(Time from Vo @ 10% Vo
nominal to Vo @ 90% of Vo
nominal)
w/ Load = resistor + 330 µF
capacitor
Turn-on Output Overshoot
Input Reflected Ripple Current
Conditions/Description
Min
Nom
Max
Units
All
0.5
30
ms
Vo
Full Load, 12μH source inductance
2
13.2
200
-
-
2
VDC
mA p-p
Inrush Transient
it
A
2
s
Output Specifications
All specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted.
Parameter
Output Voltage Set Point
(Vin = 48V, Iout = ½ full load, 25°C)
Output Current
Output Ripple
(DC to 20MHz, 25°C)
Output Line regulation
(Vi=36V to 75V, Iout = full load, 25°C)
Output Load regulation
(lout from 0 to full load)
Output Temperature Regulation:
(Tcase =-40°C to +110°C)
Transient Response
(50% to 75% Load Step, Io/
Δ
t=1A/µs,
with 220µF, ESR<0.07ohm on output
side)
Peak Deviation
Settling Time (Vo, 1% of Vo)
Admissible Load Capacitance
Output Current Limit Threshold*
Switching Frequency
Overvoltage Protection,
Hiccup, auto recovery
Over all input voltage and load
conditions
14
Vo
I
rated
, Nom Vin
Io
11
-
330
110
135
350
15
-
13
10
5000
150
V
ms
μF
%I
rated
kHz
VDC
Conditions/Description
Vo
Io
Vo
Vo
Vo
Vo
Min
11
0
25
3
500
± 0.03
Nom
11.5
Max
13
21
70
8
Units
VDC
A
mVp-p
mV
mV
%/°C
* Overcurrent protection is non-latching with auto recovery.
MCD10089 Rev. 1.1, 8-Oct-08
Page 3 of 9
www.power-one.com
QKS48T21120 DC-DC Bus Converter Data Sheet
Quarter-Brick with 48VDC Input; 12VDC @ 21A Output
Feature Specifications
All specifications apply over specified input voltage, output load, and temperature range, unless otherwise noted.
Parameter
Remote On/Off, Primary Side
Positive Logic
Off – State Voltage
On – State Voltage
Negative Logic (-N option)
Off – State Voltage
On – State Voltage
Open Circuit Voltage (internal pull up
circuit at On/Off pin)
Sink Current-Logic Low
Thermal Shutdown
(PCB temperature)
Hysteresis (Latching Optional)
Min
-0.5
2.5
2.5
-0.5
Nom
Max
0.3
40
40
0.3
Units
VDC
VDC
VDC
VDC
VDC
mA
°C
5
0.50
+129
20
+137
* Overtemperature protection is auto recovery via hysteresis loop. Optionally, latched overtemperature protection can specified by adding “S1”
in the special options field of the part number (see page 9).
MCD10089 Rev. 1.1, 8-Oct-08
Page 4 of 9
www.power-one.com
QKS48T21120 DC-DC Bus Converter Data Sheet
Quarter-Brick with 48VDC Input; 12VDC @ 21A Output
Efficiency Curve
Shutdown Feature Description
The ON/OFF pin in the QKS48T21120 converter
functions as a normal soft shutdown. It is referenced
to the –Vin pin (see Figure 2). With the positive
logic, when the ON/OFF pin is pulled low, the output
is turned off and the unit goes into a very low input
power mode.
With negative logic, when the ON/OFF pin is pulled
low, the unit is turned on.
An open collector switch is recommended to control
the voltage between the ON/OFF pin and the -Vin
pin of the converter. The ON/OFF pin is pulled up
internally, so no external voltage source is required.
The user should avoid connecting a resistor between
the ON/OFF pin and the +Vin pin.
Figure 1. QKS48T21120 Efficiency vs. Output Load
Typical Application
Figure 2 shows the recommended connections for
the QKS48T21120 converter.
Fuse
+Vi
+Vo
When the ON/OFF pin is used to achieve remote
control, the user must take care to insure that the pin
reference for the control is really the -Vin pin. The
control signal must not be referenced ahead of EMI
filtering, or remotely from the unit. Optically coupling
the information and locating the optical coupler
directly at the module will solve any of these
problems.
Note:
If the ON/OFF pin is not used, it can be left floating (positive logic),
or connected to the -Vin pin (negative logic).
C1
On/Off
C3
-Vi
-Vo
Figure 2. Typical Application of QKS48T21120
The QKS48T21120 converter does not require any
external components for proper operation. However,
a 100 µF low ESR input capacitor and a 330 µF
output capacitor are recommended for optimal
performance
Refer to the “Inrush Current Control Application
Note” on www.power-one.com for suggestions on
how to limit the magnitude of the inrush current.
MCD10089 Rev. 1.1, 8-Oct-08
Page 5 of 9
www.power-one.com
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