DELTA D12S2R550A

FEATURES

High Efficiency: 93.6% @ 12Vin, 5.0V/50A
out

Wide input range: 4.5V~13.8V

Output voltage programmable from 0.6Vdc
to 5.0Vdc via external resistors

No minimum load required

Fixed frequency operation

Input UVLO, output SCP, OVP.

Remote On/Off (Positive logic)

Power Good Function

RoHS 6

ISO 9001, TL 9000, ISO 14001, QS9000,
OHSAS18001 certified manufacturing facility
Delphi D12S2R550 Non-Isolated Point of Load
DC/DC Modules: 4.5V~13.8Vin, 0.6V~5.0Vout, 50A
The D12S2R550, 4.5~13.8V wide input, single output, non-isolated
point of load DC/DC converter is the latest offering from a world leader
in power systems technology and manufacturing -- Delta Electronics,
Inc. The D12S2R550 and ND/NE product families are part of the
second generation, non-isolated point-of-load DC/DC power modules
which cut the module size by almost 50% in most of the cases
compared to the first generation NC series POL modules for networking
and data communication applications. D12S2R550 product provides up
to 50A output current and the output can be resistor trimmed from
0.6Vdc to 5.0Vdc. It provides a highly efficient, high power and current
density and very cost effective point of load solution. With creative
APPLICATIONS
design technology and optimization of component placement, these

Telecom / DataCom
converters possess outstanding electrical and thermal performance, as

Distributed power architectures
well as extremely high reliability under highly stressful operating

Servers and workstations
conditions.

LAN / WAN applications

Data processing applications
DATASHEET
DS_D12S2R550_10182013
TECHNICAL SPECIFICATIONS
(Ambient Temperature=25°C, nominal Vin=12Vdc unless otherwise specified.)
PARAMETER
NOTES and CONDITIONS
D12S2R550
Min.
Typ.
Max.
Units
-0.3
0
-40
13.8
70
125
Vdc
°C
°C
4.5
13.8
V
22.8
400
20
10
Vdc
Vdc
A
mA
mA
V/mS
ABSOLUTE MAXIMUM RATINGS
Input Voltage
Operating Temperature
Storage Temperature
INPUT CHARACTERISTICS
Operating Input Voltage
Input Under-Voltage Lockout
Turn-On Voltage Threshold
Turn-Off Voltage Threshold
Maximum Input Current
No-Load Input Current
Off Converter Input Current
Input voltage slew rate
OUTPUT CHARACTERISTICS
Output Voltage Adjustment Range
Output Voltage Set Point
Output Voltage Regulation
Over Load
Over Line
Total output range
Output Voltage Ripple and Noise
Peak-to-Peak
4.3
4.0
Vin=12V, Vo=5V, Io=50A
Vin=12V, Vo=5V, Io=0A
Remote OFF
dV/dt
Refer to Fig.25 for the relations between
input and output voltage
With a 0.1% trim resistor
Vo≦1.2Vdc
Vo>1.2Vdc
Vin=Vin_min to Vin_max
Over load, line, temperature regulation
and set point
5Hz to 20MHz bandwidth
Full Load, 10uF Tan cap, total input &
output range
Output Current Range
Vin=12V, Turn OFF
Output short-circuit current, RMS value
Over Current Protection
Over Voltage Protection
DYNAMIC CHARACTERISTICS
12Vin, 5Vout
Hiccup mode
Non-latching shutdown
Output Dynamic Load Response
Settling Time
Turn-On Transient
Rise Time
Turn on Delay (power)
Turn on Delay (Remote on/off)
Turn on Transient (overshoot)
Turn off Transient (undershoot)
Maximum Output Capacitance
EFFICIENCY
Vo=0.6V
Vo=1.1V
Vo=1.2V
Vo=1.5V
Vo=1.8V
Vo=2.5V
Vo=3.3V
Vo=5.0V
FEATURE CHARACTERISTICS
Switching Frequency
ON/OFF Control
Logic High
Logic Low
Remote Sense Range
Power Good
Power Good Delay
Output to Power Good Delay Time
GENERAL SPECIFICATIONS
Calculated MTBF
Weight
0.6
5.0
Vdc
-1.0
+1.0
%Vo
-20
-1.5
-0.5
+20
+1.5
+0.5
mV
%Vo
%Vo
-3.0
+3.0
%Vo
50
mV
20
0
Output Voltage Under-shoot at Power-Off
Transient Response
300
17
A
100
mV
10
70
120
25% step load, Slew rate=10A/uS,
0.6V~1.8V output
25% step load, Slew rate=10A/uS, 2.5V~
5.0V output
12Vin, 2.5Vout, 1µF ceramic and 10µF
Tan cap
Settling to be within regulation band (to
10% Vo deviation)
From 10% to 90% of Vo
Vin=12V, Io=min-max. (Wthin 10% of Vo)
Vin=12V, Io=min-max. (Wthin 10% of Vo)
ESR ≥ 10mΩ
ESR < 10mΩ
50
A
A
%
120
150
mVpk
130
160
mVpk
20
50
µs
2
2
2
0.5%
5
5
5
mS
mS
mS
Vo
mV
µF
µF
100
20000
5000
0
0
Vin=12V, Io=50A
Vin=12V, Io=50A
Vin=12V, Io=50A
Vin=12V, Io=50A
Vin=12V, Io=50A
Vin=12V, Io=50A
Vin=12V, Io=50A
Vin=12V, Io=50A
79.0
85.0
86.5
87.3
88.9
90.7
93.1
93.6
%
%
%
%
%
%
%
%
Fixed, per phase
Positive logic (internally pulled high)
Module On (or leave the pin open)
Module Off
500
KHz
1.2
0
Vo is out off +/-10% Vo,set
Vo is within +/-10% Vo,set
0
4.0
0.2
25℃, 300LFM, 80% load
1
14
Vinmax
0.6
0.5
0.4
5.1
2
1
V
V
V
V
V
mS
mS
Mhours
grams
DS_D12S2R550_10182013
2
ELECTRICAL CHARACTERISTICS CURVES
Figure 1: Converter efficiency vs. output current
(1.1V output voltage, 5V&12V input)
Figure 2: Converter efficiency vs. output current
(1.2V output voltage, 5V&12V input)
Figure 3: Converter efficiency vs. output current
(2.5V output voltage, 5V&12V input)
Figure 4: Converter efficiency vs. output current
(5V output voltage, 9V&12V input)
Figure 5: Output ripple & noise at 12Vin, 1.1V/50A out (10mv/div,
2uS/div)
Figure 6: Output ripple & noise at 12Vin, 1.2V/50A out (10mv/div,
2uS/div)
DS_D12S2R550_10182013
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ELECTRICAL CHARACTERISTICS CURVES (CONTINUED)
Figure 7: Output ripple & noise at 12Vin, 1.8V/50A out
(10mv/div, 2uS/div)
Figure 8: Output ripple & noise at 12Vin, 2.5V/50A out (10mv/div,
2uS/div)
Figure 9: Output ripple & noise at 12Vin, 3.3V/50A out (10mv/div,
2uS/div)
Figure 10: Output ripple & noise at 12Vin, 5.0V/50A out (10mv/div,
2uS/div)
Figure 11: Turn on delay time at 12Vin, 1.1V/50A out (1mS/div)
Top trace: Enable, middle trace: PG, bottom trace: Vo
Figure 12: Turn on delay time at 12Vin, 1.2V/50A out (1mS/div)
Top trace: Enable, middle trace: PG, bottom trace: Vo
DS_D12S2R550_10182013
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ELECTRICAL CHARACTERISTICS CURVES (CONTINUED)
Figure 13: Turn on delay time at 12Vin, 1.8V/50A out (1mS/div)
Top trace: Enable, middle trace: PG, bottom trace: Vo
Figure 14: Turn on delay time at 12Vin, 2.5V/50A out (1mS/div)
Top trace: Enable, middle trace: PG, bottom trace: Vo
Figure 15: Turn on delay time at 12Vin, 3.3V/50A out (1mS/div)
Top trace: Enable, middle trace: PG, bottom trace: Vo
Figure 16: Turn on delay time at 12Vin, 5.0V/50A out (1mS/div)
Top trace: Enable, middle trace: PG, bottom trace: Vo
Figure 17: Transient Response at 12Vin, 1.1V/50A out (200uS/div)
Top trace: Vo(50mV/div),Io from 25A to 37.5A
Figure 18: Transient Response at 5Vin, 1.2V/50A out (200uS/div)
Top trace: Vo(50mV/div),Io from 25A to 37.5A
DS_D12S2R550_10182013
5
ELECTRICAL CHARACTERISTICS CURVES (CONTINUED)
Figure 19: Short Circuit Protection at 12Vin, 1.1V out (40mS/div),
Top trace: Vo(10mV/div), bottom trace: Io(50A/div)
Figure 20: Short Circuit Protection at 12Vin, 1.2V out (40mS/div),
Top trace: Vo(10mV/div), bottom trace: Io(50A/div)
Figure 21: Short Circuit Protection at 12Vin, 1.8V out (40mS/div),
Top trace: Vo(10mV/div), bottom trace: Io(50A/div)
Figure 22: Short Circuit Protection at 12Vin, 2.5V out (40mS/div),
Top trace: Vo(10mV/div), bottom trace: Io(50A/div)
Figure 23: Short Circuit Protection at 12Vin, 3.3V out(40mS/div),
Top trace: Vo(10mV/div), bottom trace: Io(50A/div)
Figure 24: Short Circuit Protection at 12Vin, 5.0V out (40mS/div),
Top trace: Vo(10mV/div), bottom trace: Io(50A/div)
DS_D12S2R550_10182013
6
DESIGN CONSIDERATIONS
FEATURES DESCRIPTIONS
The D12S2R550 uses a two phase and voltage mode
controlled buck topology. The output can be trimmed in the
range of 0.6Vdc to 5.0Vdc by a resistor from Trim pin to
Ground.
Enable (On/Off)
The converter can be turned ON/OFF by remote control.
Positive on/off (ENABLE pin) logic implies that the converter
DC output is enabled when the signal is driven high (greater
than 1.2V) or floating and disabled when the signal is driven
low (below 0.6V).
The ENABLE (on/off) input allows external circuitry to put the
D12S2R550 converter into a low power dissipation (sleep) mode.
Positive ENABLE is available as standard.
Positive ENABLE units of the D12S2R550 series are turned on if
the ENABLE pin is high or floating. Pulling the pin low will turn off
the unit. With the active high function, the output is guaranteed to
turn on if the ENABLE pin is driven above 1.2V. The output will
turn off if the ENABLE pin voltage is pulled below 0.6V.
The converter provides an open collector Power Good signal.
The power good signal is pulled low when output is not within
±10% of Vout or Enable is OFF.
Input Under-Voltage Lockout
For output voltages above 1.8V, please refer to Figure 29
below for minimum input voltage requirement for proper
module operations.
The input under-voltage lockout prevents the converter from
being damaged while operating when the input voltage is too
low. The under-voltage lockout is adjustable by adding a resistor
(Figure 30) between Enable pin and ground pin per the following
equation:
The converter can protect itself by entering hiccup mode
against over current and short circuit condition.
Re n( K) 
315
14Ven  3.8
Default lockout range is between 4.3V and 4.0V.
Safety Considerations
Unit
It is recommended that the user to provide a fuse in the input
line for safety. The output voltage set-point and the output
current in the application could define the amperage rating of
the fuse.
Vin
Vout
Enable
Trim(+)
GND
GND
Ren
5.5
Vo=5V
5.0
OUTPUT VOLTAGE(V)
4.5
Figure 26: Enable input drive circuit example.
4.0
3.5
Vo=3. 3V
3.0
Vo=2. 5V
2.5
Reflected Ripple Current and Output Ripple and Noise
Measurement
Vo=1. 8V
2.0
1.5
The measurement set-up outlined in Figure 31 has been used for
both input reflected/ terminal ripple current and output voltage
ripple and noise measurements on D12S2R550 converters.
Vo=0. 6V
1.0
0.5
0.0
3.5
4.5
5.5
6.5
7.5
8.5
9.5
10.5
11.5
12.5
13.5
14.5
Input reflected current measurement point
INPUT VOLTAGE(V)
Ltest
Figure 25: minimum input voltage required for output
voltages above 1.8V
DC-DC Converter
Vin+
Cs
Cin
Load
1uF
Ceramic
10uF
Tan
Output voltage ripple noise measurement point
Cs=330μF OS-con cap x1, Ltest=1μH, Cin=330μF OS-con cap x1
Figure 27: Input reflected ripple/ capacitor ripple current and
output voltage ripple and noise measurement setup for
D12S2R550
DS_D12S2R550_10182013
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FEATURES DESCRIPTIONS (CON.)
Over-Current and Short-Circuit Protection
The D12S2R550 modules have non-latching over-current and
short-circuit protection circuitry. When over current condition
occurs, the module goes into the non-latching hiccup mode.
When the over-current condition is removed, the module will
resume normal operation.
Output Voltage Programming
The output voltage of the D12S2R550 is trimmable by
connecting an external resistor between the trim pin and output
ground as shown Figure 33 and the typical trim resistor values
are shown in Table 1.
Unit
An over current condition is detected by measuring the voltage
drop across the inductor. The voltage drop across the inductor is
also a function of the inductor’s DCR.
Vin
Vout
Enable
Trim(+)
Note that none of the module specifications are guaranteed
when the unit is operated in an over-current condition.
GND
GND
Output Over Voltage Protection (OVP)
The converter will shut down when an output over voltage
protection is detected. Once the OVP condition is detected,
controller will stop all PWM outputs and turn on low-side
MOSFET to prevent any damage to load.
Remote Sense
The D12S2R550 provide Vo remote sensing to achieve proper
regulation at the load points and reduce effects of distribution
losses on output line. In the event of an open remote sense line,
the module shall maintain local sense regulation through an
internal resistor. The module shall correct for a total of 0.5V of
loss. The remote sense connects as shown in Figure 32.
Rtrim
Figure 29: Trimming Output Voltage
The D12S2R550 module has a trim range of 0.6V to 5.0V. The
trim resistor equation for the D12S2R550 is:
Rtrim() 
1200
Vout  0.6
Vout is the output voltage setpoint
Rtrim is the resistance between Trim and Ground
Rtrim values should not be less than 270Ω
Output
Voltage
0.6V
+1.1 V
+1.2V
+1.5 V
+1.8V
+2.5 V
+3.3 V
+5.0V
Rtrim (Ω)
open
2.4K
2K
1.33K
1K
631.6
444.4
272.7
Table 1: Typical trim resistor values
Power Good
Figure 28: Circuit configuration for remote sense
Output Capacitance
There are internal output capacitors on the D12S2R550
modules. Hence, no external output capacitor is required for
stable operation.
The converter provides an open collector signal called Power
Good. This output pin uses positive logic and is open collector.
This power good output is able to sink 4mA and set high when
the output is within ±10% of output set point. The power good
signal is pulled low when output is not within
±10% of Vout or Enable is OFF.
Paralleling
D12S2R550 converters do not have built-in current sharing
(paralleling) ability. Hence, paralleling of multiple D12S2R550
converters is not recommended.
DS_D12S2R550_10182013
8
THERMAL CONSIDERATION
THERMAL CURVES
Thermal management is an important part of the system
design. To ensure proper, reliable operation, sufficient
cooling of the power module is needed over the entire
temperature range of the module. Convection cooling is
usually the dominant mode of heat transfer.
Hence, the choice of equipment to characterize the
thermal performance of the power module is a wind
tunnel.
Thermal Testing Setup
Delta’s DC/DC power modules are characterized in
heated vertical wind tunnels that simulate the thermal
environments encountered in most electronics
equipment. This type of equipment commonly uses
vertically mounted circuit cards in cabinet racks in which
the power modules are mounted.
Figure 35: Temperature measurement location* The allowed
maximum hot spot temperature is defined at 120℃
Output Current (A)
The following figure shows the wind tunnel
characterization setup. The power module is mounted
on a test PWB and is vertically positioned within the
wind tunnel. The space between the neighboring PWB
and the top of the power module is constantly kept at
6.35mm (0.25’’).
Thermal Derating
D12S2R550A Output Current vs. Ambient Temperature and Air Velocity
@Vin=12V Vout=1.1V (Airflow From Pin1 To Pin11)
50
Natural
Convection
40
30
100LFM
200LFM
20
Heat can be removed by increasing airflow over the
module. To enhance system reliability, the power
module should always be operated below the maximum
operating temperature. If the temperature exceeds the
maximum module temperature, reliability of the unit may
be affected.
10
0
25
30
Output Current (A)
MODULE
40
45
50
55
60
65
70
Ambient Temperature (℃)
Figure 31: Output current vs. ambient temperature and air
velocity @Vin=12V, Vout=1.1V (Airflow from Pin1 to Pin11)
PWB
FANCING PWB
35
D12S2R550A Output Current vs. Ambient Temperature and Air Velocity
@Vin=5V Vout=1.2V (Airflow From Pin1 To Pin1)
50
40
Natural
Convection
30
AIR VELOCITY
AND AMBIENT
TEMPERATURE
SURED BELOW
THE MODULE
50.8(2.00")
100LFM
20
200LFM
AIR FLOW
10
0
25
Note: Wind Tunnel Test Setup Figure Dimensions are in millimeters and (Inches)
Figure 30: Wind tunnel test setup
30
35
40
45
50
55
60
65
70
Ambient Temperature (℃)
Figure 32: Output current vs. ambient temperature and air
velocity@ Vin=5V, Vout=1.2V (Airflow from Pin1 to Pin11)
DS_D12S2R550_10182013
9
MECHANICAL DRAWING
DS_D12S2R550_10182013
10
PART NUMBERING SYSTEM
D
12
S
2R5
50
A
Type of Product
Input Voltage
Product Series
Output voltage
Output current
Option Code
D - DC/DC modules
12 - 4.5 ~13.8V
S-Single
2R5-0.6~5V
50A
A
MODEL LIST
Model Name
Input Voltage
Output Voltage
Output Current
Lead Free
Efficiency, 12Vin
D12S2R550 A
4.5V~ 13.8Vdc
0.6V ~ 5.0V
50A
RoHs 6
93.6% @ 5V/50A
CONTACT: www.deltaww.com/dcdc
USA:
Telephone:
East Coast: 978-656-3993
West Coast: 510-668-5100
Fax: (978) 656 3964
Email: DCDC@delta-corp.com
Europe:
Telephone: +31-20-655-0967
Fax: +31-20-655-0999
Email: DCDC@delta-es.com
Asia & the rest of world:
Telephone: +886 3 4526107 ext.
6220~6224
Fax: +886 3 4513485
Email: DCDC@delta.com.tw
WARRANTY
Delta offers a two (2) year limited warranty. Complete warranty information is listed on our web site or is available
upon request from Delta.
Information furnished by Delta is believed to be accurate and reliable. However, no responsibility is assumed by
Delta 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 Delta. Delta reserves the right
to revise these specifications at any time, without notice .
DS_D12S2R550_10182013
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