DCM™ DC-DC Converter
DCM3623x50M13C2y7z
Isolated, Regulated DC Converter
Features & Benefits
Product Ratings
• Isolated, regulated DC-DC converter
• Up to 320W, 26.67A continuous
• 92.9% peak efficiency
VIN = 16 – 50V
POUT = 320W
VOUT = 12.0V
(7.2 – 13.2V Trim)
IOUT = 26.67A
• 823W/in3 power density
• Wide input range 16 – 50VDC
Product Description
• Safety Extra Low Voltage (SELV) 12.0V nominal output
The DCM Isolated, Regulated DC Converter is a DC-DC converter,
operating from an unregulated, wide‑range input to generate an
isolated 12.0VDC output. With its high‑frequency zero‑voltage
switching (ZVS) topology, the DCM converter consistently
delivers high efficiency across the input line range. Modular DCM
converters and downstream DC-DC products support efficient
power distribution, providing superior power system performance
and connectivity from a variety of unregulated power sources to
the point-of-load.
• 2250VDC isolation
• ZVS high-frequency switching
Enables low-profile, high-density filtering
• Fully operational current limit
• OV, OC, UV, short circuit and thermal shut down
• Military standard compliance:
MIL-STD-810G
MIL-STD-202G
MIL-STD-704E/F
(DC power characteristics only)
MIL-STD-461E/F/G
(Please contact Vicor Applications Engineering)
MIL-STD-1275E
(Applicable only for 16 – 50VIN range designs;
please contact Vicor Applications Engineering)
Leveraging the thermal and density benefits of Vicor ChiP™
packaging technology, the DCM module offers flexible thermal
management options with very low top- and bottom‑side thermal
impedances. Thermally-adept ChiP-based power components
enable customers to achieve cost effective power system solutions
with previously unattainable system size, weight and efficiency
attributes, quickly and predictably.
Package Information
• Through-hole ChiP package
Typical Applications
1.524 x 0.898 x 0.284in
[38.72 x 22.80 x 7.21mm]
• Industrial
Weight: 24.0g
[0.85oz]
• Process Control
• Transportation / Heavy Equipment
• Defense / Aerospace
Note: Product images may not highlight current product markings and cosmetic features.
DCM™ DC-DC Converter
Page 1 of 24
Rev 1.5
04/2024
DCM3623x50M13C2y7z
Typical Applications
DCM
TR
EN
EMI_GND
FT
F1
CY
L1
+IN
C1
VIN
CY
Rdm
L2
+OUT
Rd
RCOUT-EXT
Cd
COUT-EXT
–OUT
–IN
CY
Load 1
Lb
C2
Non-isolated
Point-of-Load
Regulator
CY
Load 2
Typical application 1: single DCM3623x50M13C2y7z to a non-isolated regulator and direct to load
DCM
TR
EMI_GND
EN
FT
F1
VIN
CY
CY
T1
C1
+IN
+OUT
–IN
–OUT
CY
Lb
L2
RCOUT-EXT
Rd
Cd
Rdm
COUT-EXT
C2
CY
Typical application 2: single DCM3623x50M13C2y7z with common- and differential-mode input filters
DCM™ DC-DC Converter
Page 2 of 24
Rev 1.5
04/2024
C3
C4
Load
DCM3623x50M13C2y7z
Pin Configuration
TOP VIEW
1
2
+IN A
A’ +OUT
B’ –OUT
TR B
EN C
C’ +OUT
FT D
–IN E
D’ –OUT
DCM ChiP™
Pin Descriptions
Pin Number
Signal Name
A1
Type
+IN
INPUT POWER
Function
Positive input power terminal
B1
TR
INPUT
Enables and disables trim functionality; adjusts output voltage when trim active
C1
EN
INPUT
Enables and disables power supply
D1
FT
OUTPUT
E1
–IN
INPUT POWER
RETURN
Negative input power terminal
A’2, C’2
+OUT
OUTPUT POWER
Positive output power terminal
–OUT
OUTPUT POWER
RETURN
Negative output power terminal
B’2, D’2
DCM™ DC-DC Converter
Page 3 of 24
Fault monitoring
Rev 1.5
04/2024
DCM3623x50M13C2y7z
Part Ordering Information
Part Number
Temperature Grade
Option
Tray Size
323 x 136 x 16mm
24 parts per tray
DCM3623T50M13C2T70
T = –40 to 125°C
70 = Enhanced VOUT Regulation /
DCM3623T50M13C2M70
M = –55 to 125°C
Analog Control Interface Version
Storage and Handling Information
Note: For compressive loading refer to Application Note AN:036, “Recommendations for Maximum Compressive Force of Heat Sinks.”
For handling and assembly processing refer to Application Note AN:031, “Through-Hole ChiP™ Package Soldering Guidelines.”
Parameter
Comments
Storage Temperature Range
Operating Internal Temperature Range (TINT)
Peak Temperature Top Case
(Soldering) [a]
Lead Finish
Specification
T-Grade
–40 to 125°C
M-Grade
–65 to 125°C
T-Grade
–40 to 125°C
M-Grade
–55 to 125°C
For further information, please contact factory applications
135°C
Nickel
0.51 – 2.03µm
Palladium
0.02 – 0.15µm
Gold
0.003 – 0.051µm
Weight
24.0g [0.85oz]
MSL Rating
Not applicable to through-hole ChiP products
ESD Rating
[a]
N/A
Method per Human Body Model (HBM) Test ESDA / JEDEC JDS-001-2012
Class 1C
Charged Device Model (CDM) JESD22-C101E
Class 2
Product is not intended for reflow solder attach.
Safety, Reliability and Agency Approvals
Parameter
Dielectric Withstand Test
Comments
Min
Typ
Max
Unit
IN to OUT
2250
VDC
IN to CASE
2250
VDC
OUT to CASE
707
VDC
Insulation Resistance
IN to OUT, IN to CASE, OUT to CASE at 500VDC, 1 minute
10
MΩ
MTBF
MIL-HDBK-217 FN2 Parts Count 25°C Ground Benign, Stationary,
Indoors / Computer
3.39
Telcordia Issue 2, Method I Case 3, 25°C, 100% D.C., GB, GC
5.68
cURus, 60950-1 Information Technology Equipment, Component Recognition
Agency Approvals/Standards
cTÜVus, EN IEC 62368-1, UL 62368-1, CSA-C22.2 No. 62368-1
UKCA, electrical equipment (safety) regulations
CE Marked for Low Voltage Directive and RoHS Recast Directive, as applicable
DCM™ DC-DC Converter
Page 4 of 24
Rev 1.5
04/2024
MHrs
DCM3623x50M13C2y7z
Absolute Maximum Ratings
The absolute maximum ratings below are stress ratings only. Operation at or beyond these maximum ratings can cause permanent damage to the device.
Electrical specifications do not apply when operating beyond rated operating conditions.
Parameter
Comments
Min
Max
-0.5
65.0
V
-1
1
V/µs
TR to –IN
-0.3
3.5
V
EN to –IN
-0.3
3.5
V
-0.3
3.5
V
5
mA
Output Voltage (+OUT to –OUT)
-0.5
16.0
V
Dielectric Withstand (Input to Output)
2250
Input Voltage (+IN to –IN)
Input Voltage Slew Rate
FT to –IN
Basic insulation
Average Output Current
DCM™ DC-DC Converter
Page 5 of 24
VDC
35.4
Rev 1.5
04/2024
Unit
A
DCM3623x50M13C2y7z
Electrical Specifications
Specifications apply over all line, trim and load conditions, internal temperature TINT = 25°C, unless otherwise noted. Boldface specifications apply over the
temperature range of –40°C < TINT < 125°C for T-Grade and –55°C < TINT < 125°C for M-Grade.
Attribute
Symbol
Conditions / Notes
Min
Typ
Max
Unit
16
28
50
V
Power Input Specifications
Input Voltage Range
Inrush Current (Peak)
VIN
Continuous operation
IINRP
With maximum COUT-EXT, full resistive load
25.0
A
Input Capacitance (Internal)
CIN-INT
Effective value at nominal input voltage
29.7
µF
Input Capacitance (Internal) ESR
RCIN-INT
At 1MHz
0.73
mΩ
Input Inductance (External)
LIN
1
Differential mode, with no further line bypassing
µH
No-Load Specifications
Input Power – Disabled
PQ
Input Power – Enabled with No Load
PNL
Nominal line, see Figure 3
0.4
0.5
0.5
Worst case line, see Figure 3
Nominal line, see Figure 5
3.7
5.6
6.0
Worst case line, see Figure 5
W
W
Power Output Specifications
Output Voltage Set Point
Rated Output Voltage Trim Range
Output Voltage Load Regulation
Output Voltage Accuracy
Output Voltage Light-Load Regulation
VOUT-NOM
VOUT-TRIMMING
ΔVOUT-REGULATION
%VOUT-ACCURACY
ΔVOUT-LL
VIN = 28V, nominal trim, at 100% load
Trim range over temp at full load;
Specifies the low, nominal and high trim conditions
Nominal line, nominal trim, full load and ambient
temperature
Nominal line, nominal trim and:
• Load >20% of full load and ambient temperature
• Full load and over temperature
All other conditions
(does not include light‑load regulation)
The total output voltage set-point accuracy from
the calculated VOUT based on load, temp and trim;
Excludes:
• ΔVOUT-LL
• %VOUT-REGULATION
0 – 20% load, additional VOUT, relative to VOUT
accuracy; see Design Guidelines section
11.94
12.0
12.06
V
7.2
12.0
13.2
V
-0.5
0.5
-1.0
1.0
-2.0
2.0
-3.0
3.0
%
0.00
3.12
V
%
Rated Output Power
POUT
Continuous, VOUT ≥ 12.0V
320
W
Rated Output Current
IOUT
Continuous, VOUT ≤ 12.0V
26.67
A
Output Current Limit
IOUT-LIM
Of rated IOUT max. Fully operational current limit, for
nominal trim and below.
Current Limit Delay
tIOUT-LIM
The module will power limit in a fast transient event.
Efficiency
Output Voltage Ripple
DCM™ DC-DC Converter
Page 6 of 24
η
VOUT-PP
100
1
Full load, nominal line, nominal trim
91.8
Full load, over line and temperature, nominal trim
90.1
50% load, over rated line, temperature and trim
87.8
20MHz bandwidth. At nominal trim,
minimum COUT-EXT and at least 20% rated load
Rev 1.5
04/2024
115
132
%
ms
92.9
%
636
mV
DCM3623x50M13C2y7z
Electrical Specifications (Cont.)
Specifications apply over all line, trim and load conditions, internal temperature TINT = 25°C, unless otherwise noted. Boldface specifications apply over the
temperature range of –40°C < TINT < 125°C for T-Grade and –55°C < TINT < 125°C for M-Grade.
Attribute
Symbol
Conditions / Notes
Min
Typ
Max
Unit
Power Output Specifications (Cont.)
Output Capacitance (Internal)
COUT-INT
Effective value at nominal output voltage
Output Capacitance ESR (Internal)
RCOUT-INT
At 1MHz
COUT-EXT
Output Capacitance (External)
COUT-EXT-TRANS
COUT-EXT-TRANS-TRIM
Output Capacitance ESR (External)
Initialization Delay
RCOUT-EXT
For load transients that remain >20% rated load;
excludes component temperature coefficient
For load transients down to 0% rated load,
with static trim; excludes component
temperature coefficient
For load transients down to 0% rated load,
with dynamic trimming; excludes component
temperature coefficient
At 10kHz, excludes component tolerances
135
µF
0.080
mΩ
1000
10000
µF
4000
10000
µF
10000
10000
µF
10
mΩ
tINIT
See state diagram
25
Output Turn-On Delay
tON
From rising edge EN, with VIN pre-applied;
see timing diagram
200
Output Turn-Off Delay
tOFF
From falling edge EN; see timing diagram
Soft-Start Ramp Time
tSS
At full rated resistive load with minimum COUT-EXT
Output Voltage Threshold
for Max Rated Load Current
VOUT-FL-THRESH
Output Current at Start Up
IOUT-START
Monotonic Soft-Start
Threshold Voltage
Minimum Required
Disabled Duration
Minimum Required
Disabled Duration
for Predictable Restart
Voltage Deviation (Transient)
Settling Time
DCM™ DC-DC Converter
Page 7 of 24
VOUT-MONOTONIC
tOFF-MIN
tOFF-MONOTONIC
%VOUT-TRANS
tSETTLE
During start up, VOUT must achieve this
threshold before output can support
full rated current
Max load current at start up while VOUT
is below VOUT-FL_THRESH
Output voltage rise becomes monotonic
with 10% of preload once it crosses VOUT-MONOTONIC
This refers to the minimum time a module needs
to be in the disabled state before it will attempt to
start via EN
This refers to the minimum time a module needs to
be in the disabled state before it is guaranteed to
exhibit monotonic soft-start and have predictable
start‑up timing
Minimum COUT_EXT (10 ↔ 90% load step)
Rev 1.5
04/2024
40
ms
µs
600
45
µs
ms
6.0
2.66
V
A
6.0
V
2
ms
100
ms
VIN-INIT
INITIALIZATION
SEQUENCE
EN = False
tMIN-OFF delay
NON LATCHED
FAULT
tOFF
ult
Fa oved
m
Re
Powertrain: Stopped
FT = True
tINIT delay
Powertrain: Stopped
FT = True
Powertrain: Stopped
FT = True
EN = True and
No Faults
tON delay
EN = False
tOFF delay
In
p
In ut O
pu V
tU L
VL O o
O r
VIN > VIN-UVLO+ and
not Over-temp
TR mode latched
STANDBY
or
O
VL LO
t O UV
u
t
p
In npu
I
EN = False
tOFF-MIN delay
SOFT START
VOUT Ramp Up
tss delay
Powertrain: Active
FT = Unknown
RUNNING
tSS Expiry
Ou
tpu
Regulates VOUT
Powertrain: Active
FT = False
tO
or
mp
r-te
P
Ove put UV
Out
REINITIALIZATION
SEQUENCE
tINIT delay
Powertrain: Stopped
FT = True
Fault Removed
Ov
e
Ou r-tem
tpu
p
t U or
VP
VP
tO
pu
ut
O
VP
NON LATCHED
FAULT
tFAULT
Powertrain: Stopped
FT = True
LATCHED
FAULT
EN = False
DCM™ DC-DC Converter
Rev 1.5
Page 10 of 24 04/2024
Powertrain: Stopped
FT = True
DCM™ DC-DC Converter
Rev 1.5
Page 11 of 24 04/2024
Output
Input
FT
ILOAD
FULL LOAD
IOUT
VOUT
VOUT-UVP
FULL LOAD
VOUT-NOM
TR
VTR-DIS
EN
VIN
VIN-UVLO+/VIN-INIT
VIN-OVLO+/-
tINIT
tON
1
Input Power On
- Trim Inactive
tSS
2
3
Ramp to TR
Full Load Ignored
tOFF
tMIN_OFF
4
EN
Low
tSS
tON
5
EN
High
tOFF
6
Input
OVLO
tSS
tOFF
7
Input
UVLO
tSS
tOFF
8
Input
returned
to zero
DCM3623x50M13C2y7z
Timing Diagrams
Module inputs are shown in blue; module outputs are shown in brown.
DCM™ DC-DC Converter
Rev 1.5
Page 12 of 24 04/2024
Output
Input
FT
ILOAD
FULL LOAD
IOUT
VOUT
VOUT-UVP
VOUT-NOM
FULL LOAD
TR
VTR = nom
VTR-EN
EN
VIN
VIN-UVLO+/VIN-INIT
VIN-OVLO+/-
tINIT
tON
9
Input Power On
- Trim Active
tSS
VOUT-OVP
10
Vout
based on
VTR
tOFF
11
Load dump
and reverse
current
tINIT
tON
tSS
12
Vout OVP
(primary
sensed)
13
Latched
fault cleared
RLOAD
tIOUT-LIM
14
Current Limit
with Resistive
Load
tFAULT
15
Resistive
Load with
decresing R
tINIT
16
Overload induced
Output UVP
tON
tSS
DCM3623x50M13C2y7z
Timing Diagrams (Cont.)
Module inputs are shown in blue; module outputs are shown in brown.
DCM3623x50M13C2y7z
Typical Performance Characteristics
0.50
92.5
0.45
92.0
Efficiency (%)
Power Dissipation (W)
The following figures present typical performance at TC = 25°C, unless otherwise noted. See associated figures for general trend data.
0.40
0.35
0.30
10
20
30
40
Input Voltage (V)
-40°C
25°C
50
90.0
60
20
30
40
Input Voltage (V)
Power Dissipation (W)
-40°C
25°C
50
60
Efficiency (%)
Output Voltage (V)
10
8
6
4
2
0
20
25
30
Output Current (A)
Min Trim
Low Trim
High Trim
50
60
90°C
10
20
30
40
Input Voltage (V)
25°C
93.00
92.75
92.50
92.25
92.00
91.75
91.50
91.25
91.00
10
20
30
-40°C
Nom Trim
40
Input Voltage (V)
25°C
Max Trim
Figure 7 — Ideal VOUT vs. load current, at 25°C case
50
60
90°C
Figure 6 — Full-load efficiency vs. VIN, at nominal trim
12
15
40
25°C
-40°C
14
10
93.00
92.75
92.50
92.25
92.00
91.75
91.50
91.25
91.00
90°C
16
5
30
Input Voltage (V)
Figure 4 — Full-load efficiency vs. VIN, at low trim
Figure 5 — No-load power dissipation vs. VIN, at nominal trim
0
20
-40°C
Efficiency (%)
10
10
90°C
Figure 3 — Disabled power dissipation vs. VIN
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
91.0
90.5
0.25
0.20
91.5
Figure 8 — Full-load efficiency vs. VIN, at high trim
DCM™ DC-DC Converter
Rev 1.5
Page 13 of 24 04/2024
50
90°C
60
DCM3623x50M13C2y7z
Typical Performance Characteristics (Cont.)
The following figures present typical performance at TC = 25°C, unless otherwise noted. See associated figures for general trend data.
94
35
Power Dissipation (W)
Efficiency (%)
92
90
88
86
84
82
80
78
5
10
15
20
Load Current (A)
16V Input
28V Input
25
20
15
10
30
0
50V Input
5
10
15
20
Load Current (A)
16V Input
Figure 9 — Efficiency vs. load at TCASE = -40°C, nominal trim
28V Input
25
30
50V Input
Figure 10 — Power dissipation vs. load at TCASE = -40°C,
nominal trim
30
Power Dissipation (W)
94
92
Efficiency (%)
25
5
0
90
88
86
84
82
80
25
20
15
10
5
0
5
10
15
20
Load Current (A)
16V Input
28V Input
25
30
0
50V Input
5
10
15
20
Load Current (A)
16V Input
Figure 11 — Efficiency vs. load at TCASE = 25°C, nominal trim
28V Input
25
30
50V Input
Figure 12 — Power dissipation vs. load at TCASE = 25°C,
nominal trim
30
Power Dissipation (W)
94
92
Efficiency (%)
30
90
88
86
84
82
80
25
20
15
10
5
0
5
16V Input
10
15
20
Load Current (A)
28V Input
25
30
0
50V Input
Figure 13 — Efficiency vs. load at TCASE = 90°C, nominal trim
5
16V Input
10
15
20
Load Current (A)
28V Input
25
50V Input
Figure 14 — Power dissipation vs. load at TCASE = 90°C,
nominal trim
DCM™ DC-DC Converter
Rev 1.5
Page 14 of 24 04/2024
30
DCM3623x50M13C2y7z
Typical Performance Characteristics (Cont.)
The following figures present typical performance at TC = 25°C, unless otherwise noted. See associated figures for general trend data.
Switching Frequency (kHz)
Switching Frequency (kHz)
800
700
600
500
400
300
200
100
0
10
20
40
60
80
100
Load (%)
16V Input
28V Input
800
700
600
500
400
300
200
100
0
10
20
40
Low Trim
50V Input
Figure 15 — Nominal powertrain switching frequency vs. load,
at nominal trim
60
Load (%)
Nom Trim
80
100
High Trim
Figure 16 — Nominal powertrain switching frequency vs. load,
at nominal VIN
Input Capacitance (µF)
50
45
40
35
30
25
20
15
10
5
0
0
8
16
24
32
40
48
56
64
72
80
Input Voltage (V)
Figure 17 — Effective internal input capacitance vs. applied voltage
Figure 18 — Output voltage ripple, VIN = 28V, VOUT = 12.0V,
COUT_EXT = 1000µF, RLOAD = 0.450Ω
Figure 19 — Start up from EN, VIN = 28V, COUT_EXT = 10000µF,
RLOAD = 0.450Ω
DCM™ DC-DC Converter
Rev 1.5
Page 15 of 24 04/2024
DCM3623x50M13C2y7z
Pin Functions
The DCM will latch trim behavior at application of VIN (once VIN
exceeds VIN-UVLO+), and persist in that same behavior until loss
of input voltage
+IN, –IN
Input power pins. –IN is the reference for all control pins,
and therefore a Kelvin connection for the control signals is
recommended as close as possible to the pin on the package, to
reduce effects of voltage drop due to –IN currents.
n
At application of VIN, if TR is sampled at above VTRIM-DIS-TH, the
module will latch in a non-trim mode, and will ignore the TR
input for as long as VIN is present.
n
At application of VIN, if TR is sampled at below VTRIM-EN-TH, the
TR will serve as an input to control the real time output voltage,
relative to full load, 25°C. It will persist in this behavior until VIN is
no longer present.
+OUT, –OUT
Output power pins.
If trim is active when the DCM is operating, the TR pin provides
dynamic trim control at a typical 30Hz of –3dB bandwidth over the
output voltage. TR also decreases the current limit threshold when
trimming above VOUT-NOM.
EN (Enable)
This pin enables and disables the DCM converter; when held
low the unit will be disabled. It is referenced to the –IN pin of
the converter. The EN pin has an internal pull-up to VCC through
a 10kΩ resistor.
FT (Fault)
n
Output enable: When EN is allowed to pull up above the enable
threshold, VENABLE-EN-TH, the module will be enabled. If leaving EN
floating, it is pulled up to VCC and the module will be enabled.
n
Output disable: EN may be pulled down externally below
VENABLE‑DIS‑TH in order to disable the module.
n
EN is an input only, it does not pull low in the event of a fault.
TR (Trim)
The TR pin is used to select the trim mode and to trim the output
voltage of the DCM converter. The TR pin has an internal pull-up to
VCC through a 10.0kΩ resistor.
The FT pin provides a Fault signal.
Any time the module is enabled and has not recognized a fault,
the FT pin is inactive. FT has an internal 499kΩ pull-up to VCC,
therefore a shunt resistor, RSHUNT, of approximately 50kΩ can be
used to ensure the LED is completely off when there is no fault, per
the diagram below.
Whenever the powertrain stops (due to a fault protection or
disabling the module by pulling EN low), the FT pin becomes active
and provides current to drive an external circuit.
When active, FT pin drives to VCC, with up to 4mA of external
loading. Module may be damaged from an overcurrent FT drive,
thus a resistor in series for current limiting is recommended.
The FT pin becomes active momentarily when the
module starts up.
Typical External Circuits for Signal Pins (TR, EN, FT)
DCM
VCC
10kΩ
10kΩ
Output Voltage
Reference, Current
Limit Reference and
Soft Start control
TR
Soft Start and
Fault Monitoring
EN
RTRIM
499kΩ
Fault
Monitoring
FT
RSERIES
SW
RSHUNT
Kelvin –IN connection
DCM™ DC-DC Converter
Rev 1.5
Page 16 of 24 04/2024
D
DCM3623x50M13C2y7z
Design Guidelines
Overall Output Voltage Transfer Function
Building Blocks and System Design
Taking trim (Equation 1) into account, the general equation
relating the DC VOUT to programmed trim (when active), load and
temperature is given by:
The DCM converter input accepts the full 16 – 50V range, and it
generates an isolated trimmable 12.0VDC output.
The DCM converter provides a tightly regulated output voltage;
please refer to the Output Voltage Load Regulation specification in
the Electrical Specifications table.
The DCM3623x50M13C2y7z is designed to be used in applications
where the output power requirements are up to 320W.
Soft Start
When the DCM starts, it will go through a soft start. The soft-start
routine ramps the output voltage by modulating the internal error
amplifier reference. This causes the output voltage to approximate
a piecewise linear ramp. The output ramp finishes when the
voltage reaches either the nominal output voltage, or the trimmed
output voltage in cases where trim mode is active.
During soft start, the maximum load current capability is reduced.
Until VOUT achieves at least VOUT-FL-THRESH, the output current must
be less than IOUT-START in order to guarantee start up. Note that
this is current available to the load, above that which is required to
charge the output capacitor.
Trim Mode and Output Trim Control
When the input voltage is initially applied to a DCM, and after tINIT
elapses, the trim pin voltage V TR is sampled. The TR pin has an
internal pull up resistor to VCC, so unless external circuitry pulls the
pin voltage lower, it will pull up to VCC. If the initially sampled trim
pin voltage is higher than V TRIM-DIS-TH, then the DCM will disable
trimming as long as the VIN remains applied. In this case, for all
subsequent operation the output voltage will be programmed to
the nominal. This minimizes the support components required
for applications that only require the nominal rated VOUT, and
also provides the best output set‑point accuracy, as there are no
additional errors from external trim components.
If at initial application of VIN, the TR pin voltage is prevented from
exceeding V TRIM-EN-TH, then the DCM will activate trim mode, and it
will remain active for as long as VIN is applied.
VOUT set point under full load and room temperature can be
calculated using the equation below:
VOUT-FL at 25°C = 4.99 + (9.390 • VTR / VCC) (1)
Or using the online tool, DCM Trim Calculator, find the value of V TR
or trim resistor to set the desired VOUT.
VOUT = 4.99 + (9.390 • VTR / VCC) + ΔVOUT-LL (2)
Finally, note that when the load current is below 20% of the
rated capacity, there is an additional ΔV which may add to the
output voltage, depending on the line voltage which is related to
light‑load boosting. Please see the section on light‑load boosting
below for details.
Use 0V for ΔVOUT-LL when load is above 20% of rated load. See
section on light-load boosting operation for light‑load effects on
output voltage.
Output Current Limit
The DCM features a fully operational current limit which effectively
keeps the module operating inside the Safe Operating Area (SOA)
for all valid trim and load profiles. The current limit approximates
a “brick wall” limit, where the output current is prevented from
exceeding the current limit threshold by reducing the output
voltage via the internal error amplifier reference. The current limit
threshold at nominal trim and below is typically 115% of rated
output current, but it can vary between 100% to 132%. In order
to preserve the SOA, when the converter is trimmed above the
nominal output voltage, the current limit threshold is automatically
reduced to limit the available output power.
When the output current exceeds the current limit threshold,
current limit action is held off by 1ms, which permits the DCM to
momentarily deliver higher peak output currents to the load. Peak
output power during this time is still constrained by the internal
Power Limit of the module. The fast Power Limit and relatively slow
Current Limit work together to keep the module inside the SOA.
Delaying entry into current limit also permits the DCM to minimize
droop voltage for load steps.
Sustained operation in current limit is permitted, and no de‑rating
of output power is required.
Some applications may benefit from well matched current
distribution, in which case fine tuning sharing via the trim pins
permits control over sharing. The DCM does not require this
for proper operation, due to the power limit and current limit
behaviors described here.
Current limit can reduce the output voltage to as little as the
UVP threshold (VOUT-UVP). Below this minimum output voltage
compliance level, further loading will cause the module to shut
down due to the output undervoltage fault protection.
Note that the trim mode is not changed when a DCM recovers
from any fault condition or being disabled.
Module performance is guaranteed through output voltage trim
range VOUT-TRIMMING. If VOUT is trimmed above this range, then
certain combinations of line and load transient conditions may
trigger the output OVP.
DCM™ DC-DC Converter
Rev 1.5
Page 17 of 24 04/2024
DCM3623x50M13C2y7z
Line Impedance, Input Slew Rate and Input
Stability Requirements
Connect a high-quality, low-noise power supply to the +IN and –IN
terminals. Additional capacitance may have to be added between
+IN and –IN to make up for impedances in the interconnect cables
as well as deficiencies in the source.
Excessive source impedance can bring about system stability issues
for a regulated DC-DC converter, and must either be avoided or
compensated by filtering components. A 1000µF input capacitor
is the minimum recommended in case the source impedance is
insufficient to satisfy stability requirements.
For selecting optimum value of decoupling capacitor, refer to
section 2 of the DCM Design Guide.
Additional information can be found in the filter design
application note AN:023.
Please refer to this input filter design tool to ensure input stability.
Ensure that the input voltage slew rate is less than 1V/µs,
otherwise a pre-charge circuit is required for the DCM input to
control the input voltage slew rate and prevent overstress to
input‑stage components.
Input Fuse Selection
The DCM is not internally fused in order to provide flexibility in
configuring power systems. Input line fusing is recommended at
the system level, in order to provide thermal protection in case of
catastrophic failure. The fuse shall be selected by closely matching
system requirements with the following characteristics:
n
Current rating
(usually greater than the DCM converter’s maximum current)
n
Maximum voltage rating
(usually greater than the maximum possible input voltage)
n
Ambient temperature
n
Breaking capacity per application requirements
n
Nominal melting I2t
n
Recommended fuse:
See Safety Approvals for recommended fuse
Fault Handling
Input Undervoltage Fault Protection (UVLO)
The converter’s input voltage is monitored to detect an input under
voltage condition. If the converter is not already running, then it
will ignore enable commands until the input voltage is greater than
VIN‑UVLO+. If the converter is running and the input voltage falls
below VIN‑UVLO–, the converter recognizes a fault condition, the
powertrain stops switching, and the output voltage of the unit falls.
Input voltage transients which fall below UVLO for less than tUVLO
may not be detected by the fault protection logic, in which case
the converter will continue regular operation. No protection is
required in this case.
Once the UVLO fault is detected by the fault protection logic, the
converter shuts down and waits for the input voltage to rise above
VIN-UVLO+. Provided the converter is still enabled, it will then restart.
Input Overvoltage Fault Protection (OVLO)
The converter’s input voltage is monitored to detect an input
overvoltage condition. When the input voltage is more than the
VIN‑OVLO+, a fault is detected, the powertrain stops switching, and
the output voltage of the converter falls.
After an OVLO fault occurs, the converter will wait for the input
voltage to fall below VIN‑OVLO–. Provided the converter is still
enabled, the powertrain will restart.
The powertrain controller itself also monitors the input voltage.
Transient OVLO events which have not yet been detected by the
fault sequence logic may first be detected by the controller if
the input slew rate is sufficiently large. In this case, powertrain
switching will immediately stop. If the input voltage falls back in
range before the fault sequence logic detects the out of range
condition, the powertrain will resume switching and the fault
logic will not interrupt operation. Regardless of whether the
powertrain is running at the time or not, if the input voltage does
not recover from OVLO before tOVLO, the converter fault logic will
detect the fault.
Output Undervoltage Fault Protection (UVP)
The converter determines that an output overload or short circuit
condition exists by measuring its primary sensed output voltage
and the output of the internal error amplifier. In general, whenever
the powertrain is switching and the primary-sensed output
voltage falls below VOUT‑UVP threshold, a short circuit fault will be
registered. Once an output undervoltage condition is detected,
the powertrain immediately stops switching, and the output
voltage of the converter falls. The converter remains disabled for
a time tFAULT. Once recovered and provided the converter is still
enabled, the powertrain will again enter the soft‑start sequence
after tINIT and tON.
Temperature Fault Protections (OTP)
The fault logic monitors the internal temperature of the converter.
If the measured temperature exceeds TINT‑OTP, a temperature fault
is registered. As with the undervoltage fault protection, once
a temperature fault is registered, the powertrain immediately
stops switching, the output voltage of the converter falls, and
the converter remains disabled for at least time tFAULT. Then, the
converter waits for the internal temperature to return to below
TINT‑OTP before recovering. Provided the converter is still enabled,
the DCM will restart after tINIT and tON.
Output Overvoltage Fault Protection (OVP)
The converter monitors the output voltage during each switching
cycle by a corresponding voltage reflected to the primary side
control circuitry. If the primary sensed output voltage exceeds
VOUT‑OVP, the OVP fault protection is triggered. The control
logic disables the powertrain, and the output voltage of the
converter falls.
This type of fault is latched, and the converter will not start again
until the latch is cleared. Clearing the fault latch is achieved by
either disabling the converter via the EN pin, or else by removing
the input power such that the input voltage falls below VIN‑INIT.
DCM™ DC-DC Converter
Rev 1.5
Page 18 of 24 04/2024
DCM3623x50M13C2y7z
External Output Capacitance
Thermal Considerations
The DCM converter internal compensation requires a minimum
external output capacitor. An external capacitor in the range of
1000 – 10000µF with ESR of 10mΩ is required, per DCM for
control loop compensation purposes.
Based on the thermal specified operating area shown on
page 9, the full rated power of the DCM3623x50M13C2y7z can
be processed provided that the top, bottom and leads are all held
below 95°C. These curves highlight the benefits of dual‑sided
thermal management, but also demonstrate the flexibility of the
Vicor ChiP™ platform for customers who are limited to cooling
only the top or the bottom surface.
However, some DCM models require an increase in the minimum
external output capacitor value in certain loading and trim
conditions. In applications where the load can go below 20%
of rated load but the output trim is held constant, the range of
output capacitor required is given by COUT‑EXT‑TRANS in the Electrical
Specifications table. If the load can go below 20% of rated load
and the DCM output trim is also dynamically varied, the range
of output capacitor required is given by COUT‑EXT‑TRANS‑TRIM in the
Electrical Specifications table.
Light-Load Boosting
Under light‑load conditions, the DCM converter may operate in
light‑load boosting depending on the line voltage. Light‑load
boosting occurs whenever the internal power consumption of the
converter combined with the external output load is less than the
minimum power transfer per switching cycle. In order to maintain
regulation, the error amplifier will switch the powertrain off and on
repeatedly, to effectively lower the average switching frequency,
and permit operation with no external load. During the time
when the powertrain is off, the module internal consumption is
significantly reduced, and so there is a notable reduction in no-load
input power in light‑load boosting. When the load is less than 20%
of rated IOUT, the output voltage may rise by a maximum of 3.12V,
above the output voltage calculated from trim, temperature and
load line conditions.
The OTP sensor is located on the top side of the internal PCB
structure. Therefore in order to ensure effective overtemperature
fault protection, the case bottom temperature must be constrained
by the thermal solution such that it does not exceed the
temperature of the case top.
The ChiP package provides a high degree of flexibility in that it
presents three pathways to remove heat from internal power
dissipating components. Heat may be removed from the top
surface, the bottom surface and the leads. The extent to which
these three surfaces are cooled is a key component for determining
the maximum power that is available from a ChiP, as can be seen
from Figure 20.
Since the ChiP has a maximum internal temperature rating, it is
necessary to estimate this internal temperature based on a real
thermal solution. Given that there are three pathways to remove
heat from the ChiP, it is helpful to simplify the thermal solution into
a roughly equivalent circuit where power dissipation is modeled as
a current source, isothermal surface temperatures are represented
as voltage sources and the thermal resistances are represented as
resistors. Figure 20 shows the “thermal circuit” for a DCM3623
ChiP, in an application where both case top and case bottom,
and leads are cooled. In this case, the DCM power dissipation is
PDTOTAL and the three surface temperatures are represented as
TCASE_TOP, TCASE_BOTTOM, and TLEADS. This thermal system can now
be very easily analyzed with simple resistors, voltage sources, and a
current source.
This analysis provides an estimate of heat flow through the various
pathways as well as internal temperature.
MAX INTERNAL TEMP
Thermal Resistance Top
θINT-TOP ºC / W
Thermal Resistance Bottom
θINT-BOTTOM ºC / W
Power Dissipation (W)
TCASE_BOTTOM(°C)
Thermal Resistance Leads
θINT-LEADS ºC / W
+
–
TLEADS(°C)
+
–
TCASE_TOP(°C)
Figure 20 — Double-side cooling and leads thermal model
DCM™ DC-DC Converter
Rev 1.5
Page 19 of 24 04/2024
+
–
DCM3623x50M13C2y7z
Alternatively, equations can be written around this circuit and
analyzed algebraically:
Symbol
Thermal Impedance
(°C/W)
θINT-TOP
2.0
to maximum-temperature internal
component from isothermal top
θINT-LEADS
4.4
to maximum-temperature internal
component from isothermal leads
θINT-BOTTOM
2.4
to maximum-temperature internal
component from isothermal bottom
TINT – PD1 • θINT-TOP = TCASE_TOP
TINT – PD2 • θINT-BOTTOM = TCASE_BOTTOM
PDTOTAL = PD1+ PD2+ PD3
Where TINT represents the internal temperature and PD1, PD2, and
PD3 represent the heat flow through the top side, bottom side, and
leads respectively.
Table 1 — Thermal data
Thermal Resistance Leads
θINT-LEADS ºC / W
TCASE_BOTTOM(°C)
Power Dissipation (W)
17.7Ws/°C
MAX INTERNAL TEMP
Thermal Resistance Top
θINT-TOP ºC / W
Thermal Resistance Bottom
θINT-BOTTOM ºC / W
Thermal Capacity
Maximum Power Dissipation (W)
TINT – PD3 • θINT-LEADS = TLEADS
TLEADS(°C)
+
–
TCASE_TOP(°C)
+
–
Figure 21 — One-side cooling and leads thermal model
Figure 21 shows a scenario where there is no bottom side cooling.
In this case, the heat flow path to the bottom is left open and the
equations now simplify to:
Thermal Resistance Bottom
θINT-BOTTOM ºC / W
Power Dissipation (W)
40
30
20
10
0
0
20
40
60
Temperature (°C)
Top and leads only
at temperature
80
100
Top, leads and
bottom at
temperature
Figure 23 — Thermal specified operating area: max power
dissipation vs. case temp for arrays or
current‑limited operation
PDTOTAL = PD1+ PD3
Thermal Resistance Top
θINT-TOP ºC / W
50
Top only at
temperature
TINT – PD1 • θINT-TOP = TCASE_TOP
TINT – PD3 • θINT-LEADS = TLEADS
Definition of Estimated
Thermal Resistance
MAX INTERNAL TEMP
Thermal Resistance Leads
θINT-LEADS ºC / W
TCASE_BOTTOM(°C)
TLEADS(°C)
TCASE_TOP(°C)
+
–
Figure 22 — One-side cooling thermal model
Figure 22 shows a scenario where there is no bottom side and
leads cooling. In this case, the heat flow path to the bottom is left
open and the equations now simplify to:
TINT – PD1 • θINT-TOP = TCASE_TOP
PDTOTAL = PD1
Vicor provides a suite of online tools, including a simulator and
thermal estimator which greatly simplify the task of determining
whether or not a DCM thermal configuration is sufficient for a
given condition. These tools can be found at:
www.vicorpower.com/powerbench.
DCM™ DC-DC Converter
Rev 1.5
Page 20 of 24 04/2024
DCM3623x50M13C2y7z
Standalone Operation
COUT-EXT:
electrolytic or tantalum capacitor, 1000µF
≤ C3 ≤ 10000µF;
C3, C 4:
additional ceramic /electrolytic capacitors, if needed
for output ripple filtering;
In order to help sensitive signal circuits reject potential noise,
additional components are recommended:
The following Figure 24 shows the configuration of the
Enhanced VOUT DCM. An input filter is required to attenuate
noise coming from the input source. In case of the excessive line
inductance, a properly‑sized decoupling capacitor CDECOUPLE is
required as shown in the following figure.
R2:
301Ω, facilitate noise attenuation for TR pin;
FB1, C5: FB1 is a ferrite bead with an impedance of at least
10Ω at 100MHz. C5 can be a ceramic capacitor of
0.1µF. Facilitate noise attenuation for EN pin.
Note: Use an RCR filter network as suggested in the application
note AN:030 to reduce the noise on the signal pins.
If signal pins (TR, EN, FT) are not used, they can be left floating,
and DCM will work in the nominal output condition.
When common‑mode noise in the input side is not a concern, TR
and EN can be driven and FT received using –IN as a reference.
Filter components
Input filter: The choice of the input filter components varies up
on the low line and maximum output power of the
DCM. Refer to the Filtering Guidelines Introduction
section in the DCM Design Guide to design
an input filter.
Output filter:
Reference
Designator
Value
C2
80μF
Mfg. Part Number & Count/DCM
GRM32EC72A106KE05L, #8
L2
0.33μH
744309033, #1
Rdm
0.05Ω
RL2512FK-070R05L, #1
Lb1
72nH
IFLR2727EZER72NM01, #1
EMI_GND
F1
VIN
CDECOUPLE
CY
L1
C1
VTR
VEN
R2
DCM
TR
EN
FB1
Rdm
FT
C5
Rd
Cd
CY
Figure 24 — Enhanced VOUT DCM configuration circuit
DCM™ DC-DC Converter
Rev 1.5
Page 21 of 24 04/2024
CY
+IN
+OUT
–IN
–OUT
L2
ROUT-EXT
COUT-EXT
CY
Lb1
C2
C3
C4
Load
DCM3623x50M13C2y7z
DCM Module Product Outline Drawing Recommended PCB Footprint and Pinout
3623 THRU HOLE
(Reference DWG # 40260 Rev 5)
38.72±.38
1.524±.015
11.43
.450
19.36
.762
0
1.52
.060
(2) PL.
11.40
.449
0
0
22.80±.13
.898±.005
1.02
.040
(3) PL.
0
1.52
.060
(4) PL.
TOP VIEW (COMPONENT SIDE)
.05 [.002]
7.21±.10
.284±.004
SEATING
.
PLANE
4.17
.164
(9) PL.
0
18.60
.732
18.60
.732
.41
.016
(9) PL.
8.25
.325
8.00
.315
2.75
.108
0
0
2.75
.108
1.38
.054
4.13
.162
1.38
.054
8.00
.315
0
8.25
.325
8.00±.08
.315±.003
4.13±.08
.162±.003
1.38±.08
.054±.003
+IN
0
2.03
.080
PLATED THRU
.25 [.010]
ANNULAR RING
(2) PL.
2.75±.08
.108±.003
-OUT
TR
0
EN
FT
8.00±.08
.315±.003
8.25±.08
.325±.003
+OUT
-IN
+OUT
2.75±.08
.108±.003
-OUT
8.25±.08
.325±.003
0
1.38±.08
.054±.003
0
18.60±.08
.732±.003
1.52
.060
PLATED THRU
.25 [.010]
ANNULAR RING
(3) PL.
18.60±.08
.732±.003
BOTTOM VIEW
RECOMMENDED HOLE PATTERN
(COMPONENT SIDE)
NOTES:
1- UNLESS OTHERWISE SPECIFIED DIMENSIONS ARE MM [INCH]
2- TOLERANCES ARE:
DECIMALS
X.XX [X.XX] = ±0.25 [0.01]
X.XXX [X.XXX] = ±0.127 [0.005]
ANGLES = ±1°
DCM™ DC-DC Converter
Rev 1.5
Page 22 of 24 04/2024
2.03
.080
PLATED THRU
.38 [.015]
ANNULAR RING
(4) PL.
DCM3623x50M13C2y7z
Revision History
Revision
Date
1.0
07/25/17
Initial release
1.1
01/27/20
Updated typical applications
Output voltage regulation specification format change
Updated state and timing diagrams
Updated trim descriptions and typical external circuits diagram
1.2
08/31/20
Added MIL-STD info
1.3
11/06/20
Typo correction
1.4
05/12/22
1.5
03/29/24
Description
Updated agency approvals
Updated typical applications
Added insulation resistance specification
Added C-grade part number and related specs
Updated standalone operation
Updated format, pages added
Updated agency approvals
Removed C-grade part number and related specs
Revised thermal specified operating area
DCM™ DC-DC Converter
Rev 1.5
Page 23 of 24 04/2024
Page Number(s)
N/A
2
5
8 - 10
16, 17
1
1
1, 4
2
4
4, 6, 7
22
ALL
1, 4
4, 6, 7
9
DCM3623x50M13C2y7z
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Information furnished by Vicor is believed to be accurate and reliable. However, no responsibility is assumed by Vicor for its use. Vicor
makes no representations or warranties with respect to the accuracy or completeness of the contents of this publication. Vicor reserves
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Specifications are subject to change without notice.
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DCM™ DC-DC Converter
Rev 1.5
Page 24 of 24 04/2024
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