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date 01/14/2021
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SERIES: VX78-500 │ DESCRIPTION: NON-ISOLATED DC SWITCHING REGULATOR
FEATURES
• wide input
• pin-out compatible with linear regulators
• encapsulated
• UL & CSA approved
• high efficiency up to 95%
• no-load input current as low as 0.2 mA
• wide operating temp: -40°C to +85°C
• supports negative output
• short circuit protection on the output
• EN 62368-1
MODEL input
voltage1
output
voltage
output
current
output
power
ripple
& noise2
eciency3
typ
(Vdc)
range
(Vdc) (Vdc)
max
(mA)
max
(W)
max
(mVp-p)
typ
(%)
VX7803-500 24 4.75~36 3.3 500 1.65 75 86
VX7805-500 24
12
6.5~36
7~31
5
-5
500
-300
2.5
1.5
75
75
90
80
VX78039-500 24 12~36 9 500 4.5 75 93
VX78012-500 24
12
15~36
8~24
12
-12
500
-150
6
1.8
75
75
94
84
VX7815-500 24
12
19~36
8~21
15
-15
500
-150
7.5
2.25
75
75
95
85
Notes: 1. For input voltages higher than 30 Vdc, a 22 µF / 50 V input capacitor is required.
2. Tested at nominal input, 10~100% load, 20 MHz bandwidth, with 10 µF electrolytic and 1 µF ceramic capacitor on the output. At loads below 10%, the max ripple and
noise of the 3.3 & 5 Vdc outputs will be 150 mVp-p, and the other outputs will be 2% Vo.
3. Measured at min Vin, full load.
4. All specications are measured at Ta=25°C, humidity < 75%, nominal input voltage, and rated output load unless otherwise specied.
PART NUMBER KEY
Base Number
VX78 XX - 500
Output Voltage Output Current
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date 01/14/2021 │ page 2 of 7CUI Inc │ SERIES: VX78-500 │ DESCRIPTION: NON-ISOLATED DC SWITCHING REGULATOR
INPUT
parameter conditions/description min typ max units
operating input voltage1for positive output applications
for negative output applications
4.75
7
24
12
36
31
Vdc
Vdc
lter capacitor lter
input reverse polartiy protection no
no-load input current positive outputs 0.2 1.5 mA
Note: 1. See Model section on page 1 for specic input voltage ranges.
OUTPUT
parameter conditions/description min typ max units
maximum capacitive load2for positive output applications
for negative output applications
680
330
μF
μF
voltage accuracy
at full load, input voltage range
3.3 Vdc output model
all other models
±2
±2
±4
±3
%
%
line regulation at full load, input voltage range ±0.2 ±0.4 %
load regulation at nominal input, 10~100% load ±0.4 ±0.6 %
switching frequency at nominal input voltage, full load 550 850 kHz
transient recovery time at nominal input voltage, 25% load step change 0.2 1 ms
transient response deviation at nominal input voltage, 25% load step change 50 250 mV
temperature coecient at full load ±0.03 %/°C
Note: 2. The maximum capacitive load was tested at nominal input voltage, full load.
PROTECTIONS
parameter conditions/description min typ max units
short circuit protection continuous, auto recovery
SAFETY AND COMPLIANCE
parameter conditions/description min typ max units
safety approvals certied to 62368-1: EN
certied to 60950-1: UL
EMI/EMC EN 55032, EN 55024
conducted emissions CISPR22/EN55022, class B (external circuit required, see Figure 6-b)
radiated emissions CISPR22/EN55022, class B (external circuit required, see Figure 6-b)
ESD IEC/EN61000-4-2, contact ± 4kV, class B
radiated immunity IEC/EN61000-4-3, 10V/m, class A
EFT/burst IEC/EN61000-4-4, ± 1kV, class B (external circuit required, see Figure 6-a)
surge IEC/EN61000-4-5, line-line ± 1kV, class B (external circuit required, see Figure 6-a)
conducted immunity IEC/EN61000-4-6, 3 Vr.m.s, class A
MTBF as per MIL-HDBK-217F, 25°C 2,000,000 hours
RoHS 2011/65/EU
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date 01/14/2021 │ page 3 of 7CUI Inc │ SERIES: VX78-500 │ DESCRIPTION: NON-ISOLATED DC SWITCHING REGULATOR
10 Sec. Max.
Wave Soldering Time
4 Sec. Max.
Peak Temp. 260°C Max.
Time (sec.)
Temperature (°C)
250
200
150
100
50
0
ENVIRONMENTAL
parameter conditions/description min typ max units
operating temperature see derating curve -40 85 °C
storage temperature -55 125 °C
storage humidity non-condensing 5 95 %
SOLDERABILITY
parameter conditions/description min typ max units
wave soldering see wave soldering prole 260 °C
MECHANICAL
parameter conditions/description min typ max units
dimensions 11.60 x 7.55 x 10.16 [0.457 x 0.297 x 0.400 inch] mm
case material black ame-retardant heat-proof plastic (UL94V-0)
weight 1.8 g
MECHANICAL DRAWING
units: mm [inch]
tolerance: ±0.25[±0.010]
pin diameter tolerance: ±0.10[±0.004]
PIN CONNECTIONS
PIN +OUTPUT -OUTPUT
1 +VIN +VIN
2 GND -VOUT
3 +VOUT GND
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date 01/14/2021 │ page 4 of 7CUI Inc │ SERIES: VX78-500 │ DESCRIPTION: NON-ISOLATED DC SWITCHING REGULATOR
DERATING CURVE
Ambient Temperature (°C)
Load (%)
-40
60
80
100
40
20
04085
Temperature Derating Curve
(Natural Convention)
120
120
71
0
EFFICIENCY CURVES
4.75 8 12 16 20 24 28 32 36
88
86
84
82
Efficiency (%)
80
78
Input Voltage (Vdc)
76
Load Current (%)
10 20 30 40 50 60 70 80 90 100
82
80
78
76
74
Efficiency (%)
72
70
84
VX7803-500 Eciency Curve
Positive Output, Eciency vs. Input Voltage
(at full load)
VX7803-500 Eciency Curve
Positive Output, Eciency vs. Load Current
(at Vin nominal)
15 18 21 24 27 30 33 36
96
94
92
90
88
Efficiency (%)
86
84
Input Voltage (Vdc)
82
80
Load Current (%)
10 20 30 40 50 60 70 80 90 100
96
94
92
88
86
Efficiency (%)
84
82
98
90
VX78012-500 Eciency Curve
Positive Output, Eciency vs. Input Voltage
(at full load)
VX78012-500 Eciency Curve
Positive Output, Eciency vs. Load Current
(at Vin nominal)
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date 01/14/2021 │ page 5 of 7CUI Inc │ SERIES: VX78-500 │ DESCRIPTION: NON-ISOLATED DC SWITCHING REGULATOR
EFFICIENCY CURVES (CONTINUED)
8 12 16 20 24
88
86
84
82
Efficiency (%)
80
78
Input Voltage (Vdc)
76
74
Load Current (%)
10 20 30 40 50 60 70 80 90 100
82
80
78
76
74
Efficiency (%)
72
70
84
86
88
VX78012-500 Eciency Curve
Negative Output, Eciency vs. Input Voltage
(at full load)
VX78012-500 Eciency Curve
Negative Output , Eciency vs. Load Current
(at Vin nominal)
19 20 22 24 26 28 30 32 34 36
98
96
94
92
Efficiency (%)
90
88
Input Voltage (Vdc)
86
84
Load Current (%)
10 20 30 40 50 60 70 80 90 100
96
94
92
88
86
Efficiency (%)
84
82
90
VX7815-500 Eciency Curve
Positive Output, Eciency vs. Input Voltage
(at full load)
VX7815-500 Eciency Curve
Positive Output, Eciency vs. Load Current
(at Vin nominal)
8 12 15 18 21
90
88
86
Efficiency (%)
84
82
Input Voltage (Vdc)
80
78
Load Current (%)
10 20 30 40 50 60 70 80 90 100
86
84
82
80
78
Efficiency (%)
76
74
88
90
VX7815-500 Eciency Curve
Negative Output, Eciency vs. Input Voltage
(at full load)
VX7815-500 Eciency Curve
Negative Output, Eciency vs. Load Current
(at Vin nominal)
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date 01/14/2021 │ page 6 of 7CUI Inc │ SERIES: VX78-500 │ DESCRIPTION: NON-ISOLATED DC SWITCHING REGULATOR
Table 1
1
3
2
+Vin
GND
-Vout
C2
GND
DC/DC
1
2
3+Vout
C1
C3 C4
LDM
DC/DC
Model Number C1, C3
(ceramic capacitor)
C2, C4
(ceramic capacitor)
VX7803-500 10 μF/50 V 22 μF/10 V
VX7805-500 10 μF/50 V 22 μF/10 V
VX78039-500 10 μF/50 V 22 μF/16 V
VX78012-500 10 μF/50 V 22 μF/25 V
VX7815-500 10 μF/50 V 22 μF/25 V
External Capacitor Table
TYPICAL APPLICATION CIRCUIT
Positive Output Application Circuit Negative Output Application Circuit
Positive and Negative Output Paralleling Application Circuit
+V
in
GNDGND
DC/DC
1
2
3+Vou
t
C1 C2
+Vin
GN DGN D
DC/DC
12
3
-Vout
C1 C2
Figure 1
Figure 3
Figure 2
EMC RECOMMENDED CIRCUIT
DC/DC
Vin
LDM2
E
C0
LDM1
MOV
FUSE
D
C5
V
in
GN
D
+
+Vo
GN DLO
AD
C2C1
Table 2Figure 6
Recommended external circuit components
FUSE choose according to actual input current
MOV S20K30
LDM1 82 µH
C0 680 µF/50 V
C1, C2 see Table 1
C5 4.7 µF/50 V
LDM2 12 µH
Note: 1. C1 & C2 (C3 & C4) are required and should be connected as close to the module pins as possible.
2. To reduce the output ripple further, it is recommended to connect an “LC” lter at the output terminal with a recommended value of 10~47 µH for the L component. (See
Figures 4 & 5).
3. When using application circuit in Figure 3, a 10 µH LDM component is recommended to reduce the interference.
Positive Output Ripple Reduction Circuit Negative Output Ripple Reduction Circuit
3
+Vin
GND
Vout
1
DC/DC
C1
22 F
μ
2
C2
L
2
+Vin
GND
Vout
1DC/DC
C1
22 F
μ
3
C2
L
Figure 4 Figure 5
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date 01/14/2021 │ page 7 of 7CUI Inc │ SERIES: VX78-500 │ DESCRIPTION: NON-ISOLATED DC SWITCHING REGULATOR
CUI oers a two (2) year limited warranty. Complete warranty information is listed on our website.
CUI reserves the right to make changes to the product at any time without notice. Information provided by CUI is believed to be accurate and reliable. However, no responsibility is
assumed by CUI for its use, nor for any infringements of patents or other rights of third parties which may result from its use.
CUI products are not authorized or warranted for use as critical components in equipment that requires an extremely high level of reliability. A critical component is any component of a
life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to aect its safety or eectiveness.
Headquarters
20050 SW 112th Ave.
Tualatin, OR 97062
800.275.4899
Fax 503.612.2383
cui.com
techsupport@cui.com
rev. description date
1.0 initial release 05/18/2017
1.01 features and safety line updated, packaging removed 01/14/2021
The revision history provided is for informational purposes only and is believed to be accurate.
REVISION HISTORY
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