Miniature 24V Input, 1W Isolated
UNREGULATED DC/DC CONVERTERS
1997 Burr-Brown Corporation
PDS-1383C
Printed in U.S.A. February, 1999
FEATURES
q
STANDARD JEDEC PLASTIC PACKAGE
q
LOW PROFILE: 0.15" (3.8mm)
q
SYNCHRONIZABLE
q
OUTPUT SHORT CIRCUIT PROTECTION
q
THERMAL SHUTDOWN
q
STARTS INTO ANY CAPACITIVE LOAD
q
EFFICIENCY: 76% (
15V Out)
q
1000Vrms ISOLATION
q
400kHz SWITCHING
q
93 MILLION HOURS MTTF
q
AVAILABLE IN TAPE AND REEL
DESCRIPTION
The DCP0124 family is a series of high efficiency,
24V input isolated DC/DC converters. In addition to
1W nominal galvanically isolated output power capa-
bility, the range of DC/DCs are also fully
synchronizable. The devices feature thermal shutdown,
and overload protection is implemented via watchdog
circuitry. Advanced power-on reset techniques give
superior reset performance and the devices will start
into any capacitive load up to full power output.
The DCP01 family is implemented in standard-molded
IC packaging, giving outlines suitable for high volume
assembly.
DCP0124
Series
I
BIAS
Power
Stage
V
OUT
2
Reset
800kHz
Oscillator
Watch-dog/
start-up
PSU
Thermal
Shutdown
SYNC
OUT
SYNC
IN
V
S
0V
Power Controller IC
0V
APPLICATIONS
q
POINT OF USE POWER CONVERSION
q
GROUND LOOP ELIMINATION
q
DATA ACQUISITION
q
INDUSTRIAL CONTROL AND
INSTRUMENTATION
q
TEST EQUIPMENT
DCP0124
DCP0124
International Airport Industrial Park Mailing Address: PO Box 11400, Tucson, AZ 85734 Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 Tel: (520) 746-1111
Twx: 910-952-1111 Internet: http://www.burr-brown.com/ Cable: BBRCORP Telex: 066-6491 FAX: (520) 889-1510 Immediate Product Info: (800) 548-6132
2
DCP0124
SPECIFICATIONS
At T
A
= +25
C, V
S
= +24V, unless otherwise specified.
DCP0124 SERIES
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
OUTPUT
Power
V
S
+ 4%
1
W
100% Full Load
0.92
W
Voltage (V
NOM
)
(1)
DCP012405
75% Full Load
4.75
5
5.25
V
DCP012415D (+V)
75% Full Load
+14.25
+15
+15.75
V
DCP012415D (V)
75% Full Load
12
15
15.75
V
Voltage vs Temperature
0.08
%/
C
Short Circuit Duration
V
S
10%
Indefinite
Ripple
C
L
= O/P Capacitor = 11
F
25
mVp-p
100% Full Load
INPUT
Nominal Voltage (V
S
)
24
V
Voltage Range
10
10
%
Supply Current
100% Full Load
59
mA
Reflected Ripple Current
C
IN
= I/P Capacitor = 1
F
8
mArms
50% Full Load
ISOLATION
Voltage
(2)
1s Flash Test
1
kVrms
Continuous Voltage
(3)
1
kVrms
Insulation Resistance
>1
G
Input/Output Capacitance
2.5
pF
LOAD REGULATION
DCP012405
10% to 100% Load
17
23
%
10% to 75% Load
9
%
75% to 100% Load
4
%
DCP012415D
10% to 100% Load
22
35
%
10% to 25% Load
11
%
25% to 75% Load
8
%
75% to 100% Load
4
%
SWITCHING/SYNCHRONIZATION
Oscillator Frequency (f
OSC
)
Switching Frequency = f
OSC
/2
800
kHz
Sync Input Low
0
0.8
V
Sync Input Current
V
SYNC
= +2V
48
A
Reset Time
3.8
s
SYNC
OUT
Frequency
400
kHz
GENERAL
No Load Current
DCP012405
0% Full Load
14
mA
DCP012415D
0% Full Load
17
mA
Efficiency
DCP012405
100% Full Load
65
%
10% Full Load
34
%
DCP012415D
100% Full Load
76
%
10% Full Load
36
%
MTTF
(3)
T
A
= +85
C
136,000
hrs
T
A
= +55
C
2,630,000
hrs
T
A
= +25
C
92,600,000
hrs
Weight
14-Pin PDIP
1.08
g
THERMAL SHUTDOWN
Die Temperature
115
140
C
Shutdown Current
3
mA
TEMPERATURE RANGE
Operating
40
100
C
NOTES: (1) 100 % load current = 1W/V
NOM
typical. (2) Rated working voltage = 130Vrms (IEC950 convention). (3) Life test data.
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes
no responsibility for the use of this information, and all use of such information shall be entirely at the user's own risk. Prices and specifications are subject to change
without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant
any BURR-BROWN product for use in life support devices and/or systems.
3
DCP0124
DCP0124
1
2
5
6
7
14
8
V
S
0V
0V
+V
OUT
NC
SYNC
IN
SYNC
OUT
DCP0124
1
2
5
6
7
14
8
V
S
0V
0V
+V
OUT
V
OUT
SYNC
IN
SYNC
OUT
Top View
DIP
PIN CONFIGURATION (Single)
Top View
DIP
PIN CONFIGURATION (Dual)
PIN DEFINITION (Single)
PIN #
PIN NAME
DESCRIPTION
1
V
S
Voltage Input.
2
0V
Input Side Common.
5
0V
Output Side Common.
6
+V
OUT
+Voltage Out.
7
NC
No Connection.
8
SYNC
OUT
Unregulated 400kHz Output from Transformer.
14
SYNC
IN
Synchronization Pin.
PIN DEFINITION (Dual)
PIN #
PIN NAME
DESCRIPTION
1
V
S
Voltage Input.
2
0V
Input Side Common.
5
0V
Output Side Common.
6
+V
OUT
+Voltage Out.
7
V
OUT
Voltage Out.
8
SYNC
OUT
Unregulated 400kHz Output from Transformer.
14
SYNC
IN
Synchronization Pin.
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Burr-Brown
recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling
and installation procedures can cause damage.
ESD damage can range from subtle performance degrada-
tion to complete device failure. Precision integrated circuits
may be more susceptible to damage because very small
parametric changes could cause the device not to meet its
published specifications.
Input Voltage ........................................................................................ 29V
Storage Temperature ...................................................... 60
C to +150
C
Lead Temperature (soldering, 10s) ................................................. 300
C
ABSOLUTE MAXIMUM RATINGS
DCP01
Basic Model Number: 1W Product
Voltage Input:
24V In
Voltage Output:
5V Out
Dual Output:
Package Code:
P = 14-Pin Plastic DIP
P-U = 14-Pin Plastic Dip Gull Wing
ORDERING INFORMATION
24
05
(
)
( D )
PACKAGE
SPECIFIED
DRAWING
TEMPERATURE
PACKAGE
ORDERING
TRANSPORT
PRODUCT
PACKAGE
NUMBER
(1)
RANGE
MARKING
NUMBER
(2)
MEDIA
Single
DCP012405
14-Pin PDIP
010-1
40
C to +100
C
DCP012405P
DCP012405P
Rails
DCP012405
14-Pin PDIP Gull Wing
010-2
40
C to +100
C
DCP012405P-U
DCP012405P-U
Rails
"
"
"
"
"
DCP012405P-U/700
Tape and Reel
Dual
DCP012415D
14-Pin PDIP
010-1
40
C to +100
C
DCP012415DP
DCP012415DP
Rails
DCP012415D
14-Pin PDIP Gull Wing
010-2
40
C to +100
C
DCP012415DP-U
DCP012415DP-U
Rails
"
"
"
"
"
DCP012415DP-U/700
Tape and Reel
NOTES: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. (2) Models with a slash (/) are
available only in Tape and Reel in the quantities indicated (e.g., /700 indicates 700 devices per reel). Ordering 700 pieces of DCP012405P-U/700 will get a single
700-piece Tape and Reel. For detailed Tape and Reel mechanical information, refer to Appendix B of Burr-Brown IC Data Book.
PACKAGE/ORDERING INFORMATION
4
DCP0124
TYPICAL PERFORMANCE CURVES
At T
A
= +25
C, unless otherwise noted.
0
40
Load (%)
Peak-to-Peak Ripple Voltage (mV)
PEAK-TO-PEAK RIPPLE VOLTAGE vs LOAD
50
60
70
80
90
100
10
20
30
500
450
400
350
300
250
200
150
100
50
0
C
L
= 1.1F
C
L
= 11F
C
L
= 100nF
10
Load (%)
Efficiency (%)
DCP012405
EFFICIENCY vs LOAD
50
75
100
25
70
65
60
55
50
45
40
35
30
0
10
20
30
40
50
60
70
80
90
100
Load (%)
Output Voltage (V)
DCP012405
OUTPUT VOLTAGE vs LOAD
5.6
5.5
5.4
5.3
5.2
5.1
5.0
4.9
4.8
4.7
0
10
20
30
40
50
60
70
80
90
100
Load (%)
rms Ripple Current (mA)
REFLECTED r ms RIPPLE CURRENT vs LOAD
140
120
100
80
60
40
20
0
C
IN
= 1F
C
IN
= 100F
Load (%)
Efficiency (%)
DCP012415D
EFFICIENCY vs LOAD
25
50
100
75
10
80
75
70
65
60
55
50
45
40
35
30
Load (%)
Output Voltage (V)
DCP012415D
OUTPUT VOLTAGE vs LOAD
50
75
100
10
25
18.5
18.0
17.5
17.0
16.5
16.0
15.5
15.0
14.5
14.0
+V
OUT
V
OUT
5
DCP0124
TYPICAL PERFORMANCE CURVES
(CONT)
At T
A
= +25
C, unless otherwise noted.
40
40
Temperature (C)
Frequency (%)
SWITCHING FREQUENCY vs TEMPERATURE
60
80
100
120
20
0
20
101
100
99
98
97
96
95
94
93
92
21.6
Input Voltage (V)
Output Voltage (V)
DCP012405
OUTPUT VOLTAGE vs INPUT VOLTAGE (75% Load)
25.2
26.4
22.8
24.0
5.8
5.6
5.4
5.2
5.0
4.8
4.6
4.4
4.2
4.0
100
75
50
10
V
OUT
Load (%)
V
OUT
(V)
DCP012415D
LOAD BALANCE (+V
OUT
LOAD = 100%)
20
15
10
5
0
5
10
15
20
+V
OUT
V
OUT
40
20
0
20
40
60
80
100
Temperature (C)
Output Power (W)
OUTPUT POWER vs TEMPERATURE
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
21
Input Voltage (V)
Output Voltage (V)
DCP012415D
OUTPUT VOLTAGE vs INPUT VOLTAGE (75% Load)
26
27
22
23
24
25
17.5
17.0
16.5
16.0
15.5
15.0
14.5
14.0
13.5
13.0
+V
OUT
V
OUT
100
150
75
50
10
V
OUT
Load (%)
V
OUT
(V)
DCP012415D
LOAD BALANCE (+V
OUT
LOAD = 10%)
20
15
10
5
0
5
10
15
20
+V
OUT
V
OUT
6
DCP0124
FUNCTIONAL DESCRIPTION
OVERVIEW
The DCP0124 offers up to 1W of unregulated output power
from a 24V input source with a typical efficiency of up to
76%. This is achieved through highly integrated packaging
technology and the implementation of a custom power stage
and control IC.
POWER STAGE
This uses a pull-pull, center-tapped topology switching at
400kHz (divide by 2 from 800kHz oscillator).
OSCILLATOR AND WATCHDOG
The on-board 800kHz oscillator provides the switching
frequency via a divide by 2 circuit and allows synchroniza-
tion via the SYNC
IN
pins. To synchronize any number of
DCP01 family of devices, simply tie the SYNC
IN
pins
together (see the Synchronization section). The watchdog
circuitry protects the DC/DC against a stopped oscillator and
checks the oscillator frequency which will shut down the
output stage if it drops below a certain threshold--i.e., it will
be tri-stated after approximately 10
s.
FIGURE 1. Standard Interface.
THERMAL SHUTDOWN
The DCP0124 is also protected by thermal shutdown. If the
on-chip temperature reaches a predetermined value, the DC/
DC will shutdown. This effectively gives indefinite short
circuit protection for the DC/DC.
SYNCHRONIZATION
Any number of DCP01 family devices can be synchro-
nized by connecting the SYNC
IN
pins on the devices
together (see Figure 1). All the DCP01 devices will then
self-synchronize.
This same synchronization method applies to any V
IN
ver-
sion of the DCP01 family, allowing synchronization of
various V
OUT
and V
IN
DC/DCs.
The SYNC
OUT
pin gives an unrectified 400kHz signal from
the transformer. This can be used to set the timing of external
circuitry on the output side. In noise sensitive applications
any pick-up from the SYNC
OUT
pin can be minimized by
putting a guard ring round the pin (see Figure 2).
Bottom View
FIGURE 2. SYNC
OUT
Guard Ring.
DIVIDE BY 2 RESET
Isolated DC/DC converter performance normally suffers
after power reset. This is because a change in the steady state
transformer flux creates an offset after power-up. The DCP01
family does not suffer from this problem. This is achieved
through a patented
(1)
technique employed on the divide by 2
reset circuitry resulting in no change in output phase after
power interruption.
CONSTRUCTION
The DCP0124's basic construction is the same as standard
ICs. There is no substrate within the molded package. The
DCP0124 is constructed using an IC, rectifier diodes, and a
wound magnetic toroid on a leadframe. As there is no solder
within the package, the DCP0124 does not require any
special PCB assembly processing. This results in an isolated
DC/DC with inherently high reliability.
ADDITIONAL FUNCTIONS
DISABLE/ENABLE
The DCP0124 can be disabled or enabled by driving the
SYNC
IN
pin with an open drain CMOS gate. If the SYNC
IN
pin is pulled low, the DCP0124 will disable. The disable time
depends on the output loading but the internal shutdown takes
DCP0124xxx
1
2
5
6
7
14
8
V
S
0V
0V
Out+
C
1
470nF
C
5
470nF
DCP0105xxx
1
2
5
6
7
14
8
V
S
0V
0V
Out+
C
2
470nF
DCP0105xxx
1
2
5
6
7
14
8
V
S
0V
0V
Out+
SYNC
IN
SYNC
IN
SYNC
IN
C
3
470nF
+5V
+24V
1 per DCP01
C
4
470nF
+24V
Out 1
+Out 1
Out 2
+5V
+Out 2
Out 3
+Out 3
7
DCP0124
up to 10
s. Making the gate open drain will re-enable the
DCP0124. However, there is a trade-off in using this function;
the DCP0124 quiescent current may increase and the on-chip
oscillator may run slower. This degradation in performance is
dependent on the external CMOS gate capacitance, therefore
the smaller the capacitance, the lower the performance de-
crease. Driving the SYNC
IN
pin with a CPU type tri-state
output, which has a low output capacitance, offers the lowest
reduction in performance.
DECOUPLING
Ripple Reduction
The high switching frequency of 400kHz allows simple
filtering. To reduce ripple, it is recommended that 0.47
F
capacitors are used on V
S
and V
OUT
(see Figure 3). Dual
outputs should both be decoupled to pin 5. In applications
where power is supplied over long lines and output loading
is high, or there is significant inductance at the output, it
may be necessary to use a 2.2
F capacitor on the input to
insure startup.
There is no restriction on the size of the output capacitor used
to reduce ripple. The DCP0124 will start into any capacitive
load. Low ESR capacitors will give the best reduction.
EXTERNAL SYNCHRONIZATION
The DCP0124 can be synchronized externally if required
using a simple external interface. Figure 4 shows a universal
interface using a 4066 quad switch. The CTL and SYNC
ON
pins are used to select external synchronization or self-
synchronization.
This interface can also be used to stop (disable) the DCP0124.
FIGURE 4. Universal Interface.
CTL
SYNC
ON
FUNCTION
1
1
External Sync
--
0
Self-Sync
0
1
Device Stop
FIGURE 3. DCP012405 Fully Loaded.
DCP0124xxx
1
2
5
6
7
14
8
V
CC
0V
0V
+V
OUT
V
OUT
SYNC
I/O
1A
I/O
1B
U1
CONT
C
3
470nF
C
6
470nF
(One Per
DC/DC)
DCP0115xxx
1
2
5
6
7
14
8
V
CC
0V
0V
+V
OUT
SYNC
R
1
33k
R
2
33k
DCP0115xxx
1
2
5
6
7
14
8
V
CC
0V
0V
+V
OUT
SYNC
C
4
470nF
+5V
+5V
0V
+Out 2
0V
+Out 3
I/O
1A
I/O
1B
U3
CONT
I/O
1A
I/O
1B
U4
CONT
I/O
1A
I/O
1B
U5
CONT
SYNC ON
FREQ IN
CTL
R
3
33k
0V
0V
0V
0V
C
5
470nF
+24V
0V
4066
C
2
470nF
C
1
470nF
+24V
0V
+Out 1
Out 1
+5V
1
2
5
6
V
S
0V
0V
V
Out
C
1
0.47F
C
2
0.47F
R
2
330
+24V
R
1
27
2W
2W
DCP012405
8
DCP0124
1. To predict the output voltage at 100% load take the mea-
sured or specified voltage at 75% load and multiply by
(1 + Load Reg 75% to 100%). For example a DCP012405P
typical V
OUT
at 100% load will be 5V
x
(1 4%) = 4.8V.
2. To predict the output voltage at 10% load take the mea-
sured or specified voltage at 75% load and multiply by
(1 + Load Reg 10% to 75%). For example a DCP012405P
typical V
OUT
at 10% load will be 5V
x
(1 + 9%) = 5.4V.
3. To predict the output voltage at 25% load on higher V
OUT
versions take the measured or specified voltage at 75%
load and multiply by (1 + Load Reg 25% to 75%). For
example a DCP012415DP typical +V
OUT
at 25% load will
be 12V
x
(1 + 8%) = 13.0V. To then estimate the voltage
at 10% load take the previously calculated +V
OUT
at
25% load and multiply by (1 + Load Reg 10% to 25%).
In this case the typical +V
OUT
at 10% load will be 13.0V
x
(1 + 11%) = 14.4V.
To obtain predictions for loads other than those specified
assume the V
OUT
versus load characteristic is linear between
the load points and calculate accordingly. The 10% to 100%
load specification guarantees the maximum voltage excursion
for any load between 10% to 100% with respect to V
OUT
at
75% load.
The above does not take into consideration line regulation and
assumes a nominal input voltage. The 1:1 line regulation of the
DCP01 family means that a percentage change in the input
will give a corresponding percentage change in the output.
Connecting the DCP0124 in Series
Multiple DCP01 isolated 1W DC/DC converters can be
connected in series to provide non-standard voltage rails.
This is possible by utilizing the floating outputs provided by
the DCP01's galvanic isolation.
Connect the positive V
OUT
from one DCP01 to the negative
V
OUT
(0V) of another (see Figure 5). If the SYNC
IN
pins are
tied together, the self-synchronization feature of the DCP01
will prevent beat frequencies on the voltage rails. The SYNC
feature of the DCP01 allows easy series connection without
external filtering which is necessary in competing solutions.
The outputs on dual output DCP01 versions can also be
connected in series to provide 2 times the magnitude of
V
OUT
(see Figure 6). For example, a dual 15V DCP012415D
could be connected to provide a 30V rail.
Connecting the DCP0124 in Parallel
If the output power from one DCP0124 is not sufficient, it
is possible to parallel the outputs of multiple DCP01s (see
Figure 7). Again, the SYNC feature allows easy synchroni-
zation to prevent power-rail beat frequencies at no additional
filtering cost.
PREDICTING OUTPUT VOLTAGE VERSUS LOAD
The Load Regulation specifications are calculated as fol-
lows:
CONDITION
CALCULATION
10% to 100% Load
(V
OUT
at 10% load V
OUT
at 100% load)/ V
OUT
at 75% load
10% to 25% Load
(V
OUT
at 10% load V
OUT
at 25% load)/ V
OUT
at 25% load
10% to 75% Load
(V
OUT
at 10% load V
OUT
at 75% load)/ V
OUT
at 75% load
75% to 100% Load
(V
OUT
at 75% load V
OUT
at 100% load)/ V
OUT
at 75% load
FIGURE 5. Connecting the DCP0124 in Series.
DCP
01
V
OUT 1
V
SUPPLY
V
S
0V
DCP
01
V
OUT 2
V
OUT1
+ V
OUT 2
SYNC
IN
SYNC
IN
V
S
0V
0V
0V
COM
9
DCP0124
FIGURE 7. Connecting Multiple DCP0124s in Parallel.
DCP
01
0V
0V
V
OUT
V
SUPPLY
V
S
0V
DCP
01
V
OUT
2 x Power Out
SYNC
IN
SYNC
IN
V
S
0V
COM
15.24 (0.600)
11.8 (0.464)
14-Pin
All Leads on 2.54mm Pitch
Dimensions in mm (inches)
1.9 (0.075)
2.54 (0.100)
1.2 (0.047)
FIGURE 8. PCB Pad Size and Placement for "U" Package.
DCP
01
+V
OUT
V
SUPPLY
+V
OUT
V
OUT
V
OUT
0V
V
S
0V
COM
FIGURE 6. Connecting Dual Outputs in Series.
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