SBVS028A - DECEMBER 2000 - REVISED APRIL 2004
Miniature, 2W Isolated
REGULATED DC/DC CONVERTERS
DCR02 SERIES
FEATURES
D
UL1950 Recognized
D
DIP-18 and SO-10 Packages
D
55W/in
3
(3.3W/cm
3
) Power Density
D
Device-to-Device Synchronization
D
Thermal Protection
D
1000Vrms Isolation
D
400kHz Switching
D
125 FITS at 55
C
D
Short-Circuit Protection
D
12V, 24V Inputs
D
5V Outputs
APPLICATIONS
D
Point-of-Use Power Conversion
D
Digital Interface Power
D
Ground Loop Elimination
D
Power-Supply Noise Reduction
DESCRIPTION
The DCR02 family is a series of high-efficiency,
input-isolated, output-regulated DC/DC converters. In
addition to 2W nominal, galvanically-isolated output power
capability, this range of converters offers very low output
noise and high accuracy.
The DCR02 family is implemented in standard molded IC
packaging, providing standard JEDEC outlines suitable
for high-volume assembly.
The DCR is manufactured using the same technology as
standard IC packages, thereby achieving very high
reliability.
Input
Controller
LDO
R egulator
ENABLE
V
REC
SYNC
V
S
ERROR
V
OUT
0V
IN
0V
OUT
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Copyright
2000-2004, Texas Instruments Incorporated
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date. Products
conform to specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all parameters.
DCR02 SERIES
SBVS028A - DECEMBER 2000 - REVISED APRIL 2004
www.ti.com
2
This integrated circuit can be damaged by ESD. Texas Instruments 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 degradation 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.
ORDERING INFORMATION
(1)
PRODUCT
PACKAGE-LEAD
PACKAGE
DESIGNATOR
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
MARKING
ORDERING
NUMBER
TRANSPORT MEDIA,
QUANTITY
DIP-18
NVE
-40
C to +70
C
DCR021205P
DCR021205P
Rail, 20
DCR021205
SO-10(2)
DVS
-40
C to +70
C
DCR021205P-U
DCR021205P-U
Rail, 20
DCR021205
SO-10(2)
DVS
-40
C to +70
C
DCR021205P-U
DCR021205P-U/700
Tape and Reel, 700
DIP-18
NVE
-40
C to +70
C
DCR022405P
DCR022405P
Rail, 20
DCR022405
SO-10(2)
DVS
-40
C to +70
C
DCR022405P-U
DCR022405P-U
Rail, 20
DCR022405
SO-10(2)
DVS
-40
C to +70
C
DCR022405P-U
DCR022405P-U/700
Tape and Reel, 700
(1) For the most current package and ordering information, refer to our web site at www.ti.com.
(2) SO-10 packages have 18 pins, but only 10 pins are active.
SUPPLEMENTAL ORDERING INFORMATION
Basic Model Number: 1W Product
Voltage Input:
12V In
Voltage Output:
5V Out
Package Code:
P = 18-Pin Plastic DIP
P-U = SO-10
DCR02
12
05
(P)
PIN ASSIGNMENTS
NVE and DVS
PACKAGES
(TOP VIEW)
DCR02
1
2
7
8
9
18
17
12
11
10
V
S
NC
V
REC
0V
OUT
V
O
SYNC
0V
IN
ERROR
ENABLE
DNC
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range unless otherwise noted(1)
DCR02 SERIES
UNIT
Input Voltage
DCR0212
15
V
Input Voltage
DCR0224
29
V
Storage Temperature
-60 to +125
C
Lead Temperature (soldering, 10s)
+270
C
(1) Stresses above these ratings may cause permanent damage.
Exposure to absolute maximum conditions for extended periods
may degrade device reliability. These are stress ratings only, and
functional operation of the device at these or any other conditions
beyond those specified is not implied.
Terminal Functions
TERMINAL
NAME
NO.
I/O
DESCRIPTION
VS
1
I
Voltage input
NC
2
No connection
VREC
7
O
Rectified output
0VOUT
8
O
Output ground
VO
9
O
Voltage output
DNC
10
Do not connect
ENABLE
11
O
Output voltage enable
ERROR
12
O
Error flag active low
0VIN
17
I
Input ground
SYNC
18
I
Synchronization input
NOTE: I = input and O = output.
DCR02 SERIES
SBVS028A - DECEMBER 2000 - REVISED APRIL 2004
www.ti.com
3
ELECTRICAL CHARACTERISTICS
At TA = +25
C, VS = nominal, IOUT = 10mA, COUT = 0.1
F ceramic, and CIN = 2.2
F ceramic, unless otherwise noted(1).
DCR02 SERIES
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Output
Setpoint
DCR021205
5
V
Setpoint
DCR022405
5
V
Setpoint accuracy
0.5
2.0
%
Maximum Output
Current
DCR021205
400
mA
Maximum Output
Current
DCR022405
400
mA
Output short-circuit protected
Duration
Infinite
Line regulation
DCR021205
1
mV/V
Line regulation
DCR022405
1
mV/V
Over line and load
10mA to 400mA load, over input voltage range
1.0
2.5
%
Versus temperature
-40
C to +70
C
1.0
%
DCR0212 ripple
20MHz bandwidth, 50% load(1)
18
mVPP
Ripple and noise
DCR0212 noise
100MHz bandwidth, 50% load(1)
20
mVPP
Ripple and noise
DCR0224 ripple
20MHz bandwidth, 50% load(1)
18
mVPP
DCR0224 noise
100MHz bandwidth, 50% load(1)
25
mVPP
Input
Nominal voltage, VS
DCR021205
12
V
Nominal voltage, VS
DCR022405
24
V
Voltage range
-10
+10
%
IO = 0mA
15
mA
DCR021205
IO = 10mA
23
mA
Supply current
DCR021205
IO = 400mA
250
mA
Supply current
IO = 0mA
15
mA
DCR022405
IO = 10mA
17
mA
DCR022405
IO = 400mA
129
mA
Reflected ripple current
20MHz bandwidth, 100% load(1)
8
mAPP
Isolation
Voltage
1s flash test
1
kVrms
Voltage
60s test, UL1950(2)
1
kVrms
Input/output capacitance
25
pF
Output Enable Control
Logic high input voltage
2.0
VREC
V
Logic high input current
2.0 < VENABLE < VREC
100
nA
Logic low input voltage
-0.2
0.5
V
Logic low input current
0 < VENABLE < 0.5
100
nA
Error Flag
Logic high open collector leakage
VERROR = 5V
10
A
Logic low output voltage
Sinking 2mA
0.4
V
Thermal Shutdown
Junction temperature
Temp activated
+150
C
Junction temperature
Temp deactivated
+130
C
(1) Ceramic capacitors, CIN = 2.2
F, CFILTER = 1
F, and COUT = 0.1
F.
(2) During UL1950 recognition test only.
DCR02 SERIES
SBVS028A - DECEMBER 2000 - REVISED APRIL 2004
www.ti.com
4
ELECTRICAL CHARACTERISTICS (continued)
At TA = +25
C, VS = nominal, IOUT = 10mA, COUT = 0.1
F ceramic, and CIN = 2.2
F ceramic, unless otherwise noted(1).
DCR02 SERIES
PARAMETER
UNITS
MAX
TYP
MIN
TEST CONDITIONS
Synchronization Pin
Max external capacitance on SYNC pin
3
pF
Internal oscillator frequency
720
800
880
kHz
External synchronization frequency
720
880
kHz
External synchronization signal high
2.5
2.5
5.0
V
External synchronization signal low
0
0.4
V
Temperature Range
Operating
-40
+70
C
(1) Ceramic capacitors, CIN = 2.2
F, CFILTER = 1
F, and COUT = 0.1
F.
(2) During UL1950 recognition test only.
DCR02 SERIES
SBVS028A - DECEMBER 2000 - REVISED APRIL 2004
www.ti.com
5
FUNCTIONAL DESCRIPTION
OVERVIEW
The DCR02 series offers isolation from an unregulated
power supply operating from a choice of input voltages.
This series provides a variety of regulated output voltages
at a nominal output power of 2W.
POWER STAGE
The input supply is chopped at a frequency of 400kHz
(internal oscillator divided by 2), which is used to drive the
center-tapped toroidal transformer.
RECTIFICATION
The transformer output is full wave rectified and smoothed
by the external capacitor connected to V
REC
.
REGULATOR
The internal low-dropout regulator provides a
well-regulated output voltage throughout the operating
range of the device.
OSCILLATOR AND WATCHDOG
The DCR02 uses an internal saw-tooth generator to
provide the 800kHz onboard oscillator that is used to drive
the power switching circuit. The operation of the oscillator
is monitored by the watchdog, which will tri-state the output
driver circuit if the oscillator fails or if the SYNC pin is taken
low (shutdown mode). When the SYNC pin is returned
high, normal operation resumes.
SYNCHRONIZATION
If more than one DCR02 is being used, beat frequencies
and other electrical interference can be generated. This
interference is due to the small variations in switching
frequencies between the converters. The DCR02
overcomes this by allowing devices to be synchronized to
one another. Up to eight devices can be synchronized by
connecting the SYNC pins together, with care being taken
to minimize the capacitance of tracking.
Significant stray capacitance on the SYNC pin reduces the
frequency of the internal oscillator. If this reduction is large,
the DCR02 may be taken out with its optimized operating
parameters, and saturation of the magnetics may result,
damaging the device.
If devices are synchronized, it should be noted that all
devices will draw maximum current simultaneously at start
up. This can cause the input voltage to dip. Should it fall
below the minimum input voltage, the devices may not
start up. A low equivalent series resistance (ESR) 2.2
F
ceramic capacitor should be connected as close to the
device input pins as possible.
If more than eight devices are required to be synchronized,
it is recommended that external synchronization be used.
Details of this procedure are contained in application
report SBAA035, External Synchronization of the
DCP01/02 Series of DC/DC Converters, available for
download at www.ti.com.
CONSTRUCTION
The DCR02 is manufactured using the same technology
as standard IC packages. There is no substrate within the
package. The DCR02 is constructed using a driver IC,
low-dropout voltage regulator, rectifier diodes, and a
wound magnetic toroid, all mounted on a leadframe. The
DCR02 requires no special printed circuit board (PCB)
assembly processing, since there is no solder within the
package. The result is an isolated DC/DC converter with
inherently high reliability.
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