The compact DFA20 Series provides power densities up to 11 watts
per cubic inch (0.67 watts per cm
3
). Ideal for battery operated
industrial, medical control and remote data collection systems, this
converter has fully filtered inputs and outputs. Complete overload
protection with independent pulse-by-pulse current limiting and an
overtemperature shutdown ensures reliable system operation. The
output of the converter is electrically isolated, thereby allowing the
output to be configured as a positive or negative output voltage.
FEATURES
• Remote ON/OFF and TRIM
• Overcurrent Protection and Thermal Shutdown
• Efficiencies to 83%
• 700V Isolation, Up to 1544V on 48V Converters
• Power Density up to 11 Watts per Cubic Inch
• Five-Side Shielded Case
• Extended Range Input (2:1)
BOTTOM VIEW
2.02
(51.31)
SIDE VIEW
0.040 (1.02) DIA
6 PLACES
0.700
(17.78)
0.600
(15.24)
0.400
(10.16)
0.300
(7.62)
0.000
0.100
(2.54)
0.51
(13.0)
5
1
2
6
2.02
(51.31)
3
7
0.25
(6.35)
0.11
(2.8)
0.000
1.800
(45.72)
Mechanical tolerances unless otherwise noted:
X.XX dimensions: ±0.020 inches
X.XXX dimensions: ±0.005 inches
NOTES
(1) All parameters measured at Tc = 25°C, nominal input voltage and full rated load unless otherwise noted.
Refer to the Technical Reference Section for the definition of terms, measurement circuits and other
information.
(2) The Case is tied to the -Input, Pin 2.
(3) The functional temperature range is intended to give an additional data point for use in evaluating this
power supply. At the low functional temperature the power supply will function with no side effects,
however, sustained operation at the high functional temperature will reduce expected operational life.
The data sheet specifications are not guaranteed beyond the case operating range.
(4) The case thermal impedance is specified as the case temperature rise over ambient per package watt
dissipated.
0.45
(11.43)
0.000
Rev. 04/2000
1
DFA20 SERIES – SINGLE OUTPUT
NOTES
(1)
All parameters measured at Tc=25°C, nominal input voltage and full rated load unless otherwise
noted. Refer to the Technical Reference Section for the definition of terms, measurement circuits and
other information.
Noise is measured per Technical Reference Section. Measurement bandwidth is 0-20 MHz for peak-
peak measurements, 10 kHz to 1 MHz for RMS measurements. Output noise is measured with a
0.01µF ceramic in parallel with a 1µF/35V Tantalum capacitor located 1" away from the converter to
simulate your PCB’s standard decoupling. Input reflected ripple is measured into a 10µH source
impedance.
(3)
(4)
Short term stability is specified after a 30 minute warmup at full load, constant line and recording
the drift over a 24 hour period.
The input ripple rejection is specified for DC to 120 Hz ripple with a modulation amplitude of 1% of
Vin.
(2)
2
DFA20 SERIES – SINGLE OUTPUT
DFA20 SERIES APPLICATION NOTES:
External Capacitance Requirements
No external capacitance is required for operation of the DFA20
Series. The use of input capacitors with less than 0.5 ESR may
cause peaking in the input filter and degrade filter performance.
External output capacitance is not required for operation, however
it is recommended that 1 F to 10 F of tantalum and 0.001 to
0.1 F ceramic capacitance be selected for reduced system noise.
Additional output capacitance may be added for increased
filtering, but should not exceed 400 F.
Negative Outputs
A negative output voltage may be obtained by connecting the
+OUT to circuit ground and connecting -OUT as the negative
output.
Remote ON/OFF Operation
The remote ON/OFF pin may be left floating if this function is not
used. It is recommended to drive this pin with an open collector
arrangement or a relay contact. When the ON/OFF pin is pulled
low with respect to the -INPUT, the converter is placed in a low
power drain state.
Output TRIM
The TRIM pin may be used to adjust the output ±5% from the
nominal setting. This function allows adjustment for voltage drops
in the system wiring, as well 5.2 volt outputs for ECL applications.
Figure 1 shows the proper connections to use this function. A
trimpot value of 10K should be used for 3.3 and 5 volt outputs.
A trimpot value of 20K should be used for 12 and 15 volt
outputs. If the TRIM function is not required the pin may be
left floating.
+OUT
5
TRIM
7
-OUT
6
USING TRIMPOT
10K
LOAD
+OUT
5
TRIM
DOWN
TRIM
7
-OUT
6
USING FIXED RESISTORS
LOAD
TRIM
UP
Figure 1.
DFA20 SERIES BLOCK DIAGRAM
OUTPUT POWER DERATING
20
ISOLATION TRANSFORMER
THERMAL SHUTDOWN
5
+
+ OUTPUT
15
POWER OUTPUT
+ INPUT
1
– INPUT
2
LC
INPUT
FILTER
CURRENT
MODE
PWM
6
- OUT
10
+
ON/OFF
7
TRIM
3
ISOLATED
FEEDBACK
–
5
FIVE SIDED SHIELDED COPPER CASE
LOW TC
BANDGAP
REFERENCE
0
50
60
70
80
90
AMBIENT TEMPERATURE
100
NUCLEAR AND MEDICAL APPLICATIONS Power-One products are not authorized for use as critical components in life support systems, equipment used in hazardous environments,
or nuclear control systems without the express written consent of the President of Power-One, Inc.
TECHNICAL REVISIONS The appearance of products, including safety agency certifications pictured on labels, may change depending on the date manufactured. Specifications are
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