F
EATURES
•
•
•
•
•
•
•
•
•
•
•
–40°C to + 85°C operation
19 to 40 VDC input
Fully Isolated
Optocoupler feedback
Fixed frequency, 245 kHz typical
Topology – Push-Pull Forward
50 V for up to 50 ms transient protection
Inhibit/sync function
Indefinite short circuit protection
Remote sense on single models
Up to 84% efficiency
DC/DC C
ONVERTERS
28 V
OLT
I
NPUT
SINGLE
5
12
15
HR700 SERIES
70 WATT
MODELS
VDC O
UTPUT
DUAL
±12
±15
TRIPLE
+5 & ±12
+5 & ±15
Size (max.): 3.20 x 2.46 x 0.595 inches
(81.3 x 62.5 x 15.11 mm)
See Section B8, case L, for dimensions.
Weight:
140 grams typical
Screening: Standard only.
See Section B9 for screening description.
DESCRIPTION
HR700 Series DC/DC converters offer up to 70 watts of power from
single, dual, or triple outputs in one package. The converters
combine the small size and high reliability of hybrid-based compo-
nents, the high efficiency of switching regulators, and the isolation,
regulation, and low noise characteristics of linear regulators.
provided by detecting peak primary switching current on a cycle
basis and limiting it to approximately 130% of the full load input
current. This method results in quick and positive current limiting
under short circuit conditions.
HR700 Series DC/DC converters are designed to provide full power
operation over the input voltage range of 19 to 40 VDC. Operation
below an input of 19 volts is possible with derated output power.
Outputs are available as 5, 12, and 15 VDC single, dual and triple
outputs. The converters typically provide greater than 80% effi-
ciency over the entire input range. Line regulation is typically within
0.1% and load regulation within 0.2%.
SMALL SIZE
The HR700 converters are manufactured using techniques that
provide very small size and low profile components. Each converter
uses less than eight square inches of board areas and is 0.595
inches high or less. The overall power density is 20 watts per cubic
inch.
LOW NOISE
The HR700 Series converters offer low noise on both the input and
output lines. A two section, four pole, LC input filter is included to
provide very low reflected line ripple current. Output ripple is main-
tained at less than 50 mV p-p for single and dual models and 85 mV
p-p for triple output models.
HIGH RELIABILITY
Assembled using thick-film technology, the HR700 parts use the
same manufacturing procedures and quality controls that we apply
to converters designed for commercial airliners, the space shuttle,
advanced fighter aircraft, and other high reliability applications. The
steel cases are hermetically sealed in a dry nitrogen environment
and are guaranteed a maximum leak rate of less than 10
-3
atm-
cc/sec. All devices are 100% electrically tested.
INHIBIT
/
SYNC FEATURE
An inhibit/sync pin is standard on all models of the HR700 Series
converters. The pin serves as both an output inhibit and as a
synchronization input. In the inhibit mode an open collector TTL
compatible low (<0.8 V) will disable internal switching thereby
inhibiting the unit’s output. Inhibiting in this manner results in an
extremely low quiescent current.
HIGH PERFORMANCE
The HR700 series parts are high efficiency, low noise, pulse-width
modulated converters which use a quasi-square wave forward
converter design with a nominal switching frequency of 245 kHz.
Isolation between input an output is provided with a transformer in
the forward power loop and a wide band, temperature insensitive,
optical link in the feedback control loop. Short circuit protection is
B4-33
HR700 SERIES
70 WATT
ABSOLUTE MAXIMUM RATINGS
DC/DC C
ONVERTERS
SYNC AND INHIBIT
Sync In (245 to 370 kHz.)
• Duty cycle 70% min, 98% max.
• Logic low 0.8V max
• Logic high 4.5 V min
• Referenced to input common
• If sync is not used, leave unconnected
Inhibit TTL Open Collector
• Logic low (output disabled)
Inhibit pin current 1 mA max
• Referenced to input common
• Logic high (output enabled)
V =
≥
4.5V
TYPICAL CHARACTERISTICS
Output Voltage Temperature Coefficient
• 150 ppm/°C, typical
Input to Output Capacitance
• 160 pF, typical
Isolation
• 100 megohm minimum at 500 V
Conversion Frequency
• Free run mode 245 kHz, typical
Inhibit Pin Voltage (unit enabled)
• 4.5 to 5.5 V
Output Power
• 60 to 70 watts depending on model
Lead Soldering Temperature (10 sec per lead)
• 300°C
Storage Temperature Range (Case)
• –55°C to +125°C
RECOMMENDED OPERATING CONDITIONS
Input Voltage Range
• 19 to 40 VDC continuous (see Derating)
Case Operating Temperature (Tc)
• –40°C to +85°C full power
DERATING OUTPUT POWER/CURRENT AND INPUT VOLTAGE
Temperatures are referenced to the temperature at the converter’s baseplate
• Linearly derate output power/current from 100% at 85°C to 0% at 125°C.
• Above 105°C linearly derate steady state input voltage to 33 volts at 125°C.
• Indefinite short circuit protection is not guaranteed above 85°C case.
• Operation below an input voltage of 19 volts, including operation in MIL-
STD-704E emergency power conditions, is possible with derated output
power. See Figures 10 and 11.
Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, free run, unless otherwise specified.
SINGLE OUTPUTS
PARAMETER
OUTPUT
VOLTAGE
OUTPUT
CURRENT
OUTPUT
POWER
OUTPUT
RIPPLE
LINE
REGULATION
LOAD
REGULATION
INPUT
VOLTAGE
INPUT
CURRENT
INPUT REFL.
RIPPLE
EFFICIENCY
STARTUP
DELAY
CONDITION
FULL LOAD
V
IN
= 19 TO 40
Tc = –55°C TO +85°C
FULL LOAD BW
≤
2 MHz
V
IN
= 19 TO 40
NO LOAD TO FULL
HR701-2805
MIN
4.90
—
—
—
—
—
19
NO LOAD
INHIBITED
FULL LOAD
BW
≤10
MHz
WITH LOW
IMPEDANCE SOURCE
—
—
—
77
—
TYP
5.00
—
—
30
10
10
28
75
30
10
80
5
MAX
5.10
12.00
60
100
30
30
40
100
35
50
—
10
HR701-2812
MIN
TYP MAX
HR701-2815
MIN.
TYP
MAX
UNITS
VDC
A
W
mV p-p
mV
mV
VDC
mA
mA p-p
%
ms
11.75 12.00 12.25
—
—
—
—
—
19
—
—
—
80
—
—
—
30
10
10
28
70
30
10
83
8
5.83
70
100
30
30
40
100
35
50
—
10
14.75 15.00 15.25
—
—
—
—
—
19
—
—
—
80
—
—
—
30
10
10
28
70
30
10
83
8
4.67
70
100
30
30
40
100
35
50
—
10
B4-34
DC/DC C
ONVERTERS
DUAL AND TRIPLE OUTPUTS
PARAMETER
OUTPUT
VOLTAGE
CONDITION
FULL
LOAD
MAIN
DUAL
MAIN
DUAL
MIN
HR702-2812
TYP
MAX
—
—
—
±11.75 ±12.00 ±12.25
—
—
—
—
—
MAIN
DUAL
MAIN
DUAL
MAIN
DUAL
—
—
—
—
—
—
—
2.92
—
35
—
—
30
—
10
—
25
—
5.5
—
66.5
70
—
100
—
30
—
50
HR702-2815
MIN
TYP
MAX
HR703-28512
MIN
TYP
MAX
MIN
HR700 SERIES
70 WATT
HR703-28515
TYP
MAX
UNITS
VDC
Electrical Characteristics: 25°C Tc, 28 VDC Vin, 100% load, free run, unless otherwise specified.
—
—
—
4.90
5.05
5.15
4.90
4.95
5.10
±14.75 ±15.00 ±15.25 ±11.50 ±11.80 ±12.10 ±15.05 ±15.30 ±15.75
—
—
—
—
—
—
—
—
—
—
—
—
2.33
—
35
—
—
30
—
10
—
25
—
4.4
—
66.5
70
—
100
—
30
—
50
—
—
—
—
—
—
—
—
—
—
—
4.0
1.67
20
20
—
50
50
2
100
5
480
10.0
4.2
50
50
60
100
100
25
225
30
750
—
—
—
—
—
—
—
—
—
—
—
4.0
1.33
20
20
—
50
50
2
100
5
300
10.0
3.33
50
50
60
100
100
25
225
30
600
OUTPUT
V
IN
=
CURRENT
1, 2
19 TO 40
OUTPUT
POWER
1, 2
OUTPUT
RIPPLE
MAIN
±DUAL
TOTAL
FULL LOAD
BW
≤
2 MHz
A
W
mV p-p
mV
mV
LINE
V
IN
=
REGULATION 19 TO 40
NO LOAD
LOAD
3
REGULATION TO FULL
DUAL
CROSS
4
REGULATION +P
O
= 3 W TO 35 W
–P
O
= 35 W
+P
O
= 20 W TO 50 W
–P
O
= 50 W TO 20 W
CROSS
5
MAIN +P
O
= 30 W
REGULATION DUAL
+P
O
= 3 W TO 27 W
–P
O
= 27 W TO 3 W
MAIN
+P
O
= 3 W TO 30 W
DUAL ±P
O
= 15 W
INPUT
VOLTAGE
INPUT
CURRENT
INPUT REFL.
RIPPLE
EFFICIENCY
STARTUP
DELAY
NO LOAD
INHIBITED
FULL LOAD
BW
≤10
MHz
—
—
1.5
2.0
3.0
4.0
—
—
1.5
2.0
3.0
3.5
—
—
—
—
—
—
—
—
—
—
—
—
%
—
—
—
—
—
—
—
2.3
6.0
—
2.3
5.0
%
—
19
—
—
—
80
—
—
28
75
25
15
83
15
—
40
100
35
50
—
25
—
19
—
—
—
80
—
—
28
75
25
15
83
15
—
40
100
35
50
—
25
—
19
—
—
—
79
—
5.4
28
85
30
15
84
6
9.0
40
115
35
50
—
10
—
19
—
—
—
79
—
5.0
28
60
30
15
84
6
7.0
40
115
35
50
—
10
VDC
mA
mA p-p
%
ms
Notes
1. On dual output models the maximum combined output power is 70 watts.
A maximum of 95% (66.5 W) is available from any single output.
2. On triple output models the maximum combined output power is 60 watts.
A maximum of 50 watts is available from a single output.
3. Balanced loads
4. Regulation effect on the negative dual output during the defined conditions.
5. Regulation effect on both dual outputs during the defined conditions.
B4-35
HR700 SERIES
70 WATT
DC/DC C
ONVERTERS
THERMAL MANAGEMENT
H
EAT
S
INK
R
ECOMMENDATIONS
An HR700 Series converter in still air (other than convective
currents) and with no conductive cooling paths other than through
electrical connections at the pins will exhibit a thermal resistance of
approximately 4°C / watt. In cases where this value proves to be too
high it is recommended that additional heat sinking be supplied. The
simplest method of accomplishing this is to firmly attach the
converter to a PCB thereby providing a conductive thermal path.
Secondly it is recommended that airflow be provided over the
converter. Although each situation requires a thorough thermal
analysis these two measures can reduce the thermal resistance to
as low as 2°C / watt. If calculations indicate further heat sinking is
required it is recommended that additional thermal mass be
provided either under the base plate or on top of the converter's
mounting flanges or both.
C
ALCULATING
M
AXIMUM
A
MBIENT
T
EMPERATURE
The HR700 Series of DC/DC converters has an upper operating
temperature of + 85°C at the baseplate of the case. The degree of
heat sinking required to remain within this limit may be determined
from Figure 1 which shows the maximum allowed internal power
dissipation (P
DISS
vs. ambient temperature for various heat sink
thermal resistances. P
DISS
may be calculated as:
P
DISS
= P
OUT
/ efficiency – P
OUT
The efficiency for all combinations of P
OUT
and V
IN
for the various
models may be obtained from the graphs on the preceding pages.
Example: Converter = HR702-2815, T
AMB
= 70°C,
V
IN
= 28 VDC, P
OUT
= 45 watts
Efficiency = 85% (From Figure 7)
P
DISS
= (45 / 85) – 45 = 7.95 watts
From Figure 1 we can see that this situation will require thermal
resistance of approximately 4.5°C / watt.
Conversely we may also find the maximum ambient temperature
which can be tolerated if we know the heat sink thermal resistance.
Example: Converter = HR701-2805, V
IN
= 28 VDC, P
OUT
= 45 W.
Thermal Resistance = 3°C / watt.
Efficiency = 83.5% (From Figure 3)
P
DISS
= (45 / 0.835) – 45 = 8.89 watts.
From Figure 1 we can see that the maximum allowed ambient
temperature is approximately 75°C.
20
W
/W C/W
°
C/W
°
C/
4
°
CU=3
°
U=2 U=0
U=
15
Watts
10
5
20° 40° 60° 80° 100° 120° 140°
Degrees Centigrade
Internal Power Dissipation (max)
vs. Ambient Temperature
F
IGURE
1
B4-36
DC/DC C
ONVERTERS
PIN OUT
HR700 SERIES
70 WATT
Squared corner indicates pin one.
1
2
3
4
Pin
1
2
3
4
5
6
7, 8
9, 10
Single Output
Positive Input
Case Ground
Input Common
Inhibit/Sync In
Negative Sense
Positive Sense
Output Common
Positive Output
Dual Output
Positive Input
Case Ground
Input Common
Inhibit/Sync In
Negative Output
Positive Output
Output Common
No Connection
Triple Output
Positive Input
Case Ground
Input Common
Inhibit/Sync In
Negative Aux. Output
Positive Aux. Output
Output Common
Main (+5) Output
BOTTOM VIEW
HR700
See Section B8, case L, for dimensions.
9
7
5
10
8
6
F
IGURE
2: P
IN
O
UT
MODEL NUMBERING KEY
HR70
Base Model
Number of Outputs
(1 = single, 2 = dual, 3 = triple)
Input Voltage
Output Voltage
(Main and aux. Vout for triple models)
2 - 28
12
B4-37
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