04/01/04

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HYBRID-HIGH RELIABILITY
DC/DC CONVERTERS

ATR28XXS SERIES

Description

16 to 40 VDC Input Range (28 VDC Nominal)

3.3V, 5V, 12V and 15V Outputs Available

Indefinite Short Circuit and Overload

Protection

Up to 35 W/in

Power Density

30 Watt Output Power Models

Fast Loop Response for Superior Transient

Characteristics

Operating Temperature Range from -55°C to

+125°C

Popular Industry Standard Pin-Out

Resistance Seam Welded Case for Superior

Long Term Hermeticity

Ceramic Feed-thru Pins

External Synchronization

Efficiencies up to 84%

Shutdown from External Signal

Military Screening

Features

ATR

28V Input, Single Output

The advanced feedback design provides fast loop
response for superior line and load transient characteristics
and offers greater reliability and radiation tolerance
than devices incorporating optical feedback circuits.

Three standard temperature grades are offered with
screening options. Refer to Part Number section. These
devices can be provided in a standard plug-in package
for PC mounting or in a flanged package for more
severe environments.

These converters are manufactured in a facility certified
to MIL-PRF-38534. All processes used to manufacture
these converters have been qualified to enable
Advanced Analog to deliver compliant devices.

Four screening grades are available to satisfy a wide
range of requirements. The CH grade converters are
fully compliant to MIL-PRF-38534 for class H. The HB
grade converters are processed to full class H screening
but do not have class H element evaluation as required
by MIL-PRF-38534. Both grades are fully tested to
confirm operation over the full military temperature
range without derating of output power. The ES version
is a full temperature device without the full class H or
element evaluation. The non-suffix device is a low cost
limited temperature range option. Variations in electrical,
mechanical and screening can be accommodated.

Extensive computer simulation using complex
modeling enables rapid design modification to
be provided. Contact IR Santa Clara with specific
requirements.

The ATR28XXS Series of DC/DC converters feature
high power density and an extended temperature range
for use in military and industrial applications. Designed
to MIL-STD-704D input requirements, these devices
have nominal 28VDC inputs with 3.3V, 5V, 12V and
15V single outputs to satisfy a wide range of requirements.
The circuit design incorporates a pulse width
modulated single forward topology operating in the
feed-forward mode at a nominal switching frequency
of 550KHz. Input to output isolation is achieved through
the use of transformers in the forward and feedback
circuits.

PD - 94549A

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ATR28XXS Series

ABSOLUTE MAXIMUM RATINGS
Input Voltage -0.5V to 50V
Soldering Temperature 300

C for 10 seconds

Case Temperature Operating -55

C to +125

Storage -65

C to +135

Specifications

ATR2803R3S

Table I. Electrical performance Characteristics

Limits

Test

Symbol

Conditions

-55°C TC +125°C

= 28VDC ±5%, C

= 0

Unless otherwise specified

Group A

Subgroups

Device

Types

Min

Max

Units

Output voltage

OUT

= 0

3.25

3.35

2,3

3.20

3.40

Output current

OUT

= 16, 28, and 40 VDC

1,2,3

7500

Output ripple voltage

RIP

= 16, 28, and 40 VDC

B.W. = 20Hz to 2 MHz

1,2,3

mV p-p

Line regulation

LINE

= 16, 28, and 40 VDC

OUT

= 0, 3000, and 6000mA

±20

2,3

±30

Load regulation

LOAD

= 16,28, and 40 VDC

OUT

= 0, 3000, and 6000mA

1,2,3

±50

Input current

OUT

= 0, inhibit (pin 2)

Tied to input return (pin 10)

1,2,3

OUT

= 0, inhibit (pin 2) = open

Input ripple current

RIP

OUT

=6000mA

B.W. = 20Hz to 2 MHz

1,2,3

mA p-p

Efficiency

OUT

=6000mA

2,3

Isolation

ISO

Input to output or any pin

to case (except pin 8) at

500 VDC, TC =+25°C

100

Capacitive load

4, 5

No effect on dc performance

TC =+25°C

500

µF

Power dissipation

load fault

Overload, TC = +25°C

Short Circuit

1,2,3

Switching frequency

OUT

= 7500mA

4,5,6

500

600

KHz

Sync frequency range

SYNC

OUT

= 7500mA

4,5,6

500

700

KHz

Output response to step

TLOAD

Load step 50% to/from 100%

4,5,6

-500

+500

mV pk

transient load changes

Load step 50% to/from 100%

4,5,6

-500

+500

Recovery time step

LOAD

Load step 50% to/from 100%

100

transient load changes

7, 8

5,6

200

µs

100

Load step 50% to/from 100%

5,6

200

Output response to transient

step line changes

5, 9

TLINE

Input step 16V to/from

40VDC, I

OUT

= 7500mA

4,5,6

±500

mV pk

For Notes to Specifications, refer to page 3

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ATR28XXS Series

Table I. Electrical performance Characteristics -

continued

ATR2803R3S

Notes to Specifications

1 Parameter guaranteed by line and load regulation tests.
2 Bandwidth guaranteed by design. Tested for 20 KHz to 2 MHz.
3 Output voltage measured at load with remote sense leads connected across load.
4 Capacitive load may be any value from 0 to the maximum limit without compromising dc performance. A capacitive load in excess of
the maximum limit will not disturb loop stability but may interfere with the operation of the load fault detection circuitry, appearing
as a short circuit during turn on.
5 Parameter shall be tested as part of design characterization and after design or process changes. Thereafter parameters shall be
guaranteed to the limits specified in table I.
6 An overload is that condition with a load in excess of the rated load but less than that necessary to trigger the short circuit
protection and is the condition of maximum power dissipation.
7 Load step transition time between 2 and 10 microseconds.
8 Recovery time is measured from the initiation of the transient to where V

OUT

has returned to within ±1 percent of V

OUT

at 50 percent

load.
9 Input step transition time between 2 and 10 microseconds.
10 Turn on delay time measurement is for either a step application of power at the input or the removal of a ground signal from the
inhibit pin

(pin 2) while power is applied to the input.

Limits

Symbol

Conditions

-55°C TC +125°C

= 28VDC ±5%, C

= 0

Unless otherwise specified

Group A

Subgroups

Device

Types

Min

Max

Units

Recovery time transient step

line changes

5, 8, 9

LINE

Input step 16V to/from

40VDC, I

OUT

= 7500mA

4,5,6

Turn on overshoot

VTon

OUT

= 10% to 100% of Load

4,5,6

350

mV pk

Turn on delay

Ton

OUT

=0 and 7500mA

4,5,6

Load fault recovery

5, 10

4,5,6

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ATR28XXS Series

Specifications

For Notes to Specifications, refer to page 5

ABSOLUTE MAXIMUM RATINGS
Input Voltage -0.5V to 50V
Soldering Temperature 300

C for 10 seconds

Case Temperature Operating -55

C to +125

Storage -65

C to +135

Table II. Electrical performance Characteristics

Limits

Test Symbol

Conditions

-55

+125

= 28VDC

5%, C

= 0

Unless otherwise specified

Group A

Subgroups

Device

Types

Min Max

Units

Output voltage

OUT

= 0

4.95

5.05

2,3

4.90

5.10

Output current

OUT

= 16, 28, and 40 VDC

1,2,3

6000

Output ripple voltage

RIP

= 16, 28, and 40 VDC

B.W. = 20Hz to 2 MHz

1,2,3 01

p-p

Line regulation

LINE

= 16, 28, and 40 VDC

OUT

= 0, 3000, and 6000mA

1 01

2,3

Load regulation

LOAD

= 16,28, and 40 VDC

OUT

= 0, 3000, and 6000mA

1,2,3 01

Input current

OUT

= 0, inhibit (pin 2)

Tied to input return (pin 10)

1,2,3 01

OUT

= 0, inhibit (pin 2) = open

Input ripple current

RIP

OUT

=6000mA

B.W. = 20Hz to 2 MHz

1,2,3 01

p-p

Efficiency E

OUT

=6000mA 1

2,3

Isolation

ISO

Input to output or any pin
to case (except pin 8) at
500 VDC, TC =+25

1 01

100

Capacitive load

4, 5

No effect on dc performance
TC =+25

4 01

500

Power dissipation
load fault

Overload, TC = +25

Short

Circuit

1,2,3

Switching frequency

OUT

= 6000mA

4,5,6

500

600

KHz

Sync frequency range

SYNC

OUT

= 6000mA

4,5,6

500

700

KHz

Output response to step

TLOAD

3000mA to/from 6000mA

4,5,6

-500

+500

mV pk

transient load changes

500mA to/from 3000mA

4,5,6

-500

+500

Recovery time step

LOAD

3000mA

to/from

6000mA

100

transient load changes

7, 8

5,6 01 200

500mA to/from 3000mA

100

5,6

200

Output response to transient
step line changes

5, 9

TLINE

Input step 16V to/from
40VDC, I

OUT

= 6000mA

4,5,6 01

500

mV pk

ATR2805S

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ATR28XXS Series

Notes to Specifications

Table II. Electrical performance Characteristics -

continued

ATR2805S

Limits

Test Symbol

Conditions

-55

+125

= 28VDC

5%, C

= 0

Unless otherwise specified

Group A

Subgroups

Device

Types

Min Max

Units

Recovery time transient step
line changes

5, 8, 9

LINE

Input step 16V to/from
40VDC, I

OUT

= 6000mA

4,5,6 01

Turn on overshoot

VTon

OUT

=0 and 6000mA

4,5,6

500

mV pk

Turn on delay

Ton

OUT

=0 and 6000mA

4,5,6

Load fault recovery

5, 10

4,5,6

01 25 ms

1 Parameter guaranteed by line and load regulation tests.
2 Bandwidth guaranteed by design. Tested for 20 KHz to 2 MHz.
3 Output voltage measured at load with remote sense leads connected across load.
4 Capacitive load may be any value from 0 to the maximum limit without compromising dc performance. A capacitive load in excess of
the maximum limit will not disturb loop stability but may interfere with the operation of the load fault detection circuitry, appearing
as a short circuit during turn on.
5 Parameter shall be tested as part of design characterization and after design or process changes. Thereafter parameters shall be
guaranteed to the limits specified in table II.
6 An overload is that condition with a load in excess of the rated load but less than that necessary to trigger the short circuit
protection and is the condition of maximum power dissipation.
7 Load step transition time between 2 and 10 microseconds.
8 Recovery time is measured from the initiation of the transient to where V

OUT

has returned to within ±1 percent of V

OUT

at 50 percent

(pin 2) while power is applied to the input.

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