Datasheet ISR2805DURH, ISR2805DSRH, ISR2805DKURH, ISR2805DKSRH, ISR2800DKSRH Datasheet (MSK)

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4704 Dey Road Liverpool, N.Y. 13088 (315) 701-6751

M.S.KENNEDY CORP.

ISO 9001 CERTIFIED BY DSCC

ISR2800D

RADIATION HARDENED

HIGH-POWER, HIGH EFFICIENCY

DC-DC POWER CONVERTER

DESCRIPTION:

The ISR2800D is the first in a series of radiation-hardened, high-reliability power supplies to be offered by MSK.

The ISR2800D is specifically optimized to drive transmit/receive (T/R) modules in Phased Array Antennas (PAA), but

as a result of its high-performance capabilities and numerous built-in features, it is ideal for many other applications.

The ISR2800D utilizes two DC-DC converters to optimize power conversion efficiency and facilitate voltage sequenc-

ing necessary to protect T/R modules during power-up and power-down. A small flyback converter, referenced to

input return and switching at 200kHz, is used to provide electrical input-output isolation, generate nominal +10VDC

bias voltages for the input and output control circuits of the power supply, and generate a nominal -5VDC negative

output voltage for the T/R modules. The negative output voltage for the T/R modules is cross-regulated via a tap on

the flyback transformer and referenced to output return. A low drop-out (LDO) linear regulator is then used to further

post-regulate this output voltage to ensure tight regulation and low ripple, typically less than 5mVp-p. A single

transistor forward converter, referenced to output return and switching at 100kHz, provides the positive adjustable

output voltage. They are enclosed in a hermetic Silicon Aluminum (SiAl) package and weigh less than TBD grams.

The package utilizes rugged ceramic feed-through Glid-Cop pins and is sealed using parallel seam welding.

FEATURES:

82.5W Output Power

18-40VDC Steady-state Input Voltage Range

Adjustable Positive Output Voltage - 3.3V to 5.0V

Fixed -5V Negative Output

Typical 90% Efficiency from Half Load to Full Load

Total Dose - 100krad(Si)(max)

Single-Event Effects - LET>82MeV-cm²/mg

SEGR Hardened MOSFETs

Integrated Circuits are SEL Immune

Internal EMI Filter meets MIL-STD-461

Input Inrush Current Limiting

Remote Sense for Main Output Voltage

Soft-start Circuitry Prevents Output Voltage Overshoot

Input Undervoltage Lockout

Output Overload and Short Circuit Protection

Output Overvoltage Protection

Synchronization Capability

External Inhibit

Rev. - 3/01

PRELIMINARY

TYPICAL APPLICATIONS

Geostationary (GEO) Earth Orbit Satellites

Low Earth Orbit (LEO) Satellites

Deep Space Satellites/Probes

Communication Systems

PIN-OUT INFORMATION

CROW BAR

-5V OUT

VOUT RTN

+VOUT

VOUT RTN

+VOUT

VOUT RTN

+VOUT

VOUT RTN

+VOUT

REM SENSE

VOUT ADJ

VOUT OVP ADJ

PRI INHIBIT

ETERM

INPUT

INPUT RTN

INPUT

INPUT RTN

INPUT

INPUT RTN

INPUT

INPUT RTN

SEC ON/OFF

SYNC OUT

SYNC IN

Page 2

-0.5V to +50V

Internally Limited

-0.5V to +50V

-0.5V to +5.0V

+Vout ±0.5V

+300°C for 10 seconds

-55°C to 85°C

-55°C to 150°C

Input Voltage Range

Ouput Power

PRI Inhibit

Sec On/Off

Sync In

Rem Sense

Lead Temperature

Operating Temperature

Storage Temperature

ABSOLUTE MAXIMUM RATINGS

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Rev. - 3/01

PRELIMINARY

EQUIVALENT SCHEMATIC

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INPUT CHARACTERISTICS

Input Voltage

-5VOUT

Output Converter Frequency

Output Voltage

Output Current

Output Power

Output Ripple

Output Current Limit

Output Over-voltage Limit

+VOUT

Output Converter Frequency

Output Voltage Adjustable Range

Output Voltage Regulation

Output Current

Output Power

Output Ripple

Output Current Limit

Output Over-voltage Limit

Output Step-load Response

Output Step-line Response

Output Step-line Recovery Time

Output Efficiency

+VOUT

Power Supply Efficiency

TURN-ON RESPONSE

-5VOUT Output Overshoot

-5VOUT Output Turn-on Time

+VOUT Overshoot

+VOUT Turn-on Time

Max.

240

-4.75

500

2.5

1.75

-5.50

115

5.00

5.0

1.0

24.0

130

1.6

200

500

Typ.

200

-5.00

200

1.50

-6.00

100

0.0

0.4

21.3

120

0.8

Min.

-0.5

160

-5.25

1.25

-6.50

3.30

-5.0

16.0

110

-1.6

KHz

mVp-p

KHz

%Vo

%Vo-p-p

%Vo

%Vo-p

Steady-state

Transient, ≤ 50ms

Zero Load to/from Half Load, VIN=22-40VDC

Recovery to within ±1% of VOUT

18V to/from 40V

18V to/from 40V, Recovery to within 1% of VOUT

+VOUT=5V, IOUT=8-16A; -IOUT=-200mA

+VOUT=5V, IOUT=16A; -IOUT=-500mA

Input Voltage Stepped from 0 to 28VDC

Parameter

Units

ISR2800D

Test Conditions

Group A

Subgroup

1,2,3

4,5,6

1,2,3

4,5,6

1,2,3

4,5,6

1,2,3

4,5,6

1,2,3

4,5,6

1,2,3

4,5,6

ELECTRICAL SPECIFICATIONS

Rev. A 10/99

PRELIMINARY

Output Step-load Recovery Time

4,5,6

Continued on next page

-50

Page 4

ELECTRICAL SPECIFICATIONS CONTINUED

Rev. - 3/01

PRELIMINARY

NOTES:

1 -55°C ≤ Tc ≤ 85°C, V

IN=18-40VDC, IOUT-MAIN=0-16A, IOUT-AUX=0-500mA, unless otherwise specified

2 This parameter is an operating condition and is verified during device testing.

3 This parameter shall be guaranteed by design and need not be tested.

4 Typical parameters are representative of actual device performance but are for reference only.

5 Subgroup 1,4 TA=TC=+25°C

2,5 T

A=TC=+125°C

3,6 T

A=TC=-55°C

PRI INHIBIT INPUT

Input Voltage Range

Open Circuit Voltage

Input (Sink) Current

SEC ON/OFF

Input Voltage Range

Open Circuit Voltage

Input (Sink) Current

POWER DISSIPATION

Load Fault

PRI Input Inhibit Active

Sec Output Inhibit Active

MISC

Line Rejection

Isolation

Unit Weight

CAPACITIVE LOAD

-5VOUT

+VOUT

SHORT CIRCUIT RECOVERY TIME

-5VOUT

+VOUT

SYNC OUT

Amplitude

SYNC IN

Input Threshold

Frequency Range

Input Current

Min Pulse Width

CROW BAR

Output High Voltage

Output High Current

Max.

2.5

0.05

TBD

288

200

500

5.0

400

500

Typ.

MΩ

grams

µF

KHz

Main Output Short Circuit

IOUT=0A

DC to 50KHz

Input to Output, Input to Case, Output to Case Tested at 100VDC

No effect on DC Performance.

Outputs returns to within 1% of nominal voltage

IOUT≤10mA

VSYNC=3.5V

Parameter

Units

ISR2800D

Test Conditions

Group A

Subgroup

1,2,3

4,5,6

1,2,3

4,5,6

1,2,3

4,5,6

1,2,3

Min.

-0.5

100

3.5

250

Page 5

Rev. - 3/01

PRELIMINARY

PRI INHIBIT - Allows on/off control from circuits referenced to the input return. Main and auxiliary outputs

are on when this pin is left open and off when this pin is shorted to input return.

ETERM - Allows control of PRI Inhibit pin in electrically noisy environments. This pin bypasses the internal

EMI filter to the internal ground reference and must be isolated. Connecting this pin to the PRI inhibit will

disable the unit.

INPUT - Input power terminals to connect to primary power source. All of these pins must be connected by

the user.

INPUT RTN - Input power terminals to connect to primary power source. All of these pins must be con-

nected by the user.

SEC ON/OFF - Allows on/off control from circuits referenced to the output return. +Vout and -5Vout

outputs are on when this pin is left open. +Vout is off when this pin is shorted to output return.

SYNC OUT - Allows user to synchronize other devices to the operating frequency of the converter. This AC

coupled pin can drive up to 50Ω with an output level of 3.4V.

SYNC IN - Allows user control of the converter operating frequency within a limited range. If unused,

connect to output return, or leave open. This pin has an input impedance of 50Ω.

CROW BAR - Allows user control to ensure proper voltage sequencing during fault conditions. This com-

mand may be used to activate a crowbar circuit on the main output to guarantee proper power down

sequencing. This output should normally be buffered (e.g. to drive the gate of a FET) in timing critical

sequencing applications. For non-critical timing or high impedance input devices, it may be used directly.

Otherwise, it should be left open.

-5VOUT - Provides 2.5W of negative five volt, low noise bias power.

SEC RTN - Output power return terminals to connect to isolated secondary loads. This is the return ground

reference for both the outputs. All of these pins must be connected by the user.

+VOUT - Main adjustable output voltage. Output power terminals connect to isolated secondary loads.

This output is adjustable from 3.3V to 5V. All of these pins must be connected by the user.

REM SENSE - Remote sense allows user to connect to a remote location near the load for point of regulation.

This overcomes a limited amount of voltage drop in the distribution network. Otherwise, connect this pin to

the +Vout output.

VOUT ADJ - Allows adjustment of the +Vout voltage over the allowable range using an external resistor

from this pin to the output return.

VOUT OVP ADJ - Allows adjustment of the over-voltage protection (OVP) threshold to match the (adjust-

able) main output voltage. Threshold is adjusted by connecting a resistor from this pin to the output return.

APPLICATION NOTES

ISR2800D PIN DESCRIPTIONS

Page 6

Rev. - 3/01

PRELIMINARY

APPLICATION NOTES CONT'D

BASIC ARCHITECTURE:

MSK power converters utilize two DC-DC converters to opti-

mize power efficiency and to provide internal housekeeping power

while magnetically isolating the power bus from the load. A small

flyback converter, referenced to input return, is used to provide

electrical input-output isolation and will generate nominal +10VDC

bias voltages for the input and output control circuits of the power

supply. A single transistor forward converter, referenced to out-

put return, provides the main output voltage.

FLYBACK CONVERTER:

The flyback converter uses peak current-mode Pulse Width

Modulator (PWM) control and operates in discontinuous conduc-

tion-mode. Regulation is achieved by sampling the input bias volt-

age directly and feeding it back to the control circuit of the flyback

converter, which is referenced to input return.

FORWARD CONVERTER:

The forward converter uses voltage Mode Pulse Width Modu-

lator (PWM) control with input voltage feed-forward and operates

in continuous conduction-mode. Regulation is achieved by sam-

pling the output voltage directly and feeding it back to the control

circuit of the forward converter, which is referenced to output

return. Since the main output voltage is directly regulated without

the use of magnetically-coupled feedback, superior voltage regula-

tion can be achieved. A single-stage L-C output filter reduces the

typical output ripple to less than 25mVp-p.

SYNCHRONOUS RECTIFICATION:

Synchronous rectification is used to achieve high-conversion

efficiency over a half to full output load range and allows con-

verter operation in continuous conduction-mode down to zero out-

put load. This capability results in far superior dynamic perfor-

mance when the load is stepped to or from a zero load condition,

and is particularly critical in pulsed Phased Array Antenna and

modern microprocessor applications which have high peak current

demands and fast load transients.

INPUT EMI FILTER:

The input EMI filter is comprised of a multi-stage L-C filter

which provides attenuation of the differential-mode emissions from

the power supply. A balun, in conjuction with very small line-to-

chassis and return-to-chassis capacitors, provides attenuation of

the common-mode emissions from the power supply. Together

these components enable the power supply to meet the conducted

emission requirements of MIL-STD-461.

INRUSH CURRENT LIMITING:

Inrush current limiting circuitry limits initial peak input charg-

ing current at turn-on to less than two times maximum steady-

state input current. Consequently, even when the input voltage to

the power supply is instantaneously stepped, peak charging cur-

rent is well controlled.

UNDERVOLTAGE LOCKOUT:

An undervoltage lockout circuit prevents the power supply from

operating when the input line voltage is too low to maintain the

output voltage. The converter will not start until the line voltage

rises to approximately 17V and will shut down when the input

voltage drops below approximatley 16V. The approximate 1V of

hysteresis reduces the possibility of line noise interfereing with

the converter during power-up and power-down.

SOFT-START:

Soft-start circuitry associated with both the flyback and for-

ward converters is guaranteed to prevent output voltage over-

shoot during power-up for both the auxiliary and main output volt-

ages.

USER-ADJUSTABLE MAIN OUTPUT:

The +VOUT output voltage is user-adjustable over a range of

3.3VDC to 5VDC. Setting the positive output voltage is accom-

plished by using a single external resistor. The output voltage

may be programmed by the user to any desired voltage within this

range. The table below shows the value of resistance necessary

to set several common output voltages. The equation below may

be used to determine the resistor value required for other set points.

The output voltage may be adjusted up to 6V and down to 3V, but

some performance specifications will not be met.

Output Voltage Adjust Resistor Value (in KΩ)

f(Vout) = -6.7

f(3.0) = 2.98 x 10³

f(3.3) = 141.95

f(5.0) = 8.22

f(5.2) = 5.97

OVERVOLTAGE PROTECTION (OVP):

Overvoltage protection is provided for both the negative and

positive output voltages of the power supply. The overvoltage

protection circuit for the negative output voltage limits peak volt-

age to approximately 120% of nominal. The overvoltage limit for

the positive output voltage is programmable with a single external

resistor. It is recommended that this overvoltage limit be set at

approximately 120% of nominal.

The overvoltage protection is programmable over a limited range

using only a single external resistor. The OVP voltage may be

programmed by the user to any desired voltage within this range.

The OVP set point should be coordinated with the positive output

voltage and set to approximately 110% to 120% of the nominal

output. The table below shows the value of resistance necessary

to set the OVP to 120% for several common output voltages. The

equation below may be used to determine the resistor value re-

quired for other set points.

Output Voltage Over-Voltage Protection (OVP) Adjust Resistor Value

(in KΩ)

g(OVP) = -3.44

g(3.6) = 238.12

g(3.96) = 22.51

g(6) = 0.84

g(6.24) = 0.46

VOLTAGE SEQUENCING:

Output voltage sequencing is provided to protect T/R modules

from damage when used in PAA applications. During power-up,

the positive output voltage remains off until the negative output

voltage has reached normal regulation limits. During power-down,

a crowbar command is available to ensure that the positive output

voltage falls to 10% or less of its steady state value before the

negative output voltage falls more than 20% from its nominal value.

During fault mode the crowbar command allows user control of

the crowbar circuit on the positive output to ensure proper voltage

sequencing for application specific requirements.

2.5

0.04975Vout-0.1484166

10.4667

OVP-3.55667

Page 7

Rev. - 3/01

PRELIMINARY

APPLICATION NOTES CONT'D

RADIATION PERFORMANCE

MSK converters give you superior radiation performance with-

out the highs and lows of using "typical" DC-DC converters. The

design represents a break from the traditional hardening method

of simply replacing commercial die elements with radiation screened

die in an off-the-shelf DC-DC converter design.

Special design techniques implemented at both the module

level and the transistor circuit element level were used to harden

the DC-DC converters. Here are some of the engineering steps

taken to guarantee the radiation performance.

TOTAL DOSE HARDNESS:

The converters employ a fully magnetically-isolated configura-

tion allowing the positive converter output to be regulated directly

without the use of opto-couplers. Galvanic isolation between in-

put and output is provided by the flyback converter and a small

gate-drive transformer which couples the PWM drive signal to the

main switching MOSFET. This approach provides optimum out-

put voltage regulation and avoids the gain degrading effects of

total ionizing dose on opto-couplers which can result in converter

failure.

SINGLE-EVENT EFFECTS HARDNESS:

All critical ICs in the converter use a latch-up immune,

dielectrically-isolated, BiCMOS process that prevents converter

components from entering a potentially catastrophic latched state.

The heart of the DC-DC converter is the Single-Event Effects

hardened PWM. The chip has SEU-immune CMOS soft-start con-

trol logic which will not upset in a heavy ion environment. The on-

chip overcurrent comparator employs a redundant cross-checking

comparator design. Error amp circuitry incorporates redundant

wire OR differential input stages which prevent the amplifier out-

put from over-ranging, which could cause excessive output pulse

widths leading to overcurrent fault sequencing, transformer core

saturation or power switch overstress. The toggle Flip/Flop (F/F)

and all pulse control logic functions have been designed in SEU-

immune CMOS to keep pulse phase integrity from being upset.

The PWM used in the flyback circuitry incorporates these

same improvements with the exception of the soft-start func-

tion.

DC-DC converters use comparator ICs to control various

converter functions such as input inrush current limiting, input

undervoltage lockout, start-up regulator shutdown, output ov-

ervoltage protection, and main/auxiliary output voltage sequenc-

ing. A high-energy ion striking the comparator can cause any

of these functions to fail or inadvertantly activate causing un-

wanted power supply interruptions. The MSK converters em-

ploy a new hardened, SEU immune, quad comparator. The

chip uses triple redundant bipolar comparators for analog preci-

sion, and is backed by SEU-immune voting logic which ensures

that no single-particle error can propagate to the output.

The potential for catastrophic single-event gate rupture in

MOSFET's has led to the development of MOSFET's with ox-

ide structures which resist breakdown up to fully rated MOSFET

voltage potential under fully off-biased conditions. All MOSFET's

used in the converters mitigate Single-Event Gate Rupture ef-

fects up to 82 MeV-cm²/mg.

A PROVEN DESIGN METHODOLOGY

The power supplies were developed using a proven, conserva-

tive design methodology which includes selecting radiation-hard-

ened and established reliability components and fully de-rated to

the requirements of MIL-STD-975, MIL-STD-1547 and GSFC PPL-

21 Appendix B. Proprietary radiation-hardened silicon gate (RSG)

process for integrated circuits ensures total dose capability to

300krads and immunity to single-event latch-up (SEL). Radiation-

hardened power MOSFETs virtually eliminate the possibility of

single-event gate rupture and single-event burn-out. Direct regu-

lation is utilized instead of opto-couplers to minimize temperature,

radiation and aging sensitivity. The Cadence Analog Work Bench

(AWB) tool set, including Sensitivity/Worst Case and Monte Carlo

tools, was used extensively to predict and optimize circuit perfor-

mance for both beginning and end-of-life. Thorough design analy-

sis include Worst Case, Component Stress and Reliability (MTBF).

MSK's DC-DC converters offer high reliability through "tried

and true" methods of passive component procurement and hybrid

construction techniques. All stacked capacitors are procured, pre-

assembled (stacked) and up screened by the capacitor manufac-

turer. Capacitor mounting procedures are performed per the

supplier's guidelines. Magnetics, resistors and capacitors are all

procured to the highest standards. Full component level traceabil-

ity is maintained on all high-rel lots. Final hybrid assembly and

screening is available up to MIL-PRF-38534 Class K or Class H

requirements.

Page 8

Rev. - 3/01

PRELIMINARY

TYPICAL SYSTEM OPERATION

A typical application shows the ISR2805DSKE connections to an arbitrary load. The remote

sense line is used to eliminate voltage drop in the positive distribution lead. The negative output

provides bias to hold the gate of FET drive transistors off in radiation environments. A FET crowbar

circuit is driven directly to discharge the filter capacitance at the load during shutdown. The two

resistors connected to the OVP and VOUT ADJ pins set the output over voltage limit and output

voltage to the required values. Also illustrated is a connection to synchronize two converters to a

master clock. An isolated connection is shown to inhibit both converter outputs from the primary

referenced input voltage as well as a secondary ON/OFF command referenced to the output to

shutdown the positive output.

Page 9

The information contained herein is believed to be accurate at the time of printing. MSK reserves the right to make

changes to its products or specifications without notice, however, and assumes no liability for the use of its products.

Please visit out website for the most recent revision of this datasheet.

MECHANICAL SPECIFICATIONS

M.S. Kennedy Corp.

4704 Dey Road, Liverpool, New York 13088

Phone (315) 701-6751

FAX (315) 701-6752

www.mskennedy.com

ISR2800DKSRH

The above example is a Class K adjustable dual output rad-hard converter

RAD-HARD

LEAD CONFIGURATIONS

S= STRAIGHT; U= BENT UP; D= BENT DOWN

SCREENING

BLANK= INDUSTRIAL; E= EXTENDED RELIABILITY;

H= CLASS H; K= CLASS K

DUAL OUTPUT

OUTPUT VOLTAGE

+ADJ/-5V

NOMINAL INPUT VOLTAGE

GENERAL PART NUMBER

ORDERING INFORMATION

NOTE: ALL DIMENSIONS ARE ±0.010 INCHES UNLESS OTHERWISE LABELED.

ESD Triangle indicates Pin 1.

Rev. - 3/01

PRELIMINARY