military power{ Reliable Power. Reliable Source }

About On Systems. {

On Systems are leading designers and

manufacturers of COTS power supplies and

complete power conversion equipment for

harsh military environments including Land,

Sea and Air applications.

Focussed entirely on power conversion, our highly experienced team can work with you to ensure that your power conversion requirement is delivered on time and on budget, by utilising a combination of standard COTS modules and semi custom design capabilities.

Our comprehensive range of standard, high quality AC-DC and DC-DC converters, ranging from PCB mounted units of a few watts to large system units of several kW, significantly shorten the development time, ensuring that the most cost effective, reliable, low risk, compliant power converters are selected from the outset of a program.

Fully compliant productOur thorough knowledge of the harsh environments required for Military

COTS power supplies drives our development teams to deliver standard

products that meet the rigours of:

DEF-STAN 61-5 Issue 6, DO-160,

MIL-STD 1275 and MIL-STD 704

surges and transients that protect

your equipment from electrical

damage.

Standard EMC filters and modules

ensure compliance to DEF-STD

59-411 Land Class A, MIL-STD

461 and TEMPEST, our team

can work with you to select the

optimum filter using our in house

pre-compliance EMC test facility.

DEF-STAN 0035, DO 160

and MIL-STD 810 Harsh

environmental specifications

are met with standard product

and are supported for use in

your product with our detailed

application notes.

SURGES AND TRANSIENTS

DEF-STAN 61-5 Issue 6

MIL-STD 1275

MIL-STD 704

EMC AND IMMUNITY

DEF-STAN 59-411 Land Class A

MIL-STD 461

TEMPEST

ENVIRONMENTAL

DEF-STD 0035

MIL-STD 810

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Our in house development team

uses a comprehensive range

of software products to model

your requirement. This up front

design capability ensures that

the optimum design is chosen

very early on in a program to

significantly reduce the design

effort of using standard modules

or providing a complete power

convertor product.

All of our standard Military COTS

products are available as 3D solid

models to reduce your design in

effort backed by industry leading

technical support.

Comprehensive design capabilities

and engineering expertise

Although many applications can

be satisfied using our range of

standard building block modules,

increasingly scarce in house

resource can be freed up by

outsourcing the entire power

supply system.

We offer a highly controlled,

project managed design resource

that can work with you from initial

design concept to final delivery of

a fully compliant power supply or

power system. All of our semi-

custom designs follow our strict

QMS procedures and are supplied

with thorough Design Verification

Testing (DVT) and type test.

Semi-custom design capability

High quality products

Designed and manufactured in the UK to our strict Quality Management

processes of BS EN 9100, ISO14001, IPC-A-610 and J-STD-001 our military

COTS power supplies offer a fully traceable bill of materials with high levels

of workmanship ensuring long service life.

Gated design process

Initial Concept

Specification & Proposal

Product Design & 3D Models

DVT & Prototype

Product Approval

Released to Production

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Thorough in house

test capability

All of our units are subjected to

thorough testing using our in

house test capabilities providing

full parametric operational test

results. This thorough testing

virtually eliminates infant

mortality whilst still maintaining

a cost effective product is

repeatedly delivered.

Urgent Operational

Requirement (UOR)

support

Our UK based design team can

react quickly to support your

UOR requirements by offering a

fast track, immediate response to

your power supply needs. Fast

delivery of standard or modified

stock products, matched by

a dynamic procurement and

supply chain management team

dramatically shortens design-in

and production supply times.

Design with

confidence

All of our Military COTS power

supplies are free from ITAR

restrictions and can therefore be

used with confidence in any UK

military program without the

fear of any future restriction of

supply.

Leading edge R&D and business focus

We consistently invest in R&D to ensure that we provide industry leading

products that offer high efficiency, high power density off the shelf products

that maintain our ethos of COTS power supplies.

Working closely with customers, suppliers and industry champions we

continuously improve the key attributes required to grow our portfolio

of products and our business with strategically important customers and

contracts in the military market.

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Useful Reference Guide to Military SpecificationsThere are two commonly used specifications in the military market; UK MOD DEF-STANs and USA MIL-STDs.

This guide serves to demonstrate some of the key factors that need to be considered when choosing

a power supply for electronic equipment.

Surges and TransientsMost military vehicles are 24V DC systems, commonly referred to as 28V systems. Connected electrical equipment has to meet MIL-STD-1275

and DEF-STAN 61-5 part 6, Avionic equipment has to meet MIL-STD-704.

The figures below show the surges and transients associated with MIL-STD-1275.

Mil 1275 –D surges and Transients for Normal Mode and Generator Mode

0

-250

-300

-200

-150

-100

-50

0

50

100

150

200

250

300

100 200 300 400 500 600 700 800 900 1000

RECOVERY TIME (mS)

Envelope of Spikes in Normal Operating Mode for 28 VDC Systems

VO

LTS

250V, 70µs

-250V, 70µs

40V, 1mS

25V TO 30V

-40V, 1mS

STEADY STATE VOLTAGE

0

-250

-300

-200

-150

-100

-50

0

50

100

150

200

250

300

100 200 300 400 500 600 700 800 900 1000

RECOVERY TIME (mS)

Envelope of Spikes in Generator-only Mode for 28 VDC Systems

VO

LTS

250V, 70µs

-250V, 70µs

100V, 1mS

23V TO 33V

-100V, 1mS

STEADY STATE VOLTAGE

DEF-STAN 61-5 part 6 issue 6This standard covers both 12V and 24V vehicle systems. It differentiates between the voltages seen in the vehicle original fit equipment,

(Platform) and those seen by any externally connected equipment (Terminal).

On Systems power supplies are designed to meet the harsher Platform equipment levels as standard.

PLATFORM AND TERMINAL EQUIPMENT OPERATING VOLTAGES

NOMINAL 12V NOMINAL 24V

TERMINAL EQUIPMENT

PLATFORM EQUIPMENT

TERMINAL EQUIPMENT

PLATFORM EQUIPMENT

LOWER VOLTAGE 9V 9V 18V 18V

UPPER VOLTAGE 16V 19V 32V 38V

0

5

0

10

15

20

25

30

35

40

45

100 200 300 400 500 600 700 800 900 1000

RECOVERY TIME (mS)

Envelope of Surges in Normal Operating Mode for 28 VDC Systems

VO

LTS

40V, 50mS

18V, 500mS

32V, 500mS

23V, 600mS

STEADY STATE VOLTAGE LIMITS

32V30V

23V25V

18V

0

10

0

20

30

40

50

60

70

80

90

100

110

100 200 300 400 500 600 700 800 900 1000

RECOVERY TIME (mS)

Envelope of Surges in Generator-only Mode for 28 VDC Systems

VO

LTS

100V, 50mS

STEADY STATE VOLTAGE LIMITS

40V

33V

16V23V

15V

40V, 500mS

16V, 600mS15V, 500mS

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Short Transients

SurgesThe figures below show the harsher surges and long transients for terminal equipment in 12V and 24V vehicles.

0.001

0

5

10

15

20

25

0.1 ∞1.00.01

RECOVERY TIME (SECONDS)

DETA03.A – 12V LIMITS

PEA

K V

OLT

AG

E (V

OLT

S)

20V, 0.05s

16V, 0.1s

11.5V, 0.5s

15V, 1.0s

12.5V, 1.0s

STEADY STATE >1s

DETA03.A – 24V LIMITS

0.001

0

10

20

30

40

50

0.1 ∞1.00.01

RECOVERY TIME (SECONDS)

PEA

K V

OLT

AG

E (V

OLT

S)

40V, 0.05s

32V, 0.1s

25V, 0.5s

30V, 1.0s

25V, 1.0s

STEADY STATE >1s

12VSYSTEM VOLTAGE 24V

Pulse amplitude -150V -200V

Positive pulse

Durations: t1 = 100µS t2=10mS t3=90mS Impedance = 50Ω

100V 200V

These transients simulate the spike present from relay switch arcing and other electro mechanical switch bounce. The unit must withstand

both positive and negative short transients, positive transients are identical in shape to those shown above.

NEGATIVE PULSE TRANSIENTS

0

Vs

VA

t3t2

t1

V

Load DumpA very harsh surge is the load dump. This is present in vehicle systems that have a loose battery connection.

This is classed as an extreme condition and equipment is allowed to turn off during the surge. On Systems have products that can operate

through this surge without turning off. This is particularly useful in systems that have a long re-boot time.

0

50

0

100

150

200

250

50 100 150 200 250 300 350 400

TIME (ms)

Parameter 12V 61-5 System 24V 61-5 System 24V 1275 System

Vpk 111V 202V 100V

Rise time 10ms 10mS 0mS

Period 0mS 0mS 50mS

Decay time 400ms 350mS 10mS

Energy 4j/Amp 30J/Amp 3J/Amp

Source impedance 0.5 Ohms 1 Ohm 0.5 Ohms

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MIL-STD-704, 28V DC equipment which is required to operate in emergency conditions, must do so with an extended DC steady state range

between 16 and 29 volts. This does not apply to 270V DC equipment.

DO 160 classifies equipment into four categories, A B Z and D, the result is a more complex document that cannot be captured in this

reference guide. The electrical specification is similar to MIL-STD-704, and common requirements include 50mS holdup for category B

equipment and 200mS for category Z. This large holdup time can challenge the design of the power supply, On Systems have products

that conform to both requirements in a compact footprint.

0.00040

60

80

100

120

140

160

180

200

TIME FROM ONSET OF TRANSIENT (SECONDS)

Envelope of Normal AC Voltage Transients

VO

LTS,

DC 118V, 0.0875s

0.025 0.050 0.075 0.100 0.025 0.125 0.150 0.175

108V, 0.080s

80V, 0.010s

180V, 0.010s

118V

108V

113V

0.00010

20

30

40

50

60

TIME FROM ONSET OF TRANSIENT (SECONDS)

Envelope of Normal Voltage Transients for 28 Volts DC Systems

VO

LTS,

DC

29V, 0.0825s

0.025 0.050 0.075 0.100 0.025 0.125 0.150 0.175

22V, 0.1000s18V, 0.0150s

50V, 0.0125s

0180

200

220

240

260

280

300

320

340

TIME FROM ONSET OF TRANSIENT (SECONDS)

Envelope of Normal AC Voltage Transients for 270 Volts DC Systems

VO

LTS,

DC

0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1

250V, 0.040s

200V, 0.010s

330V, 0.020s

280V

250V

280V, 0.040s

MIL STD 704F & DO 160F – Avionic systems

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EMC and SusceptibilityThe USA standard MIL-STD-461 and UK standard DEF-STAN-59-411 (replaced DEF-STAN-59-41) are used to limit the amount of electrical

noise introduced onto the electrical system, and ensure that electrically coupled noise on the system doesn’t affect the equipment.

EMC emissions are the most difficult to achieve compliance to and the levels are shown in the figures below.

MIL-STD-461F – Limits for all systems including the relaxation levels for different input voltages.

DEF-STAN-59-411 – Limits for Land Service Use for different classes of equipment.

Environmental SpecificationsUSA Specification MIL-STD-810 land air and sea and UK Specification DEF-STAN-0035, define the limits and severity levels that the equipment

will be subjected to. The levels of shock, vibration, temperature, water ingress, atmospheric pollution and humidity vary considerably

depending on where the equipment is installed.

It is vital that these environmental requirements are considered when designing in a power supply to ensure a long equipment lifetime.

Thermal management along with mechanical integration have the largest impact on reliability, On Systems engineers have considerable

knowledge of selecting and designing in a power supply to ensure that you use a reliable, cost effective product in your equipment.

10Hz0

20

40

60

80

100

120

140

FREQUENCY

CO

ND

UC

TED

EM

ISSI

ON

CU

RR

ENT

dBµA

100Hz 1kHz 10kHz 100kHz 1MHz 10MHz 100MHz 1GHz

Class D

Class C

Class B

Class A

150MHz, 40dB

4kHz, 130dB

300kHz, 40dB

500Hz, 130dB

150MHz,25dB600kHz,25dB

150MHz, 10dB1.2MHz, 10dB

150MHz, 0dB2MHz, 0dB

NOMINAL EUT SOURCE VOLTAGE (AC & DC) LIMIT RELAXATION

28V BASIC CURVE

115V

220V

270V

=/> 440V

6dB

9dB

10dB

12dB

10k40

50

60

70

80

90

100

110

FREQUENCY (Hz)

LIM

IT L

EVEL

(dB

µV

)

100k 1M 10M 100M

BASIC CURVE

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This useful reference guide is intended to demonstrate the requirements of Military power supplies, it is not intended for use as a design document and On Systems recommends that

original copies of the specifications must be used for equipment design. On Systems cannot accept responsibility if this document is used outside it’s intended purpose.

On Systems Limited

Telephone 0844 809 4608enquiries@on-systems.co.uk

www.on-systems.co.uk{