Flameproof Power

Metal Film Resistors

FA Series

Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com

Issue B · 03.02

Welwyn Components

146

Application Notes

1. If the resistors are to dissipate full rated power, it is

recommended that the terminations should not be

soldered closer than 4mm from the body.

2. Due to operating temperature limitations imposed by some

pcb materials, derating may be necessary. An estimate of

the temperature rise to be expected can be calculated using

the thermal impedance figures given under Electrical Data.

b

6

6

c

≤ 1.4 mm

Packaging

All FA Series resistors are normally supplied tape packed ready

for loading onto automatic sequencing and insertion

machines.

Component wires will not protrude beyond the outside edge

of the tapes.

Alternative packaging available by request.

Lead Formed resistors can also be supplied. Standard options

of Lancet, Radial and Goalpost forming are shown in Lead

Form Information section.

Marking

Resistors are colour coded with 4 bands.

IEC 62 colours are used.

Solvent Resistance

The body protection and marking are resistant to all normal

industrial cleaning solvents suitable for printed circuits.

Flammability

The resistors will not burn or emit incandescent particles

under any condition of applied temperature or power

overload.

Construction

The resistance element is a precisely controlled thin film of

metal alloy on a high purity ceramic core, protected by a

cement coating applied so that terminations remain

completely clear.

This permits a well defined body length, (clean lead to clean

lead dimension L).

Terminations

Material

Solder-coated copper wire.

Strength

The terminations meet the requirements of

IEC 68.2.21

Solderability

The terminations meet the requirements of

IEC 115-1, Clause 4.17.3.2

CECC 40101-019/40101-024

Actual Performance

Requirements

Maximum

Typical

Load at commercial rating: 1000 hrs at 70°C

∆R %

not specified

3

1

Load at CECC rating: 1000 hrs at 70°C

2

2

1

Load at 35% rated power: 1000 hrs at 125°C

∆R %

2

1

0.7

Dry heat: 1000 hours at 155°C

∆R %

not specified

1

0.7

Shelf life: 12 months at room temperature

∆R %

not specified

0.5

0.5

Derating

35% of rated power at 125°C

zero at 235°C

Short term overload

∆R %

0.5

0.2

0.02

Climatic

∆R %

2

0.5

0.5

Climatic category

∆R %

55/125/56

55/125/56

Long term damp heat

∆R %

2

2

0.5

Temperature rapid change

∆R %

0.5

0.25

0.05

Resistance to solder heat

∆R %

0.5

0.25

0.07

Vibration and bump

∆R %

0.5

0.1

0.01

Performance Data

Type

FA025

FA05

FA1

FA94

Large ammo pack

5000

2500

1000

1000

Standard Quantities Per Package

Type

b

c

FA025/FA05

52

5

FA1

67

10

FA94

77

10