Open Air Resistor

Metal Element Current Sense

OAR & OAR-TP Series

• 4222 South Staples Street • Corpus Christi Texas 78411 USA

Wire and Film Technologies Division

Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com

Physical Data

Dimensions (Inches and (mm))

F

E

C

B

A

e

p

y

T

C

R

I

OAR-1

0.450 +0.040/-0.020

(11.43 +1.020/-0.508)

0.27 Typ

0.32 (8.12) max

0.125 ±0.030

(3.18 ±0.762)

0.065 +0.010/-0.005

(1.65 +0.254/-0.127)

0.040 ±0.002

(1.02 ±0.051)

OAR-3

0.600 +0.040/-0.020

(15.24 +1.020/0.508)

0.65 Typ

0.92 (23.4) max

0.125 ±0.030

(3.18 ±0.762)

0.065 +0.010/-0.005

(1.65 +0.254/-0.127)

0.040 ±0.002

(1.02 ±0.051)

OAR-5

0.800 +0.040/-0.020

(20.32 +1.020/-0.508)

0.65 Typ

0.88 (22.4) max

0.125 ±0.030

(3.18 ±0.762)

0.065 +0.010/-0.005

(1.65 +0.254/-0.127)

0.040 ±0.002

(1.02 ±0.051)

B

C

A

E

F

On lower ranges stand-off may be

eliminated

NOTE:

Contact factory for:

1. Variations of “A” dimension.

2. Different lead diameter.

Test Point (Kelvin connection)

The thermal images (not simulations) above are of the OAR products at their respective power rating. Notice the

solder joint temperature is much lower than the hotspot. The unique construction of the OAR isolates the tempera-

ture of the hotspot from the circuit board material preventing damage to the circuit board. Additionally, the thermal

energy is dissipated to the air instead of being conducted into the circuit board potentially causing a nearby power

component to exceed its rating.

The standard test circuit board consists of a four layer FR4 material with 2 ounce (70µm) outer layers and 1 ounce

(35µm) inner layers, which is typical of many industry designs. The test conditions were in ambient temperature

conditions, approximately 22 °C with no forced air. Contact TT electronics for more details or for other thermal image

test data for specific resistance values and power levels.

Thermal Image Data

OAR-1 5 mΩ @ 1 Watt

Hot Spot:

87°C

Solder Joint: 45°C

OAR-3 5 mΩ @ 3 Watt

Hot Spot:

160°C

Solder Joint: 70°C

OAR-5 5 mΩ @ 5 Watt

Hot Spot:

230°C

Solder Joint: 96°C

OAR

Open Air Resistor

Metal Element Current Sense

OAR Series Issue June 2011 Sheet 2 of 3

• 4222 South Staples Street • Corpus Christi Texas 78411 USA

Wire and Film Technologies Division

Telephone: 361 992 7900 • Facsimile: 361 992 3377 • Website: www.irctt.com

Physical Data

Dimensions (Inches and (mm))

F

E

C

B

A

e

p

y

T

C

R

I

OAR-1

0.450 +0.040/-0.020

(11.43 +1.020/-0.508)

0.27 Typ

0.32 (8.12) max

0.125 ±0.030

(3.18 ±0.762)

0.065 +0.010/-0.005

(1.65 +0.254/-0.127)

0.040 ±0.002

(1.02 ±0.051)

OAR-3

0.600 +0.040/-0.020

(15.24 +1.020/0.508)

0.65 Typ

0.92 (23.4) max

0.125 ±0.030

(3.18 ±0.762)

0.065 +0.010/-0.005

(1.65 +0.254/-0.127)

0.040 ±0.002

(1.02 ±0.051)

OAR-5

0.800 +0.040/-0.020

(20.32 +1.020/-0.508)

0.65 Typ

0.88 (22.4) max

0.125 ±0.030

(3.18 ±0.762)

0.065 +0.010/-0.005

(1.65 +0.254/-0.127)

0.040 ±0.002

(1.02 ±0.051)

B

C

A

E

F

On lower ranges stand-off may be

eliminated

NOTE:

Contact factory for:

1. Variations of “A” dimension.

2. Different lead diameter.

Test Point (Kelvin connection)

The thermal images (not simulations) above are of the OAR products at their respective power rating. Notice the

solder joint temperature is much lower than the hotspot. The unique construction of the OAR isolates the tempera-

ture of the hotspot from the circuit board material preventing damage to the circuit board. Additionally, the thermal

energy is dissipated to the air instead of being conducted into the circuit board potentially causing a nearby power

component to exceed its rating.

The standard test circuit board consists of a four layer FR4 material with 2 ounce (70µm) outer layers and 1 ounce

(35µm) inner layers, which is typical of many industry designs. The test conditions were in ambient temperature

conditions, approximately 22 °C with no forced air. Contact TT electronics for more details or for other thermal image

test data for specific resistance values and power levels.

Thermal Image Data

OAR-1 5 mΩ @ 1 Watt

Hot Spot:

87°C

Solder Joint: 45°C

OAR-3 5 mΩ @ 3 Watt

Hot Spot:

160°C

Solder Joint: 70°C

OAR-5 5 mΩ @ 5 Watt

Hot Spot:

230°C

Solder Joint: 96°C

OAR

Open Air Resistor

Metal Element Current Sense

OAR Series Issue June 2011 Sheet 2 of 3

PhysicalData

Type

A

Bmax

C

E

F

OAR1

0.32(8.12)

OAR1TP

0.3(7.8)

OAR3

0.92(23.4)

OAR3TP

<R005

1.0(25.4)

OAR3TP

≥R005

OAR5

0.88(22.4)

OAR5TP

1.1(27.9)

Make Possible

11.14

General Note

TT Electronics reserves the right to make changes in product specification without notice or liability.

All information is subject to TT Electronics’ own data and is considered accurate at time of going to print.

© TT Electronics plc

www.ttelectronicsresistors.com