Northern Airborne Technology 246 - Manual (Page 5)

Model 246 Isolation Amplifier
SM246 Installation and Operation Manual
Section 1 Rev: 1.00 Issue 2 Page 1-1
ENG-FORM: 800-0113.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
Section 1 Description
1.1 Introduction
Information in this section consists of product description, design features and specifications for the
Model 246 Isolation Amplifier. All derivative product information shall be contained in the applicable
manual supplement, which may be obtained from NAT as required.
Review all notes, warnings and cautions.
1.2 Product Description
The Model 246 Isolation Amplifier is an electronic device capable of driving 100 mWrms into a
600 Ohm load. It is intended as a direct replacement for the Collins model 356C-4. The Model 246 is
also capable of driving 5 Wrms into an 8 Ohm load.
1.3 Design Features
The Model 246 Isolation Amplifier is based on a solid-state integrated circuit. It has a 470 Ohm
differential input and an output compatible with a 600 Ohm or a 4 Ohm load. It provides an internal gain
adjustment (accessible through a hole in the cover) of 4.5 dB to 42 dB and is capable of supplying a
minimum of 100 mW into a 600 Ohm load. It will drive headphones with impedance ratings of 4 to 600
ohms. With the unit adjusted for a gain of 40 dB, an input level of 77.5 mVrms will produce an output
level of 7.75 Vrms (100 mW into 600 ohms.)
1.4 Specifications
1.4.1 Electrical Specifications
Input 0.0775 Vrms into 470 ohms
Output
100 mWrms into 600 ohms at <1 % distortion
Microphone Bias 15 Vdc at 30 ±5 mA (enabled by internal jumper)
Output Noise
70 dB below 100 mW
Power Supply
<0.5 amp at 28 Vdc, 1 A circuit breaker recommended
1.4.2 Physical Specifications
Height 1.53" (38.86 mm) max
Depth 2.81" (71.37 mm) max including flanges
Width 2.78" (70.61 mm) max excluding connector
Weight 0.35 lbs (159 g)