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Weehawken Tunnel VHF Repeater System
User/Maintenance Handbook
Handbook N.-Weehawken_VHF Issue No:-A Date:-05/08/05
Page:-
58 of 75
7.10 Dual DC/DC Converter (13-001803)
7.10.1 Description
This unit is employed where it is necessary to derive two fixed voltage power supply rails from
some higher voltage. Typically it is used to derive 5, 8, 12 or 15V from a 24V input.
The circuit is based upon a pair of LM257 series variable voltage regulators (LM2576, 12 &
15V & LM2575, 5V), which are each capable of supplying an absolute maximum of 1.5A
output current. Note that at full output current, the dissipation of the device must remain within
design limits, bearing in mind the voltage which is being dropped across it. The maximum
allowable dissipation will also depend on the efficiency of the heatsink on which the device is
mounted.
7.10.2 Technical Specification
PARAMETER SPECIFICATION
Operating voltage: 21 – 27V DC
Output voltage: 12V & 12V (typical)
Output current: 1.0A (maximum per o/p)
Connections: Screw Terminal Block
operational: -10%C to +60%C Temperature
range
storage -20%C to +70%C
PCB Size: 85 x 63mm