|
|
PDF ECO7703 Data sheet ( Hoja de datos )
| Número de pieza | ECO7703 | |
| Descripción | Power Transformers | |
| Fabricantes | Philips | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de ECO7703 (archivo pdf) en la parte inferior de esta página. Total 8 Páginas | ||
|
No Preview Available !
TECHNICAL PUBLICATION
Power transformers for the
frequency range of 30 − 80 MHz
www.DataESCOh77e03et4U.com
www.DataSheet4U.com
1 page  
Philips Semiconductors
Power transformers for the frequency
range of 30 − 80 MHz
Technical Publication
ECO7703
7 WINDING LOSSES
In this frequency range conventional transformers can not be used because of their stray-inductance. The only suitable
type is the transmission line transformer. For the windings we can choose a.o:
Twisted enamelled copper wire
Miniature twin lead
Coaxial cable with P.T.F.E. isolation, available in several diameters and characteristic resistances.
The first and second are not recommended for high power operation. The third type is e.g. available in 50 Ohms version
with diameters of 1.7 and 2.8 mm. Some important properties of these cables at 80 MHz are given in Table 3.
Table 3
Outside diameter
1.7
2.8
mm
Power loss
0.40
0.24
dB/m
Power handling capability 100 200 W
At lower frequencies the power loss is less and the power handling capability higher.
8 PRACTICAL EXAMPLE
Suppose that in a 100 W transmitter the output transistors are connected in push-pull. The optimum load impedance
between the collectors is 12.5 Ω and this must be transformed to 50 Ω. Then we need a symmetrical 1 : 4 impedance
transformer plus a balun. The first one will be worked out in detail. A schematic diagram is given in Fig.1.
handbook, halfpage
+V/2
12.5 Ω
−V/2
AB
+V
O 50 Ω
−V
MGH958
Fig.1 Schematic diagram
From Table 2 we see that this transformer can be made with one 36 mm toroid but also with two 23 mm toroids, in which
case the power handling capability is still 120 W. The latter solution is more attractive because it is smaller.
The optimum characteristic impedance for each winding is 25 Ω which can realized by the parallel connection of two 50 Ω
cables of 1.7 mm diameter. As the power is transported through 4 cables, each cable is loaded with 25 W being a quarter
of the allowable maximum.
1998 Mar 23
5
5 Page | ||
| Páginas | Total 8 Páginas | |
| PDF Descargar | [ Datasheet ECO7703.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| ECO7703 | Power Transformers | Philips |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |