MicroHAM MK2R Manual de usuario descargar pdf (Pagina 4)

All nine switches function in the same manner. When their input goes high, their output

switches high. All unselected outputs float at ground level if connected to the antenna

switch relays.

Please note: Output for 160m-15m bands are doubled, two outputs are connected together

for higher current output. Output current capability is min. 350mA per output, but the total

dissipation of whole IC must be kept under 2W. The average output Darlington pair

saturation voltage is 1.7V, therefore the power supply must deliver at least 13.7V for the

12V relays ! More information can be found in the datasheets for UDN2981 or TD62783.

The Band Decoder is powered through either the K6 terminal block or via the “data” cable

from the transceiver. Diodes D1 and D3 isolate these two sources to prevent circulating

currents in case voltage is applied to both inputs simultaneously. If the voltage drop 0.5V [at

the diode is significant for the function, you must use higher power supply voltage. 14-15V

should be enough for 12V relays. If you can’t use higher supply voltage than 13,8V then

remove the appropriate diode and substitute a wire bridge in its place. D2 is a protection

transient voltage suppression diode P6KE18A with the 18V clamping level for the protection

of the relays from overvoltage. If you want to optionally use 24V relays then replace D2 with

P6KE27A or with P6KE30A for 26V relays.

BCD decoder CMOS4028 is powered from 5V monolithic stabilizer IC4 – 78L05. Resistor

networks R5 and R7 with the capacitors C4-C7 are for EMI protection.

The Band Decoder can be connected to the transceiver via DIN8 connector K7 or via header

connector K8. The pinout of K7 is the same as on the YAESU transceivers.

Band data pinout at Yaesu DIN8 band data connector.

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MicroHAM MK2R Manual de usuario Pagina 4