Product specifications

Hardware Description
5-10 80-99240-1 Rev. D
• POWER for an active translator Diagnostic cable
• PROGRAM to enable programming of the modem
Note
Normal field usage does not require that a cable be connected to the
Diagnostic port on the modem, since that port is typically used for
development and programming only.
DC Power
The GSP-1620 modem requires input DC power ranging from
5.6 V to 16 V, with 1 Amp (maximum). The modem DC input
power must be clean (maximum of 50 mV peak-peak ripple
and noise) and must be within the absolute maximum voltage
range of 5.6 V to 16 V under all conditions. For typical DC
power consumption limits, see Power Consumption on page
5-12.
The GSP-1620 modem uses a DC/DC converter to source its
internal operating voltages and behaves like a constant
power load over varying input voltages that has a varying
input impedance when the modem is transmitting data. This
creates a potential for oscillations on the DC power line if the
input impedance of the modem is lower than that of the power
supply sourcing the power.
The approximate minimum input impedance of the modem is
given by R = V
2
/P
max
where V is the operating voltage of the
modem and P
max
is the maximum power consumed by the
modem. For example, the minimum input impedance of the
modem at 12V would be approximately 12*12/5.4 = 26.7
Ohms. Any DC power supply capable of supplying the peak
demand of 5.4W at 12V would have this output impedance.
Additional design margin of at least 20% is recommended
beyond this minimum value.
Care should be taken that if additional EMI filtering is added
(see EMI Filtering on page 5-11), the impedance as seen by
the modem’s input power supply does not exceed this value.