Components  R&S SM300 
Version 04  90   
Service Manual SM300: 1147.1652.00                Instrument Part No SM300: 1147.1498.03  
4.2.4 Generator module 
Two single 
boards
The generator modules consists of two single boards, each located in a shielded 
module frame. The backplane is connected to one module only, the digital board. 
This provides connection to the power supply and the USB. 
Internal
connection
The  internal  connection  between  the  boards  (operating  voltages,  signals)  is 
located at the rear of the module in the wiring area. 
Front
connectors
All  generator  modules  are  extended  toward  the  front.  The  measurement 
connector  mounted  to  the front  of  the module  is  inserted  through an  opening  in 
the front panel where they are accessible for the user. 
4.2.5 Power Supply 
Power supplied 
  AC voltage from 100 V to 240 V with 50 Hz to  60 Hz 
Operating
voltages 
  5 V for digital circuits 
  3.3 V for digital circuits 
  ± 5.5 V for analog modules 
  ± 15 V for analog modules 
  +12 V for display 
  Unregulated voltage in the range from 10.5 V to 17.5 V;  
Used for generation of individual voltages on the modules 
  The total power consumption in the instrument is limited to <70 W. 
USB-compatible
microcontroller
The  power  supply  module  also  contains  a  USB-compatible  microcontroller.
It handles
  Power management 
  Monitoring of operating voltage and temperature 
  Fan control 
  Instrument identification 
  Recording of operating time, etc.