Power Supply Group Operation - Keysight N5227A Service Manual

Theory of Operation

Power Supply Group Operation

Power Supply Group Operation
The A20 power supply assembly is a switching power supply operating at 103 kHz switching frequency. The
input power ranges for the power supply are 90 to 132 Vac or 195 to 250 Vac. The power supply
automatically senses the input voltage and switches between these two ranges.
WARNING Supply voltages which oscillate between the two normal input ranges of the autoranging
line voltage input will damage the power supply. In rare cases, this damage has become a
user safety concern. If unstable power levels are expected, the analyzer input power must
be buffered by a line conditioner.
The dc output voltages of the A20 power supply assembly are:
• +15 V analog
• +9 V analog
• +3.3 V analog
• +5.2 V analog
• +15 V standby (always on)
• +32 V analog
• 15 V analog
• 5.2 V analog
• 7 V analog
• +5.1 V standby
• +12 V digital
• +3.35 V digital
• +5.1 V digital
The +15 V standby supply remains on continuously whenever the power supply is plugged in. This supply is
used to provide power to front panel LEDs and CPU components when the analyzer is turned off.
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PNA Series Microwave Network Analyzers
Service Guide N5227-90001
N5227A