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MX2020 DC Power Distribution Module (-48 V) Description

In the DC power configuration, the MX2020 router contains up to four DC PDMs located at the rear of the chassis in slots PDM0/Input0 through PDM3/Input1 (bottom to top). A minimum of one PDM is required per subsystem (two PDMs per MX2020 chassis) for nonredundant power. The DC PDMs provide power interface to seven or nine power supply modules (PSMs).

Four PDMs provide full redundancy for the MX2020 router. In a redundant configuration, a total of twenty-eight 60-A or 80-A feeds (7-feed DC PDMs), and a total of thirty-six 60-A or 80-A feeds ( 9-feed DC PDMs) are supported.


The power backplane for a subsystem distributes regulated 52 VDC to all boards supplied by that subsystem.

Each DC PDM has seven or nine DC inputs (–48 VDC) and return terminals for each input), (see Figure 1). You can select 60-A or 80-A input feed capacity on the DC PDM by setting the DIP switch on the PDM to the rated amperage of the DC power input feeds.


The selected input capacity applies to all inputs of this PDM. Selecting 60-A reduces the available power output capacity of the PSMs supplied by this PDM.

Figure 1: MX2020 DC PDMMX2020 DC PDM

The type of feed that you use on the DC PDM (60-A or 80-A) depends on the distribution scheme and distribution equipment. With a 60-A feed, the maximum power supply output power is limited to 2100 W while the maximum power supply input power is limited to 2400 W. With an 80-A feed, the maximum power supply output is limited to 2500 W while maximum power supply input power is limited to 2800 W. The system power management software calculates the available and used power based on DIP switch positions in the PDM.