Datasheet

Chapter 2. Features
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Accepts the complete range of CM4 modules
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External +12V PSU
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2 × Full-size HDMI 2.0 connectors
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Gigabit Ethernet RJ45 with POE support
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2 × USB 2 Socket, with header for two more sockets
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Micro USB socket for updating the CM4
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Micro SD Card socket for CM4Lite modules.
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PCIe Gen 2 socket
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Standard Fan connector
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External power connector (+5V, +12V)
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2 × MIPI DSI display FPC connectors (22pin 0.5mm pitch cable)
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2 × MIPI CSI-2 camera FPC connectors (22pin 0.5mm pitch cable)
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Raspberry Pi HAT connector
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RTC with Battery socket and ability to wake up CM4
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Jumpers to disable features, e.g Wireless, EEPROM writing
2.1. CM4 Module Connectors
The two CM4 module connectors are positioned so the onboard wireless antenna is at the edge of the board for best
wireless performance.
2.2. PSU input
The main PSU input (J19) is a 2.1mm DC tip positive +12V input. On board there is a +12V to +5V DC-DC converter to
power the CM4. There is also an on-board +12V to +3.3V DC-DC converter PSU which is only used for the PCIe slot. The
+12V input feeds the +12V PCIe slot, the external PSU connect and the FAN connector directly. If these aren’t being used
then a wider input supply is possible ( +7.5V to +26V).
With a +12V supply via the DC barrel jack the external PSU connector ( J20, +5V, +12V ) is ideal to connect to PCIe cards
that require external PSU. You should ensure that the PSUs aren’t over loaded. J20 Mating connector is known as "Berg"
Part number AMP / TE Connectivity 171822-4 or similar.
The exact current required from the +12V PSU is dependent on the application and what is connected to the Raspberry Pi
Compute Module 4 IO Board. It is recommended to budget 9W for the CM4.
If you want to supply an external +5v supply to the board e.g. via J20 or via POE J9 then it is recommended that L5 is
removed. Removing L5 will prevent the on board +5v and +3.3v supplies from starting up and +5v coming out of the DC
JACK socket ( J19 ).
2.3. Dual Full size HDMI 2.0 connectors
The CM4 does most of the interfacing required for the HDMI interface so that most signals are directly connected to the
CM4. HDMI connectors require a +5V supply, this is provided on the Raspberry Pi Compute Module 4 IO Board via a
Raspberry Pi Compute Module 4 IO Board
2.1. CM4 Module Connectors 4