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2011 Microchip Technology Inc.
DS22288A-page 5
MCP2210
1.5
USB Transceiver
The MCP2210 has a built-in, USB 2.0, full-speed
transceiver internally connected to the USB module.
The USB transceiver obtains power from the VUSB pin,
which is internally connected to a 3.3V internal
regulator. The best electrical signal quality is obtained
when VUSB is locally bypassed with a high-quality
ceramic capacitor.
The internal 3.3V regulator draws power from the VDD
pin. In certain scenarios, where VDD is lower than
3.3V+ internal LDO dropout, the VUSB pin must be tied
to an external regulated 3.3V. This will allow the USB
transceiver to work correctly, while the I/O voltage in
the rest of the system can be lower than 3.3V. As an
example, in a system where the MCP2210 is used and
the I/O required is of 2.2V, the VDD of the chip will be
tied to the 2.2V digital power rail, while the VUSB pin
must be connected to a regulated 3.3V power supply.
1.5.1
INTERNAL PULL-UP RESISTORS
The MCP2210 device has built-in pull-up resistors
designed to meet the requirements for full-speed USB.
1.5.2
MCP2210 POWER OPTIONS
The following are the main power options for the
MCP2210:
USB Bus Powered (5V)
Self Powered (from 3.3V to 5V), while the VUSB
pin is supplied with 3.3V (regulated). If the VDD is
powered with 5V, then the VUSB will be powered
by the internal regulator and the VUSB pin will
need only a decoupling capacitor
1.5.2.1
Internal Power Supply Details
MCP2210 offers various options for power supply. To
meet the required USB signaling levels, MCP2210
device incorporates an internal LDO used solely by the
USB transceiver, in order to present the correct D+/D
voltage levels.
Figure 1-1 shows the internal connections of the USB
transceiver LDO in relation with the VDD power supply
rail. The output of the USB transceiver LDO is tied to
the VUSB line.
A capacitor connected to the VUSB pin is required if the
USB transceiver LDO provides the 3.3V supply to the
transceiver.
FIGURE 1-1:
MCP2210 INTERNAL
POWER SUPPLY DETAILS
The provided VDD voltage has a direct influence on the
voltage levels present on the GPIO and SPI module
pins (GP8-GP0, MOSI, MISO and SCK). When VDD is
5V, all of these pins will have a logical ‘1’ around 5V
For applications that require a 3.3V logical ‘1’ level,
VDD must be connected to a power supply providing
the 3.3V voltage. In this case, the internal USB
transceiver LDO cannot provide the required 3.3V
power. It is necessary to also connect the VUSB pin of
the MCP2210 to the 3.3V power supply rail. This way,
the USB transceiver is powered up directly from the
3.3V power supply.
1.5.2.2
USB Bus Powered (5V)
In Bus Power Only mode, the entire power for the
application is drawn from the USB (see
Figure 1-2).
This is effectively the simplest power method for the
device.
FIGURE 1-2:
BUS POWER ONLY
LDO
3.3V
USB
Transceiver
D+
VDD
VUSB
D-
IN
OUT
VDD
VUSB
VSS
VBUS