MCP2210
1.5
USB Transceiver
FIGURE 1-1:
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 V
USB
pin,
which is internally connected to a 3.3V internal
regulator. The best electrical signal quality is obtained
when V
USB
is locally bypassed with a high-quality
ceramic capacitor.
The internal 3.3V regulator draws power from the V
DD
pin. In certain scenarios, where V
DD
is lower than
3.3V+ internal LDO dropout, the V
USB
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 V
DD
of the chip will be
tied to the 2.2V digital power rail, while the V
USB
pin
must be connected to a regulated 3.3V power supply.
MCP2210 INTERNAL
POWER SUPPLY DETAILS
V
DD
IN
LDO
3.3V
V
USB
OUT
D+
D-
USB
Transceiver
1.5.1
INTERNAL PULL-UP RESISTORS
The provided V
DD
voltage has a direct influence on the
voltage levels present on the GPIO and SPI module
pins (GP8-GP0, MOSI, MISO and SCK). When V
DD
is
5V, all of these pins will have a logical ‘1’ around 5V
with the variations specified in
For applications that require a 3.3V logical ‘1’ level,
V
DD
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 V
USB
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.
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 V
USB
pin is supplied with 3.3V (regulated). If the V
DD
is
powered with 5V, then the V
USB
will be powered
by the internal regulator and the V
USB
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.
shows the internal connections of the USB
transceiver LDO in relation with the V
DD
power supply
rail. The output of the USB transceiver LDO is tied to
the V
USB
line.
A capacitor connected to the V
USB
pin is required if the
USB transceiver LDO provides the 3.3V supply to the
transceiver.
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
This is effectively the simplest power method for the
device.
FIGURE 1-2:
V
BUS
BUS POWER ONLY
V
DD
V
USB
V
SS
2011 Microchip Technology Inc.
DS22288A-page 5
MICROCHIP [ MICROCHIP TECHNOLOGY ]
