CP2112
Rev. 1.2
19
Alternatively, if 3.0 to 3.6 V power is supplied to the VDD pin, the CP2112 can function as a USB self-powered
device with the voltage regulator bypassed. For this configuration, tie the REGIN input to VDD to bypass the voltage
regulator. A typical connection diagram showing the device in a self-powered application with the regulator
The USB max power and power attributes descriptor must match the device power usage and configuration. See
the CP2112_SetIDs software included with the CP2112 Software Development Kit (SDK) for information on how to
customize USB descriptors for the CP2112.
Figure 11. Typical Self-Powered Connection Diagram (Regulator Bypass)
Note 3
Note 2
Note 1
VBUS
D+
D-
GND
USB
Connector
Suspend
Signals
GPIO
Signals
CP2112
GPIO.0
GPIO.1
GPIO.2
GPIO.3
VPP
SUSPEND
GPIO.4
GPIO.5
GPIO.8
GPIO.6
GPIO.7
VDD
REGIN
GND
VIO
VBUS
D+
D-
RST
0.1
F
1-5
F
VIO
4.7 k
Note 4
Note 1 : Avalanche transient voltage suppression diodes compatible with Full-speed USB should be
added at the connector for ESD protection. Use Littelfuse p/n SP0503BAHT or equivalent.
Note 2 : An external pull-up is not required, but can be added for noise immunity.
Note 3 : VIO can be connected directly to VDD or to a supply as low as 1.8 V to set the I/O interface
voltage.
Note 4 : If programming the configuration ROM via USB, add a 4.7
F capacitor between VPP
and ground. During a programming operation, do not connect the VPP pin to other
circuitry, and ensure that VDD is at least 3.3 V.
Note 5 : For self-powered systems where VDD and VIO may be unpowered when VBUS is connected
to 5 V, a resistor divider (or functionally-equivalent circuit) on VBUS is required to meet the
absolute maximum voltage on VBUS specification in the Electrical Characteristics section.
4.7
F
3.3 V
Power
To
SMBus
Slave
Devices
SDA
SCL
47 k
24 k
Note 5
(Optional)