CP2101 Silicon Laboratories Inc, CP2101 Datasheet - Page 11

• Manufacturer Part Number: CP2101
• Description: IC USB-TO-UART BRIDGE 28MLP
• Manufacturer: Silicon Laboratories Inc

Specifications of CP2101

• Applications: USB
• Interface: USB
• Voltage - Supply: 3 V ~ 3.6 V
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

CP2101
5.
The Universal Serial Bus function controller in the CP2101 is a USB 2.0 compliant full-speed device with
integrated transceiver and on-chip matching and pull-up resistors. The USB function controller manages
all data transfers between the USB and the UART as well as command requests generated by the USB
host controller and commands for controlling the function of the UART.
The USB Suspend and Resume signals are supported for power management of both the CP2101 device
as well as external circuitry. The CP2101 will enter Suspend mode when Suspend signaling is detected
on the bus. On entering Suspend mode, the CP2101 asserts the SUSPEND and SUSPEND signals.
SUSPEND and SUSPEND are also asserted after a CP2101 reset until device configuration during USB
Enumeration is complete
The CP2101 exits the Suspend mode when any of the following occur: (1) Resume signaling is detected or
generated, (2) a USB Reset signal is detected, or (3) a device reset occurs. On exit of Suspend mode, the
SUSPEND and SUSPEND signals are de-asserted.
Both SUSPEND and SUSPEND temporarily float high during a CP2101 reset. If this behavior is
undesirable, a strong pulldown (10 kΩ) can be used to ensure SUSPEND remains low during reset. See
Figure 5.1 for other recommended options.
11
Option 1: A 4.7 kΩ pull-up resistor can be added to increase noise immunity.
Option 2: A 4.7 µF tantalum capacitor can be added if powering other devices from the on-chip regulator.
Option 3: Avalanche transient voltage suppression diodes can be added for ESD protection.
Option 3:
Option 4: 10 kΩ resistor to ground to hold SUSPEND low on initial power on or device reset.
CONNECTOR
USB
VBUS
GND
USB Function Controller and Transceiver
D+
D-
Use Littlefuse p/n SP0503BAHT or equivalent.
1
3
4
4.7 µF
Option 2
TANT
C4
D1
0.1 µF
D2
1 µF
C1
C2
Figure 5.1. Typical Connection Diagram
D3
7
6
3
8
5
4
Option 3
REGIN
VBUS
VDD
GND
D+
D-
CP2101
Rev. 1.6
SUSPEND
SUSPEND
RST
DCD
DTR
DSR
TXD
RXD
RTS
CTS
RI
9
12
11
2
1
28
27
26
25
24
23
4.7 kΩ
10 kΩ
R1
R2
VDD
Option 1
Option 4
External RS-232
(to external circuitry
for USB suspend
states)
UART circuitry
transceiver or