Rev. 1.8 1/17 Copyright © 2017 by Silicon Laboratories CP2102/9
CP2102/9
SINGLE-CHIP USB-TO-UART BRIDGE
Single-Chip USB to UART Data Transfer
-Integrated USB transceiver; no external resistors
required
-Integrated clock; no external crystal required
-Internal 1024-byte programmable ROM for vendor ID,
product ID, serial number, power descriptor, release
number, and product description strings
- EEPROM (CP2102)
- EPROM (One-time programmable) (CP2109)
-On-chip power-on reset circuit
-On-chip voltage regulator
- 3.3 V output (CP2102)
- 3.45 V output (CP2109)
-100% pin and software compatible with CP2101
USB Function Controller
-USB Specification 2.0 compliant; full-speed (12 Mbps)
-USB suspend states supported via SUSPEND pins
Asynchronous Serial Data BUS (UART)
-All handshaking and modem interface signals
-Data formats supported:
- Data bits: 5, 6, 7, and 8
- Stop bits: 1, 1.5, and 2
- Parity: odd, even, mark, space, no parity
-Baud rates: 300 bps to 1 Mbps
-576 Byte receive buffer; 640 byte transmit buffer
-Hardware or X-On/X-Off handshaking supported
-Event character support
-Line break transmission
Virtual COM Port Device Drivers
-Works with existing COM port PC Applications
-Royalty-free distribution license
-Windows 8/7/Vista/Server 2003/XP/2000
-Mac OS-X/OS-9
-Linux
USBXpress™ Direct Driver Support
-Royalty-Free Distribution License
-Windows 7/Vista/XP/Server 2003/2000
-Windows CE
Example Applications
-Upgrade of RS-232 legacy devices to USB
-Cellular phone USB interface cable
-USB interface cable
-USB to RS-232 serial adapter
Supply Voltage
-Self-powered: 3.0 to 3.6 V
-USB bus powered: 4.0 to 5.25 V
Package
-RoHS-compliant 28-pin QFN (5x5 mm)
Ordering Part Numbers
-CP2102-GM
-CP2109-A01-GM
Temperature Range: –40 to +85 °C
Figure 1. Example System Diagram
CP2102/9
3.3 – 3.45 V
Voltage
Regulator
48 MHz
Oscillator
IN
OUT
SUSPEND
SUSPEND
11
12
REGIN
7
GND
3
RST 9
D+
4
D-
5
8
UART
RI
DCD
CTS
RTS
RXD
TXD
DSR
DTR
2
27
26
25
24
23
2
3
External
RS-232
transceiver
or UART
circuitry
(to external
circuitry for
USB
suspend
states)
VBUS
D-
D+
GND 4
5
6
USB
CONNECTOR
6
1
VDD
VBUS
USB Function
Controller
USB
Transceiver
640B
TX
Buffer
576B
RX
Buffer
1024B
PROM
VDD
D1 D2 D3
1
28
VPP
18
*CP2109 only
For newer designs, the CP2102N devices offer compatible footprints and are recommended for use instead
of the CP2102/9. See the Silicon Labs website (www.silabs.com/usbxpress) for more information.
CP2102/9
2 Rev. 1.8
CP2102/9
Rev. 1.8 3
TABLE OF CONTENTS
Section Page
1. System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
3. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
4. Pinout and Package Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
5. QFN-28 Package Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
6. USB Function Controller and Transceiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
7. Asynchronous Serial Data Bus (UART) Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
8. Internal Programmable ROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
9. CP2102/9 Device Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
9.1. Virtual COM Port Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
9.2. USBXpress Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
9.3. Driver Customization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
9.4. Driver Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
10. Voltage Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
11. Porting Considerations from CP2102 to CP2109 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
11.1. Pin-Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
11.2. Distinguishing Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
11.3. Differences in Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
12. Relevant Application Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
CP2102/9
4 Rev. 1.8
1. System Overview
The CP2102/9 is a highly-integrated USB-to-UART Bridge Controller providing a simple solution for updating RS-
232 designs to USB using a minimum of components and PCB space. The CP2102/9 includes a USB 2.0 full-
speed function controller, USB transceiver, oscillator, EEPROM or EPROM, and asynchronous serial data bus
(UART) with full modem control signals in a compact 5 x 5 mm QFN-28 package. No other external USB
components are required.
The on-chip programmable ROM may be used to customize the USB Vendor ID, Product ID, Product Description
String, Power Descriptor, Device Release Number, and Device Serial Number as desired for OEM applications.
The programmable ROM is programmed on-board via the USB, allowing the programming step to be easily
integrated into the product manufacturing and testing process.
Royalty-free Virtual COM Port (VCP) device drivers provided by Silicon Laboratories allow a CP2102/9-based
product to appear as a COM port to PC applications. The CP2102/9 UART interface implements all RS-232
signals, including control and handshaking signals, so existing system firmware does not need to be modified. In
many existing RS-232 designs, all that is required to update the design from RS-232 to USB is to replace the RS-
232 level-translator with the CP2102/9. Direct access driver support is available through the Silicon Laboratories
USBXpress driver set.
An evaluation kit for the CP2102 (Part Number: CP2102EK) is available. The kit includes a CP2102-based USB-to-
UART/RS-232 evaluation board, a complete set of VCP device drivers, USB and RS-232 cables, and full
documentation. Contact a Silicon Labs sales representative or go to www.silabs.com to order the CP2102
Evaluation Kit. The CP2102 Evaluation Kit serves as an evaluation kit for both the CP2102 and CP2109.
CP2102/9
Rev. 1.8 5
2. Ordering Information
Table 1. Product Selection Guide
Ordering Part
Number
Internal
Programmable
ROM (Byte)
EEPROM EPROM Calibrated
Internal
48 MHz
Oscillator
Supply
Voltage
Regulator
Lead-free
(RoHS-
Compliant)
Package
CP2102-GM* 1024 Y N Y Y Y QFN28
CP2109-A01-GM* 1024 N Y Y Y Y QFN28
*Note: Pin compatible with the CP2101-GM.
CP2102/9
6 Rev. 1.8
3. Electrical Specifications
Table 2. Absolute Maximum Ratings
Parameter Symbol Test Condition Min Typ Max Unit
Ambient Temperature under Bias TBIAS –55 — 125 °C
Storage Temperature TSTG –65 — 150 °C
Voltage on VDD with respect to GND VDD –0.3 — 4.2 V
Maximum Total Current through VDD
and GND
— — 500 mA
Maximum Output Current sunk by
RST or any I/O pin
— — 100 mA
CP2102
Voltage on any I/O Pin, VBUS, or RST
with respect to GND
–0.3 — 5.8 V
CP2109
Voltage on any I/O Pin, VBUS, or RST
with respect to GND
VDD > 3.0 V
VDD not powered
–0.3
–0.3
—
—
5.8
VDD +
3.6
V
Note: Stresses above those listed may cause permanent device damage. This is a stress rating only, and functional operation
of the devices at or exceeding the conditions in the operation listings of this specification is not implied. Exposure to
maximum rating conditions for extended periods may affect device reliability.
CP2102/9
Rev. 1.8 7
Table 3. Recommended Operating Conditions
VDD = 3.0 to 3.6 V, –40 to +85 °C unless otherwise specified
Parameter Symbol Test Condition Min Typ Max Unit
Supply Voltage VDD 3.0 3.3 3.6 V
Supply Current - USB Pull-up1IPU —200230µA
Specified Operating Temperature
Range
TA–40 — +85 °C
Thermal Resistance2θJA —32—°C/W
CP2102
Supply Current—Normal3
IREGIN
Normal Operation;
VREG Enabled
—2026mA
Supply Current—Suspended3Bus Powered;
VREG Enabled
—80100µA
CP2109
Supply Current—Normal3
IREGIN
Normal Operation;
VREG Enabled
—1723mA
Supply Current—Suspended3Bus Powered;
VREG Enabled
—90230µA
Notes:
1. The USB Pull-up supply current values are calculated values based on USB specifications. USB Pull-up supply current
is current flowing from VDD to GND through USB pull-down/pull-up resistors on D+ and D-.
2. Thermal resistance assumes a multi-layer PCB with any exposed pad soldered to a PCB pad.
3. USB Pull-up current should be added for total supply current. Normal and suspended supply current is current flowing
into VREGIN. Normal and suspended supply current is guaranteed by characterization.
CP2102/9
8 Rev. 1.8
Table 4. UART and Suspend I/O DC Electrical Characteristics
VDD = 3.0 to 3.6 V, –40 to +85 °C unless otherwise specified
Parameter Symbol Test Condition Min Typ Max Unit
Baud Rate — — 921600 bps
Input Leakage Current IL—2550µA
CP2102
Output High Voltage
VOH
IOH =–10µA
IOH =–3mA
IOH = –10 mA
VDD –0.1
VDD –0.7
—
—
—
VDD –0.8
—
—
—
V
Output Low Voltage
VOL
IOL =10µA
IOL =8.5mA
IOL =25mA
—
—
—
—
—
1.0
0.1
0.6
—
V
Input High Voltage VIH 2.0 — — V
Input Low Voltage VIL ——0.8V
CP2109
Output High Voltage
VOH
IOH =–10µA
IOH =–3mA
IOH = –10 mA
VDD –0.1
VDD –0.2
—
—
—
VDD –0.4
—
—
—
V
Output Low Voltage
VOL
IOL =10µA
IOL =8.5mA
IOL =25mA
—
—
—
—
—
0.6
0.1
0.4
—
V
Input High Voltage VIH 0.7 x VDD ——V
Input Low Voltage VIL ——0.6V
Table 5. Reset Electrical Characteristics
–40 to +85 °C unless otherwise specified
Parameter Symbol Test Condition Min Typ Max Unit
VDD Ramp Time tRMP Time to VDD ≥ 2.7 V — — 1 ms
RST Low Time to Generate a System
Reset
tRSTL 15 — — µs
CP2102
RST Input High Voltage VIHRESET 0.7 x VDD ——V
RST Input Low Voltage VILRESET — — 0.25 x VDD V
CP2109
RST Input High Voltage VIHRESET 0.75 x VDD ——V
RST Input Low Voltage VILRESET ——0.6V
CP2102/9
Rev. 1.8 9
Table 6. Voltage Regulator Electrical Specifications
–40 to +85 °C unless otherwise specified.
Parameter Symbol Test Condition Min Typ Max Unit
CP2102
Input Voltage Range VREGIN 4.0 — 5.25 V
Output Voltage VDDOUT Output Current = 1 to 100 mA* 3.0 3.3 3.6 V
VBUS Detection Input Threshold VVBUSTH 1.0 1.8 2.9 V
Bias Current —90—µA
CP2109
Input Voltage Range VREGIN 3.0 — 5.25 V
Output Voltage VDDOUT Output Current = 1 to 100 mA* 3.3 3.45 3.6 V
VBUS Detection Input Threshold VVBUSTH 2.5 — — V
Bias Current —8399µA
*Note: The maximum regulator supply current is 100 mA.
Table 7. USB Transceiver Electrical Specifications
VDD = 3.0 V to 3.6 V, –40 to +85 °C unless otherwise specified.
Parameter Symbol Test Condition Min Typ Max Unit
Transmitter
Output High Voltage VOH 2.8 — — V
Output Low Voltage VOL ——0.8V
Output Crossover Point VCRS 1.3 — 2.0 V
Output Impedance (CP2102)
ZDRV
Driving High
Driving Low
—
—
38
38
—
—
Output Impedance (CP2109) Driving High
Driving Low
—
—
36
36
—
—
Pull-up Resistance RPU Full Speed (D+ Pull-up)
Low Speed (D- Pull-up)
1.425 1.5 1.575 k
Output Rise Time TRLow Speed
Full Speed
75
4
—
—
300
20
ns
Output Fall Time TFLow Speed
Full Speed
75
4
—
—
300
20
ns
Receiver
Differential Input Sensitivity VDI | (D+) - (D-) | 0.2 — — V
Differential Input Common
Mode Range
VCM 0.8 — 2.5 V
Input Leakage Current IL Pullups Disabled — < 1.0 — µA
*Note: Refer to the USB Specification for timing diagrams and symbol definitions.
CP2102/9
10 Rev. 1.8
Table 8. EPROM Electrical Characteristics
Parameter Test Condition Min Typ Max Unit
CP2109
Voltage on VPP with respect to GND during a
ROM programming operation
VDD > 3.3 V 5.75 — VDD +
3.6
V
Capacitor on VPP for In-system Programming —4.7—µF
CP2102/9
Rev. 1.8 11
4. Pinout and Package Definitions
Table 9. CP2102/9 Pin Definitions
Name Pin # Type Description
VDD 6 Power In
Power Out
3.0–3.6 V Power Supply Voltage Input.
3.3 V Voltage Regulator Output.
See "10. Voltage Regulator" on page 19.
GND 3 Ground
RST 9 D I/O Device Reset. Open-drain output of internal POR or VDD monitor. An
external source can initiate a system reset by driving this pin low for
at least 15 µs.
REGIN 7 Power In 5 V Regulator Input. This pin is the input to the on-chip voltage regu-
lator.
VBUS 8 D In VBUS Sense Input. This pin should be connected to the VBUS signal
of a USB network. A 5 V signal on this pin indicates a USB network
connection.
NC1 /
VPP2
18
A Power
This pin should be left unconnected or tied to VDD. This pin is unused
on the CP2102 and may be connected to the Vpp programming
capacitor to maintain board compatibility with the CP2109.
VPP Programming Supply Voltage
D+ 4 D I/O USB D+
D– 5 D I/O USB D–
TXD 26 D Out Asynchronous data output (UART Transmit)
RXD 25 D In Asynchronous data input (UART Receive)
CTS 233D In Clear To Send control input (active low)
RTS 243D Out Ready to Send control output (active low)
DSR 273D in Data Set Ready control input (active low)
DTR 283D Out Data Terminal Ready control output (active low)
DCD 13D In Data Carrier Detect control input (active low)
RI 23D In Ring Indicator control input (active low)
SUSPEND 123D Out This pin is driven high when the CP2102/9 enters the USB suspend
state.
SUSPEND 113D Out This pin is driven low when the CP2102/9 enters the USB suspend
state.
NC 10, 13–22 These pins should be left unconnected or tied to VDD.
Notes:
1. For CP2102, pin is no connect (NC).
2. For CP2109, pin is VPP
. VPP can be left unconnected when not used for in-application programming.
3. Pins can be left unconnected when not used.
CP2102/9
12 Rev. 1.8
Figure 2. QFN-28 Pinout Diagram (Top View)
4
5
6
7
2
1
3
11
12
13
14
9
8
10
18
17
16
15
20
21
19
25
26
27
28
23
22
24
CP2102/9
Top View
DCD
RI
GND
D+
D-
VDD
REGIN
VBUS
RST
NC
SUSPEND
SUSPEND
NC
NC
NC
NC
NC
NC / VPP
NC
NC
NC
NC
CTS
RTS
RXD
TXD
DSR
DTR
GND
CP2102/9
Rev. 1.8 13
5. QFN-28 Package Specifications
Figure 3. QFN-28 Package Drawing
Table 10. QFN-28 Package Dimensions
Dimension Min Typ Max Dimension Min Typ Max
A 0.80 0.90 1.00 L 0.35 0.55 0.65
A1 0.00 0.02 0.05 L1 0.00 — 0.15
A3 0.25 REF aaa 0.15
b 0.18 0.23 0.30 bbb 0.10
D 5.00 BSC. ddd 0.05
D2 2.90 3.15 3.35 eee 0.08
e 0.50 BSC. Z 0.44
E 5.00 BSC. Y 0.18
E2 2.90 3.15 3.35
Notes:
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing per ANSI Y14.5M-1994.
3. This drawing conforms to the JEDEC Solid State Outline MO-220, variation VHHD except for
custom features D2, E2, Z, Y, and L, which are toleranced per supplier designation.
4. Recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small Body
Components.
CP2102/9
14 Rev. 1.8
Figure 4. QFN-28 Recommended PCB Land Pattern
Table 11. QFN-28 PCB Land Pattern Dimensions
Dimension Min Max Dimension Min Max
C1 4.80 X2 3.20 3.30
C2 4.80 Y1 0.85 0.95
E 0.50 Y2 3.20 3.30
X1 0.20 0.30
Notes:
General
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and Tolerancing is per the ANSI Y14.5M-1994 specification.
3. This Land Pattern Design is based on the IPC-7351 guidelines.
Solder Mask Design
4. All metal pads are to be non-solder mask defined (NSMD). Clearance between the solder
mask and the metal pad is to be 60 µm minimum, all the way around the pad.
Stencil Design
5. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should be used
to assure good solder paste release.
6. The stencil thickness should be 0.125 mm (5 mils).
7. The ratio of stencil aperture to land pad size should be 1:1 for all perimeter pins.
8. A 3x3 array of 0.90 mm openings on a 1.1 mm pitch should be used for the center pad to
assure the proper paste volume (67% Paste Coverage).
Card Assembly
9. A No-Clean, Type-3 solder paste is recommended.
10. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification for Small
Body Components.
CP2102/9
Rev. 1.8 15
6. USB Function Controller and Transceiver
The Universal Serial Bus function controller in the CP2102/9 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 CP2102/9 device as well
as external circuitry. The CP2102/9 will enter Suspend mode when Suspend signaling is detected on the bus. On
entering Suspend mode, the CP2102/9 asserts the SUSPEND and SUSPEND signals. SUSPEND and SUSPEND
are also asserted after a CP2102/9 reset until device configuration during USB Enumeration is complete.
The CP2102/9 exits 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 CP2102/9 reset. If this behavior is undesirable, a
strong pulldown (10 k) can be used to ensure SUSPEND remains low during reset. See Figure 5 for other
recommended options.
Figure 5. Typical Connection Diagram
1
CP2102/9
SUSPEND
SUSPEND
11
12
REGIN
7
GND
3
RST 9
D+
4
D-
5
8
C4
0.1 F
RI
DCD
CTS
RTS
RXD
TXD
DSR
DTR
2
1
28
27
26
25
24
23
2
3
External RS-232
transceiver or
UART circuitry
(to external circuitry
for USB suspend
states)
VBUS
D-
D+
GND 4
5
6
USB
CONNECTOR
6VDD
VBUS
VDD
R1
4.7 k
D1 D2 D3
Option 1
Option 3
C3
4.7 F
Option 2
Option 1: A 4.7 k pull-up resistor can be added to increase noise immunity.
Option 2: A 4.7 µF capacitor can be added if powering other devices from the on-chip regulator.
Option 3: Avalanche transient voltage suppression diodes should be added for ESD protection.
Option 3: Use Littlefuse p/n SP0503BAHT or equivalent.
Option 4: 10 k resistor to ground to hold SUSPEND low on initial power on or device reset.
Option 5: A 4.7 µF capacitor can be added for in-system programming (CP2109 only).
VPP
C5
4.7 F
Option 5
18
R2
10 k
Option 4
C2
0.1 F
C1
1.0 F
CP2102/9
16 Rev. 1.8
7. Asynchronous Serial Data Bus (UART) Interface
The CP2102/9 UART interface consists of the TX (transmit) and RX (receive) data signals as well as the RTS,
CTS, DSR, DTR, DCD, and RI control signals. The UART supports RTS/CTS, DSR/DTR, and X-On/X-Off
handshaking.
The UART is programmable to support a variety of data formats and baud rates. If the Virtual COM Port drivers are
used, the data format and baud rate are set during COM port configuration on the PC. If the USBXpress drivers are
used, the CP2102/9 is configured through the USBXpress API. The data formats and baud rates available are
listed in Table 12.
Table 12. Data Formats and Baud Rates
Data Bits 5, 6, 7, and 8
Stop Bits 1, 1.51, and 2
Parity Type None, Even, Odd, Mark, Space
Baud Rates2300, 600, 1200, 1800, 2400, 4000, 4800, 7200, 9600, 14400, 16000, 19200, 28800, 38400,
51200, 56000, 57600, 64000, 76800, 115200, 128000, 153600, 230400, 250000, 256000,
460800, 500000, 576000, 9216003
Notes:
1. 5-bit only.
2. Additional baud rates are supported. See “AN721: CP210x/CP211x Device Customization Guide”.
3. 7 or 8 data bits only.
CP2102/9
Rev. 1.8 17
8. Internal Programmable ROM
The CP2102 includes an internal electrically erasable programmable read-only memory (EEPROM), and the
CP2109 includes an internal one-time programmable (OTP) erasable programmable read-only memory (EPROM).
Either may be used to customize the USB Vendor ID (VID), Product ID (PID), Product Description String, Power
Descriptor, Device Release Number and Device Serial Number as desired for OEM applications. If the EEPROM/
EPROM is not programmed with OEM data, the default configuration data shown in Table 13 is used. The
EEPROM has a typical endurance of 100,000 write cycles with a data retention of 100 years. The EPROM can only
be written one time and cannot be erased.
While customization of the USB configuration data is optional, it is recommended to customize the VID/PID
combination. A unique VID/PID combination will prevent the driver from conflicting with any other USB driver. A
vendor ID can be obtained from http://www.usb.org/ or Silicon Laboratories can provide a free PID for the OEM
product that can be used with the Silicon Laboratories VID. It is also recommended to customize the serial number
if the OEM application is one in which it is possible for multiple CP2102/9-based devices to be connected to the
same PC.
The internal programmable ROM is programmed via the USB. This allows the OEM's USB configuration data and
serial number to be written to the CP2102/9 on-board ROM during the manufacturing and testing process. A stand-
alone utility for programming the internal programmable ROM is available from Silicon Laboratories. A library of
routines provided in the form of a Windows® DLL is also available. This library can be used to integrate the
programmable ROM programming step into custom software used by the OEM to streamline testing and serial
number management during manufacturing.
USB descriptors can be locked to prevent future modification on the CP2102. The CP2109 can be programmed in-
system over the USB interface by adding a capacitor to the PCB. If configuration ROM is to be programmed in-
system, a 4.7 μF capacitor must be added between the VPP pin and ground. No other circuitry should be
connected to VPP during a programming operation, and VDD must remain at 3.3 V or higher to successfully
write to the configuration ROM.
Table 13. Default USB Configuration Data
Name Value
Vendor ID 10C4h
Product ID EA60h
Power Descriptor (Attributes) 80h
Power Descriptor
(Max. Power)
32h
Release Number 0100h
CP2102 Serial Number 0001 (63 characters maximum)
CP2109 Serial Number Unique 8 character ASCII string (63 characters maximum)
CP2102 Product Description String “CP2102 USB to UART Bridge Controller” (126 characters maximum)
CP2109 Product Description String “CP2109 USB to UART Bridge Controller” (126 characters maximum)
CP2102/9
18 Rev. 1.8
9. CP2102/9 Device Drivers
There are two sets of device drivers available for the CP2102/9 devices: the Virtual COM Port (VCP) drivers and
the USBXpress Direct Access drivers. Only one set of drivers is necessary to interface with the device.
The latest drivers are available at http://www.silabs.com/support/Pages/software-downloads.aspx.
9.1. Virtual COM Port Drivers
The CP2102/9 Virtual COM Port (VCP) device drivers allow a CP2102/9-based device to appear to the PC's
application software as a COM port. Application software running on the PC accesses the CP2102/9-based device
as it would access a standard hardware COM port. However, actual data transfer between the PC and the CP2102/
9 device is performed over the USB interface. Therefore, existing COM port applications may be used to transfer
data via the USB to the CP2102/9-based device without modifying the application. See “AN197: Serial
Communications Guide for the CP210x” for Example Code for Interfacing to a CP2102/9 using the Virtual COM
drivers.
9.2. USBXpress Drivers
The Silicon Laboratories USBXpress drivers provide an alternate solution for interfacing with CP2102/9 devices.
No Serial Port protocol expertise is required. Instead, a simple, high-level application program interface (API) is
used to provide simpler CP210x connectivity and functionality. The USBXpress for CP210x Development Kit
includes Windows device drivers, Windows device driver installer and uninstallers, and a host interface function
library (host API) provided in the form of a Windows Dynamic Link Library (DLL). The USBXpress driver set is
recommended for new products that also include new PC software. The USBXpress interface is described in
“AN169: USBXpress® Programmer's Guide.”
9.3. Driver Customization
In addition to customizing the device as described in "8. Internal Programmable ROM" on page 17, the drivers and
the drivers installation package can be also be customized. See “AN220: USB Driver Customization” for more
information on generating customized VCP and USBXpress drivers.
9.4. Driver Certification
The default drivers that are shipped with the CP2102/9 are Microsoft WHQL (Windows Hardware Quality Labs)
certified. The certification means that the drivers have been tested by Microsoft and their latest operating systems
(2000, Server 2003, XP, Vista, 7, and 8) will allow the drivers to be installed without any warnings or errors. Some
installations of Windows will prevent unsigned drivers from being installed at all.
The customized drivers that are generated using the AN220 software are not automatically certified. They must
first go through the Microsoft Driver Reseller Submission process. Contact Silicon Laboratories support for
assistance with this process.
CP2102/9
Rev. 1.8 19
10. Voltage Regulator
The CP2102/9 includes an on-chip 5 to 3 V voltage regulator. This allows the CP2102/9 to be configured as either
a USB bus-powered device or a USB self-powered device. These configurations are shown in Figure 6, Figure 7,
Figure 8, Figure 9, and Figure 10. When enabled, the 3 V voltage regulator output appears on the VDD pin and can
be used to power external 3 V devices. See Table 6 for the voltage regulator electrical characteristics.
Alternatively, if 3 V power is supplied to the VDD pin, the CP2102/9 can function as a USB self-powered device with
the voltage regulator disabled. For this configuration, it is recommended that the REGIN input be tied to the 3 V net
to disable the voltage regulator. In addition, if VDD or REGIN may be unpowered while VBUS is 5 V, a resistor
divider (or functionally-equivalent circuit) shown in Note 1 of Figure 8 and Figure 10 is required to meet the
absolute maximum voltage on VBUS specification in Table 2.
The USB max power and power attributes descriptor must match the device power usage and configuration. See
“AN721: CP210x/CP211x Device Customization Guide” for information on how to customize USB descriptors for
the CP2102/9.
Note: It is recommended to connect additional decoupling capacitance (e.g., 0.1 µF in parallel with 1.0 µF) to the REGIN input.
Figure 6. Configuration 1: USB Bus-Powered
Voltage Regulator (REG0)5 V In
3 V Out
VBUS Sense
REGIN
VBUS
From VBUS
To 3 V
Power Net
Device
Power Net
VDD
CP2102/9
1.0 F0.1 F
4.7 F0.1 F
CP2102/9
20 Rev. 1.8
Figure 7. CP2102 Configuration 2: USB Self-Powered
Figure 8. CP2109 Configuration 2: USB Self-Powered
4.7 F0.1 F
Voltage Regulator (REG0)5 V In
3 V Out
VBUS Sense
REGIN
VBUS
To 3V
Power Net
Device
Power Net
VDD
CP2102
From 5 V
Power Net
From VBUS
1.0 F0.1 F
4.7 F0.1 F
Voltage Regulator (REG0)5 V In
3 V Out
VBUS Sense
REGIN
VBUS
To 3V
Power Net
Device
Power Net
VDD
CP2109
From 5 V
Power Net
From VBUS
1.0 F0.1 F
Note 1 : For self-powered systems where VDD or REGIN 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.
47 k
24 k
Note 1
(Optional)
CP2102/9
Rev. 1.8 21
Figure 9. CP2102 Configuration 3: USB Self-Powered, Regulator Bypassed
Figure 10. CP2109 Configuration 3: USB Self-Powered, Regulator Bypassed
4.7 F0.1 F
Voltage Regulator (REG0)5 V In
3 V Out
VBUS Sense
REGIN
VBUS
From 3 V
Power Net
Device
Power Net
VDD
CP2102
From VBUS
1.0 F0.1 F
4.7 F0.1 F
Voltage Regulator (REG0)5 V In
3 V Out
VBUS Sense
REGIN
VBUS
From 3 V
Power Net
Device
Power Net
VDD
CP2109
1.0 F0.1 F
From VBUS
47 k
24 k
Note 1
(Optional)
Note 1 : For self-powered systems where VDD or REGIN 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.
CP2102/9
22 Rev. 1.8
11. Porting Considerations from CP2102 to CP2109
This section highlights the differences between the CP2102 and CP2109. These devices are designed to be pin-
compatible, and thus require very minor changes when porting hardware between devices. The CP2109 is an
updated, cost-reduced version of the CP2102 with a one-time programmable ROM.
11.1. Pin-Compatibility
The CP2109 is pin-compatible with the CP2102 with a single exception; the CP2109 requires an additional
capacitor between VPP and GND for in-application programming. This capacitor is not required after the CP2109
EPROM has been successfully programmed or if the CP2109 does not need to be customized in system.
11.2. Distinguishing Factors
The CP2102 has 1024 bytes of EEPROM for vendor ID (VID), product ID (PID), serial number, power descriptor,
release number, and product description strings. This configuration EEPROM can be written and re-written multiple
times. The CP2109 has 1024 bytes of one-time programmable EPROM for configuration. This configuration
EPROM can only be written one time.
The CP2109 may require an additional capacitor on VPP if in-application programming is desired.
The CP2102 default serial number is always “0001”. Every CP2109 is programmed from the factory with a unique
serial number.
11.3. Differences in Electrical Specifications
Table 14 and Table 15 list differences in absolute maximum and electrical specifications between the CP2102 and
CP2109. Refer to "3. Electrical Specifications" on page 6 for the comprehensive electrical specifications.
Table 14. Differences in Absolute Maximum Specifications between CP2102 and CP2109
Parameter Symbol Test Condition CP2102 CP2109 Unit
Voltage on any I/O Pin, VBUS, or RST with
respect to GND, Maximum
VDD > 3.0 V
VDD not powered
5.8
5.8
5.8
VDD + 3.6
V
Table 15. Differences in Electrical Specifications between CP2102 and CP2109
Parameter Symbol Test Condition CP2102 CP2109 Unit
Supply Current—Normal, Typical IREGIN Normal Operation;
VREG Enabled
20 17 mA
Supply Current—Normal, Maximum IREGIN Normal Operation;
VREG Enabled
26 23 mA
Supply Current—Suspended, Typical IREGIN Bus Powered;
VREG Enabled
80 90 µA
Supply Current—Suspended, Maximum IREGIN Bus Powered;
VREG Enabled
100 230 µA
Output High Voltage, Minimum VOH IOH =–3mA V
DD –0.7 V
DD –0.2 V
Output High Voltage, Typical VOH IOH =–10mA V
DD –0.8 V
DD –0.4 V
Output Low Voltage, Maximum VOL IOL = 8.5 mA 0.6 0.4 V
Output Low Voltage, Typical VOL IOL =25mA 1.0 0.6 V
Input High Voltage, Minimum VIH 2.0 0.7 x VDD V
Input Low Voltage, Maximum VIL 0.8 0.6 V
CP2102/9
Rev. 1.8 23
RST Input High Voltage, Minimum VIHRESET 0.7 x VDD 0.75 x VDD V
RST Input Low Voltage, Maximum VILRESET 0.25 x VDD 0.6 V
Regulator Input Voltage Range, Minimum VREGIN 4.0 3.0 V
Regulator Output Voltage, Minimum VDDOUT Output Current = 1
to 100 mA*
3.0 3.3 V
Regulator Output Voltage, Typical VDDOUT Output Current = 1
to 100 mA*
3.3 3.45 V
VBUS Detection Input Threshold, Minimum VVBUSTH 1.0 2.5 V
VBUS Detection Input Threshold, Typical VVBUSTH 1.8 — V
VBUS Detection Input Threshold, Maximum VVBUSTH 2.9 — V
Regulator Bias Current, Typical 90 83 µA
Regulator Bias Current, Maximum —99µA
USB Transceiver Output Impedance, Typical ZDRV Driving High
Driving Low
38
38
36
36
Ω
Voltage on VPP with respect to GND during a
ROM programming operation, Minimum
VDD > 3.3 V — 5.75 V
Voltage on VPP with respect to GND during a
ROM programming operation, Maximum
VDD > 3.3 V — VDD + 3.6 V
Capacitor on VPP for In-application
Programming, Typical
—4.7µF
Table 15. Differences in Electrical Specifications between CP2102 and CP2109 (Continued)
Parameter Symbol Test Condition CP2102 CP2109 Unit
CP2102/9
24 Rev. 1.8
12. Relevant Application Notes
The following application notes are applicable to the CP2102/9. The latest versions of these application notes and
their accompanying software are available at:
http://www.silabs.com/products/mcu/Pages/ApplicationNotes.aspx.
AN169: USBXpress® Programmer's Guide—This application note describes the USBXpress API interface
and includes example code.
AN197: Serial Communications Guide for the CP210x—This application note describes how to use the
standard Windows COM port function to communicate with the CP2102/9 and includes example code.
AN220: USB Driver Customization—This application note describes how to use the AN220 software to
customize the VCP or USBXpress drivers with OEM information.
AN721: CP210x/CP211x Device Customization Guide—This application note describes how to use the
AN721 software to configure the USB parameters on the CP2102/9 devices.
CP2102/9
Rev. 1.8 25
DOCUMENT CHANGE LIST
Revision 1.0 to Revision 1.1
Updated “Linux 2.40” bullet on page 1.
Changed MLP to QFN throughout.
Revision 1.1 to Revision 1.2
Added additional supported operating systems on
page 1.
Changed VDD conditions of Tables 3 and 4 from a
minimum of 2.7 to 3.0 V.
Updated typical and max Supply Current number in
Table 3.
Removed tantalum requirement in Figure 5.
Consolidated Sections 8 and 9.
Added Section "12. Relevant Application Notes" on
page 24.
Revision 1.2 to Revision 1.3
Updated Figure 1 on page 1.
Updated Figure 5 on page 15.
Updated Maximum VBUS Detection Input Threshold
in Table 6 on page 9.
Revision 1.3 to Revision 1.4
Updated Table 4 RST Input Low Voltage
Updated Table 10, Note 4.
Updated Table 11, Note 10.
Revision 1.4 to Revision 1.5
Added CP2109.
Updated Single-Chip USB to UART Data Transfer
bullet on page 1.
Added CP2109 to Ordering Part Numbers on page
1.
Updated Section "1. System Overview" on page 4.
Updated Figure 1.
Added Section "2. Ordering Information" on page 5.
Added Symbol columns to Tables in Section "3.
Electrical Specifications" on page 6.
Updated Table 3.
-Added CP2109, Note 1, Note 2.
-Updated thermal resistance spec.
-Updated normal supply current spec.
Updated Table 4, added CP2109, added Baud Rate.
Updated Table 5, added CP2109, added VDD Ramp
Time.
Moved Table 6.
Updated Table 6, added CP2109.
Added Table 7.
Added Table 8.
Updated Table 9.
-Updated pin 18 spec, Note 1, Note 2.
Updated Figure 2, added CP2109, pin 18.
Updated Section "6. USB Function Controller and
Transceiver" on page 15, added CP2109.
Updated Figure 5, added CP2109, Option 5.
Updated Section "8. Internal Programmable ROM"
on page 17, added CP2109.
Updated Table 12.
-Updated Note 2 app note reference.
Updated Table 13.
-Added CP2109.
Updated Table 15.
-Updated normal maximum and suspended maximum
supply current specs.
Updated Section "10. Voltage Regulator" on page
19, changed AN144 to AN721.
Added Section "11. Porting Considerations from
CP2102 to CP2109" on page 22.
Updated "11.2. Distinguishing Factors" on page 22.
-Updated CP2102 default serial number to “0001”.
Updated Section "12. Relevant Application Notes"
on page 24.
-Replaced AN144/AN205 with AN721.
Revision 1.5 to Revision 1.6
Added mention of VBUS in Table 2, “Absolute
Maximum Ratings,” on page 6 and split out port I/O
maximums for CP2102 and CP2109.
Added VPP voltage specifications to Table 8,
“EPROM Electrical Characteristics,” on page 10.
Updated "10. Voltage Regulator" on page 19 to add
CP2109 absolute maximum voltage on VBUS
requirements in self-powered systems.
Updated "11.3. Differences in Electrical
Specifications" on page 22 to include the new or
modified specifications.
Revision 1.6 to Revision 1.7
Added Note to front page.
Revision 1.7 to Revision 1.8
January 20, 2017
Revised front page note.
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