PACUSB-U1 Datasheet, PDF (5/7 Pages) California Micro Devices Corp – Upstream USB Port Terminator

PACUSB-U1/U2/U3
Application Information
The PACUSB-U1/U2/U3 is targeted for upstream USB
ports (peripherals). It provides series termination, EMI
filtering, and ESD protection for the two USB data lines
D+ and D-.
The USB Specification revision 1.1 provides for two
data rates:
• The Full Speed signaling bit rate at 12 Mbits per
second, and
• The Low Speed signaling bit rate at 1.5 Mbits per
second.
The speed is selected by connecting one of the data
lines (D+ or D-) to a 3.3V supply voltage via a 1.5kΩ
pull-up resistor (R2).
Connections for Full Speed Operation
Full Speed devices have the pull-up resistor (R2) con-
nected to the D+ data line, as shown in Figure 1. Pin1
is tied to the D+ line of the USB controller. Pin 6 is con-
nected to the D+ line on the USB connector.
Connections for Low Speed Operation
Low Speed devices have the pull-up resistor (R2) con-
nected to the D- data line, as shown in Figure 2. Pin 1
is tied to the D- line of the USB controller; pin 6 is con-
nected to the D- line on the USB connector.
PACUSB-Ux
D+
1
R1
IN1
D1_i
C1
USB
CONTROLLER
2
GND
GND
C1
GND
D-
3
IN2
D2_i
R1
SC70-6
6
D+
OUT 1
R2 ^D1_c
3.3V
5
Vcc
V_3.3
USB
CONNECTOR
4
D-
OUT 2
D2_c
Figure 1. Full Speed Connection
PACUSB-Ux
D-
1
R1
IN1
D1_i
C1
USB
CONTROLLER
2
GND
GND
C1
GND
D+
3
IN2
D2_i
R1
SC70-6
6
D-
OUT 1
R2 ^D1_c
3.3V
5
Vcc
V_3.3
USB
CONNECTOR
4
D+
OUT 2
D2_c
Figure 2. Low Speed Connection
© 2006 California Micro Devices Corp. All rights reserved.
05/01/06
490 N. McCarthy Blvd., Milpitas, CA 95035-5112 ● Tel: [phone] ● Fax: [phone] ● www.cmd.com 5