Document
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USBUFxxW6
EMI FILTER AND LINE TERMINATION FOR USB UPSTREAM PORTS
A.S.D.™
APPLICATIONS EMI Filter and line termination for USB upstream ports on: - USB Hubs - PC peripherals FEATURES Monolithic device with recommended line termination for USB upstream ports Integrated Rt series termination and Ct bypassing capacitors. Integrated ESD protection Small package size
s s s s
SOT323-6L
DESCRIPTION The USB specification requires upstream ports to be terminated with pull-up resistors from the D+ and D- lines to Vbus. On the implementation of USB systems, the radiated and conducted EMI should be kept within the required levels as stated by the FCC regulations. In addition to the requirements of termination and EMC compatibility, the computing devices are required to be tested for ESD susceptibility. The USBUFxxW6 provides the recommended line termination while implementing a low pass filter to limit EMI levels and providing ESD protection which exceeds IEC61000-4-2 level 4 standard. The device is packaged in a SOT323-6L which is the smallest available lead frame package (50% smaller than the standard SOT23). BENEFITS
s s
FUNCTIONAL DIAGRAM
3.3 V Rt D1 Ct Rp D4
Grd
3.3 V
Rt D2 Ct D3
s
s
s
EMI / RFI noise suppression Required line termination for USB upstream ports ESD protection exceeding IEC61000-4-2 level 4 High flexibility in the design of high density boards Tailored to meet USB 1.1 standard
Rt CODE 01 CODE 02 Tolerance 33Ω 22Ω ±10%
Rp 1.5kΩ 1.5kΩ ±10%
Ct 47pF 47pF ±20%
TM: ASD and TRANSIL are a trademarks of STMicroelectronics.
March 2002 - Ed: 3A
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USBUFxxW6
COMPLIES WITH THE FOLLOWING ESD STANDARDS: IEC61000-4-2, level 4 ±15 kV (air discharge) ±8 kV (contact discharge) MIL STD 883E, Method 3015-7 Class 3 C = 100 pF R = 1500 Ω 3 positive strikes and 3 negative strikes (F = 1 Hz)
ABSOLUTE RATINGS (Tamb = 25°C) Symbol VPP Parameter ESD discharge IEC 61000-4-2, air discharge ESD discharge IEC 61000-4-2, contact discharge ESD discharge - MIL STD 883E - Method 3015-7 Maximum junction temperature Storage temperature range Lead solder temperature (10 second duration) Operating temperature range Power rating per resistor Value ±16 ±9 ±25 150 - 55 to +150 260 0 to 70 100 Unit kV kV kV °C °C °C °C mW
Tj Tstg TL Top Pr
TECHNICAL INFORMATION Fig. A1: USB Standard requirements
3.3V 1.5k
Rt
D+
Twisted pair shielded
D+
Rt Ct Rt
Full-speed or Low-speed USB Transceiver
Ct Rt
Full-speed USB Transceiver
DHost or Hub port
Ct 15k 15k
Zo = 90ohms 5m max
DCt
Hub 0 or Full-speed function
FULL SPEED CONNECTION
3.3V 1.5k
Rt
D+
Untwisted unshielded
D+
Rt Ct Rt
Full-speed or Low-speed USB Transceiver
Ct Rt
Low-speed USB Transceiver
DHost or Hub port
Ct 15k 15k
3m max
DCt
Hub 0 or Low-speed function
LOW SPEED CONNECTION
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USBUFxxW6
APPLICATION EXAMPLE Fig. A2: Implementation of ST' solutions for USB ports
Downstream port
Host/Hub USB por transceivert
USBDF01W5
Rt D+ in Ct Rd D+ out
USBUF01W6
D2 Gnd D1
Upstream port
D+
Per.