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USBUF01P6
EMI FILTER AND LINE TERMINATION FOR USB UPSTREAM PORTS
IPADTM
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
SOT-666IP (Internal Pad) FUNCTIONAL DIAGRAM
3.3 V Rt D1 Ct Rp D4
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 USBUF01P6 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 SOT-666 which is the smallest available lead frame package (45% smaller than the standard SOT323). BENEFITS 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 2.0 standard (low speed and high speed data transmission)
Grd
3.3 V
Rt D2 Ct D3
COMPLIES WITH THE FOLLOWING STANDARDS:
IEC61000-4-2 level4: 15kV (air discharge) 8kV (contact discharge)
MIL STD 883E-Method 3015-7: Class 3 C = 100 pF R = 1500 3 positive strikes and 3 negative strikes (F = 1 Hz)
Order Codes Part Number USBUF01P6
Marking U
May 2004
REV. 2
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USBUF01P6
ABSOLUTE MAXIMUM RATING (Tamb = 25C) Symbol VPP ESD discharge Parameter IEC61000-4-2 air discharge IEC61000-4-2 contact discharge MIL STD 883E - Method 3015-7 Value 16 9 25 150 -55 to +150 260 -40 to + 85 Unit kV C C C C
Tj Tstg TL Top
Junction temperature Storage temperature range Maximum lead temperature for soldering during 10 s at 5mm for case Operating temperature range
ELECTRICAL CHARACTERISTICS (Tamb = 25C) Symbol VRM VBR VCL IRM IPP T VF Rd Parameter Stand-off voltage Breakdown voltage Clamping voltage Leakage current Peak pulse current Voltage temperature coefficient
Slope = 1/Rd
I
IF
VCL VBR VRM IRM
VF V
Forward voltage drop Dynamic resistance
IPP
Symbol VBR IRM Rt Rp Ct
Test conditions IR = 1 mA VRM = 3.3V per line Tolerance 10% Tolerance 10% Tolerance 20%
Min. 6
Typ.
Max. 10 500
Unit V nA W kW pF
33 1.5 47
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USBUF01P6
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
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+
Peripheral transceiver
D+
D+
CABLE
D+
Ct Rt Ct Rt 3.3 V Rp
Gnd
Gnd Ct Rd D- in Rt D- out
D-
D-
DD3
3.3V
D4
D-
FULL SPEED CONNECTION
Downstream port
Host/Hub USB por transceivert
USBDF01W5
Rt D+ in Ct Rd D+ out
USBUF01W6
D2 Gnd D1
Upstream port
D+
Peripheral transceiver
D+
D+
CABLE
D+
Ct Rt Ct Rt 3.3 V Rp
Gnd
Gnd Ct Rd D- in Rt D- out
D-
D-
DD3
3.3V
D4
D-
LOW SPEED CONNECTION
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USBUF01P6
EMI FILTERING Current FCC regulations requires that class B computing devices meet specified maximum levels for both radiated and conducted EMI. - Radiated EMI covers the frequency range from 30MHz to 1GHz. - Conducted EMI covers the 450kHz to 30MHz range. For the types of devices utilizing the USB, the most difficult test to pass is usually the radiated EMI test. For this reason the USBUF01P6 device is aiming to minimize radiated EMI. The differential signal (D+ and D-) of the USB does not contribute significantly to radiated or conducted EMI because the magnetic field of both conductors cancels each other. The inside of the PC environment is very noisy and designers must minimize noise coupling from the different sources. D+ and D- must not be routed near high speed lines (clocks spikes). Induced common mode noise can be minimized by running pairs of USB signals parallel to each other and running grounded guard trace on each side of the signal pair from the USB controller to the USBUF device. If possible, locate the USBUF device physically near the USB connectors. Distance between the USB controller and the USB connector must be minimized. The 47pF (Ct) capacitors are used to bypass high frequency energy to ground and for edge control, and are placed between the driver chip and the series termination resistors (Rt). Both C t and R t should be placed as close to the driver chip as is practicable. The USBUF01P6 ensures a filtering protection against ElectroMagnetic and RadioFrequency Interferences thanks to its low-pass filter structure. This filter is characterized by the following parameters: - cut-off frequency - Insertion loss - high frequency rejection. Fig. A3: USBUF01P6 typical attenuation curve.
0.00 dB -2.50 -5.00 -7.50
TEST BOARD
UUx
Fig. A4: Measurement configuration.
50
-10.00 -12.50 -15.00 -17.50 -20.00 -22.50 -25.00 1.0M 3.0M 10.0M 30.0M f/Hz 100.0M 300.0M 1.0G 3.0G
Vg
50
ESD PROTECTION In addition to the requirements of termination and EMC compatibility, computing devices are required to be tested for ESD susceptibility. This test is described in the IEC 61000-4-2 and is already in place in Europe. This test requires that a device tolerates ESD events and remains operational without user intervention. The USBUF01P6 is particularly optimized to perform ESD protection. ESD protection is based on the use of device which clamps at:
V CL = V BR + R d I PP
This protection function is splitted in 2 stages. As shown in figure A5, the ESD strikes are clamped by the first stage S1 and then its remaining overvoltage is applied to the second stage through the resistor Rt. Such a configuration makes the output voltage very low at the output.
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USBUF01P6
Fig. A5: USBUF01P6 ESD clamping behavior.
Rg
S1
Rt
S2
Rd
VPP
Vinput Voutput
Rd
Rload
VBR
VBR
Device to be protected
ESD Surge
USBUF01P6
Fig. A6: Measurement board.
ESD SURGE 15kV Air Discharge
TEST BOARD
U
Vin
Vout
To have a good approximation of the remaining voltages at both Vin and Vout stages, we give the typical dynamical resistance value Rd. By taking into account these following hypothesis : Rt>R d, R g>Rd and Rload>Rd, it gives these formulas:
R g V BR + R d V g Vinput = ---------------------------------------------Rg R t V BR + R d Vinput Voutput = --------------------------------------------------------Rt
The results of the calculation done for Vg=8kV, Rg=330 (IEC61000-4-2 standard), V BR=7V (typ.) and Rd = 2 (typ.) give: Vinput = 55.48 V Voutput = 10.36 V This confirms the very low remaining voltage across the device to be protected. It is also important to note that in this approximation the parasitic inductance effect was not taken into account. This could be few tenths of volts during few ns at the Vinput side. This parasitic effect is not present at the Voutput side due the low current involved after the resistance R t. The measurements done hereafter show very clearly (fig. A7) the high efficiency of the ESD protection : - no influence of the parasitic inductances on Voutput stage - Voutput clamping voltage very close to VBR (breakdown voltage) in the positive way and -VF (forward voltage) in the negative way
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USBUF01P6
Fig. A7: Remaining voltage at both stages S1 (Vinput) and S2 (Voutput) during ESD surge.
a: Positive surge
b: Negative surge
Please note that the USBUF01P6 is not only acting for positive ESD surges but also for negative ones. For these kinds of disturbances it clamps close to ground voltage as shown in fig. A7b.
ORDERING INFORMATION Part Number USBUF01P6 Marking U Package SOT-666IP Weight 2.9 mg Base qty 3000 Delivery mode Tape & reel
REVISION HISTORY Table 1: Revision history Date September-2003 01-Juin-2004 Revision 1 2 First issue SOT-666 Internal Pad version package change Description of Changes
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USBUF01P6
PACKAGE MECHANICAL DATA SOT-666IP (internal Pad)
b L3 e
DIMENSIONS REF. A Millimeters Min. 0.53 0.13 1.50 1.05 1.50 1.10 0.23 0.11 0.10 0.05 0.83 Ref 0.14 0.20 8 12 0.25 0.34 8 Max. 0.60 0.18 1.70 1.25 1.70 1.30 0.43 0.26 0.30 Inches Min. 0.021 0.005 0.059 0.041 0.059 0.043 0.009 0.004 0.004 0.002 0.032 0.006 0.010 0.013 0.020 0.008 12 Max. 0.024 0.007 0.067 0.049 0.067 0.051 0.017 0.010 0.012 -
L1
L4
A3 D D2 E E1 E2 L1 L2 L3 L4 b b1 e e1
b1
e1
(4x)
A A3
D
E
E1
0.50 Bsc
L2
FOOT PRINT DIMENSIONS (in millimeters)
0.36 0.20
MECHANICAL SPECIFICATIONS Lead plating Lead plating thickness Tin-lead 5m min 25m max Sn / Pb (70% to 90%Sn) 10m max Molded epoxy UL94V-0
0.20
0.84
Lead material
0.62 2.30
1.26
Lead coplanarity Body material
0.30
Flammability
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners (c) 2004 STMicroelectronics - All rights reserved STMicroelectronics GROUP OF COMPANIES Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States www.st.com
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