USB6B1

USB6B1 Data line protection Applications Where transient overvoltage protection in sensitive equipment is required, such as: ■ ■ ■ ■ ■ ■ Universal Serial Bus ports RS-423 interfaces RS-485 interfaces ISDN equipment T1/E1 line cards HDSL / ASDL interfaces SO-8 Order Codes Part Numbers USB6B1 USB6B1RL Marking USB62 USB62 Features ■ ■ ■ ■ Full diode bridge with integrated clamping protection Breakdown voltage: VBR = 6 V min. Peak pulse power dissipation: PPP = 500 W (8/20 µs) Very low capacitance, compatible with high debit data or signal rates. Functional diagram VCC I/O1 I/O2 GND VCC I/O1 I/O2 GND Description In order to prevent fast transients from leading to severe damages in a high speed data system, a specific protection has been developed by STMicroelectronics. The USB6B1 protects the two input lines against overvoltage. Besides, this device also keeps the power rails in a safe limit thanks to the integrated Transil diode. Complies with the following standards: MIL STD 883C - Method 3015-6 class 3 C = 100 pF R = 1500 Ω Benefits ■ ■ ■ ■ Provides protection for each line and between the supply voltage and GND: 25 A, 8/20 µs. High ESD protection level: up to level 3 per MIL STD 883C-Method 3015-6 Separated inputs and outputs (so-called 4-point structure) to improve ESD susceptibility. Comprehensive package pin-out for immediate implementation. 3 positive strikes and 3 negative strikes (F = 1 Hz) IEC 61000-4-2 level 4 15 kV (air discharge) 8 kV (contact discharge) August 2006 Rev 10 1/9 www.st.com 9 Characteristics USB6B1 1 Characteristics Table 1. Symbol Absolute maximum ratings Parameter IEC61000-4-2 contact discharge IEC61000-4-2 air discharge MIL STD883C-Method 30 15-6 8/20 µs 8/20 µs Value 8 15 4 500 25 A 2/10 µs Storage temperature range Operating temperature range Lead solder temperature (10 s duration) 40 - 55 to + 150 - 40 to + 85 260 °C °C °C Unit VPP PPP IPP Tstg Top TL Peak pulse voltage Peak pulse power Peak pulse current kV W Table 2. Symbol VBR IRM Electrical characteristics (Tamb = 25° C) Value Parameter Min Typ Max Breakdown voltage between VBUS and GND Leakage current Capacitance between pins D+ and DVOSC = 30 mV, F = 1 MHz, VR = 0 V IR = 1 mA VRM = 5.25 V VCC not connected 15 25 6 10 V µA pF pF Unit C Capacitance between pins D+(or D-) and GND VCC = 5 V VOSC = 30 mV, F = 1 MHz, VR = 5 V 2/9 USB6B1 Characteristics Figure 1. Peak power dissipation versus initial junction temperature Figure 2. Relative variation of leakage current versus junction temperature (typical values) Ppp[Tj initial]/Ppp[Tj initial=25°C] 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 -40 -20 0 20 40 60 80 100 120 140 160 1.0 10.0 IR[Tj] / IR[Tj=25°C] Tj initial(°C) 0.1 -40 -20 0 20 Tj(°C) 40 60 80 100 120 140 Figure 3. Relative variation of breakdown voltage versus junction temperature (typical values) 1.10 VBR[Tj] / VBR[Tj=25°C] 1.05 1.00 0.95 Tj(°C) 0.90 -40 -20 0 20 40 60 80 100 120 140 3/9 Technical information USB6B1 2 2.1 Technical information Surge protection The USB6B1 is optimized to perform surge protection based on the rail to rail topology. The clamping voltage VCL can be estimated as follow: VCL+ = VCC + VF for positive surges VCL - = - VF for negative surges with: VF =Vt + rd.Ip VF = forward drop voltage, Vt = forward drop threshold voltage Note: The estimations do not take into account phenomena due to parasitic inductances. Figure 4. Surge behavior Figure 5. ESD behavior: optimized layout and addition of a 100 nF capacitor Lw REF2=+Vcc C=100nF ESD SURGE Vf I/O Lw +Vcc Lw di dt ESD SURGE I/O di Vcl+ = Vcc+Vf+Lw dt surge >0 di surge 0 surge