ESDA25B1 (R) TRANSIL ARRAY FOR ESD PROTECTION Application Specific Discretes A.S.D. APPLICATIONS Where transient overvoltage protection in ESD sensitive equipment is required, such as : - COMPUTER - PRINTERS - COMMUNICATION SYSTEMS It is particulary recommended for RS232 I/O port protection where the line interface withstands only 2 kV ESD surges. FEATURES SO-8 6 BIDIRECTIONAL TRANSIL FUNCTIONS VERY LOW CAPACITANCE : C= 20 pF @ VRM 150 W peak pulse power (8/20 s) DESCRIPTION FUNCTIONAL DIAGRAM The ESDA25B1 is a monolithic voltage suppressor designed to protect components which are connected to data and transmission lines against EDS. I/O 1 1 8 I/O 6 I/O 2 2 7 I/O 5 I/O 3 3 6 I/O 4 GND 4 5 GND BENEFITS High ESD protection level : up to 25 kV High integration Suitable for high density boards COMPLIES WITH THE FOLLOWING STANDARDS : IEC 1000-4-2 : level 4 MIL STD 883C-Method 3015-6 : class 3 (human body model) October 1999 - Ed : 2 1/5 ESDA25B1 ABSOLUTE MAXIMUM RATINGS (Tamb = 25C) Symbol Parameter Value Unit VPP Electrostatic discharge MIL STD 883C - Method 3015-6 25 kV PPP Peak pulse power (8/20s) 150 W Tstg Tj Storage temperature range Maximum junction temperature - 55 to + 150 125 C C TL Maximum lead temperature for soldering during 10s 260 C ELECTRICAL CHARACTERISTICS (Tamb = 25C) Symbol Parameter VRM Stand-off voltage VBR Breakdown voltage VCL Clamping voltage IRM Leakage current IPP Peak pulse current T Voltage temperature coefficient C Capacitance Rd Dynamic resistance Types VBR min. IR @ max. note 1 ESDA25B1 T C max. typ. max. typ. note 1 note 2 note 3 0V bias @ VRM V V mA A V 10-4/C pF 25 30 1 2 24 1.5 9.7 15 note 1 : Between any I/O pin and Groung note 2 : Square pulse, Ipp = 25A, tp=2.5s. note 3 : VBR = T* (Tamb -25C) * VBR (25C) 2/5 Rd IRM ESDA25B1 CALCULATION OF THE CLAMPING VOLTAGE USE OF THE DYNAMIC RESISTANCE The ESDA family has been designed to clamp fast spikes like ESD. Generally the PCB designers need to calculate easily the clamping voltage VCL. This is why we give the dynamic resistance in addition to the classical parameters. The voltage across the protection cell can be calculated with the following formula: VCL = VBR + Rd IPP As the value of the dynamic resistance remains stable for a surge duration lower than 20s, the 2.5s rectangular surge is well adapted. In addition both rise and fall times are optimized to avoid any parasitic phenomenon during the measurement of Rd. Where Ipp is the peak current through the ESDA cell. DYNAMIC RESISTANCE MEASUREMENT The short duration of the ESD has led us to prefer a more adapted test wave, as below defined, to the classical 8/20s and 10/1000s surges. I Ipp 2s t tp = 2.5s 2.5s duration measurement wave. 3/5 ESDA25B1 Fig. 1 : Peak power dissipation versus initial junction temperature. Fig. 2 : Peak pulse power versus exponential pulse duration (Tj initial = 25 C). Ppp[Tj initial]/Ppp[Tj initial=25C] 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Ppp(W) 2000 1000 100 Tj initial(C) 0 25 50 75 tp(s) 100 125 150 Fig. 3 : Clamping voltage versus peak pulse current (Tj initial = 25 C). Rectangular waveform tp = 2.5 s. 10 1 10 100 Fig. 4 : Capacitance versus reverse applied voltage (typical values). C(pF) Ipp(A) 50.0 20 F=1MHz Vosc=30mV tp=2.5s 10 10.0 5 1.0 2 VCL(V) 0.1 20 25 30 35 40 VR(V) 45 50 55 60 Fig. 5 : Relative variation of leakage current versus junction temperature (typical values). IR[Tj] / IR[Tj=25C] 200 100 10 Tj(C) 1 25 4/5 50 75 100 125 1 1 2 5 10 30 ESDA25B1 ORDER CODE ESDA 25 B 1 RL PACKAGING: RL = Tape and reel = Tube ESD ARRAY VBR min PACKAGE : SO-8 Bidirectionel MARKING : Logo, Date Code, E25B1 PACKAGE MECHANICAL DATA SO-8 Plastic DIMENSIONS REF. Millimeters Min. A a1 a2 a3 b b1 C c1 D E e e3 F L M S Typ. Max. Min. Typ. Max. 1.75 0.25 0.004 1.65 0.85 0.026 0.48 0.014 0.25 0.007 0.5 0.010 45 (typ) 5.0 0.189 6.2 0.228 0.069 0.010 0.065 0.033 0.019 0.010 0.020 0.1 0.65 0.35 0.19 0.25 4.8 5.8 1.27 3.81 3.8 0.4 Inches 0.197 0.244 0.050 0.150 4.0 0.15 1.27 0.016 0.6 8 (max) 0.157 0.050 0.024 Packaging : Preferred packaging is tape and reel. Weight : 0.08g. 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 (c) 1999 STMicroelectronics - Printed in Italy - All rights reserved. STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A. http://www.st.com 5/5