hai What is the supply current for ALTERA APEX series FPGA EP20K30E(1.8 voltage).The operating frequency of FPGA is 50Mhz Regards Gopalakrishnan.S -----Original Message----- From: Henrik G. Madsen [mailto:hgm@xxxxxxxxxxx] Sent: Monday, December 02, 2002 1:55 PM To: peter.zhu@xxxxxxxxxx; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: How to select the pullup/pulldwon resistor Hey Peter For unused inputs the issue is simple and a matter of pure math and how = much noise margin you would like to have. If you look at a datasheet for a SN74LS74A, it specify the maximum input = leakage current in high and low state Iih =3D 40uA (Vi=3D2.7V)=20 Iil =3D -0.8mA (Vi=3D0.4V) If the minimum supply voltage is 4.5V (5V +-10%) and you want a noise = margin of 400mV (standard for TTL), then the pullup and pulldown = resistor values are giving by. Rpullup <=3D (4.5V -(2.0V +0.4V))/ 40uA =3D 52.5 k ohm Rpulldown <=3D (0.8V-0.4V)/ 0.8mA =3D 0.5 k ohm The huge difference in requirement to the pullup and pulldown is caused = by the difference in leakage current and the distance from Vih/Vil to = the supply voltages. In modern CMOS electronic, the leakage current is lower and the Vih/Vil = are placed more symmitrically between power supplies. On top of that you often wnat to reduce the number of different types of = components as much as possible to reduce production cost. Hence many schematics will only contain a couple of different resistor = values, hence a simple pullup might be a 2.77k +- 0.1% because the size = and precission is necessary somewhere else in the schematic. Regards /Henrik -----Original Message----- From: peter zhu [mailto:peter.zhu@xxxxxxxxxx] Sent: 28. november 2002 12:47 To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] How to select the pullup/pulldwon resistor Hi all: In hardware design, we often encounter the problem of pullup or pulldown = resistor, i very puzzled about it: 1.how to determine pullup or pulldown. 2.how to determine the value of pullup or pulldown resistor. These are two common hardware design problem. I hope can see some = detailed materials about it. Help me! Regards! ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages=20 Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu -- Attached file included as plaintext by Ecartis -- -- File: Wipro_Disclaimer.txt **************************Disclaimer************************************ Information contained in this E-MAIL being proprietary to Wipro Limited is 'privileged' and 'confidential' and intended for use only by the individual or entity to which it is addressed. You are notified that any use, copying or dissemination of the information contained in the E-MAIL in any manner whatsoever is strictly prohibited. *************************************************************************** ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu