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Joined Dec 18, 2002 Messages 261 Helped 3 Reputation 6 Reaction score 1 Trophy points 1,298 Activity points 2,173 74ls 74hc hello what is the difference between 74ls and 74hc i know that the first is schottky and second cmos what is the difference and where to use each kind ,and what is the advantage and disadvantge of each familly any help? links,pdf,whatever... G 
Joined Jun 19, 2003 Messages 11 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Location Brazil Activity points 110 difference between74 hc, 74ls and 74c hello look the link **broken link removed** or **broken link removed** or **broken link removed** bye W 
Joined Mar 27, 2002 Messages 72 Helped 6 Reputation 12 Reaction score 2 Trophy points 1,288 Location wherever I go - there I am! Activity points 948 difference between 74ls 74hc ZeleC: The main difference between the LS and HC is the logic of 74XX. The 74LS is Transistor to Transistor logic. Uses Shottky transistors to reduce the stored charge and get higher switching speeds then with conventional bipolar transistors. The 74HC uses MOSFET technology. Therefore can operate with wider variety of voltages. Power consumption better then TTL (but increases at higher frequencies). Has better noise margins so can work in noisy environments compared to TTL. 74HC are becoming more and more better replacements to older 74LS Transition speeds are not too much different. Prop delays for: 74LS - tpLH and tpHL about 15 nsec. 74HC - tpd about 18 nsec. I don't know if this helps but, I hope this answers some questions. WA 
Joined Jul 19, 2002 Messages 4,624 Helped 489 Reputation 980 Reaction score 151 Trophy points 1,343 Location Middle Earth Activity points 46,689 74ls vs 74hc The HC family was intended to exactly duplicate the speed of the LS but with lower power due to being CMOS. B 
Joined Jun 24, 2003 Messages 106 Helped 2 Reputation 4 Reaction score 1 Trophy points 1,298 Activity points 1,209 74 ac hc difference There are a number of other interesting differences. For example, the HC circuits draw very little current at the inputs if you compare it with HC. At the same time, HC (Highspeed CMOS) also preserves other characteristics of the CMOS families, for example you can use 3.0V to power it (and even less, I don't have a datasheet here). Of course, if you to this, the maximum logical levels on the inputs change (with a 3V power suply you won't be able to tie 5V directly to an input, you need at least some minimal level adjustment). This is very interesting for people that design low-speed level shifters (5V-3.3V, seen for example in parallel port to JTAG adapters). Watch it, there is also HCT (Highspeed CMOS, TTL compatible) that makes the power range compatible with the LS series, so you can't power it from 3V. And then there are VHC, LVX, LVC, LVT and others, just to confuse you completely 
Joined Sep 19, 2001 Messages 121 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,296 Activity points 757 74ls projects The low power at low freq only. On the high speed, it req approximate as ttl LS series. D 
Joined May 7, 2001 Messages 48 Helped 1 Reputation 2 Reaction score 1 Trophy points 1,288 Location middle USA Activity points 365 difference between hc and vhc One point that was implied, but maybe not stated. HC has the same functions as the corresponding TTL part, but the parameters are different. i.e. they are not interchangeable in a actual cicuit! The HCT line was introduced to be closer fit and can be interchanged in some cases. D 
Joined May 10, 2004 Messages 1 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 8 74 family 74c 74hc 74ls What's the diffirent between 74hc and 74ac (hc and ac)? Z 
Joined Oct 13, 2003 Messages 331 Helped 9 Reputation 18 Reaction score 6 Trophy points 1,298 Location Hungary Activity points 3,511 difference between 74ls and 74hc Hope it helps 8) : Device Families: TTL (74xx) True TTL 74L Low power 74S Schottky 74H High speed 74LS Low power - Schottky 74AS Advanced - Schottky 74ALS Advanced - Low power - Schottky 74F(AST) Fast - (Advanced - Schottky) 74C CMOS...................check Vcc levels 74HC (U) High speed - CMOS (Unbuffered output) 74HCT High speed - CMOS - TTL inputs 74AHC Advanced - High speed - CMOS 74AHCT Advanced - High speed - CMOS - TTL inputs 74FCT (-A) Fast - CMOS - TTL inputs (speed variations) 74FCT (-T, -AT) Fast - CMOS - TTL inputs (speed variations) 74AC Advanced - CMOS 74ACT Advanced - CMOS - TTL inputs 74FACT AC, ACT (Q) series 74ACQ Advanced - CMOS - Quiet outputs 74ACTQ Advanced - CMOS - TTL inputs - Quiet outputs Bus Driver Families 74ABT Advanced - BiCMOS - Technology 74ABTE ABT - Enhanced Transceiver Logic 74ABTH Advanced - BiCMOS - Technology - bus Hold 74BCT BiCMOS - TTL inputs 74BTL Backplane - Transceiver - Logic 74GTL Gunning - Transceiver - Logic 74GTLP GTL Plus Low Voltage Families 74ALB Advanced - Low Voltage - BiCMOS 74LV (U) Low - Voltage (Unbuffered output) 74LVC (R) (U) LV - CMOS (damping Resistor)(Unbuffered output) 74LVCH Low - Voltage - CMOS - bus Hold 74ALVC Advanced - Low - Voltage - CMOS 74LVT (R) (U) LV - TTL (damping Resistor(Unbuffered output) 74LVTZ Low - Voltage - TTL - High Impedance power-up 74ALVC (R) ALV - CMOS (bus Hold) (damping Resistor) 74ALVCH Advanced - Low - Voltage - CMOS - bus Hold 74LCX LV - CMOS (operates with 3v & 5v supplies) 74VCX LV - CMOS (operates with 1.8v & 3.6v supplies 4000 True CMOS (non-TTL levels) Zed B Joined Jan 3, 2003 Messages 281 Helped 19 Reputation 38 Reaction score 13 Trophy points 1,298 Location Turkey Activity points 2,208 ttl hc hct ac ls comparison If we compare the logic levels; LSTTL, compatible with TTL HCT, compatible with TTL HC, not compatible with TTL B Joined Jun 24, 2003 Messages 106 Helped 2 Reputation 4 Reaction score 1 Trophy points 1,298 Activity points 1,209 difference between cmos 74hc and 74 hct series HC - High-speed CMOS AC - Advanced CMOS ( higher speeds that HC ) HCT - High-speed CMOS, TTL compatible (voltage levels compatible with TTL logic levels) ACT - Advanced CMOS, TTL compatible (same) If you need high speed (check the actual datasheets for numerical values) use ACT. Otherwise you can safely stick to HCT. Joined Sep 19, 2001 Messages 121 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,296 Activity points 757 74ls and 74hc 
Joined Dec 23, 2001 Messages 413 Helped 11 Reputation 24 Reaction score 10 Trophy points 1,298 Activity points 3,212 difference 74ahc 74hc series you should to download these datasheet and find difference C Joined Feb 4, 2010 Messages 1 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,285 Re: 74LS & 74hc Ive got question. Can i use 74AHC to translate voltage level from 3V to 5V ? [device 1] - ----3V ----- [74AHC with GND on output_enable_input] ---- 5V? [device2] When connected like this im getting 2V output with 3V on input and its something wrong. Do i need AHCT? or HCT? plz hlp me ! B Joined May 22, 2010 Messages 1 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Location Germany Activity points 1,284 Re: 74LS & 74hc 
Joined Apr 1, 2011 Messages 15,614 Helped 2,912 Reputation 5,836 Reaction score 3,050 Trophy points 1,393 Location Minneapolis, Minnesota, USA Activity points 116,925 Sept. 2018 -Links in post #2 are no longer valid. One article at least can be seen at this link: www.ti.com/lit/ml/scyb004b/scyb004b.pdf 
Joined Apr 17, 2014 Messages 26,186 Helped 4,923 Reputation 9,869 Reaction score 5,774 Trophy points 1,393 Activity points 176,046 In addition to post#15: For 3.3V --> 5.0V translation: use 74AHCT family. Supplied with 5.0V. The difference between AHC and AHCT is the input level. While a AHCT is happy with 3.3V input levels, an AHC is at the edge. It's not safe because it's not guaranteed that V_OH(3V3) > V_IH(5V). Klaus 
Joined Apr 17, 2013 Messages 2,725 Helped 859 Reputation 1,722 Reaction score 850 Trophy points 1,393 Activity points 18,445 A necro-thread has resurrected. 
Joined Nov 7, 2006 Messages 9,651 Helped 1,191 Reputation 2,401 Reaction score 1,219 Trophy points 1,403 Location Brazil Activity points 55,967
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- Thread starter ZeleC
- Start date Jun 29, 2003
ZeleC
Full Member level 5
Joined Dec 18, 2002 Messages 261 Helped 3 Reputation 6 Reaction score 1 Trophy points 1,298 Activity points 2,173 74ls 74hc hello what is the difference between 74ls and 74hc i know that the first is schottky and second cmos what is the difference and where to use each kind ,and what is the advantage and disadvantge of each familly any help? links,pdf,whatever... G gpenga
Newbie level 6
Joined Jun 19, 2003 Messages 11 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Location Brazil Activity points 110 difference between74 hc, 74ls and 74c hello look the link **broken link removed** or **broken link removed** or **broken link removed** bye W WA
Member level 4
Joined Mar 27, 2002 Messages 72 Helped 6 Reputation 12 Reaction score 2 Trophy points 1,288 Location wherever I go - there I am! Activity points 948 difference between 74ls 74hc ZeleC: The main difference between the LS and HC is the logic of 74XX. The 74LS is Transistor to Transistor logic. Uses Shottky transistors to reduce the stored charge and get higher switching speeds then with conventional bipolar transistors. The 74HC uses MOSFET technology. Therefore can operate with wider variety of voltages. Power consumption better then TTL (but increases at higher frequencies). Has better noise margins so can work in noisy environments compared to TTL. 74HC are becoming more and more better replacements to older 74LS Transition speeds are not too much different. Prop delays for: 74LS - tpLH and tpHL about 15 nsec. 74HC - tpd about 18 nsec. I don't know if this helps but, I hope this answers some questions. WA flatulent
Advanced Member level 6
Joined Jul 19, 2002 Messages 4,624 Helped 489 Reputation 980 Reaction score 151 Trophy points 1,343 Location Middle Earth Activity points 46,689 74ls vs 74hc The HC family was intended to exactly duplicate the speed of the LS but with lower power due to being CMOS. B bogdanm
Advanced Member level 4
Joined Jun 24, 2003 Messages 106 Helped 2 Reputation 4 Reaction score 1 Trophy points 1,298 Activity points 1,209 74 ac hc difference There are a number of other interesting differences. For example, the HC circuits draw very little current at the inputs if you compare it with HC. At the same time, HC (Highspeed CMOS) also preserves other characteristics of the CMOS families, for example you can use 3.0V to power it (and even less, I don't have a datasheet here). Of course, if you to this, the maximum logical levels on the inputs change (with a 3V power suply you won't be able to tie 5V directly to an input, you need at least some minimal level adjustment). This is very interesting for people that design low-speed level shifters (5V-3.3V, seen for example in parallel port to JTAG adapters). Watch it, there is also HCT (Highspeed CMOS, TTL compatible) that makes the power range compatible with the LS series, so you can't power it from 3V. And then there are VHC, LVX, LVC, LVT and others, just to confuse you completely Zenner
Full Member level 2
Joined Sep 19, 2001 Messages 121 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,296 Activity points 757 74ls projects The low power at low freq only. On the high speed, it req approximate as ttl LS series. D dipchip
Member level 2
Joined May 7, 2001 Messages 48 Helped 1 Reputation 2 Reaction score 1 Trophy points 1,288 Location middle USA Activity points 365 difference between hc and vhc One point that was implied, but maybe not stated. HC has the same functions as the corresponding TTL part, but the parameters are different. i.e. they are not interchangeable in a actual cicuit! The HCT line was introduced to be closer fit and can be interchanged in some cases. D D&S
Newbie level 1
Joined May 10, 2004 Messages 1 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 8 74 family 74c 74hc 74ls What's the diffirent between 74hc and 74ac (hc and ac)? Z Zedman
Full Member level 6
Joined Oct 13, 2003 Messages 331 Helped 9 Reputation 18 Reaction score 6 Trophy points 1,298 Location Hungary Activity points 3,511 difference between 74ls and 74hc Hope it helps 8) : Device Families: TTL (74xx) True TTL 74L Low power 74S Schottky 74H High speed 74LS Low power - Schottky 74AS Advanced - Schottky 74ALS Advanced - Low power - Schottky 74F(AST) Fast - (Advanced - Schottky) 74C CMOS...................check Vcc levels 74HC (U) High speed - CMOS (Unbuffered output) 74HCT High speed - CMOS - TTL inputs 74AHC Advanced - High speed - CMOS 74AHCT Advanced - High speed - CMOS - TTL inputs 74FCT (-A) Fast - CMOS - TTL inputs (speed variations) 74FCT (-T, -AT) Fast - CMOS - TTL inputs (speed variations) 74AC Advanced - CMOS 74ACT Advanced - CMOS - TTL inputs 74FACT AC, ACT (Q) series 74ACQ Advanced - CMOS - Quiet outputs 74ACTQ Advanced - CMOS - TTL inputs - Quiet outputs Bus Driver Families 74ABT Advanced - BiCMOS - Technology 74ABTE ABT - Enhanced Transceiver Logic 74ABTH Advanced - BiCMOS - Technology - bus Hold 74BCT BiCMOS - TTL inputs 74BTL Backplane - Transceiver - Logic 74GTL Gunning - Transceiver - Logic 74GTLP GTL Plus Low Voltage Families 74ALB Advanced - Low Voltage - BiCMOS 74LV (U) Low - Voltage (Unbuffered output) 74LVC (R) (U) LV - CMOS (damping Resistor)(Unbuffered output) 74LVCH Low - Voltage - CMOS - bus Hold 74ALVC Advanced - Low - Voltage - CMOS 74LVT (R) (U) LV - TTL (damping Resistor(Unbuffered output) 74LVTZ Low - Voltage - TTL - High Impedance power-up 74ALVC (R) ALV - CMOS (bus Hold) (damping Resistor) 74ALVCH Advanced - Low - Voltage - CMOS - bus Hold 74LCX LV - CMOS (operates with 3v & 5v supplies) 74VCX LV - CMOS (operates with 1.8v & 3.6v supplies 4000 True CMOS (non-TTL levels) Zed B bunalmis
Full Member level 5
Joined Jan 3, 2003 Messages 281 Helped 19 Reputation 38 Reaction score 13 Trophy points 1,298 Location Turkey Activity points 2,208 ttl hc hct ac ls comparison If we compare the logic levels; LSTTL, compatible with TTL HCT, compatible with TTL HC, not compatible with TTL B bogdanm
Advanced Member level 4
Joined Jun 24, 2003 Messages 106 Helped 2 Reputation 4 Reaction score 1 Trophy points 1,298 Activity points 1,209 difference between cmos 74hc and 74 hct series HC - High-speed CMOS AC - Advanced CMOS ( higher speeds that HC ) HCT - High-speed CMOS, TTL compatible (voltage levels compatible with TTL logic levels) ACT - Advanced CMOS, TTL compatible (same) If you need high speed (check the actual datasheets for numerical values) use ACT. Otherwise you can safely stick to HCT. Zenner
Full Member level 2
Joined Sep 19, 2001 Messages 121 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,296 Activity points 757 74ls and 74hc D&S said: What's the diffirent between 74hc and 74ac (hc and ac)? Click to expand...gate delay. A
alphi
Advanced Member level 1
Joined Dec 23, 2001 Messages 413 Helped 11 Reputation 24 Reaction score 10 Trophy points 1,298 Activity points 3,212 difference 74ahc 74hc series you should to download these datasheet and find difference C czat85
Newbie level 1
Joined Feb 4, 2010 Messages 1 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Activity points 1,285 Re: 74LS & 74hc Ive got question. Can i use 74AHC to translate voltage level from 3V to 5V ? [device 1] - ----3V ----- [74AHC with GND on output_enable_input] ---- 5V? [device2] When connected like this im getting 2V output with 3V on input and its something wrong. Do i need AHCT? or HCT? plz hlp me ! B barepic
Newbie level 1
Joined May 22, 2010 Messages 1 Helped 0 Reputation 0 Reaction score 0 Trophy points 1,281 Location Germany Activity points 1,284 Re: 74LS & 74hc Ive got question. Can i use 74AHC to translate voltage level from 3V to 5V ? [device 1] - ----3V ----- [74AHC with GND on output_enable_input] ---- 5V? [device2] When connected like this im getting 2V output with 3V on input and its something wrong. Click to expand...Why you need this? There are some buffers which will work from 2V supply and are tolerant to 5V inputs, but you want the other way. Why? B
BradtheRad
Super Moderator
Staff member Joined Apr 1, 2011 Messages 15,614 Helped 2,912 Reputation 5,836 Reaction score 3,050 Trophy points 1,393 Location Minneapolis, Minnesota, USA Activity points 116,925 Sept. 2018 -Links in post #2 are no longer valid. One article at least can be seen at this link: www.ti.com/lit/ml/scyb004b/scyb004b.pdf KlausST
Advanced Member level 7
Joined Apr 17, 2014 Messages 26,186 Helped 4,923 Reputation 9,869 Reaction score 5,774 Trophy points 1,393 Activity points 176,046 In addition to post#15: For 3.3V --> 5.0V translation: use 74AHCT family. Supplied with 5.0V. The difference between AHC and AHCT is the input level. While a AHCT is happy with 3.3V input levels, an AHC is at the edge. It's not safe because it's not guaranteed that V_OH(3V3) > V_IH(5V). Klaus schmitt trigger
Advanced Member level 5
Joined Apr 17, 2013 Messages 2,725 Helped 859 Reputation 1,722 Reaction score 850 Trophy points 1,393 Activity points 18,445 A necro-thread has resurrected. andre_luis
Super Moderator
Staff member Joined Nov 7, 2006 Messages 9,651 Helped 1,191 Reputation 2,401 Reaction score 1,219 Trophy points 1,403 Location Brazil Activity points 55,967 schmitt trigger said: A necro-thread has resurrected. Click to expand...Someone had reported that the above links were not valid anymore. Status Not open for further replies.
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