Hi guys! Hope all is well.
I was going through a JAMECO catalog last night and found that ICs with the same exact function exist under different IC numbers. Do you know why this is the case?
For example:
7400N DIP-14 Quad 2-input pos. NAND gate
74C00N DIP-14 Quad 2-input pos. NAND gate
74HC00N DIP-14 Quad 2-input pos. NAND gate
74HCT00N DIP-14 Quad 2-input pos. NAND gate

thank you

 

Did you check the datasheet???

 

As integrated circuits in the 7400 series were made in different technologies, usually compatibility was retained with the original TTL logic levels and power supply voltages. An integrated circuit made in CMOS is not a TTL chip since it uses field-effect transistors (FETs) and not bipolar junction transistors, but similar part numbers are retained to identify similar logic functions and electrical (power and I/O voltage) compatibility in the different subfamilies. Over 40 different logic subfamilies use this standardized part number scheme.[7]

Bipolar
74 – Standard TTL, the original logic family had no letters between the "74" and the part number. 10ns gate delay, 10mw dissipation, 4.75–5.25V, released in 1966.[8]
74L – Low Power, Larger resistors allowed 1 mW dissipation at the cost of a very slow 33nS gate delay. Obsolete, replaced by 74LS or CMOS technology. Introduced 1971.[9]
74H – High Speed. 6ns gate delay but 22 mW power dissipation. Used in 1970s era supercomputers. Still produced but generally superseded by the 74S series. Introduced in 1971.
74S – High Speed Schottky, Implemented with Schottky diode clamps at the inputs to prevent charge storage, this provides faster operation than the 74 and 74H series at the cost of increased power consumption and cost. 3ns gate delay, 20 mW dissipation, released in 1971.
74LS – Low Power Schottky. Implemented using the same technology as 74S but with reduced power consumption and switching speed. Typical 10ns gate delay, a remarkable (for the time) 2 mW dissipation, 4.75–5.25V.
74AS – Advanced Schottky, the next iteration of the 74S series with greater speed and fan-out despite lower power consumption. Implemented using the 74S's technology with "miller killer" circuitry to speed up the low-to-high transition. 1.7 ns gate delay, 8 mW, 4.5–5.5V.
74ALS – Advanced Low Power Schottky, Same technology as 74AS but with the speed/power tradeoff of the 74LS. 4nS, 1.2 mW, 4.5–5.5V.
74F – Fast, Fairchild's version of TI's 74AS. 3.4nS, 6 mW, 4.5–5.5V. Introduced in 1978.
CMOS
C – CMOS 4–15 V operation similar to buffered 4000 (4000B) series
HC – High-speed CMOS, similar performance to LS, 12 ns. 2.0–6.0V.
HCT – High speed, compatible logic levels to bipolar parts
AC – Advanced CMOS, performance generally between S and F
ACQ – Advanced CMOS with Quiet outputs
AHC – Advanced high-speed CMOS, three times as fast as HC
ALVC – Low voltage – 1.8 to 3.3 V, Time Propagation Delay (TPD) < 3 ns@3.3 V 
ALVT – Low voltage – 2.5 to 3.3 V, 5 V tollerant inputs, high current <= 64mA, TPD < 3 ns@2.5 V
AUC – Low voltage – 0.8 to 2.5 V, TPD < 2.5 ns@1.8 V 
AUP – Low voltage – 0.8 to 3.6 V (3.3 V typically), TPD 15.6/8.2/4.3ns@1.2/1.8/3.3V, partial power down specified (IOFF), Inputs protected
AVC – Low voltage – 1.8 V to 3.3 V, TPD < 3.2 ns@1.8 V, Bus hold, IOFF
FC – Fast CMOS, performance similar to F
LCX – CMOS with 3 V supply and 5 V tolerant inputs
LV – Low-voltage CMOS – 2.0 to 5.5 V supply and 5 V tolerant inputs
LVC – Low voltage – 1.65 to 3.3 V and 5 V tolerant inputs, tpd < 5.5 ns@3.3 V, tpd < 9 ns@2.5 V
LV-A – 2.5 to 5 V, 5 V tolerant inputs, TPD < 10 ns@3.3 V, bus hold, IOFF, low noise
LVT – Low voltage – 3.3 V, 5V tolerant inputs, high output current < 64mA, TPD < 3.5 ns@3.3 V, IOFF, low noise
LVQ – Low voltage – 3.3 V
LVX – Low voltage – 3.3 V with 5 V tolerant inputs
VHC – Very-high-speed CMOS – 'S' performance in CMOS technology and power

 

As integrated circuits in the 7400 series were made in different technologies, usually compatibility was retained with the original TTL logic levels and power supply voltages. An integrated circuit made in CMOS is not a TTL chip since it uses field-effect transistors (FETs) and not bipolar junction transistors, but similar part numbers are retained to identify similar logic functions and electrical (power and I/O voltage) compatibility in the different subfamilies. Over 40 different logic subfamilies use this standardized part number scheme.[7]

Bipolar
74 – Standard TTL, the original logic family had no letters between the "74" and the part number. 10ns gate delay, 10mw dissipation, 4.75–5.25V, released in 1966.[8]
74L – Low Power, Larger resistors allowed 1 mW dissipation at the cost of a very slow 33nS gate delay. Obsolete, replaced by 74LS or CMOS technology. Introduced 1971.[9]
74H – High Speed. 6ns gate delay but 22 mW power dissipation. Used in 1970s era supercomputers. Still produced but generally superseded by the 74S series. Introduced in 1971.
74S – High Speed Schottky, Implemented with Schottky diode clamps at the inputs to prevent charge storage, this provides faster operation than the 74 and 74H series at the cost of increased power consumption and cost. 3ns gate delay, 20 mW dissipation, released in 1971.
74LS – Low Power Schottky. Implemented using the same technology as 74S but with reduced power consumption and switching speed. Typical 10ns gate delay, a remarkable (for the time) 2 mW dissipation, 4.75–5.25V.
74AS – Advanced Schottky, the next iteration of the 74S series with greater speed and fan-out despite lower power consumption. Implemented using the 74S's technology with "miller killer" circuitry to speed up the low-to-high transition. 1.7 ns gate delay, 8 mW, 4.5–5.5V.
74ALS – Advanced Low Power Schottky, Same technology as 74AS but with the speed/power tradeoff of the 74LS. 4nS, 1.2 mW, 4.5–5.5V.
74F – Fast, Fairchild's version of TI's 74AS. 3.4nS, 6 mW, 4.5–5.5V. Introduced in 1978.
CMOS
C – CMOS 4–15 V operation similar to buffered 4000 (4000B) series
HC – High-speed CMOS, similar performance to LS, 12 ns. 2.0–6.0V.
HCT – High speed, compatible logic levels to bipolar parts
AC – Advanced CMOS, performance generally between S and F
ACQ – Advanced CMOS with Quiet outputs
AHC – Advanced high-speed CMOS, three times as fast as HC
ALVC – Low voltage – 1.8 to 3.3 V, Time Propagation Delay (TPD) < 3 ns@3.3 V 
ALVT – Low voltage – 2.5 to 3.3 V, 5 V tollerant inputs, high current <= 64mA, TPD < 3 ns@2.5 V
AUC – Low voltage – 0.8 to 2.5 V, TPD < 2.5 ns@1.8 V 
AUP – Low voltage – 0.8 to 3.6 V (3.3 V typically), TPD 15.6/8.2/4.3ns@1.2/1.8/3.3V, partial power down specified (IOFF), Inputs protected
AVC – Low voltage – 1.8 V to 3.3 V, TPD < 3.2 ns@1.8 V, Bus hold, IOFF
FC – Fast CMOS, performance similar to F
LCX – CMOS with 3 V supply and 5 V tolerant inputs
LV – Low-voltage CMOS – 2.0 to 5.5 V supply and 5 V tolerant inputs
LVC – Low voltage – 1.65 to 3.3 V and 5 V tolerant inputs, tpd < 5.5 ns@3.3 V, tpd < 9 ns@2.5 V
LV-A – 2.5 to 5 V, 5 V tolerant inputs, TPD < 10 ns@3.3 V, bus hold, IOFF, low noise
LVT – Low voltage – 3.3 V, 5V tolerant inputs, high output current < 64mA, TPD < 3.5 ns@3.3 V, IOFF, low noise
LVQ – Low voltage – 3.3 V
LVX – Low voltage – 3.3 V with 5 V tolerant inputs
VHC – Very-high-speed CMOS – 'S' performance in CMOS technology and power

Kermit2,
I hope that wasnt all from memory, but thanks. I just printed it and taped it to the wall.

 

Wikipedia, but still useful for reference.

 

Thanks, nice to know it is there. My wife just donated to the Wikipedia fundraiser. She said the kids have learned more from Wikipedia than school this year.

 

Kermit2,
I hope that wasnt all from memory, but thanks. I just printed it and taped it to the wall.

http://en.wikipedia.org/wiki/7400_series#7400_series_derivative_families
Scroll to the end of the text in the section: 7400 series derivative families

 

The bottom line is do not mix families unless you know the differences.

Stay within these families:

Bipolar family:
7400
74L00
74LS00
74ALS00


CMOS family:

74C00
74HC00
74HCT00
CD4000

 

The letter tags can be simplified a bit from that large list;
C = CMOS
H = high speed
T = TTL input voltage levels
(most are single alpha char tags)

LS = Low power Schottky
(that one is a two char tag)
etc.