Description of TTL, ECL and CMOS Glue Logic Families

TTL (74xx) True TTL
74LLow power
74HHigh speed
74LSLow power - Schottky
74ASAdvanced - Schottky
74ALSAdvanced - Low power - Schottky
74F(AST)Fast - (Advanced - Schottky)
74CCMOS.......check Vcc level
74HC (U)High speed - CMOS (Unbuffered output)
74HCS (U)High speed - CMOS (SOS CMOS, Radiation hardened)
74HCTHigh speed - CMOS - TTL inputs
74AHCAdvanced - High speed - CMOS
74AHCTAdvanced - High speed - CMOS - TTL inputs
74FCT (-A,T,AT)Fast - CMOS - TTL inputs (speed variations)
74ACAdvanced - CMOS
74ACS (U)High speed - CMOS (SOS CMOS, Radiation hardened)
74ACTAdvanced - CMOS - TTL inputs
74ACTS (U)High speed - CMOS - TTL inputs (SOS CMOS, Radiation hardened)
74FACTAC, ACT (Q) series
74ACQAdvanced - CMOS - Quiet outputs
74ACTQAdvanced - CMOS - TTL inputs - Quiet outputs
74AVCAdvanced very low voltage CMOS
74AUCAdvanced ultra-low voltage CMOS
74AUPAdvanced ultra-low power
74UHSUltra High Speed
74ULPUltra Low Power
Bus Driver Families
74ABTAdvanced - BiCMOS - Technology
74ABTEABT - Enhanced Transceiver Logic
74ABTHAdvanced - BiCMOS - Technology - bus Hold
74BCTBiCMOS - TTL inputs
74BTLBackplane - Transceiver - Logic (BiCMOS)
74CBTCross Bar Technology
74CBTLVCBT Low Voltage
74CBTKCBT - Active Clamp
74FBFuturebus+ [limited usage, see the Futurebus Interface page
74GTLGunning - Transceiver - Logic [200MHz, Point-to-Point]
74GTLPGTL - Plus [120MHz, Multi-Point, Backplane]
74SSTVSeries Stub Terminated Logic
74TVCTranslation voltage clamp
Low Voltage Families
74ALBAdvanced - Low Voltage - BiCMOS
74LV (U)Low - Voltage (Unbuffered output) (CMOS)
74LVC (R) (U)LV - CMOS (damping Resistor)(Unbuffered output)
74LVCHLow - Voltage - CMOS - bus Hold
74ALVCAdvanced - Low - Voltage - CMOS
74LVT (R) (U)LV - TTL (damping Resistor(Unbuffered output) (BiCMOS)
74LVTZLow - Voltage - TTL - High Impedance power-up
74ALVC (R)ALV - CMOS (bus Hold) (damping Resistor)
74ALVCHAdvanced - Low - Voltage - CMOS - bus Hold
74LCXLV - CMOS (operates with 3v and 5v supplies)
74VCXLV - CMOS (operates with 1.8v and 3.6v supplies
74CBTLVCBT - Low Voltage
4000True CMOS (non-TTL levels, may use different Vcc)
ECL Device Families:
MECL I8nS* [in production between 1962 to 1977]
MECL II2nS* [in production between 1966 to 1979]
MECL III(16XX) 1nS* .......* = Rise & Fall Time [introduced in 1968]
101xx100 series 10K ECL, 3.5nS* [introduced in 1971]
102xx200 series 10K ECL, 2.5nS*
108xx800 series 10K ECL, voltage compensated, 3.5nS*
10Hxxx10K - High speed, voltage compensated, 1.8nS* [introduced in 1981]
10Exxx10K - ECLinPS, voltage compensated, 800pS*
10EPxxx10K - ECLinPS Plus, voltage compensated, 160pS*
10ELxxx10K - ECLinPS Lite, Single gate, voltage compensated, 275pS*
100xxx100K, temperature compensated
100Hxxx100K - High speed, temperature compensated
100Exxx100K - ECLinPS, temp, voltage comp., 800pS*
High Speed Differential Signaling Families:
ECLSee above Emitter Coupled Logic
PECLPositive ECL, uses +5volts as Vcc; See above
LVPECLLow Voltage PECL, uses +3.3 volts as Vcc; See above
LVDSLow Voltage Differential Signaling, 400mV differential signal swing
CMLCommon Mode Logic, 800mV differential signal swing
PCMLPseudo Common Mode Logic, 200mV differential signal swing

There are additional signaling types; however, many do not exist as a logic family.
FPGA's, Memory devices or other high-end logic devices may use different signaling levels.
The IC bus page list the addition digital interface levels.

This is a listing of TTL, ECL and CMOS Glue Logic Families, with a short description of how they differ from one another. The 74xx families are shown above, but the 54xx families also applies. The 74 designates commercial temperature ranges and the 54 designates operation at Military temperature ranges. Component manufacturers may be found by clicking the Components icons at the bottom of the page. In general, none of the logic families listed above will operate with any other logic family, the voltage thresholds are different for each logic family.
Refer to the Logic Family Voltage Translation page for interfacing techniques between logic families. Back to the Logic Design Page

The CMOS [74C] families listed under the 'true' TTL header are CMOS devices, but not 'true' CMOS devices. They're more CMOS than TTL but don't switch at CMOS levels, designed to work with TTL devices. To be considered a CMOS [54C] logic device the entire internal structure needs to be CMOS, otherwise the component would draw current like a TTL IC.

Many of the earlier logic families are obsolete or at least in decline. Some families are still only in production to support legacy programs.
The oldest of the logic families include the 'L', S, LS, C, and HC glue logic families.

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Modified: 1/23/12
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