Logic Circuits

Logic CircuitsLogic Circuits

Turn to Real World from Logic

Real World: Real World: Electrical CharacteristicsElectrical Characteristics

LOGIC simulator

Scope

Think of Physics, other than LOGIC

TTL and CMOS IOTTL and CMOS IO

CMOS input only consumes leakage current

What is 1, 0 and High, LowWhat is 1, 0 and High, Low

Logic 1

Logic 0

output

Logic 1

Logic 0

inputNoiseMargin

VoltageVCC

Invalid

VOH

GND

VIH

VIL

5V VIH VIL VOH VOLTTL 2.0 0.8 2.4 0.4CMOS 3.5 1.5 4.4 0.33

3.3VCMOS 2.0 0.8 2.4 0.4

HIGH

LOWVOL

CMOS

=Vcc-0.1

=Gnd+0.1

Nosie MarginNosie Margin

Interface: Check Data SheetInterface: Check Data Sheet

Open Collector/Drain, Wire-OR, Open Collector/Drain, Wire-OR, LEVEL SHIFTERLEVEL SHIFTER

OPEN DRAIN

Tri-State, Hi Impedence, FloatingTri-State, Hi Impedence, FloatingCMOS

TTL

Propagation DelayPropagation Delay

TPLHtPHLrising time: trfalling time: tf

min, typ, max

Timing Hazard, GlitchTiming Hazard, Glitch

1

1

Fanout, LoadingFanout, Loading

Unit Loads = IOH/IIH = IOL/IIL = 400 μA/40 μA = 16 mA/1.6 mA = 10

TTLCMOS

Cap-load vs Freq

Schmitt Trigger InputSchmitt Trigger Input

Driving Strength and NosieDriving Strength and Nosie

Water PipeInductance

Logic CircuitsLogic Circuits

More On MAX II Device

MAX II, IO BankMAX II, IO Bank

MAX II, Power SupplyMAX II, Power Supply

MAX II, 3.3V LVTTL, LVCMOSMAX II, 3.3V LVTTL, LVCMOS

MAX II, 5.0V ComaptibilityMAX II, 5.0V Comaptibility

DIRECT DRIVE to 5VTTL3.3V ---> 2.4V

MAAX II, ACMAAX II, AC

MAX II IOEMAX II IOE

3.3V(400mv)2.5V(190mv)

25K~95KOhm

EPM1270T144C5ESEPM1270T144C5ES

SummarySummary

● TTL, CMOS basic characteristic● Voltage Level, Noise Margin● Logic: DC Level, propagation delay, fan-out● Open Collector/Drain, Wire-OR, Hi-Z● Schmitt Trigger Input● MAX II IO Bank, Power Supply● MAX II IOE, Interface● MAX II Data Sheet●