IN74HCT138A 1-OF-8 DECODER/DEMULTIPLEXER High-Performance Silicon-Gate CMOS The IN74HCT138A is identical in pinout to the LS/ALS138. The IN74HCT138A may be used as a level converter for interfacing TTL or NMOS outputs to High Speed CMOS inputs. The IN74HCT138A decodes a three-bit Address to one-ofeight active-lot outputs. This device features three Chip Select inputs, two active-low and one active-high to facilitate the demultiplexing, cascading, and chip-selecting functions. The demultiplexing function is accomplished by using the Address inputs to select the desired device output; one of the Chip Selects is used as a data input while the other Chip Selects are held in their active states. • TTL/NMOS Compatible Input Levels • Outputs Directly Interface to CMOS, NMOS, and TTL • Operating Voltage Range: 4.5 to 5.5 V • Low Input Current: 1.0 µA ORDERING INFORMATION IN74HCT138AN Plastic IN74HCT138AD SOIC TA = -55° to 125° C for all packages PIN ASSIGNMENT LOGIC DIAGRAM FUNCTION TABLE PIN 16 =VCC PIN 8 = GND Inputs CS1 CS2 CS3 A2 A1 A0 X X H X X X X H X X X X L X X X X X H L L L L L H L L L L H H L L L H L H L L L H H H L L H L L H L L H L H H L L H H L H L L H H H Outputs Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7 H H H H H H H H H H H H H H H H H H H H H H H H L H H H H H H H H L H H H H H H H H L H H H H H H H H L H H H H H H H H L H H H H H H H H L H H H H H H H H L H H H H H H H H L H = high level (steady state) L = low level (steady state) X = don’t care 1 IN74HCT138A MAXIMUM RATINGS* Symbol Parameter Value Unit VCC DC Supply Voltage (Referenced to GND) -0.5 to +7.0 V VIN DC Input Voltage (Referenced to GND) -1.5 to VCC +1.5 V VOUT DC Output Voltage (Referenced to GND) -0.5 to VCC +0.5 V IIN DC Input Current, per Pin mA ±20 IOUT DC Output Current, per Pin mA ±25 ICC DC Supply Current, VCC and GND Pins mA ±50 PD Power Dissipation in Still Air, Plastic DIP+ 750 mW SOIC Package+ 500 Tstg Storage Temperature -65 to +150 °C 260 TL Lead Temperature, 1 mm from Case for 10 °C Seconds (Plastic DIP or SOIC Package) * Maximum Ratings are those values beyond which damage to the device may occur. Functional operation should be restricted to the Recommended Operating Conditions. +Derating - Plastic DIP: - 10 mW/°C from 65° to 125°C SOIC Package: : - 7 mW/°C from 65° to 125°C RECOMMENDED OPERATING CONDITIONS Symbol Parameter VCC DC Supply Voltage (Referenced to GND) VIN, VOUT DC Input Voltage, Output Voltage (Referenced to GND) TA Operating Temperature, All Package Types t r, tf Input Rise and Fall Time (Figure 2) Min 4.5 0 Max 5.5 VCC Unit V V -55 0 +125 500 °C ns This device contains protection circuitry to guard against damage due to high static voltages or electric fields. However, precautions must be taken to avoid applications of any voltage higher than maximum rated voltages to this high-impedance circuit. For proper operation, VIN and VOUT should be constrained to the range GND≤(VIN or VOUT)≤VCC. Unused inputs must always be tied to an appropriate logic voltage level (e.g., either GND or VCC). Unused outputs must be left open. 2 IN74HCT138A DC ELECTRICAL CHARACTERISTICS(Voltages Referenced to GND) Guaranteed Limit VCC Symbol Parameter Test Conditions V 25 °C ≤85 ≤125 to °C °C -55°C VOUT=0.1 V or VCC-0.1 V 4.5 VIH Minimum High2.0 2.0 2.0 Level Input 5.5 2.0 2.0 2.0 IOUT≤ 20 µA Voltage VOUT=0.1 V or VCC-0.1 V 4.5 VIL Maximum Low 0.8 0.8 0.8 Level Input 5.5 0.8 0.8 0.8 IOUT ≤ 20 µA Voltage VIN=VIH or VIL VOH Minimum High4.5 4.4 4.4 4.4 Level Output 5.5 5.4 5.4 5.4 IOUT ≤ 20 µA Voltage VIN=VIH or VIL 4.5 3.98 3.84 3.7 IOUT ≤ 4.0 mA VIN=VIH or VIL VOL Maximum Low4.5 0.1 0.1 0.1 Level Output 5.5 0.1 0.1 0.1 IOUT ≤ 20 µA Voltage VIN=VIH or VIL 4.5 0.26 0.33 0.4 IOUT ≤ 4.0 mA IIN Maximum Input VIN=VCC or GND 5.5 ±0.1 ±1.0 ±1.0 Leakage Current VIN=VCC or GND ICC Maximum 5.5 4.0 40 160 Quiescent Supply IOUT=0µA Current (per Package) VIN = 2.4 V, Any One Additional ≥25°C to ∆ICC Quiescent Supply Input 55°C 125°C VIN=VCC or GND, Other Current Inputs 5.5 2.9 2.4 IOUT=0µA 3 Unit V V V V µA µA mA IN74HCT138A AC ELECTRICAL CHARACTERISTICS(VCC =5.0 V, CL=50pF,Input tr=tf=6.0 ns) Guaranteed Limit Unit Symbol Parameter 25 °C ≤85°C ≤125 to °C -55°C tPLH, Maximum Propagation Delay, Input A to 30 38 45 ns tPHL Output Y (Figures 1 and 4) tPLH, Maximum Propagation Delay , CS1 to 27 34 41 ns tPHL Output Y (Figures 2 and 4) tPLH, Maximum Output Transition Time , CS2 30 38 45 ns tPHL or CS3 to Output Y (Figures 3 and 4) 15 19 22 ns tTLH, tTHL Maximum Output Transition Time, Any Output (Figures 2 and 4) CIN Maximum Input Capacitance 10 10 10 pF CPD Power Dissipation Capacitance (Per Enabled Output) Used to determine the no-load dynamic power consumption: PD=CPDVCC2f+ICCVCC Figure 1. Switching Waveforms Typical @25°C,VCC=5.0 V 51 pF Figure 2. Switching Waveforms 4 IN74HCT138A Figure 3. Switching Waveforms Figure 4. Test Circuit EXPANDED LOGIC DIAGRAM 5