TECHNICAL DATA IN74HC138A 1-of-8 Decoder/Demultiplexer High-Performance Silicon-Gate CMOS The IN74HC138A is identical in pinout to the LS/ALS138. The device inputs are compatible with standard CMOS outputs; with pullup resistors, they are compatible with LS/ALSTTL outputs. The IN74HC138A decodes a three-bit Address to one-of-eight active-low 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. • Outputs Directly Interface to CMOS, NMOS, and TTL • Operating Voltage Range: 2.0 to 6.0 V • Low Input Current: 1.0 µA ORDERING INFORMATION IN74HC138AN Plastic IN74HC138AD SOIC TA = -55° to 125° C for all packages • High Noise Immunity Characteristic of CMOS Devices PIN ASSIGNMENT LOGIC DIAGRAM FUNCTION TABLE Inputs PIN 16 =VCC PIN 8 = GND Outputs CS1 CS2 CS3 A2 A1 A0 Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7 X X H X H X L X X X X X X X X X X X H H H H 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 L L L L L L L L L L L L L H H L H L H L H H H H L H H H H L H H H H L H H H H H H H H H H H H H H H H H H H H L L L L L L L L H H H H L L H H L H L H H H H H H H H H H H H H H H H H L H H H H L H H H H L H H H H L H = high level (steady state) L = low level (steady state) X = don’t care 141 IN74HC138A MAXIMUM RATINGS* Symbol Parameter Value Unit -0.5 to +7.0 V VCC DC Supply Voltage (Referenced to GND) VIN DC Input Voltage (Referenced to GND) -1.5 to VCC +1.5 V DC Output Voltage (Referenced to GND) -0.5 to VCC +0.5 V DC Input Current, per Pin ±20 mA IOUT DC Output Current, per Pin ±25 mA ICC DC Supply Current, VCC and GND Pins ±50 mA PD Power Dissipation in Still Air, Plastic DIP+ SOIC Package+ 750 500 mW -65 to +150 °C 260 °C VOUT IIN Tstg TL Storage Temperature Lead Temperature, 1 mm from Case for 10 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 VCC VIN, VOUT Parameter DC Supply Voltage (Referenced to GND) DC Input Voltage, Output Voltage (Referenced to GND) TA Operating Temperature, All Package Types tr, tf Input Rise and Fall Time (Figure 2) VCC =2.0 V VCC =4.5 V VCC =6.0 V Min Max Unit 2.0 6.0 V 0 VCC V -55 +125 °C 0 0 0 1000 500 400 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. 142 IN74HC138A DC ELECTRICAL CHARACTERISTICS(Voltages Referenced to GND) VCC V 25 °C to -55°C ≤85 °C ≤125 °C Unit VOUT=0.1 V or VCC-0.1 V IOUT≤ 20 µA 2.0 4.5 6.0 1.5 3.15 4.2 1.5 3.15 4.2 1.5 3.15 4.2 V Maximum Low Level Input Voltage VOUT=0.1 V or VCC-0.1 V IOUT ≤ 20 µA 2.0 4.5 6.0 0.5 1.35 1.8 0.5 1.35 1.8 0.5 1.35 1.8 V Minimum High-Level Output Voltage VIN=VIH or VIL IOUT ≤ 20 µA 2.0 4.5 6.0 1.9 4.4 5.9 1.9 4.4 5.9 1.9 4.4 5.9 V 4.5 6.0 3.98 5.48 3.84 5.34 3.7 5.2 2.0 4.5 6.0 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 VIN=VIH or VIL IOUT ≤ 4.0 mA IOUT ≤ 5.2 mA 4.5 6.0 0.26 0.26 0.33 0.33 0.4 0.4 Symbol Parameter VIH Minimum High-Level Input Voltage VIL VOH Test Conditions VIN=VIH or VIL IOUT ≤ 4.0 mA IOUT ≤ 5.2 mA VOL Guaranteed Limit Maximum Low-Level Output Voltage VIN=VIH or VIL IOUT ≤ 20 µA V IIN Maximum Input Leakage Current VIN=VCC or GND 6.0 ±0.1 ±1.0 ±1.0 µA ICC Maximum Quiescent Supply Current (per Package) VIN=VCC or GND IOUT=0µA 6.0 4.0 40 160 µA 143 IN74HC138A AC ELECTRICAL CHARACTERISTICS(CL=50pF,Input tr=tf=6.0 ns) Guaranteed Limit VCC Symbol Parameter V 25 °C to -55°C ≤85°C ≤125°C Unit tPLH, tPHL Maximum Propagation Delay, Input A to Output Y (Figures 1 and 4) 2.0 4.5 6.0 135 27 23 170 34 29 205 41 35 ns tPLH, tPHL Maximum Propagation Delay , CS1 to Output Y (Figures 2 and 4) 2.0 4.5 6.0 110 22 19 140 28 24 165 33 28 ns tPLH, tPHL Maximum Propagation Delay , CS2 or CS3 to Output Y (Figures 3 and 4) 2.0 4.5 6.0 120 24 20 150 30 26 180 36 31 ns tTLH, tTHL Maximum Output Transition Time, Any Output (Figures 2 and 4) 2.0 4.5 6.0 75 15 13 95 19 16 110 22 19 ns - 10 10 10 pF CIN CPD Maximum Input Capacitance Power Dissipation Capacitance (Per Package) Typical @25°C,VCC=5.0 V Used to determine the no-load dynamic power consumption: PD=CPDVCC2f+ICCVCC 55 Figure 1. Switching Waveforms 144 Figure 2. Switching Waveforms pF IN74HC138A Figure 3. Switching Waveforms Figure 4. Test Circuit EXPANDED LOGIC DIAGRAM 145