74AC138 3 TO 8 LINE DECODER (INVERTING) ■ ■ ■ ■ ■ ■ ■ ■ ■ HIGH SPEED: tPD = 4.5ns (TYP.) at VCC = 5V LOW POWER DISSIPATION: ICC = 4µA(MAX.) at TA=25°C HIGH NOISE IMMUNITY: VNIH = V NIL = 28 % VCC (MIN.) 50Ω TRANSMISSION LINE DRIVING CAPABILITY SYMMETRICAL OUTPUT IMPEDANCE: |IOH| = IOL = 24mA (MIN) BALANCED PROPAGATION DELAYS: tPLH ≅ tPHL OPERATING VOLTAGE RANGE: VCC (OPR) = 2V to 6V PIN AND FUNCTION COMPATIBLE WITH 74 SERIES 138 IMPROVED LATCH-UP IMMUNITY DESCRIPTION The 74AC138 is an advanced high-speed CMOS 3 TO 8 LINE DECODER (INVERTING) fabricated with sub-micron silicon gate and double-layer metal wiring C2MOS tecnology. If the device is enabled, 3 binary select inputs (A, B, and C) determine which one of the outputs will go low. If enable input G1 is held low or either G2A DIP SOP TSSOP ORDER CODES PACKAGE TUBE DIP SOP TSSOP 74AC138B 74AC138M T&R 74AC138MTR 74AC138TTR or G2B is held high, the decoding function is inhibited and all the 8 outputs go to high. Tree enable inputs are provided to ease cascade connection and application of address decoders for memory systems. All inputs and outputs are equipped with protection circuits against static discharge, giving them 2KV ESD immunity and transient excess voltage. PIN CONNECTION AND IEC LOGIC SYMBOLS April 2001 1/10 74AC138 INPUT AND OUTPUT EQUIVALENT CIRCUIT PIN DESCRIPTION PIN No SYMBOL 1, 2, 3 4, 5 6 15, 14, 13, 12, 11, 10, 9, 7 8 16 A, B, C G2A, G2B G1 Y0 to Y7 GND VCC NAME AND FUNCTION Address Inputs Enable Inputs Enable Input Outputs Ground (0V) Positive Supply Voltage TRUTH TABLE INPUTS OUTPUTS ENABLE SELECT G2B G2A G1 C B A Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7 X X H L L L L L L L L X H X L L L L L L L L L X X H H H H H H H H X X X L L L L H H H H X X X L L H H L L H H X X X L H L H L H L H H H H L H H H H H H H H H H H L H H H H H H H H H H H L H H H H H H H H H H H L H H H H H H H H H H H L H H H H H H H H H H H L H H H H H H H H H H H L H H H H H H H H H H H L X : Don’t Care LOGIC DIAGRAM This logic diagram has not be used to estimate propagation delays 2/10 74AC138 ABSOLUTE MAXIMUM RATINGS Symbol VCC Parameter Supply Voltage Value Unit -0.5 to +7 V -0.5 to VCC + 0.5 -0.5 to VCC + 0.5 V DC Input Diode Current ± 20 mA IOK DC Output Diode Current ± 20 mA IO DC Output Current ± 50 mA ± 400 mA VI DC Input Voltage VO DC Output Voltage IIK ICC or IGND DC VCC or Ground Current Tstg Storage Temperature TL Lead Temperature (10 sec) V -65 to +150 °C 300 °C Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied. RECOMMENDED OPERATING CONDITIONS Symbol VCC Parameter Supply Voltage Value Unit 2 to 6 V VI Input Voltage 0 to VCC V VO Output Voltage 0 to VCC V Top Operating Temperature -55 to 125 °C 8 ns/V dt/dv Input Rise and Fall Time VCC = 3.0, 4.5 or 5.5V (note 1) 1) VIN from 30% to 70% of V CC 3/10 74AC138 DC SPECIFICATIONS Test Condition Symbol VIH VIL VOH VOL II ICC IOLD IOHD Parameter High Level Input Voltage Low Level Input Voltage High Level Output Voltage Low Level Output Voltage Input Leakage Current Quiescent Supply Current Dynamic Output Current (note 1, 2) TA = 25°C VCC (V) 3.0 4.5 5.5 3.0 4.5 5.5 Value VO = 0.1 V or VCC-0.1V Min. Typ. 2.1 3.15 3.85 1.5 2.25 2.75 1.5 2.25 2.75 VO = 0.1 V or VCC-0.1V Max. -55 to 125°C Min. Min. Max. 2.1 3.15 3.85 0.9 1.35 1.65 0.9 1.35 1.65 V 0.9 1.35 1.65 IO=-50 µA 2.9 2.99 2.9 2.9 4.5 IO=-50 µA 4.4 4.49 4.4 4.4 5.49 5.5 IO=-50 µA 5.4 5.4 5.4 3.0 IO=-12 mA 2.56 2.46 2.4 4.5 IO=-24 mA 3.86 3.76 3.7 4.86 Unit Max. 2.1 3.15 3.85 3.0 V V 5.5 IO=-24 mA 3.0 IO=50 µA 0.002 0.1 0.1 0.1 4.5 IO=50 µA 0.001 0.1 0.1 0.1 5.5 IO=50 µA 0.001 0.1 0.1 0.1 3.0 IO=12 mA 0.36 0.44 0.5 4.5 IO=24 mA 0.36 0.44 0.5 5.5 IO=24 mA 0.36 0.44 0.5 5.5 VI = VCC or GND ± 0.1 ±1 ±1 µA 5.5 VI = VCC or GND 4 40 80 µA VOLD = 1.65 V max 75 50 mA VOHD = 3.85 V min -75 -50 mA 5.5 4.76 1) Maximum test duration 2ms, one output loaded at time 2) Incident wave switching is guaranteed on transmission lines with impedances as low as 50Ω 4/10 -40 to 85°C 4.7 V 74AC138 AC ELECTRICAL CHARACTERISTICS (CL = 50 pF, RL = 500 Ω, Input tr = tf = 3ns) Test Condition Symbol Parameter tPLH tPHL Propagation Delay Time A, B, C to Y tPLH tPHL Propagation Delay Time G1 to Y tPLH tPHL Propagation Delay Time G2A or G2B to Y Value TA = 25°C VCC (V) -40 to 85°C -55 to 125°C Min. Typ. Max. Min. Max. Min. Max. (*) 1.5 5.5 10.5 1.5 14.0 1.5 15.4 5.0(**) 1.5 4.5 9.0 1.5 10.0 1.5 11.0 3.3(*) 1.5 6.0 10.5 1.5 14.0 1.5 15.4 (**) 5.0 1.5 4.5 11.0 1.5 10.0 1.5 11.0 3.3(*) 1.5 5.5 10.5 1.5 12.7 1.5 14.0 5.0(**) 1.5 4.5 9.0 1.5 10.0 1.5 10.0 3.3 Unit ns ns ns (*) Voltage range is 3.3V ± 0.3V (**) Voltage range is 5.0V ± 0.5V CAPACITIVE CHARACTERISTICS Test Condition Symbol Parameter TA = 25°C VCC (V) CIN Input Capacitance 5.0 CPD Power Dissipation Capacitance (note 1) 5.0 Value Min. fIN = 10MHz Typ. Max. -40 to 85°C -55 to 125°C Min. Min. Max. Unit Max. 4 pF 60 pF 1) CPD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. ICC(opr) = CPD x VCC x f IN + ICC/n (per circuit) TEST CIRCUIT CL = 50pF or equivalent (includes jig and probe capacitance) RL = R1 = 500Ω or equivalent RT = ZOUT of pulse generator (typically 50Ω) 5/10 74AC138 WAVEFORM 1: PROPAGATION DELAYS FOR INVERTING OUTPUTS (f=1MHz; 50% duty cycle) WAVEFORM 2: PROPAGATION DELAYS FOR NON-INVERTING OUTPUTS (f=1MHz; 50% duty cycle) 6/10 74AC138 Plastic DIP-16 (0.25) MECHANICAL DATA mm DIM. MIN. a1 0.51 B 0.77 TYP. inch MAX. MIN. TYP. MAX. 0.020 1.65 0.030 0.065 b 0.5 0.020 b1 0.25 0.010 D 20 0.787 E 8.5 0.335 e 2.54 0.100 e3 17.78 0.700 F 7.1 0.280 I 5.1 0.201 L Z 3.3 0.130 1.27 0.050 P001C 7/10 74AC138 SO-16 MECHANICAL DATA mm DIM. MIN. TYP. A a1 inch MAX. MIN. TYP. 1.75 0.1 0.068 0.2 a2 MAX. 0.004 0.007 1.65 0.064 b 0.35 0.46 0.013 0.018 b1 0.19 0.25 0.007 0.010 C 0.5 0.019 c1 45 (typ.) D 9.8 10 0.385 0.393 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 8.89 0.350 F 3.8 4.0 0.149 0.157 G 4.6 5.3 0.181 0.208 L 0.5 1.27 0.019 0.050 M S 0.62 0.024 8 (max.) P013H 8/10 74AC138 TSSOP16 MECHANICAL DATA mm DIM. MIN. inch TYP. A MAX. MIN. TYP. MAX. 1.1 0.433 A1 0.05 0.10 0.15 0.002 0.004 0.006 A2 0.85 0.9 0.95 0.335 0.354 0.374 b 0.19 0.30 0.0075 0.0118 c 0.09 0.20 0.0035 0.0079 D 4.9 5 5.1 0.193 0.197 0.201 E 6.25 6.4 6.5 0.246 0.252 0.256 E1 4.3 4.4 4.48 0.169 0.173 0.176 e 0.65 BSC 0.0256 BSC K 0o 4o 8o 0o 4o 8o L 0.50 0.60 0.70 0.020 0.024 0.028 A A2 A1 b e K c L E D E1 PIN 1 IDENTIFICATION 1 9/10 74AC138 Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. 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