74VHC238 3 TO 8 LINE DECODER ■ ■ ■ ■ ■ ■ ■ ■ ■ HIGH SPEED: tPD =5.5 ns (TYP.) at VCC = 5V LOW POWER DISSIPATION: ICC = 4 µA (MAX.) at TA = 25 oC HIGH NOISE IMMUNITY: VNIH = VNIL = 28% VCC (MIN.) POWER DOWN PROTECTION ON INPUTS SYMMETRICAL OUTPUT IMPEDANCE: |IOH| = IOL = 8 mA (MIN) BALANCED PROPAGATION DELAYS: tPLH ≅ tPHL OPERATING VOLTAGE RANGE: VCC (OPR) = 2V to 5.5V PIN AND FUNCTION COMPATIBLE WITH 74 SERIES 238 IMPROVED LATCH-UP IMMUNITY DESCRIPTION The 74VHC238 is an advanced high-speed CMOS 3 TO 8 LINE DECODER fabricated with sub-micron silicon gate and double-layer metal wiring C2MOS technology. If the device is enabled, 3 binary select inputs (A, B and C) determine which one of the outputs will go high. If enable input G1 is held low or either M1 (Micro Package) T (TSSOP Package) ORDER CODES : 74VHC238M 74VHC238T G2A or G2B is held high, decoding function is inhibited and all the 8 outputs go to low. Three enable inputs are provided to ease cascade connection and application of this address decoders for memory systems. Power down protection is provided on all inputs and 0 to 7V can be accepted on inputs with no regard to the supply voltage. This device can be used to interface 5V to 3V. 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 June 1999 1/8 74VHC238 INPUT EQUIVALENT CIRCUIT PIN DESCRIPTION PIN No SYMBOL 1, 2, 3 A, B, C NAME AND FUNCT ION 4, 5 G2A, G2B Enable Inputs 6 G1 Enable Input 15, 14, 13, 12, 11, 10, 9, 7 Y0 to Y7 8 GND Ground (0V) 16 VCC Positive Supply Voltage Address Inputs Outputs TRUTH TABLE INPUT S ENABL E G2B G2A G1 C X X L X X H X X H X X X L L H L L L H L L L H L L L H L L L H H L L H H L L H H L L H H OUTPUTS SELECT B X X X L L H H L L H H A X X X L H L H L H L H X:Don’t Care LOGIC DIAGRAM Thislogic diagram has notbe used to estimate propagation delays 2/8 Y0 L L L H L L L L L L L Y1 L L L L H L L L L L L Y2 L L L L L H L L L L L Y3 L L L L L L H L L L L Y4 L L L L L L L H L L L Y5 L L L L L L L L H L L Y6 L L L L L L L L L H L Y7 L L L L L L L L L L H 74VHC238 ABSOLUTE MAXIMUM RATINGS Symbol VCC Parameter Value Unit -0.5 to +7.0 V -0.5 to +7.0 V -0.5 to VCC + 0.5 V Supply Voltage VI DC Input Voltage VO DC Output Voltage IIK DC Input Diode Current - 20 mA IOK DC Output Diode Current ± 20 mA IO DC Output Current ± 25 mA ± 75 mA ICC or IGND DC VCC or Ground Current Tstg Storage Temperature TL Lead Temperature (10 sec) -65 to +150 o 300 o C C Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. RECOMMENDED OPERATING CONDITIONS Symbol VCC Parameter Supply Voltage Valu e Unit 2.0 to 5.5 V V VI Input Voltage 0 to 5.5 VO Output Voltage 0 to VCC Top dt/dv Operating Temperature V o -40 to +85 Input Rise and Fall Time (see note 1) (VCC = 3.3 ± 0.3V) (V CC = 5.0 ± 0.5V) C 0 to 100 0 to 20 ns/V ns/V 1) VIN from 30% to70%of VCC DC SPECIFICATIONS Symb ol VIH VIL VOH VOL II ICC Parameter T est Cond ition s Value o Min. Typ . Un it o T A = 25 C V CC (V) -40 to 85 C Max. Min . Max. High Level Input Voltage 2.0 1.5 1.5 3.0 to 5.5 0.7VCC 0.7VCC Low Level Input Voltage 2.0 0.5 0.5 3.0 to 5.5 0.3VCC 0.3VCC High Level Output Voltage Low Level Output Voltage Input Leakage Current Quiescent Supply Current V 2.0 IO=-50 µA 1.9 2.0 1.9 3.0 IO=-50 µA 2.9 3.0 2.9 4.5 IO=-50 µA 4.4 4.5 4.4 3.0 IO=-4 mA 2.58 4.5 IO=-8 mA 3.94 2.0 IO=50 µA 0.0 0.1 0.1 3.0 IO=50 µA 0.0 0.1 0.1 4.5 0.0 0.1 0.1 0.36 0.44 V V 2.48 3.8 V 3.0 IO=50 µA IO=4 mA 4.5 IO=8 mA 0.36 0.44 0 to 5.5 VI = 5.5V or GND ±0.1 ±1.0 µA 5.5 VI = VCC or GND 4 40 µA 3/8 74VHC238 AC ELECTRICAL CHARACTERISTICS (Input t r = tf =3 ns) Symb ol Parameter 3.3(*) 15 Value T A = 25 o C Min. Typ . Max. 8.0 12.3 3.3(*) 5.0(**) 5.0(**) 3.3(*) 3.3(*) 50 15 50 15 50 10.5 5.5 7.0 8.1 10.6 15.8 8.1 10.1 12.8 16.3 1.0 1.0 1.0 1.0 1.0 18.0 9.5 11.5 15.0 18.5 5.0 5.0(**) (**) 15 50 5.4 6.9 8.1 10.1 1.0 1.0 9.5 11.5 (*) 15 50 15 50 8.1 10.6 5.7 7.2 12.3 15.8 8.1 10.1 1.0 1.0 1.0 1.0 14.5 18.0 9.5 11.5 V CC (V) tPLH tPHL Propagation Delay Time A, B, C to Y tPLH tPHL Propagation Delay Time G1 to Y tPLH tPHL Propagation Delay Time G2A, G2B to Y Test Co ndition CL (pF ) 3.3 3.3(*) 5.0(**) 5.0(**) Un it -40 to 85 o C Min . Max. 1.0 14.5 ns ns ns (*) Voltage range is 3.3V ± 0.3V (**) Voltage range is 5V ± 0.5V CAPACITIVE CHARACTERISTICS Symb ol Parameter T est Cond ition s Value T A = 25 o C Min. Typ . Max. 10 C IN Input Capacitance 4 CPD Power Dissipation Capacitance (note 1) 37 Un it -40 to 85 o C Min . Max. 10 pF pF 1) CPD isdefined as the value of the IC’sinternal equivalent capacitance which is calculated fromthe operating current consumption without load. (Referto Test Circuit).Average operating current can be obtained by the following equation. ICC(opr) = CPD • VCC • fIN + ICC TEST CIRCUIT CL = 15/50 pF or equivalent (includes jig and probe capacitance) RL = R1 = 500Ω orequivalent RT = ZOUT of pulse generator (typically 50Ω) 4/8 74VHC238 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) 5/8 74VHC238 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 6/8 74VHC238 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 7/8 74VHC238 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. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. 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