74VHCT138A 3 TO 8 LINE DECODER (INVERTING) ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ HIGH SPEED: tPD = 7.6 ns (TYP.) at VCC = 5V LOW POWER DISSIPATION: ICC = 4 µA (MAX.) at TA=25°C COMPATIBLE WITH TTL OUTPUTS: VIH = 2V (MIN.), VIL = 0.8V (MAX) POWER DOWN PROTECTION ON INPUTS & OUTPUTS SYMMETRICAL OUTPUT IMPEDANCE: |IOH| = IOL = 8 mA (MIN) BALANCED PROPAGATION DELAYS: tPLH ≅ tPHL OPERATING VOLTAGE RANGE: VCC(OPR) = 4.5V to 5.5V PIN AND FUNCTION COMPATIBLE WITH 74 SERIES 138 IMPROVED LATCH-UP IMMUNITY LOW NOISE: VOLP = 0.8V (MAX.) DESCRIPTION The 74VHCT138A is an advanced high-speed CMOS 3 TO 8 LINE DECODER (INVERTING) 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 low. When enable input G1 is held low or either G2A or G2B is held high, the decoding function is inhibited and all the 8 outputs go to high. SOP TSSOP Table 1: Order Codes PACKAGE T&R SOP TSSOP 74VHCT138AMTR 74VHCT138ATTR The three enable inputs are provided to ease cascade connection and application of address decoders for memory systems. Power down protection is provided on all inputs and outputs 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 since all inputs are equipped with TTL threshold. All inputs and outputs are equipped with protection circuits against static discharge, giving them 2KV ESD immunity and transient excess voltage. Figure 1: Pin Connection And IEC Logic Symbols December 2004 Rev. 3 1/12 74VHCT138A Figure 2: Input Equivalent Circuit Table 2: Pin Description PIN N° 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 Table 3: 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 Figure 3: Logic Diagram This logic diagram has not be used to estimate propagation delays 2/12 74VHCT138A Table 4: Absolute Maximum Ratings Symbol VCC Parameter Value Unit Supply Voltage -0.5 to +7.0 V VI DC Input Voltage -0.5 to +7.0 V VO DC Output Voltage (see note 1) -0.5 to +7.0 V VO DC Output Voltage (see note 2) -0.5 to VCC + 0.5 V IIK DC Input Diode Current - 20 mA IOK DC Output Diode Current ± 20 mA IO DC Output Current ± 25 mA ICC or IGND DC VCC or Ground Current Tstg Storage Temperature TL Lead Temperature (10 sec) ± 50 mA -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 1) VCC = 0V 2) High or Low State Table 5: Recommended Operating Conditions Symbol VCC Parameter Supply Voltage Value Unit 4.5 to 5.5 V VI Input Voltage 0 to 5.5 V VO Output Voltage (see note 1) 0 to 5.5 V VO Output Voltage (see note 2) Top Operating Temperature dt/dv Input Rise and Fall Time (see note 3) (VCC = 5.0 ± 0.5V) 0 to VCC V -55 to 125 °C 0 to 20 ns/V 1) VCC = 0V 2) High or Low State 3) VIN from 0.8V to 2V 3/12 74VHCT138A Table 6: DC Specifications Test Condition Symbol VIH VIL VOH VOL II ICC +ICC IOPD Parameter TA = 25°C VCC (V) High Level Input Voltage Low Level Input Voltage High Level Output Voltage 4.5 to 5.5 4.5 to 5.5 Value Min. Typ. Max. 2 -40 to 85°C -55 to 125°C Min. Min. Max. 2 0.8 Max. 2 0.8 Unit V 0.8 V 4.5 IO=-50 µA 4.4 4.5 IO=-8 mA 3.94 Low Level Output Voltage 4.5 IO=50 µA 0.1 0.1 0.1 4.5 IO=8 mA 0.36 0.44 0.55 Input Leakage Current Quiescent Supply Current Additional Worst Case Supply Current 0 to 5.5 VI = 5.5V or GND ± 0.1 ± 1.0 ± 1.0 µA 5.5 VI = VCC or GND 4 40 40 µA 5.5 One Input at 3.4V, other input at VCC or GND 1.35 1.5 1.5 mA 0 VOUT = 5.5V 0.5 5.0 5.0 µA Output Leakage Current 4.5 0.0 4.4 4.4 3.8 3.7 V V Table 7: AC Electrical Characteristics (Input tr = tf = 3ns) Test Condition Symbol Parameter VCC (V) CL (pF) tPLH tPHL Propagation Delay Time A, B, C, to Y Propagation Delay Time G1 to Y Propagation Delay Time G2A, G2B to Y 5.0(*) (*) tPLH tPHL tPLH tPHL Value TA = 25°C -55 to 125°C Typ. Max. Min. Max. Min. Max. 15 7.6 10.4 1.0 12.0 1.0 12.0 5.0 50 8.1 11.4 1.0 13.0 1.0 13.0 5.0(*) 15 6.6 9.1 1.0 10.5 1.0 10.5 5.0(*) 50 7.1 10.1 1.0 11.5 1.0 11.5 5.0(*) 15 7.0 9.6 1.0 11.0 1.0 11.0 (*) 50 7.5 10.6 1.0 12.0 1.0 12.0 5.0 Min. -40 to 85°C Unit ns ns ns (*) Voltage range is 5.0V ± 0.5V Table 8: Capacitive Characteristics Test Condition Symbol Parameter Value TA = 25°C Min. Typ. Max. 10 CIN Input Capacitance 6 CPD Power Dissipation Capacitance (note 1) 36 -40 to 85°C -55 to 125°C Min. Min. Max. 10 Unit Max. 10 pF 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 fIN + ICC 4/12 74VHCT138A Figure 4: Test Circuit CL =15/50pF or equivalent (includes jig and probe capacitance) RT = ZOUT of pulse generator (typically 50Ω) Figure 5: Waveform - Propagation Delays For Inverting Outputs (f=1MHz; 50% duty cycle) 5/12 74VHCT138A Figure 6: Waveform - Propagation Delays For Non-inverting Outputs (f=1MHz; 50% duty cycle) 6/12 74VHCT138A SO-16 MECHANICAL DATA DIM. mm. MIN. TYP A a1 inch MAX. MIN. TYP. 1.75 0.1 0.068 0.25 a2 MAX. 0.004 0.010 1.64 0.063 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 e3 0.050 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.) 0016020D 7/12 74VHCT138A TSSOP16 MECHANICAL DATA mm. inch DIM. MIN. TYP A MAX. MIN. TYP. MAX. 1.2 A1 0.05 A2 0.8 b 0.047 0.15 0.002 0.004 0.006 1.05 0.031 0.039 0.041 0.19 0.30 0.007 0.012 c 0.09 0.20 0.004 0.0079 D 4.9 5 5.1 0.193 0.197 0.201 E 6.2 6.4 6.6 0.244 0.252 0.260 E1 4.3 4.4 4.48 0.169 0.173 0.176 1 e 0.65 BSC K 0˚ L 0.45 A 0.60 0.0256 BSC 8˚ 0˚ 0.75 0.018 8˚ 0.024 0.030 A2 A1 b e K c L E D E1 PIN 1 IDENTIFICATION 1 0080338D 8/12 74VHCT138A Tape & Reel SO-16 MECHANICAL DATA mm. inch DIM. MIN. A TYP MAX. MIN. 330 MAX. 12.992 C 12.8 D 20.2 0.795 N 60 2.362 T 13.2 TYP. 0.504 22.4 0.519 0.882 Ao 6.45 6.65 0.254 0.262 Bo 10.3 10.5 0.406 0.414 Ko 2.1 2.3 0.082 0.090 Po 3.9 4.1 0.153 0.161 P 7.9 8.1 0.311 0.319 9/12 74VHCT138A Tape & Reel TSSOP16 MECHANICAL DATA mm. inch DIM. MIN. A MAX. MIN. 330 13.2 TYP. MAX. 12.992 C 12.8 D 20.2 0.795 N 60 2.362 T 10/12 TYP 0.504 22.4 0.519 0.882 Ao 6.7 6.9 0.264 0.272 Bo 5.3 5.5 0.209 0.217 Ko 1.6 1.8 0.063 0.071 Po 3.9 4.1 0.153 0.161 P 7.9 8.1 0.311 0.319 74VHCT138A Table 9: Revision History Date Revision 16-Dec-2004 3 Description of Changes Order Codes Revision - pag. 1. 11/12 74VHCT138A 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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