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(R)
74VHCT245A
OCTAL BUS TRANSCEIVER (3-STATE)
PRELIMINARY DATA
s s
s
s
s
s
s
s
s s
HIGH SPEED: tPD = 4.5 ns (TYP.) at VCC = 5V LOW POWER DISSIPATION: ICC = 4 A (MAX.) at TA = 25 oC 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 245 IMPROVED LATCH-UP IMMUNITY LOW NOISE: VOLP = 0.9V (Max.)
M (Micro Package)
T (TSSOP Package)
ORDER CODES : 74VHCT245AM 74VHCT245AT level of the DIR input. The enable input G can be used to disable the device so that the busses are effectively isolated. All inputs and outputs are equipped with protection circuits against static discharge, giving them 2KV ESD immunity and transient excess voltage. IT IS PROHIBITED TO APPLY A SIGNAL TO A TERMINAL WHEN IT IS IN OUTPUT MODE AND WHEN A BUS TERMINAL IS FLOATING (HIGH IMPEDANCE STATE) IT IS REQUESTED TO FIX THE INPUT LEVEL BY MEANS OF EXTERNAL PULL DOWN OR PULL UP RESISTOR.
DESCRIPTION The 74VHCT245A is an advanced high-speed CMOS OCTAL BUS TRANSCEIVER (3-STATE) fabricated with sub-micron silicon gate and double-layer metal wiring C2MOS technology. This IC is intended for two-way asynchronous communication between data busses; the direction of data trasmission is determined by the
PIN CONNECTION AND IEC LOGIC SYMBOLS
August 1999
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74VHCT245A
INPUT/OUTPUT EQUIVALENT CIRCUIT
INPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
PIN No 1 2, 3, 4, 5, 6, 7, 8, 9 18, 17, 16, 15, 14, 13, 12, 11 19 10 20 SYMBOL DIR A1 to A8 B1 to B8 NAME AND FUNCT ION Directional Control Data Inputs/Outputs Data Inputs/Outputs
G GND VCC
Output Enable Input Ground (0V) Positive Supply Voltage
TRUTH TABLE
INPUT G L L H
X:"H" or "L" Z: High impedance
F UNCTION DIR L H X A BUS OUTPUT INPUT Z B BUS INPUT OUTPUT Z
OUT PUT A=B B=A Z
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74VHCT245A
ABSOLUTE MAXIMUM RATINGS
Symbol VCC VI VI/O VI/O IIK IOK IO Tstg TL Supply Voltage DC Input Voltage (DIR, G) DC Bus I/O Voltage (see note 1) DC Bus I/O Voltage (see note 2) DC Input Diode Current DC Output Diode Current DC Output Current Storage Temperature Lead Temperature (10 sec) Parameter Value -0.5 to +7.0 -0.5 to +7.0 -0.5 to +7.0 -0.5 to VCC + 0.5 - 20 20 25 75 -65 to +150 300 Unit V V V V mA mA mA mA
o o
ICC or IGND DC VCC or Ground Current
C C
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied. 1) Output in OffState 2) High or Low State. IO absolute maximum rating must be observed.
RECOMMENDED OPERATING CONDITIONS
Symbol VCC VI VI/O VI/O Top dt/dv Supply Voltage Input Voltage (DIR, G) Bus I/O Voltage (see note 1) Bus I/O Voltage (see note 2) Operating Temperature Input Rise and Fall Time (see note 3) (V CC = 5.0 0.5V) Parameter Valu e 4.5 to 5.5 0 to 5.5 0 to 5.5 0 to VCC -40 to +85 0 to 20 Unit V V V V
o
C
ns/V
1) Output in OffState 2) High or Low State. IO absolute maximum rating must be observed. 3) VIN from 0.8 to 2V
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74VHCT245A
DC SPECIFICATIONS
Symb ol Parameter T est Cond ition s V CC (V) VIH VIL VOH VOL IOZ High Level Input Voltage Low Level Input Voltage High Level Output Voltage Low Level Output Voltage High Impedance Output Leakage Current Input Leakage Current Quiescent Supply Current Additional Worst Case Supply Current Output Leakage Current 4.5 to 5.5 4.5 to 5.5 4.5 4.5 4.5 4.5 5.5 0 to 5.5 5.5 5.5 I O =-50 A IO=-8 mA I O=50 A IO=8 mA VI = VIH or VIL VO = 0V to 5.5V VI = 5.5V or GND VI = VCC or GND One Input at 3.4V, other input at VCC or GND VOUT = 5.5V 4.4 3.94 0.0 0.1 0.36 0.25 4.5 Min. 2 0.8 4.4 3.8 0.1 0.44 2.5 Typ . Value T A = 25 o C Max. -40 to 85 o C Min . 2 0.8 Max. V V Un it
V V A
II ICC ICC
0.1 4 1.35
1.0 40 1.5
A A mA
IOPD
0
0.5
5.0
A
AC ELECTRICAL CHARACTERISTICS (Input t r = tf =3 ns)
Symb ol Parameter Test Co ndition V CC (*) C L (pF) (V) 5.0 5.0 5.0 5.0 5.0 5.0 15 50 15 50 50 50 RL = 1K RL = 1K Value T A = 25 o C Min. Typ . Max. 4.5 7.5 5.5 9.0 10.0 9.5 8.5 14.5 15.5 15.0 1.0 Un it -40 to 85 o C Min . Max. 1.0 8.5 1.0 1.0 1.0 1.0 9.5 15.5 16.5 16.0 1.0
tPLH tPHL tPZL tPZH tPLZ tPHZ tOSLH tOSHL
Propagation Delay Time Output Enable Time Output Disable Time Output to Output Skew Time (note 1)
ns ns ns ns
(*) Voltage range is 5V 0.5V Note 1: Parameter guaranteed by design. tsoLH = |tpLHm- tpLHn|, tsoHL = |tpHLm - tpHLn|
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74VHCT245A
CAPACITIVE CHARACTERISTICS
Symb ol Parameter Test Co nditions Min. C IN CI/O CPD Input Capacitance Bus Input Capacitance Power Dissipation Capacitance (note 1) T yp. 4 8 13 Valu e T A = 25 oC Max. 10 -40 to 85 o C Min. Max. 10 pF pF pF Un it
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 operting current can be obtained by the following equation. ICC(opr) = CPD * VCC * fIN + ICC/8(per circuit)
DYNAMIC SWITCHING CHARACTERISTICS
Symb ol Parameter T est Cond ition s V CC (V) VOLP VOLV VIHD VILD Dynamic Low Voltage Quiet Output (note 1, 2) Dynamic High Voltage Input (note 1, 3) Dynamic Low Voltage Input (note 1, 3) 5.0 -0.9 5.0 5.0 C L = 50 pF 2 0.8 Min. Typ . 0.6 -0.6 V Value T A = 25 o C Max. 0.9 -40 to 85 o C Min . Max. Un it
1) Worst case package. 2) Max number of outputs defined as (n). Data inputs are driven 0V to 3.0V, (n -1) outputs switching and one output at GND. 3) Max number of data inputs (n) switching. (n-1) switching 0V to3.0V. Inputs under test switching: 3.0V to threshold (VILD), 0V to threshold (VIHD), f=1MHz.
TEST CIRCUIT
T EST tPLH , tPHL tPZL , tPLZ tPZH , tPHZ
CL = 15/50 pF or equivalent (includes jig and probe capacitance) RL = R1 = 1K orequivalent RT = ZOUT of pulse generator (typically 50)
SW IT CH Open VCC GND
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74VHCT245A
WAVEFORM 1: PROPAGATION DELAYS (f=1MHz; 50% duty cycle)
WAVEFORM 2: OUTPUT ENABLE AND DISABLE TIME (f=1MHz; 50% duty cycle)
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74VHCT245A
SO-20 MECHANICAL DATA
DIM. MIN. A a1 a2 b b1 C c1 D E e e3 F L M S 7.40 0.50 12.60 10.00 1.27 11.43 7.60 1.27 0.75 8 (max.) 0.291 0.19 13.00 10.65 0.35 0.23 0.50 45 (typ.) 0.496 0.393 0.050 0.450 0.299 0.050 0.029 0.512 0.419 0.10 mm TYP. MAX. 2.65 0.20 2.45 0.49 0.32 0.013 0.009 0.020 0.004 MIN. inch TYP. MAX. 0.104 0.007 0.096 0.019 0.012
P013L
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74VHCT245A
TSSOP20 MECHANICAL DATA
mm MIN. A A1 A2 b c D E E1 e K L 0o 0.50 0.05 0.85 0.19 0.09 6.4 6.25 4.3 6.5 6.4 4.4 0.65 BSC 4o 0.60 8o 0.70 0o 0.020 0.10 0.9 TYP. MAX. 1.1 0.15 0.95 0.30 0.2 6.6 6.5 4.48 0.002 0.335 0.0075 0.0035 0.252 0.246 0.169 0.256 0.252 0.173 0.0256 BSC 4o 0.024 8o 0.028 0.004 0.354 MIN. inch TYP. MAX. 0.433 0.006 0.374 0.0118 0.0079 0.260 0.256 0.176
DIM.
A
A2 A1 b e K c L E
D
E1
PIN 1 IDENTIFICATION
1
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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. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a trademark of STMicroelectronics (c) 1999 STMicroelectronics - Printed in Italy - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - Canada - China - France - Germany - Italy - Japan - Korea - Malaysia - Malta - Mexico - Morocco - The Netherlands Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. http://www.st.com .
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