ST 74VHCT245A User Manual

74VHCT245A

OCTAL BUS TRANSCEIVER (3-STATE)

■HIGH SPEED: tPD = 4.5 ns (TYP.) at VCC = 5V

■LOW POWER DISSIPATION: ICC = 4 A (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 245

■IMPROVED LATCH-UP IMMUNITY

■LOW NOISE: VOLP = 0.9V (MAX.)

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

SOP	TSSOP
Table 1: Order Codes
PACKAGE	T & R
SOP	74VHCT245AMTR
TSSOP	74VHCT245ATTR

direction of data transmission is determined by 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.

All floating bus terminals during High Z State must be held HIGH or LOW.

Figure 1: Pin Connection And IEC Logic Symbols

December 2004	Rev. 4
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74VHCT245A

Figure 2: Input/ Output Equivalent Circuit

	Figure 3: Input Equivalent Circuit		Table 2: Pin Description
			PIN N°	SYMBOL	NAME AND FUNCTION
			1	DIR	Directional Control
			2, 3, 4, 5, 6,	A1 to A8	Data Inputs/Outputs
			7, 8, 9
			18, 17, 16,	B1 to B8	Data Inputs/Outputs
			15, 14, 13,
			12, 11
			19	G	Enable Input
			10	GND	Ground (0V)
			20	VCC	Positive Supply Voltage
	Table 3: Truth Table
	INPUTS		FUNCTION		OUTPUT
	G	DIR	A BUS	B BUS
	L	L	OUTPUT	INPUT	A = B
	L	H	INPUT	OUTPUT	B = A
	H	X	Z	Z	Z

X : Don‘t Care

Z : High Impedance

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					74VHCT245A
Table 4: Absolute Maximum Ratings
Symbol			Parameter	Value		Unit
VCC	Supply Voltage			-0.5 to +7.0		V
VI	DC Input Voltage (DIR,	G)		-0.5 to +7.0		V
VI/O	DC BUS I/O Voltage (see note 1)			-0.5 to +7.0		V
VI/O	DC BUS I/O 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			±	75	mA
Tstg	Storage Temperature			-65 to +150		°C
TL	Lead Temperature (10 sec)			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)Output in OFF State

2)High or Low State. IO absolute maximum rating must be observed

Table 5: Recommended Operating Conditions

Symbol	Parameter	Value	Unit
VCC	Supply Voltage	4.5 to 5.5	V
VI	Input Voltage	0 to 5.5	V
VI/O	BUS I/O Voltage (see note 1)	0 to 5.5	V
VI/O	BUS I/O Voltage (see note 2)	0 to VCC	V
Top	Operating Temperature	-55 to 125	°C
dt/dv	Input Rise and Fall Time (see note 3) (VCC = 5.0 ± 0.5V)	0 to 20	ns/V

1)Output in OFF State

2)High or Low State. IO absolute maximum rating must be observed

3)VIN from 0.8V to 2V

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74VHCT245A

Table 6: DC Specifications

		Test Condition									Value
Symbol	Parameter	VCC					TA = 25°C				-40 to 85°C			-55 to 125°C			Unit
		(V)				Min.		Typ.	Max.		Min.	Max.		Min.	Max.
VIH	High Level Input	4.5 to				2					2			2			V
	Voltage	5.5
VIL	Low Level Input	4.5 to								0.8			0.8			0.8	V
	Voltage	5.5
VOH	High Level Output	4.5		IO=-50 A		4.4		4.5			4.4			4.4			V
	Voltage
		4.5		IO=-8 mA		3.94					3.8			3.7
VOL	Low Level Output	4.5		IO=50 A				0.0		0.1			0.1			0.1	V
	Voltage
		4.5		IO=8 mA						0.36		0.44			0.55
IOZ	High Impedance	5.5		VI = VIH or VIL					±	0.25		±	2.5		±	2.5	A
	Output Leakage			VO = 0V to 5.5V
	Current
II	Input Leakage	0 to		VI = 5.5V or GND					± 0.1			±	1.0		±	1.0	A
	Current	5.5
ICC	Quiescent Supply	5.5		VI = VCC or GND						4			40			40	A
	Current
+ICC	Additional Worst			One Input at 3.4V,
	Case Supply	5.5		other input at VCC						1.35			1.5			1.5	mA
	Current			or GND
IOPD	Output Leakage	0		VOUT = 5.5V						0.5			5.0			5.0	A
	Current
Table 7: AC Electrical Characteristics (Input tr = tf = 3ns)
		Test Condition									Value
Symbol	Parameter	VCC (*)		CL			TA = 25°C				-40 to 85°C			-55 to 125°C			Unit
		(V)		(pF)		Min.		Typ.	Max.		Min.	Max.		Min.	Max.
tPLH	Propagation Delay	5.0		15				4.5		7.5	1.0		8.5	1.0	10.0		ns
tPHL	Time	5.0		50				5.3		8.7	1.0		9.5	1.0	11.0
tPZL	Output Enable	5.0		15	RL = 1KΩ			9.0		13.8	1.0	15.0		1.0	16.0		ns
tPZH	Time	5.0		50				9.7		14.8	1.0	16.0		1.0	17.0
tPLZ	Output Disable	5.0		50	RL = 1KΩ			10.0		15.4	1.0	16.5		1.0	17.5		ns
tPHZ	Time
tOSLH	Output to Output	5.0		50						1.0			1.0			1.0	ns
tOSHL	Skew Time (note 1)

(*) Voltage range is 5.0V ± 0.5V

Note 1: Parameter guaranteed by design. tsoLH = |tpLHm - tpLHn|, tsoHL = |tpHLm - tpHLn|

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