ST 74VHC157 User Manual

74VHC157

QUAD 2 CHANNEL MULTIPLEXER

■HIGH SPEED: tPD = 4.1 ns (TYP.) at VCC = 5V

■LOW POWER DISSIPATION: ICC = 4 A (MAX.) at TA=25°C

■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 157

■IMPROVED LATCH-UP IMMUNITY

■LOW NOISE: VOLP = 0.8V (MAX.)

DESCRIPTION

The 74VHC157 is an advanced high-speed CMOS QUAD 2-CHANNEL MULTIPLEXER fabricated with sub-micron silicon gate and double-layer metal wiring C2MOS technology.

It consists of four 2-input digital multiplexer with common select and strobe inputs. It is a non-inverting multiplexer. When the STROBE

SOP TSSOP

Table 1: Order Codes

PACKAGE	T & R
SOP	74VHC157MTR
TSSOP	74VHC157TTR

input is held high selection of data is inhibited and all the outputs become low. The SELECT decoding determines whether the A or B inputs get routed to their corresponding Y outputs.

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.

Figure 1: Pin Connection And IEC Logic Symbols

November 2004	Rev. 4
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74VHC157

Figure 2: Input Equivalent Circuit	Table 2: Pin Description
	PIN N°	SYMBOL	NAME AND FUNCTION
	1	SELECT	Common Data Select
			Inputs
	2, 5, 11, 14	1A to 4A	Data Inputs From Source
			A
	3, 6, 10, 13	1B to 4B	Data Inputs From Source
			B
	4, 7, 9, 12	1Y to 4Y	Multiplexer Outputs
	15	STROBE	Strobe Input
	8	GND	Ground (0V)
	16	VCC	Positive Supply Voltage

Table 3: Truth Table

				INPUTS			OUTPUT
	STROBE		SELECT		A	B	Y
	H		X		X	X	L
	L		L		L	X	L
	L		L		H	X	H
	L		H		X	L	L
	L		H		X	H	H

X : Don’t care

Figure 3: Logic Diagram

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				74VHC157
Table 4: Absolute Maximum Ratings
Symbol	Parameter	Value			Unit
VCC	Supply Voltage	-0.5 to +7.0			V
VI	DC Input Voltage	-0.5 to +7.0			V
VO	DC Output Voltage	-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	±	50		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

Table 5: Recommended Operating Conditions

	Symbol	Parameter		Value	Unit
	VCC	Supply Voltage		2 to 5.5	V
	VI	Input Voltage		0 to 5.5	V
	VO	Output Voltage		0 to VCC	V
	Top	Operating Temperature		-55 to 125	°C
	dt/dv	Input Rise and Fall Time (note 1) (VCC = 3.3 ±	0.3V)	0 to 100	ns/V
		(VCC = 5.0 ±	0.5V)	0 to 20

1) VIN from 30% to 70% of VCC

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74VHC157

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		2.0			1.5				1.5		1.5
	Voltage		3.0 to			0.7VCC				0.7VCC		0.7VCC		V
			5.5
VIL	Low Level Input		2.0						0.5		0.5		0.5
	Voltage		3.0 to						0.3VCC		0.3VCC		0.3VCC	V
			5.5
VOH	High Level Output		2.0	IO=-50 A		1.9		2.0		1.9		1.9
	Voltage
			3.0	IO=-50 A		2.9		3.0		2.9		2.9
			4.5	IO=-50 A		4.4		4.5		4.4		4.4		V
			3.0	IO=-4 mA		2.58				2.48		2.4
			4.5	IO=-8 mA		3.94				3.8		3.7
VOL	Low Level Output		2.0	IO=50 A				0.0	0.1		0.1		0.1
	Voltage
			3.0	IO=50 A				0.0	0.1		0.1		0.1
			4.5	IO=50 A				0.0	0.1		0.1		0.1	V
			3.0	IO=4 mA					0.36		0.44		0.55
			4.5	IO=8 mA					0.36		0.44		0.55
II	Input Leakage		0 to	VI = 5.5V or GND					± 0.1		± 1		± 1	A
	Current		5.5
ICC	Quiescent Supply		5.5	VI = VCC or GND					4		40		40	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		3.3(*)	15				6.2	9.7	1.0	11.5	1.0	11.5
tPHL	Time
			3.3(*)	50				8.7	13.2	1.0	15.0	1.0	15.0
	A, B to Y													ns
			5.0(**)	15				4.1	6.4	1.0	7.5	1.0	7.5
			5.0(**)	50				5.6	8.4	1.0	9.5	1.0	9.5
tPLH	Propagation Delay		3.3(*)	15				8.4	13.2	1.0	15.5	1.0	15.5
tPHL	Time
			3.3(*)	50				10.9	16.7	1.0	19.0	1.0	19.0
	SELECT to Y													ns
			5.0(**)	15				5.3	8.1	1.0	9.5	1.0	9.5
			5.0(**)	50				6.8	10.1	1.0	11.5	1.0	11.5
tPLH	Propagation Delay		3.3(*)	15				8.7	13.6	1.0	16.0	1.0	16.0
tPHL	Time STROBE to Y
			3.3(*)	50				11.2	17.1	1.0	19.5	1.0	19.5	ns
			5.0(**)	15				5.6	8.6	1.0	10.0	1.0	10.0
			5.0(**)	50				7.1	10.6	1.0	12.0	1.0	12.0
(*) Voltage range is 3.3V ±		0.3V
(**) Voltage range is 5.0V ±		0.5V

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