ST 74LCX157 User Manual

74LCX157

Low voltage CMOS Quad 2 channel multiplexer with 5V tolerant inputs

Features

■5V tolerant inputs

■High speed:

–tPD = 6.0ns (Max) at VCC = 3V

■Power down protection on inputs and outputs

■Symmetrical output impedance:

–|IOH| = IOL = 24mA (Min) at VCC = 3V

■PCI bus levels guaranteed at 24mA

■Balanced propagation delays:

–tPLH tPHL

■Operating voltage range:

–VCC (Opr) = 2.0V to 3.6V

■Pin and function compatible with 74 series 157

■Latch-up performance exceeds 500mA (JESD 17)

■ESD performance:

–HBM > 2000V

(MIL STD 883 method 3015); MM > 200V

SO-16	TSSOP16

Description

The 74LCX157 is a low voltage CMOS Quad 2 channel multiplexer fabricated with sub-micron silicon gate and double-layer metal wiring C2MOS technology. It is ideal for low power and high speed 3.3V applications; it can be interfaced to 5V signal environment for inputs.

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

It has same speed performance at 3.3V than 5V AC/ACT family, combined with a lower power consumption.

All inputs and outputs are equipped with protection circuits against static discharge, giving them 2KV ESD immunity and transient excess voltage.

Order codes

Part number	Package	Packaging
74LCX157MTR	SO-16	Tape and reel
74LCX157TTR	TSSOP16	Tape and reel
February 2007	Rev 6	1/17
		www.st.com

Contents	74LCX157

Contents

1	Logic symbols and I/O equivalent circuit . . . . . . . . . . . . . . . . . . . . . . .		. 3
2	Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		4
	2.1	Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4
	2.2	Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4
	2.3	Truth table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
	2.4	Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
3	Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		6
	3.1	Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
4	Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		7
5	Test circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		9
6	Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		10
7	Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		11
8	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		16

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74LCX157	Logic symbols and I/O equivalent circuit

1 Logic symbols and I/O equivalent circuit

Figure 1. IEC logic symbols

Figure 2. Input and output equivalent circuit

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Pin settings	74LCX157

2 Pin settings

2.1Pin connection

Figure 3. Pin connection (top through view)

2.2	Pin description
	Table 1. 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 input
			STROBE
	8		GND		Ground (0V)
	16		VCC		Positive supply voltage

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74LCX157	Pin settings

2.3Truth table

Table 2. 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
Note:	X : Do not care

2.4 Logic diagram

Figure 4. Logic diagram

Note:

This logic diagram has not to be used to estimate propagation delays

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Maximum rating	74LCX157

3 Maximum rating

stressing the device above the rating listed in the “absolute maximum ratings” table may cause permanent damage to the device. these are stress ratings only and operation of the device at these or any other conditions above those indicated in the operating sections of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. refer also to the STMicroelectronics sure program and other relevant quality documents.

Table 3. 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 (VCC = 0V)	-0.5 to +7.0	V
VO	DC output voltage (high or low state) (1)	-0.5 to VCC + 0.5	V
IIK	DC input diode current	-50	mA
IOK	DC output diode current (2)	-50	mA
IO	DC output current	± 50	mA
ICC	DC supply current per supply pin	± 100	mA
IGND	DC ground current per supply pin	± 100	mA
Tstg	Storage temperature	-65 to +150	°C
TL	Lead temperature (10 sec)	300	°C

1.IO absolute maximum rating must be observed

2.VO < GND

3.1Recommended operating conditions

Table 4. Recommended operating conditions

Symbol	Parameter	Value	Unit
VCC	Supply voltage (1)	2.0 to 3.6	V
VI	Input voltage	0 to 5.5	V
VO	Output voltage (VCC = 0V)	0 to 5.5	V
VO	Output voltage (high or low state)	0 to VCC	V
IOH, IOL	High or low level output current (VCC = 3.0 to 3.6V)	± 24	mA
IOH, IOL	High or low level output current (VCC = 2.7V)	± 12	mA
Top	Operating temperature	-40 to 85	°C
dt/dv	Input rise and fall time (2)	0 to 10	ns/V

1.Truth table guaranteed: 1.5V to 3.6V

2.VIN from 0.8V to 2V at VCC = 3.0V

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