ST 74LCX257 User Manual

74LCX257

LOW VOLTAGE CMOS QUAD 2 CHANNEL MULTIPLEXER WITH 5V TOLERANT INPUTS AND OUTPUTS (3-STATE)

■5V TOLERANT INPUTS AND OUTPUTS

■HIGH SPEED:

tPD = 6.0 ns (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 24 mA

■BALANCED PROPAGATION DELAYS: tPLH tPHL

■OPERATING VOLTAGE RANGE:

VCC(OPR) = 2.0V to 3.6V (1.5V Data Retention)

SOP TSSOP

Table 1: Order Codes

PACKAGE	T & R
SOP	74LCX257MTR
TSSOP	74LCX257TTR

■PIN AND FUNCTION COMPATIBLE WITH 74 SERIES 257

■LATCH-UP PERFORMANCE EXCEEDS 500mA (JESD 17)

■ESD PERFORMANCE:

HBM > 2000V (MIL STD 883 method 3015); MM > 200V

DESCRIPTION

The 74LCX257 is a low voltage CMOS QUAD 2 CHANNEL MULTIPLEXER (3-STATE) 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 both inputs and outputs.

Figure 1: Pin Connection And IEC Logic Symbols

It is composed of four independent 2 channel multiplexers with common SELECT and ENABLE (OE) INPUT. The 74LCX257 is a non-inverting multiplexer. When the ENABLE INPUT is held "High", all outputs become in high impedance state. If SELECT INPUT is held "Low", "A" data is selected, when SELECT INPUT is "High", "B" data is chosen.

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.

September 2004	Rev. 4
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74LCX257

Figure 2: Input And Output 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			3	State Multiplexer Outputs
15		OE		3	State Output Enable Inputs (Active LOW)
8	GND			Ground (0V)
16	VCC			Positive Supply Voltage

Table 3: Truth Table

				INPUTS			OUTPUT
	OE		SELECT		A	B	Y
	H		X		X	X	Z
	L		L		L	X	L
	L		L		H	X	H
	L		H		X	L	L
	L		H		X	H	H

X : Don’t Care

Z : High Impedance

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Figure 3: Logic Diagram

This logic diagram has not be used to estimate propagation delays

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 (OFF State)	-0.5 to +7.0		V
VO	DC Output Voltage (High or Low State) (note 1)	-0.5 to VCC + 0.5		V
IIK	DC Input Diode Current	- 50		mA
IOK	DC Output Diode Current (note 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

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied

1)IO absolute maximum rating must be observed

2)VO < GND

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Table 5: Recommended Operating Conditions

Symbol	Parameter	Value		Unit
VCC	Supply Voltage (note 1)	2.0 to 3.6		V
VI	Input Voltage	0 to 5.5		V
VO	Output Voltage (OFF State)	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	-55 to 125		°C
dt/dv	Input Rise and Fall Time (note 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

Table 6: DC Specifications

		Test Condition			Value
Symbol	Parameter							Unit
		VCC		-40 to 85 °C		-55 to 125 °C
		(V)		Min.	Max.	Min.	Max.
VIH	High Level Input			2.0		2.0		V
	Voltage	2.7 to 3.6
VIL	Low Level Input				0.8		0.8	V
	Voltage
VOH	High Level Output	2.7 to 3.6	IO=-100 A	VCC-0.2		VCC-0.2
	Voltage
		2.7	IO=-12 mA	2.2		2.2		V
		3.0	IO=-18 mA	2.4		2.4
			IO=-24 mA	2.2		2.2
VOL	Low Level Output	2.7 to 3.6	IO=100 A		0.2		0.2
	Voltage
		2.7	IO=12 mA		0.4		0.4	V
		3.0	IO=16 mA		0.4		0.4
			IO=24 mA		0.55		0.55
II	Input Leakage	2.7 to 3.6	VI = 0 to 5.5V		± 5		± 5	A
	Current
Ioff	Power Off Leakage	0	VI or VO = 5.5V		10		10	A
	Current
IOZ	High Impedance	2.7 to 3.6	VI = VIH or VIL		± 5		± 5	A
	Output Leakage		VO = 0 to VCC
	Current
ICC	Quiescent Supply	2.7 to 3.6	VI = VCC or GND		10		10	A
	Current
			VI or VO= 3.6 to 5.5V		± 10		± 10
∆ ICC	ICC incr. per Input	2.7 to 3.6	VIH = VCC - 0.6V		500		500	A

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