ST 74LCX541 User Manual

74LCX541

Low voltage CMOS octal bus buffer (3-state) with 5V tolerant inputs and outputs

Features

■5V tolerant inputs and outputs

■High speed:

–tPD = 8.0ns (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 541

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

■ESD performance:

–HBM > 2000V

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

Order codes

SO-20

TSSOP20

Description

The 74LCX541 is a low voltage CMOS octal bus buffer (non-inverted) 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.

The 3 STATE control gate operates as two input AND such that if either G1 and G2 are high, all eight outputs are in the high impedance state. In order to enhance PC board layout the 74LCX541 offers a pinout having inputs and outputs on opposite sides of the package.

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.

Part number	Package	Packaging
74LCX541MTR	SO-20	Tape and reel
74LCX541TTR	TSSOP20	Tape and reel
January 2007	Rev 5	1/17
		www.st.com

Contents	74LCX541

Contents

1	Logic symbols and I/O equivalent circuit . . . . . . . . . . . . . . . . . . . . . . . .		3
2	Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		4
	2.1	Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4
	2.2	Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4
3	Logic states . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5

3.1 Truth table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4	Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. 6
	4.1 Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
5	Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7
6	Test circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	9
7	Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	10
8	Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11
9	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	16

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74LCX541	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	74LCX541

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, 19										Output enable inputs
				G1,			G2
	2, 3, 4, 5,		A1 to A8								Data inputs
	6, 7, 8, 9
	18, 17, 16, 15,				to						Data outputs
			Y1					Y8
	14, 13, 12, 11
	10			GND							Ground (0V)
	20			VCC							Positive supply voltage

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74LCX541	Logic states

3 Logic states

3.1Truth table

Table 2. Truth table

				Input				Output
							An
		G1			G2				Yn
		H			X		X		Z
		X			H		X		Z
		L			L		H		L
		L			L		L		H
Note:	X : Do not care
	Z : High impedance

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Maximum rating	74LCX541

4 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 (OFF state)	-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

4.1Recommended operating conditions

Table 4. Recommended operating conditions

Symsbol	Parameter	Value	Unit
VCC	Supply voltage (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	-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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