ST 74LCX541 User Manual

Low voltage CMOS octal bus buffer (3-state)

Features

■ 5V tolerant inputs and outputs

■ High speed:

–t

= 8.0ns (Max) at V

PD

■ Power down protection on inputs and outputs

■ Symmetrical output impedance:

–|I

■ PCI bus levels guaranteed at 24mA

■ Balanced propagation delays:

–t

■

Operating voltage range:
–V

■ Pin and function compatible with

| = IOL = 24mA (Min) at VCC = 3V

OH

≅ t

PLH

PHL

(Opr) = 2.0V to 3.6V

CC

74 series 541

■ Latch-up performance exceeds

500mA (JESD 17)

■ ESD performance:

– HBM > 2000V

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

CC

= 3V

74LCX541

with 5V tolerant inputs and outputs

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 C
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.

2

MOS

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

74LCX541MTR SO-20 Tape and reel

74LCX541TTR TSSOP20 Tape and reel

January 2007 Rev 5 1/17

www.st.com

17

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

2/17

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

3/17

Pin settings 74LCX541

2 Pin settings

2.1 Pin connection

Figure 3. Pin connection (top through view)

2.2 Pin description

Table 1. Pin description

Pin N° Symbol Name and function

1, 19 G1

2, 3, 4, 5,

6, 7, 8, 9

18, 17, 16, 15,

14, 13, 12, 11

10 GND Ground (0V)

20 V

, G2 Output enable inputs

A1 to A8 Data inputs

Y1 to Y8 Data outputs

CC

Positive supply voltage

4/17

74LCX541 Logic states

3 Logic states

3.1 Truth table

Table 2. Truth table

Input Output

G1

HXX Z

XHX Z

LLH L

LLL H

Note: X : Do not care

Z : High impedance

G2 An Yn

5/17

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

V

V

V

I

I

I

GND

T

T

1. IO absolute maximum rating must be observed

2. VO < GND

Supply voltage -0.5 to +7.0 V

CC

V

DC input voltage -0.5 to +7.0 V

I

DC output voltage (OFF state) -0.5 to +7.0 V

O

DC output voltage (high or low state)

O

I

DC input diode current -50 mA

IK

DC output diode current

OK

I

DC output current ±50 mA

O

DC supply current per supply pin ± 100 mA

CC

(2)

(1)

-0.5 to VCC + 0.5

-50 mA

DC ground current per supply pin ± 100 mA

Storage temperature -65 to +150 °C

stg

Lead temperature (10 sec) 300 °C

L

V

4.1 Recommended operating conditions

Table 4. Recommended operating conditions

Symsbol Parameter Value Unit

V

V

V

V

Supply voltage

CC

Input voltage 0 to 5.5 V

I

Output voltage (OFF state) 0 to 5.5 V

O

Output voltage (high or low state)

O

IOH, IOLHigh or low level output current (VCC = 3.0 to 3.6V)

I

, IOLHigh or low level output current (VCC = 2.7V)

OH

T

dt/dv

1. Truth table guaranteed: 1.5V to 3.6V

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

Operating temperature -40 to 85 °C

op

Input rise and fall time

6/17

(1)

(2)

2.0 to 3.6 V

0 to V

CC

± 24 mA

± 12 mA

0 to 10 ns/V

V