CY74FCT2257CTQCT [TI]

Quad 2-Input Multiplexer; 四2输入多路复用器


型号：	CY74FCT2257CTQCT
厂家：	TEXAS INSTRUMENTS
描述：	Quad 2-Input Multiplexer 四2输入多路复用器复用器
文件：	总6页 (文件大小：55K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

1CY74FCT2257T

Data sheet acquired from Cypress Semiconductor Corporation.

Data sheet modiﬁed to remove devices not offered.

CY74FCT2257T

SCCS038 - September 1994 - Revised March 2000

Quad 2-Input Multiplexer

Functional Description

Features

• Function and pinout compatible with FCT and F logic

• 25Ω output series resistors to reduce transmission line

reﬂection noise

• FCT-C speed at 4.3 ns max.,

FCT-A speed at 5.0 ns max.

• TTL output level versions of equivalent FCT functions

• Edge-rate control circuitry for signiﬁcantly improved

noise characteristics

• Power-off disable feature

• Fully compatible with TTL input and output logic levels

• ESD > 2000V

• Sink current 12 mA

Source current15 mA

The FCT2257T has four identical two-input multiplexers that

select four bits of data from two sources under the control of a

common data Select input (S). The I0 inputs are selected

when the Select input is LOW and the I1 inputs are selected

when the Select input is HIGH. Data appears at the output in

true non-inverted form for the FCT2257T. On-chip termination

resistors have been added to the outputs to reduce system

noise caused by reﬂections. The FCT2257T can be used to

replace the FCT257T to reduce noise in an existing design.

The FCT2257T is a logic implementation of a four-pole,

two-position switch where the position of the switch is

determined by the logic levels supplied to the select input. Out-

puts are forced to a high-impedance “OFF” state when the

Output Enable input (OE) is HIGH.

• Extended commercial temp. range of –40˚C to +85˚C

• Three-state outputs

All but one device must be in the high-impedance state to

avoid currents exceeding the maximum ratings if outputs are

tied together. Design of the output enable signals must ensure

that there is no overlap when outputs of three-state devices

are tied together.

The outputs are designed with a power-off disable feature to

allow for live insertion of boards.

Pin Configurations

Logic Block Diagram

SOIC/QSOP

Top View

GND

FCT2257T–3

FCT2257T–1

Pin Description

Function Table^[1]

Inputs

Output

Name

Description

I₀

I₁

Data Inputs

Common Select Input

Enable Inputs (Active LOW)

Data Outputs

Note:

1. H = HIGH Voltage Level, L = LOW Voltage Level, X = Don’t Care,

Z = High impedance (OFF) state.

CY74FCT2257T

Maximum Ratings^{[2, 3]}

DC Output Current (Maximum Sink Current/Pin) ......120 mA

Power Dissipation..........................................................0.5W

(Above which the useful life may be impaired. For user guide-

lines, not tested.)

Static Discharge Voltage............................................>2001V

(per MIL-STD-883, Method 3015)

Storage Temperature .................................–65°C to +150°C

Ambient Temperature with

Power Applied.............................................–65°C to +135°C

Operating Range

Ambient

Supply Voltage to Ground Potential ............... –0.5V to +7.0V

DC Input Voltage............................................ –0.5V to +7.0V

DC Output Voltage......................................... –0.5V to +7.0V

Range

Temperature

V_CC

Commercial

–40°C to +85°C

5V ± 5%

Electrical Characteristics Over the Operating Range

Parameter

V_OH

V_OL

R_OUT

V_IH

Description

Output HIGH Voltage

Output LOW Voltage

Output Resistance

Input HIGH Voltage

Input LOW Voltage

Hysteresis^[6]

Test Conditions

V_CC=Min., I_OH=–15 mA

Min.

Typ.^[5]

Max.

Unit

2.4

3.3

0.3

V_CC=Min., I_OL=12 mA

0.55

Ω

2.0

V_IL

0.8

V_H

All inputs

0.2

V_IK

Input Clamp Diode Voltage

Input HIGH Current

Input LOW Current

V_CC=Min., I_IN=–18 mA

V_CC=Max., V_IN=2.7V

V_CC=Max., V_IN=0.5V

V_CC=Max., V_OUT=2.7V

–0.7

–1.2

±1

I_IH

µA

I_IL

±1

I_OZH

Off State HIGH-Level Output

Current

I_OZL

Off State LOW-Level

Output Current

V_CC=Max., V_OUT=0.5V

–10

µA

I_OS

Output Short Circuit Current^[7]V_CC=Max., V_OUT=0.0V

–60

–120

–225

I_OFF

Power-Off Disable V_CC=0V, V_OUT=4.5V

±1

µA

Capacitance^[6]

Parameter

Description

Test Conditions

Typ.^[5]Max.

Unit

C_IN

Input Capacitance

C_OUT

Output Capacitance

Notes:

2. Unless otherwise noted, these limits are over the operating free-air temperature range.

3. Unused inputs must always be connected to an appropriate logic voltage level, preferably either V_CCor ground.

4. T_Ais the “instant on” case temperature.

5. Typical values are at V_CC=5.0V, T_A=+25˚C ambient.

6. This parameter is speciﬁed but not tested.

7. Not more than one output should be shorted at a time. Duration of short should not exceed one second. The use of high-speed test apparatus and/or sample

and hold techniques are preferable in order to minimize internal chip heating and more accurately reﬂect operational values. Otherwise prolonged shorting of

a high output may raise the chip temperature well above normal and thereby cause invalid readings in other parametric tests. In any sequence of parameter

tests, I_OStests should be performed last.

CY74FCT2257T

Power Supply Characteristics

Parameter

Description

Test Conditions

V_CC=Max., V_IN< 0.2V,

_IN> V_CC–0.2V

Typ.^[5]

Max.

Unit

I_CC

Quiescent Power Supply Current

0.1

0.2

∆I_CC

Quiescent Power Supply Current

(TTL inputs)

V_CC=Max., V_IN=3.4V,^[8]

f₁=0, Outputs Open

0.5

2.0

I_CCD

Dynamic Power Supply

Current^[9]

V_CC=Max., One Input Toggling,

50% Duty Cycle, Outputs Open, OE=GND,

0.06

0.12

mA/

MHz

V_IN< 0.2V or V_IN> V_CC–0.2V

I_C

Total Power Supply Current^[10]

V_CC=Max., 50% Duty Cycle,

Outputs Open,

One Bit Toggling at f₁=10 MHz,

0.7

1.0

0.7

1.7

1.4

2.4

OE=GND,

V_IN< 0.2V or V_IN> V_CC–0.2V

V_CC=Max.,

50% Duty Cycle, Outputs Open,

One Bit Toggling at f₁=10 MHz,

OE=GND,

V_IN=3.4V or V_IN=GND

V_CC=Max.,

1.4^[11]

50% Duty Cycle, Outputs Open,

Four Bits Toggling at f₁=2.5 MHz,

OE=GND,

V_IN< 0.2V or V_IN> V_CC–0.2V

V_CC=Max.,

5.4^[11]

50% Duty Cycle, Outputs Open,

Four Bits Toggling at f₁=2.5 MHz,

OE=GND,

V_IN=3.4V or V_IN=GND

Notes:

8. Per TTL driven input (V_IN=3.4V); all other inputs at V_CCor GND.

9. This parameter is not directly testable, but is derived for use in Total Power Supply calculations.

10. I_C

I_C

I_QUIESCENT+ I_INPUTS+ I_DYNAMIC

I_CC+∆I_CCD_HN_T+I_CCD(f₀/2 + f₁N₁)

Quiescent Current with CMOS input levels

Power Supply Current for a TTL HIGH input

(V_IN=3.4V)

I_CC

∆I_CC

D_H

N_T

I_CCD

Duty Cycle for TTL inputs HIGH

Number of TTL inputs at D_H

Dynamic Current caused by an input transition pair

(HLH or LHL)

f₀

f₁

N₁

Clock frequency for registered devices, otherwise zero

Input signal frequency

Number of inputs changing at f₁

All currents are in milliamps and all frequencies are in megahertz.

11. Values for these conditions are examples of the I_CCformula. These limits are speciﬁed but not tested.

CY74FCT2257T

Switching Characteristics Over the Operating Range^[12]

CY74FCT2257AT

Commercial

CY74FCT2257CT

Commercial

Parameter

t_PLH

t_PHL

Description

Min.

Max.

Min.

Max.

Unit

Fig. No.^[13]

Propagation Delay

I_a, I_bto Y

1.5

6.0

1.5

4.3

5.2

6.0

5.0

1, 3

t_PLH

t_PHL

Propagation Delay

S to O

1.5

10.5

8.5

1.5

1, 3

t_PZH

t_PZL

Output Enable Time

1, 7, 8

t_PHZ

t_PLZ

Output Disable Time

6.0

Ordering Information

Speed

Package

Name

Operating

Range

(ns)

Ordering Code

Package Type

16-Lead (150-Mil) QSOP

4.3

CY74FCT2257CTQCT

CY74FCT2257CTSOC/SOCT

CY74FCT2257ATQCT

Commercial

16-Lead (300-Mil) Molded SOIC

16-Lead (150-Mil) QSOP

5.0

Commercial

Notes:

12. Minimum limits are speciﬁed but not tested on Propagation Delays

13. See “Parameter Measurement Information” in the General Information section.

CY74FCT2257T

Package Diagrams

16-Lead Quarter Size Outline Q1

16-Lead Molded SOIC S1

IMPORTANT NOTICE

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accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent

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CY74FCT2257CTQCT [TI]

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