FSTU3257 [FAIRCHILD]

Quad 2:1 Multiplexer/Demultiplexer Bus Switch with -2V Undershoot Protection; 四路2 ： 1多路复用器/多路解复用器总线开关具有-2V下冲保护


型号：	FSTU3257
厂家：	FAIRCHILD SEMICONDUCTOR
描述：	Quad 2:1 Multiplexer/Demultiplexer Bus Switch with -2V Undershoot Protection 四路2 ： 1多路复用器/多路解复用器总线开关具有-2V下冲保护解复用器开关
文件：	总7页 (文件大小：92K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

August 1999

Revised April 2000

FSTU3257

Quad 2:1 Multiplexer/Demultiplexer Bus Switch

with −2V Undershoot Protection

General Description

Features

■ Undershoot hardened to −2V (A and B Ports)

The Fairchild Switch FSTU3257 is a quad 2:1 high-speed

CMOS TTL-compatible multiplexer/demultiplexer bus

switch. The low on resistance of the switch allows inputs to

be connected to outputs without adding propagation delay

or generating additional ground bounce noise.

■ Soft enable turn-on to minimize bus to bus charge

sharing during enable

■ 4Ω switch connection between two ports.

■ Minimal propagation delay through the switch.

When OE is LOW, the select pin connects the A Port to the

selected B Port output. The A and B Ports are “undershoot

hardened” with UHC protection to support an extended

range of 2.0V below ground. Fairchild’s integrated Under-

shoot Hardened Circuit UHC senses undershoot at the I/O

and responds by preventing voltage differentials from

developing and turning on the switch. When OE is HIGH,

the switch is OPEN and a high-impedance state exists

between the two ports.

■ Low l_CC

■ Zero bounce in flow-through mode.

■ Control inputs compatible with TTL level.

■ See Applications Note AN-5008 for details

Ordering Code:

Order Number

FSTU3257M

Package Number

M16A

Package Description

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow

16-Lead Quarter Size Outline Package (QSOP), JEDEC MO-137, 0.150 Wide

16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide

FSTU3257QSC

FSTU3257MTC

MQA16

MTC16

Device also available in Tape and Reel. Specify by appending suffix letter “X” to the ordering code.

UHC is a trademark of Fairchild Semiconductor Corporation.

DS500302

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Logic Diagram

Connection Diagram

Pin Descriptions

Truth Table

Pin Name

Description

Function

Disconnect

A = B₁

Bus Switch Enable

Select Input

Bus A

A = B₂

B₁–B₂

Bus B

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Absolute Maximum Ratings(Note 1)

Recommended Operating

Conditions ^{(Note 4)}

−0.5V to +7.0V

Supply Voltage (V_CC

)

DC Switch Voltage (V_S) (Note 2)

−2.0V to +7.0V Power Supply Operating (V_CC

)

4.0V to 5.5V

0V to 5.5V

DC Input Control Pin Voltage (V_IN)(Note 3)

DC Input Diode Current (l_IK) V_IN<0V

−0.5V to +7.0V Input Voltage (V_IN

)

−50mA

Output Voltage (V_OUT

)

DC Output (I_OUT

DC V_CC/GND Current (I_CC/I_GND

Storage Temperature Range (T_STG

)

128mA Input Rise and Fall Time (t_r, t_f)

)

+/− 100mA

−65°C to +150 °C

Switch Control Input

Switch I/O

0nS/V to 5nS/V

0nS/V to DC

)

Free Air Operating Temperature (T_A)

−40 °C to +85 °C

Note 1: The Absolute Maximum Ratings are those values beyond which

the safety of the device cannot be guaranteed. The device should not be

operated at these limits. The parametric values defined in the Electrical

Characteristics tables are not guaranteed at the absolute maximum rating.

The Recommended Operating Conditions tables will define the conditions

for actual device operation.

Note 2: V_Sis the voltage observed/applied at either the A or B Ports across

the switch.

Note 3: The input and output negative voltage ratings may be exceeded if

the input and output diode current ratings are observed.

Note 4: Unused control inputs must be held HIGH or LOW. They may not

float.

DC Electrical Characteristics

V_CC

T_A= −40 °C to +85 °C

Symbol

Parameter

Units

Conditions

Typ

(Note 5)

(V)

Min

Max

V_IK

Clamp Diode Voltage

HIGH Level Input Voltage

LOW Level Input Voltage

Input Leakage Current

OFF-STATE Leakage Current

Switch On Resistance

(Note 6)

4.5

4.0–5.5

5.5

−1.2

I_IN= −18mA

V_IH

V_IL

I_I

2.0

0.8

±1.0

µA

Ω

0≤ V_IN≤5.5V

0 ≤A, B ≤V_CC

I_OZ

R_ON

5.5

4.5

_IN= 0V, I_IN= 64mA

4.5

Ω

_IN= 0V, I_IN= 30mA

4.5

Ω

_IN= 2.4V, I_IN= 15mA

_IN= V_CCor GND, I_OUT= 0

4.0

Ω

I_CC

Quiescent Supply Current

Increase in I_CCper Input

5.5

µA

∆ I_CC

5.5

2.5

One input at 3.4V

Other inputs at V_CCor GND

0.0 mA ≥ I_IN≥ −50 mA

OE = 5.5V

V_IKU

Voltage Undershoot

5.5

−2.0

Note 5: Typical values are at V_CC= 5.0V and T_A= +25°C

Note 6: Measured by the voltage drop between A and B pins at the indicated current through the switch. On resistance is determined by the lower of the

voltages on the two (A or B) pins.

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AC Electrical Characteristics

_A= −40 °C to +85°C,

_L= 50pF, RU = RD = 500Ω

_CC= 4.5 – 5.5V V_CC= 4.0V

Min Max

Figure

No.

Symbol

Parameter

Units

Conditions

Min

Max

0.25

30.0

_PHL,t_PLHProp Delay Bus to Bus (Note 7)

0.25

35.0

Figures

2, 3

ns V_I= OPEN

Prop Delay, Select to Bus A

7.0

t_PZH, t_PZLOutput Enable Time, Select to Bus B

V_I= 7V for t_PZL

Figures

2, 3

Output Enable Time, OE to Bus A, B

7.0

1.5

30.0

8.4

35.0

9.8

V_I= OPEN for t_PZH

V_I= 7V for t_PLZ

t_PHZ, t_PLZOutput Disable Time, Select to Bus B

Figures

2, 3

Output Disable Time, Output Enable Time, OE to Bus A, B

1.5

8.8

9.8

V_I= OPEN for t_PHZ

Note 7: This parameter is guaranteed by design but is not tested. The bus switch contributes no propagation delay other than the RC delay of the typical On

resistance of the switch and the 50pF load capacitance, when driven by an ideal voltage the source (zero output impedance).

Capacitance (Note 8)

Symbol

Parameter

Typ

Max

Units

Conditions

V_CC= 5.0V

C_IN

Control Pin Input Capacitance

A Port

B Port

7.5

5.5

C_I/O

Input/Output Capacitance

V_CC, OE = 5.0V

C_I/OON State

Input/Output Capacitance ON State (A or B Port)

_CC= 5.0V Switch ON

Note 8: T_A= +25°C, f = 1 MHz, Capacitance is characterized but not tested.

Undershoot Characteristic (Note 9)

Symbol

Parameter

Min

Typ

_OH− 0.3

Max

Units

Conditions

V_OUTU

Output Voltage During Undershoot

2.5

Figure 1

Note 9: This is intended to characterize the device’s protective capabilities by maintaining output signal integrity during an input transient voltage undershoot

event.

FIGURE 1.

Device Test Conditions

Transient

Input Voltage (V ) Waveform

Parameter

V_IN

Value

Units

See Waveform

100K

Ω

R₁- R₂

V_TRI

11.0

V_CC

5.5

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AC Loading and Waveforms

Note: Input driven by 50Ω source terminated in 50Ω

Note: C_Lincludes load and stray capacitance

Note: Input PRR = 1.0 MHz, t_W= 500 nS

FIGURE 2. AC Test Circuit

FIGURE 3. AC Waveforms

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Physical Dimensions inches (millimeters) unless otherwise noted

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow

Package Number M16A

16-Lead Quarter Size Outline Package (QSOP), JEDEC MO-137, 0.150 Wide

Package Number MQA16

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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide

Package Number MTC16

Technology Description

The Fairchild Switch family derives from and embodies Fairchild’s proven switch technology used for several years in its

74LVX3L384 (FST3384) bus switch product.

Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and

Fairchild reserves the right at any time without notice to change said circuitry and specifications.

LIFE SUPPORT POLICY

FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT

DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD

SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or systems

which, (a) are intended for surgical implant into the

body, or (b) support or sustain life, and (c) whose failure

to perform when properly used in accordance with

instructions for use provided in the labeling, can be rea-

sonably expected to result in a significant injury to the

user.

2. A critical component in any component of a life support

device or system whose failure to perform can be rea-

sonably expected to cause the failure of the life support

device or system, or to affect its safety or effectiveness.

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