ETC FST3245MTCX

Revised December 2000
FST3245
8-Bit Bus Switch
General Description
Features
The Fairchild Switch FST3245 provides 8-bits of highspeed CMOS TTL-compatible bus switching in a standard
’245 pin-out. The low on resistance of the switch allows
inputs to be connected to outputs without adding propagation delay or generating additional ground bounce noise.
■ 4Ω switch connection between two ports.
The device is organized as an 8-bit switch. When OE is
LOW, the switch is ON and Port A is connected to Port B.
When OE is HIGH, the switch is OPEN and a high-impedance state exists between the two ports.
■ Control inputs compatible with TTL level.
■ Minimal propagation delay through the switch.
■ Low lCC.
■ Zero bounce in flow-through mode.
Ordering Code:
Order Number
Package Number
Package Description
FST3245WM
M20B
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
FST3245QSC
MQA20
20-Lead Quarter Size Outline Package (QSOP), JEDEC MO-137, 0.150 Wide
FST3245MTC
MTC20
20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Logic Diagram
Connection Diagram
Pin Descriptions
Truth Table
Pin Name
Description
OE
Bus Switch Enable
A
Bus A
B
Bus B
© 2000 Fairchild Semiconductor Corporation
DS500020
Input OE
Function
L
Connect
H
Disconnect
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FST3245 8-Bit Bus Switch
June 1997
FST3245
Absolute Maximum Ratings(Note 1)
Recommended Operating
Conditions (Note 3)
Supply Voltage (VCC )
−0.5V to +7.0V
DC Switch Voltage (VS)
−0.5V to +7.0V
Power Supply Operating (VCC)
DC Input Voltage (VIN) (Note 2)
−0.5V to +7.0V
Input Voltage (VIN)
0V to 5.5V
0V to 5.5V
DC Input Diode Current (lIK) VIN < 0V
−50mA
Output Voltage (VOUT)
DC Output (IOUT ) Sink Current
128mA
Input Rise and Fall Time (tr, tf)
+/− 100mA
DC VCC/GND Current (ICC/IGND)
Storage Temperature Range (TSTG)
4.0V to 5.5V
Switch Control Input
−65°C to +150 °C
0nS/V to 5nS/V
Switch I/O
0nS/V to DC
−40 °C to +85 °C
Free Air Operating Temperature (TA)
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” table will define the conditions
for actual device operation.
Note 2: The input and output negative voltage ratings may be exceeded if
the input and output diode current ratings are observed.
Note 3: Unused control inputs must be held HIGH or LOW. They may not
float.
DC Electrical Characteristics
Symbol
VCC
(V)
Parameter
TA = −40 °C to +85 °C
Typ
(Note 4)
Min
Units
−1.2
4.5
Conditions
Max
Clamp Diode Voltage
HIGH Level Input Voltage
4.0–5.5
VIL
LOW Level Input Voltage
4.0–5.5
0.8
V
II
Input Leakage Current
5.5
±1.0
µA
0≤ VIN ≤ 5.5V
IOZ
OFF-STATE Leakage Current
5.5
±1.0
µA
0 ≤A, B ≤ VCC
RON
Switch On Resistance
4.5
4
7
Ω
VIN = 0V, IIN = 64 mA
(Note 5)
4.5
4
7
Ω
VIN = 0V, IIN = 30 mA
2.0
V
IIN = −18 mA
VIK
VIH
V
4.5
8
15
Ω
VIN = 2.4V, IIN = 15 mA
4.0
11
20
Ω
VIN = 2.4V, IIN = 15 mA
ICC
Quiescent Supply Current
5.5
3
µA
VIN = VCC or GND, IOUT = 0
∆ ICC
Increase in ICC per Input
5.5
2.5
mA
One input at 3.4V
Other inputs at VCC or GND
Note 4: Typical values are at VCC = 5.0V and T A = +25°C
Note 5: 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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TA = −40 °C to +85 °C,
CL = 50pF, RU = RD = 500Ω
Symbol
Parameter
VCC = 4.5 – 5.5V
Min
tPHL,tPLH
Prop Delay Bus to Bus (Note 6)
tPZH, tPZL
Output Enable Time
1.5
VCC = 4.0V
Max
Min
Units
Conditions
Figure
Number
Max
0.25
0.25
ns
5.9
6.4
ns
VI = OPEN
Figures
1, 2
VI = 7V for tPZL
Figures
1, 2
VI = OPEN for tPZH
tPHZ, tPLZ
Output Disable Time
1.5
6.0
5.7
ns
VI = 7V for tPLZ
VI = OPEN for tPHZ
Figures
1, 2
Note 6: 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
Symbol
(Note 7)
Parameter
Typ
Max
Units
Conditions
CIN
Control Pin Input Capacitance
3
pF
VCC = 5.0V
CI/O
Input/Output Capacitance
5
pF
VCC, OE = 5.0V
Note 7: TA = +25°C, f = 1 MHz, Capacitance is characterized but not tested.
AC Loading and Waveforms
Note: Input driven by 50 Ω source terminated in 50 Ω
Note: C L includes load and stray capacitance
Note: Input PRR = 1.0 MHz tW = 500 ns
FIGURE 1. AC Test Circuit
FIGURE 2. AC Waveforms
3
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FST3245
AC Electrical Characteristics
FST3245
Physical Dimensions inches (millimeters) unless otherwise noted
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
Package Number M20B
20-Lead Quarter Size Outline Package (QSOP), JEDEC MO-137, 0.150 Wide
Package Number MQA20
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FST3245 8-Bit Bus Switch
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
Package Number MTC20
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:
2. A critical component in any component of a life support
device or system whose failure to perform can be reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
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 reasonably expected to result in a significant injury to the
user.
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