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Semiconductor products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON
Semiconductor data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s
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Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended
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December 2012
©1997 Fairchild Semiconductor Corporation www.fairchildsemi.com
FST3245 • Rev. 1.0.3
FST3245 — 8-Bit Bus Switch
FST3245 — 8-Bit Bus Switch
Features
4 Ω Switch Connection between Two Ports
Minimal Propagation Delay through the Switch
Low ICC
Zero Bounce in Flow-through Mode
Control Inputs Compatible with TTL Level
Description
The FST3245 switch provides eight-bits of high-speed
CMOS TTL-compatible bus switching in a standard ’245
pin-out. The low on resistance allows inputs to be
connected to outputs without adding propagation delay
or generating additional ground bounce noise.
The device is organized as an eight-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.
Ordering Information
Part Number Operating
Temperature
Range Package Packing
Method
FST3245MTCX -40 to +85°C 20-Lead Thin Shrink Small Outline Package (TSSOP),
JEDEC MO-153, 4.4 mm Wide Tape and Reel
Logic Diagram
18
11
B
0
B
7
19
2
9
/OE
A
7
A
0
Figure 1. Logic Diagram
© 1997 Fairchild Semiconductor Corporation www.fairchildsemi.com
FST3245 • Rev. 1.0.3 2
FST3245 — 8-Bit Bus Switch
Pin Configuration
1
2
3
4
5
6
7
8
9
10 11
12
13
14
15
16
17
18
19
20
A
3
A
4
A
5
A
6
A
7
NC
A
0
A
1
A
2
GND B
7
B
6
B
5
B
4
B
3
B
2
B
1
B
0
/OE
V
CC
Figure 2. Pin Configuration
Pin Descriptions
Pin # Pin Names Description
1 NC No Connnect
19 /OE Bus Switch Enable
2,3,4,5,6,7,8,9 A0,A1,A2,A3,A4,A5,A6,A7 Bus A
10 GND Ground
11,12,13,14,15,16,17,18 B7,B6,B5,B4,B3,B2,B1,B0 Bus B
20 VCC Supply Voltage
Truth Table
Input /OE Function
LOW Connect
HIGH Disconnect
© 1997 Fairchild Semiconductor Corporation www.fairchildsemi.com
FST3245 • Rev. 1.0.3 3
FST3245 — 8-Bit Bus Switch
Absolute Maximum Ratings
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended.
In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability.
The absolute maximum ratings are stress ratings only.
Symbol Parameter Min. Max. Unit
VCC Supply Voltage -0.5 7.0 V
VS DC Switch Voltage -0.5 7.0 V
VIN DC Input Voltage(1) -0.5 7.0 V
IIK DC Input Diode Current, VIN < 0 V -50 mA
IOUT DC Output Sink Current 128 mA
ICC / IGND DC VCC / GND Current ±100 mA
TSTG Storage Temperature Range -65 +150 °C
Note:
1. The input and output negative voltage ratings may be exceeded if the input and output diode current ratings are
observed.
Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended
operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not
recommend exceeding them or designing to Absolute Maximum Ratings.
Symbol Parameter Min. Max. Unit
VCC Power Supply Operating 4.0 5.5 V
VIN Input Voltage 0 5.5 V
VOUT Output Voltage 0 5.5 V
tr, tf Input Rise and Fall Time Switch Control Input(2) 0 5 ns/V
Switch I/O 0 DC
TA Operating Temperature, Free Air -40 +85 °C
Note:
2. Unused control inputs must be held HIGH or LOW. They may not float.
© 1997 Fairchild Semiconductor Corporation www.fairchildsemi.com
FST3245 • Rev. 1.0.3 4
FST3245 — 8-Bit Bus Switch
DC Electrical Characteristics
Typical values are at VCC = 5.0 V and TA = 25°C.
Symbol Parameter Conditions VCC (V) TA=-40 to +85°C Units
Min. Typ. Max.
VIK Clamp Diode Voltage IIN = -18 mA 4.5 -1.2 V
VIH High-Level Input Voltage 4.0 to 5.5 2.0 V
VIL Low-Level Input Voltage 4.0 to 5.5 0.8 V
IIN Input Leakage Current 0 ≤ VIN ≤ 5.5 V 5.5 ±1.0 µA
IOZ Off-state Leakage Current 0 ≤ A, B ≤ VCC 5.5 ±1.0 µA
RON Switch On Resistance(3)
VIN = 0 V, IIN = 64 mA 4.5 4 7
Ω
VIN = 0 V, IIN = 30 mA 4.5 4 7
VIN = 2.4 V, IIN = 15 mA 4.5 8 15
VIN = 2.4 V, IIN = 15 mA 4.0 11 20
ICC Quiescent Supply Current VIN = VCC or GND,
IOUT = 0 5.5 3 µA
ΔICC Increase in ICC per Input One Input at 3.4 V, Other
Inputs at VCC or GND 5.5 2.5 mA
Note:
3. Measured by the voltage drop between the A and B pins at the indicated current through the switch. On
resistance is determined by the lower of the voltages on the A or B pins.
AC Electrical Characteristics
TA = -40 to +85°C, CL = 50 pF, and RU = RD = 500 Ω.
Symbol Parameter Conditions
VCC = 4.5 – 5.5 V VCC = 4.0 V Units Figure
Min. Max. Min. Max.
tPHL, tPLH Propagation Delay
Bus-to-Bus(4) VIN = Open 0.25 0.25 ns Figure 3
Figure 4
tPZH ,tPZL Output Enable Time VIN = 7 V for tPZL
VIN = Open for
tPZH 1.5 5.9 6.4 ns
Figure 3
Figure 4
tPHZ, tPLZ Output Disable Time VIN = 7 V for tPLZ
VIN = Open for
tPHZ 1.5 6.0 5.7 ns
Figure 3
Figure 4
Note:
4. 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 50 pF load capacitance when driven by an
ideal voltage source (zero output impedance).
Capacitance
TA = +25°C, f = 1 MHz. Capacitance is characterized, but not tested.
Symbol Parameter Conditions Typ. Units
CIN Control Pin Input Capacitance VCC = 5.0 V 3 pF
CI/O Input/Output Capacitance VCC, /OE = 5.0 V 5 pF
© 1997 Fairchild Semiconductor Corporation www.fairchildsemi.com
FST3245 • Rev. 1.0.3 5
FST3245 — 8-Bit Bus Switch
AC Loadings and Waveforms
Notes: Input driven by 50 Ω source terminated in 50 Ω.
CL includes load and stray capacitance.
Input PRR = 1.0 MHz, tw = 500 ns.
Figure 3. AC Test Circuit
Figure 4. AC Waveforms
© 1997 Fairchild Semiconductor Corporation www.fairchildsemi.com
FST3245 • Rev. 1.0.3 6
FST3245 — 8-Bit Bus Switch
Physical Dimensions
Figure 5. 20-Lead Thin Sh rin k Small Outline Package (TSSOP), JEDEC MO-153, 4.4 mm W ide
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner
without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or
obtain the m ost recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the
warranty therein, which covers Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/
© 1997 Fairchild Semiconductor Corporation www.fairchildsemi.com
FST3245 • Rev. 1.0.3 7
FST3245 — 8-Bit Bus Switch
www.onsemi.com
1
ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.
ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent
coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. ON Semiconductor reserves the right to make changes without further notice to any products herein.
ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards,
regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor data sheets and/or
specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer
application by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not
designed, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification
in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized
application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and
expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such
claim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. This
literature is subject to all applicable copyright laws and is not for resale in any manner.
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