The industry’s only 1- to 48-Bit
Switch Solution
Fairchild Switch
Product Line Card
Bus Switch Overview
Fairchild’s Switch (FST) product line is a family of low-impedance bus, bus exchange and multiplexer/
demultiplexer switches. These devices provide high-speed bus switching. The low “ON” resistance of these
NMOS pass gates allows inputs to be connected to outputs without adding propagation delay or generating
additional ground bounce noise. Fairchild Switches are ideal for high-speed, bidirectional interfaces between
mixed-supply busses, and in design situations requiring isolation and protection.
Features and Benefits
Features
Benefits
Near zero propagation delay (0.25ns max)
High-performance products offer seamless interface to logic functions
Low “ON” resistance (5Ω) and input capacitance
Minimize bus loading
Low power consumption (3µA ICC)
Saves power, extends battery life
1- to 48-Bit configurations
Provides flexibility for applications requiring mixed-supply busses,
bus isolation or hot insertion
BGA, QSOP, SC70, SOIC, SOT23,
SSOP, TSSOP and US8 packaging
Provides package flexibility including the smallest packages available
Options with Undershoot Hardened Circuitry
(UHC™) protection
Provides highly reliable hot-swap isolation
Options with integrated 25Ω series resistors
Noise suppression
Options with integrated diode
Voltage translation
Options with precharge
Allows live insertion
Configurations
Bus Exchange Switch
A0
Bus Switch
Bus Switch
(Multiplexer/Demultiplexer)
A0
C0
1A
1B1
1B2
B0
D0
OE
Flow Control
S
S
OE
OE
B0
Switch Portfolio
Bus Switch Portfolio
Function
Part Number
TinyLogic Low-Voltage UHS Single SPST Normally
Open Analog Switch or 1-Bit Bus Switch
TinyLogic UHS 1-Bit Low-Power Bus Switch
TinyLogic UHS 1-Bit Low-Power Bus Switch with Level Shifting
2-Bit Low-Power Bus Switch
2-Bit Low-Power Bus Switch with Level Shifting
NC7SZ66
TinyLogic Low-Voltage UHS Dual SPST Normally
Open Analog Switch or 2-Bit Bus Switch
TinyLogic UHS 2-Bit Low-Power Bus Switch
TinyLogic UHS 2-Bit Low-Power Bus Switch
TinyLogic UHS 2-Bit Low-Power Bus Switch with Level Shifting
TinyLogic UHS 2-Bit Low-Power Bus Switch with Level Shifting
4-Bit Bus Switch
4-Bit Bus Switch
8-Bit Bus Switch
8-Bit Bus Switch
8-Bit Bus Switch
10-Bit Bus Switch
10-Bit Bus Switch with Precharged Outputs
10-Bit Bus Switch with -2V Undershoot Protection
NC7WB66
10-Bit Bus Switch with Precharged Outputs and
-2V Undershoot Protection
20-Bit Bus Switch
20-Bit Bus Switch
20-Bit Bus Switch with 25Ω Series Resistors
Configurable 4- to 20-Bit Bus Switch
with Selectable Level Shifting (Preliminary)
Configurable 4- to 20-Bit Bus Switch with Selectable Level
Shifting and -2V Undershoot Protection (Preliminary)
24-Bit Bus Switch
24-Bit Bus Switch with Level Shifting
24-Bit Bus Switch with Level Shifting and -2V Undershoot Protection
48-Bit Bus Switch
40- to 48-Bit Bus Switch with Level Shifting (Preliminary)
40- to 48-Bit Bus Switch with Level Shifting
and -2V Undershoot Protection (Preliminary)
FSTU6800
NC7SZ384
NC7SZD384
FST3306
FSTD3306
NC7WB3125
NC7WB3306
NC7WBD3125
NC7WBD3306
FST3125
FST3126
FST3244
FST3245
FST3345
FST3384
FST6800
FSTU3384
FST16210
FST16861
FST162861
FSTD16450
FSTUD16450
FST16211
FSTD16211
FSTUD16211
FST32211
FSTD32211
FSTUD32211
Multiplexer/Demultiplexer and Bus Exchange Switch Portfolio
Function
12- to 24-Bit Multiplexer/Demultiplexer Bus Switch
16- to 32-Bit Multiplexer/Demultiplexer Bus Switch
16- to 32-Bit Multiplexer/Demultiplexer Bus Switch
16- to 32-Bit Multiplexer/Demultiplexer
Bus Switch with -2V Undershoot Protection
16- to 32-Bit Multiplexer/Demultiplexer
Bus Switch with -2V Undershoot Protection
17- to 34-Bit Multiplexer/Demultiplexer Bus Switch
Quad 2:1 Multiplexer/Demultiplexer Bus Switch
Part Number
FST16292
FST16232
FST16233
FSTU32160
Quad 2:1 Multiplexer/Demultiplexer Bus Switch
with -2V Undershoot Protection
FSTU3257
TinyLogic Low-Voltage UHS SPDT Analog Switch
or 2:1 Multiplexer/Demultiplexer Bus Switch
TinyLogic UHS 2:1 Multiplexer/Demultiplexer Bus Switch
Dual 4:1 Multiplexer/Demultiplexer Bus Switch
10-Bit Bus Exchange Switch
18-Bit Bus Exchange Switch
24-Bit Bus Exchange Switch
24-Bit Bus Exchange Switch
NC7SB3157
www.fairchildsemi.com
FSTU32160A
FST34170
FST3257
NC7SB3257
FST3253
FST3383
FST16209
FST16212
FST16213
Switch Applications
Bus Switch Translation (FSTDxxxx)
Vcc
5V
4.3V
• Simple solution for voltage translation (5V to 3.3V)
• No speed impact
• Integrated diode
BE
VIN
VOUT
5V
TTL/CMOS
3.3V
Bus Switch Isolation
• Fairchild Switches provide circuit protection and isolate your bus from
disruption.
• When VCC is 0V, switches function as low-capacitance,
low-leakage nodes.
• Live insertion is safe using Fairchild’s UHC protection.
Precharged Outputs for Live Insertion
VBIAS
FST6800 Circuit Diagram
• The FST6800 is a flow-through 10-bit bus switch.
• B port is precharged to a user-selectable bias voltage, allowing live
insertion with minimal active host bus disruption.
OE
A
B
Data Path Routing
FST16292
• Figure A: Switching two banks of memory to a common bus. The
FST16292 is a 12- to 24-bit multiplexer/demultiplexer bus switch with
integrated 500Ω termination to ground on A2 port. Unused memory
can be terminated through 500Ω to ground.
• Figure B: Switching two peripherals to a common bus. The FST3257
is a quad 2:1 multiplexer/demultiplexer bus switch.
FST3257
1-12A1 1-12B1
System Bus
DIMM
DIMM
1-12B2
1-4B1
System Bus
1-4A1
1-4B2
External
Floppy
Drive
External
Hard
Drive
500Ω
Figure A
Undershoot Protection
Figure B
FSTU Undershoot Protection Circuit
OE
• Undershoot conditions can occur on busses that are poorly terminated,
on signals with fast edge rates or on busses that allow hot-swapping.
When undershoot occurs, voltage potential reaches a level that can
turn on the NMOS FET or other parasitic bipolar elements.
• Fairchild’s proprietary UHC protects bus switches against this
phenomenon by comparing both ports of the NMOS switch relative
to ground when the device is disabled (i.e., OE is high). The result is a
fail-safe undershoot solution with no negative side effects, such as
increased power consumption, higher RON values or increased
enable/disable times.
UHC
N1
A(n)
B(n)
Undershoot Protection Effectiveness
Input
Undershoot Protection Effectiveness
(Actual Test Circuit Input
and Output Waveforms)
3.3V
0V
-2V
Outputs
3.3V
www.fairchildsemi.com
0V
-2V
Fairchild Switch w/ UHC exhibits no
signal degradation.
Bus Switch w/ Schottky Diode
Standard Bus Switch
Switch Packages
Packaging
TSSOP
56 Lead
SSOP
56 Lead
TSSOP
48 Lead
SSOP
48 Lead
TSSOP
24 Lead
QSOP
24 Lead
FST16211
FST16212
FST16213
FST16232
FST16233
FST16292
FST34170
FSTD16211
FSTD16450
FSTU32160
FSTU32160A
FSTUD16211
FSTUD16450
FST16211
FST16212
FST16213
FST16232
FST16233
FST16292
FST16209
FST16210
FST16861
FST162861
FST16209
FST3383
FST3384
FST6800
FSTU3384
FSTU6800
FST3383
FST3384
FST6800
FSTU3384
FSTU6800
SOIC
24 Lead
TSSOP
20 Lead
QSOP
20 Lead
SOIC JEDEC
20 Lead
TSSOP
16 Lead
QSOP
16 Lead
SOIC
16 Lead
TSSOP
14 Lead
FST3383
FST3384
FST6800
FSTU3384
FSTU6800
FST3244
FST3245
FST3345
FST3244
FST3245
FST3345
FST3244
FST3245
FST3345
FST3253
FST3257
FSTU3257
FST3125
FST3126
FST3253
FST3257
FSTU3257
FST3253
FST3257
FSTU3257
FST3125
FST3126
actual size
actual size
SOIC
14 Lead
TSSOP
8 Lead
US8
SC70
6 Lead
SOT23
5 Lead
SC70
5 Lead
BGA
114 Ball
BGA
54 Ball
FST3125
FST3126
FST3306
FSTD3306
NC7WB66
NC7WB3125
NC7WB3306
NC7WBD3125
NC7WBD3306
NC7SB3157
NC7SB3257
NC7SZ66
NC7SZ384
NC7SZD384
NC7SZ66
NC7SZ384
NC7SZD384
FST32211
FSTD32211
FSTUD32211
FST16211
FSTD16211
FSTD16450
FSTUD16211
FSTUD16450
actual size
New Space-Saving Packages—Ball Grid Array (BGA)
BGA’s smaller packaging and self-aligning contacts outperform current high-pin-count, leaded packages.
• 20- to 48-Bit Ball Grid Array solutions
• Ball size diameter of 0.5mm (0.35mm solder pads) and 0.8mm pitch
• Diode options available for 5V to 3V level conversion
• Surface-accessible for single-layer-accessible layouts
www.fairchildsemi.com
Switch Cross-Reference Chart
Switch Portfolio Cross-Reference Chart
Fairchild
FST3125
FST3126
FST3244
FST3245
FST3253
FST3257
FST3306
FST3345
FST3383
FST3384
FST6800
FST16209
FST16210
FST16211
FST16212
FST16213
FST16232
FST16233
FST16292
FST16861
FST32211
FST34170
FST162861
Tear Here
FSTD3306
FSTD16211
FSTD16450
FSTD32211
FSTU3257
FSTU3384
FSTU6800
FSTU32160
FSTU32160A
FSTUD16211
FSTUD16450
FSTUD32211
NC7SB3157
NC7SB3257
NC7SZ66
NC7SZ384
NC7SZD384
NC7WB66
NC7WB3125
NC7WB3306
NC7WBD3125
NC7WBD3306
Function
4-Bit Bus Switch
4-Bit Bus Switch
8-Bit Bus Switch
8-Bit Bus Switch
Dual 4:1 Multiplexer/Demultiplexer Bus Switch
Quad 2:1 Multiplexer/Demultiplexer Bus Switch
2-Bit Low-Power Bus Switch
8-Bit Bus Switch
10-Bit Bus Exchange Switch
10-Bit Bus Switch
10-Bit Bus Switch with Precharged Outputs
18-Bit Bus Exchange Switch
20-Bit Bus Switch
24-Bit Bus Switch
24-Bit Bus Exchange Switch
24-Bit Bus Exchange Switch
16- to 32-Bit Multiplexer/Demultiplexer Bus Switch
16- to 32-Bit Multiplexer/Demultiplexer Bus Switch
12- to 24-Bit Multiplexer/Demultiplexer Bus Switch
20-Bit Bus Switch
48-Bit Bus Switch
17- to 34-Bit Multiplexer/Demultiplexer Bus Switch
20-Bit Bus Switch with 25Ω
Series Resistors in Outputs
2-Bit Low-Power Bus Switch with Level Shifting
24-Bit Bus Switch with Level Shifting
Configurable 4- to 20-Bit Bus Switch with
Selectable Level Shifting (Preliminary)
40- to 48-Bit Bus Switch with Level Shifting (Preliminary)
Quad 2:1 Multiplexer/Demultiplexer Bus Switch
with -2V Undershoot Protection
10-Bit Bus Switch with -2V Undershoot Protection
10-Bit Bus Switch with Precharged Outputs and -2V
Undershoot Protection
16- to 32-Bit Multiplexer/Demultiplexer
Bus Switch with -2V Undershoot Protection
16- to 32-Bit Multiplexer/Demultiplexer
Bus Switch with -2V Undershoot Protection
24-Bit Bus Switch with Level Shifting
and -2V Undershoot Protection
Configurable 4- to 20-Bit Bus Switch with
Selectable Level Shifting (Preliminary)
40- to 48-Bit Bus Switch with -2V Undershoot Protection
and Level Shifting (Preliminary)
TinyLogic Low-Voltage UHS SPDT Analog Switch or
2:1 Multiplexer/Demultiplexer Bus Switch
TinyLogic UHS 2:1 Multiplexer/Demultiplexer Bus Switch
TinyLogic Low-Voltage UHS Single SPST Normally
Open Analog Switch or 1-Bit Bus Switch
TinyLogic UHS 1-Bit Low-Power Bus Switch
TinyLogic UHS 1-Bit Low-Power Bus Switch
with Level Shifting
TinyLogic Low-Voltage UHS Dual SPST Normally
Open Switch or 2-Bit Bus Switch
TinyLogic UHS 2-Bit Low-Power Bus Switch
TinyLogic UHS 2-Bit Low-Power Bus Switch
TinyLogic UHS 2-Bit Low-Power Bus Switch
with Level Shifting
TinyLogic UHS 2-Bit Low-Power Bus Switch
with Level Shifting
www.fairchildsemi.com
IDT
IDT74FST3125
IDT74FST3126
IDT74FST3244
IDT74FST3245
IDT74FST3253
IDT74FST3257
—
—
IDT74FST3383
IDT74FST3384
IDT74FST6800
IDT74FST163209
IDT74FST163210
IDT74FST163211
IDT74FST163212
—
IDT74FST163232
IDT74FST163233
—
IDT74FST163861
—
—
IDT74FST1632861
Pericom
PI5C3125
PI5C3126
PI5C3244
PI5C3245
PI5C3253
PI5C3257
PI5C3306
—
PI5C3383
PI5C3384
PI5C6800
PI5C16209
PI5C16210
PI5C16211
PI5C16212
PI5C16213
—
—
PI5C16292
PI5C16861
—
—
PI5C162861
Quality (IDT)
IDTQS3125
IDTQS3126
IDTQS3244
IDTQS3245
IDTQS3253
IDTQS3257
IDTQS3306A
—
IDTQS3L383
IDTQS3L384
—
IDTQS316209
—
IDTQS316211
IDTQS316212
IDTQS316213
—
IDTQS316233
IDTQS316292
IDTQS32X861
—
—
IDTQS32X2861
TI
SN74CBT3125
SN74CBT3126
SN74CBT3244
SN74CBT3245A
SN74CBT3253
SN74CBT3257
SN74CBT3306
SN74CBT3383
SN74CBT3384
SN74CBT6800
SN74CBT16209
SN74CBT16210
SN74CBT16211
SN74CBT16212
SN74CBT16213
SN74CBT16232
SN74CBT16233
SN74CBT16292
SN74CBT16861
—
—
—
—
—
—
—
—
—
—
—
—
SN74CBTD3306
SN74CBTD16211
—
—
—
—
—
—
—
—
—
—
—
—
—
—
PI5C3384C
PI5C6800C/
PI5C6801C
PI5C32160C
—
SN74CBTS3384
SN74CBTS6800
SN74CBTK6800
—
—
PI5C32160C
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
PI5C3301
—
—
—
SN74CBT1G384
SN74CBTD1G384
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
For complete product information and design support, contact the Fairchild sales office in your area.
Product Line
FST3125
FSTD3306
FST3126
FSTD16211
FST3244
FSTD16450
FST3245
FSTD32211
FST3253
FSTU3257
FST3257
FSTU3384
FST3306
FSTU6800
FST3345
FSTU32160
FST3383
FSTU32160A
FST3384
FSTUD16211
FST6800
FSTUD16450
FST16209
FSTUD32211
FST16210
NC7SB3157
FST16211
NC7SB3257
FST16212
NC7SZ66
FST16213
NC7SZ384
FST16232
NC7SZD384
FST16233
NC7WB66
FST16292
NC7WB3125
FST16861
NC7WB3306
FST32211
NC7WBD3125
FST34170
NC7WBD3306
Americas
Customer Response Center
Fairchild Semiconductor
222 West Las Colinas Boulevard
Suite 380
Irving, TX 75039
Tel: 888-522-5372
Fax: 972-910-8036
China
Fairchild Semiconductor
Hong Kong Ltd.
Shenzhen Representative Office
Room 3107, Shun Hing Square
Di Wang Commercial Centre
5002 Shen Nan Road East
Shenzhen, P.R.C. 518008
Tel: 86-755-246-2088
Fax: 86-755-246-2092
Fairchild Semiconductor
Hong Kong Ltd.
Shanghai Representative Office
Room 1110, Shanghai International
Trade Centre
No. 2200 Yan An (W) Road
Shanghai, P.R.C. 200335
Tel: 86-21-6208-4118
Fax: 86-21-6219-7799
Finland
Fairchild Semiconductor
Itakatu 3 D 213
FIN-00930 Helsinki
Finland
Tel: 358-9-3411266
Fax: 358-9-3411292
FST162861
Ordering Codes
FST X XXX X
Family
FST = Fairchild Switch
NC7xx = TinyLogic (for xx see below)
SB = Single Switch
X
France
Fairchild Semiconductor
Centre d’ Affairs “Le Parc de Massy”
Z.I. De la Bonde
1 bis, Rue Marcel Paul - Bat.B
F-91742 Massy Cedex
France
Tel: 33-1-6930-3696
Fax: 33-1-6930-3693
SZ = Single Gate Ultra-High-Speed CMOS
WB = Dual Switch
Feature Designation
D = Diode
U = Undershoot Protection
Device Type
Package Code
Germany
Fairchild Semiconductor GmbH
Oskar-von-Miller-Strasse 4e
D-82256 Fürstenfeldbruck
Germany
Tel: 49-8141-61020
Fax: 49-8141-6102-100
Hong Kong
Fairchild Semiconductor
Hong Kong Ltd.
19/F, CMG Asia Tower
The Gateway II
15 Canton Road
Tsimshatsui, Kowloon
Hong Kong
Tel: 852-2722-8338
Fax: 852-2722-8383
Italy
Fairchild Semiconductor Srl
Via Carducci, 125
20099 Sesto San Giovanni (MI)
Italy
Tel: 39-02-249111-1
Fax: 39-02-26263424
Fairchild Korea Semiconductor, Ltd.
Kumi Office
5th Floor Shinlim Building
447-2, Songjung-Dong,
Kumi, Kyoungsangbuk-Do,
Korea, 730-090
Tel: 82-546-457-4111
Fax: 82-546-457-4121
Mexico
Fairchild Semiconductor
Av. Vallarta #6503 Flr. 14
Col. Cd Granjas
Zapopan Jalisco 45010
Mexico
Tel: 52-3-1100017
Fax: 52-3-1101878
Japan
Fairchild Semiconductor Japan Ltd.
6F Bancho-Kaikan
12-1 Gobancho, Chiyoda-ku
Tokyo, 102-0076 Japan
Tel: 81-3-5275-8380
Fax: 81-3-5275-8390
Singapore
Fairchild Semiconductor
Asia Pacific Pte. Ltd.
350 Orchard Road
#20-01/03 Shaw House
Singapore 238868
Tel: 65-836-0936
Fax: 65-838-0321/3
Fairchild Semiconductor Japan Ltd.
Osaka Office
Shin-Osaka Meiko Building 8F
4-3-12, Miyahara, Yodogawa-ku
Osaka, 532-0003 Japan
Tel: 81-6-6398-3670
Fax: 81-6-6398-3680
Sweden
Fairchild Semiconductor
Industrivagen 7
SE-171 48 Solna
Sweden
Tel: 46-8-6515530
Fax: 46-8-6515505
Korea
Fairchild Korea Semiconductor, Ltd.
82-3, Dodang-Dong,
Wonmi-Ku, Puchon,
Kyunggi-Do, Korea, 420-711
Tel: 82-32-680-1926
Fax: 82-32-680-1949
Fairchild Korea Semiconductor, Ltd.
Suwon Office
6th Floor Song-i Building,
976-12,Youngtong-Dong,
Paldal-Ku, Suwon,
Kyunggi-Do, Korea, 442-470
Tel: 82-331-205-0291-8
Fax: 82-331-205-3352
Taiwan
Fairchild Semiconductor
Hong Kong Ltd. Taiwan Branch
16/F, No.167
Tun Hwa North Road
Taipei, Taiwan
Tel: 886-2-2712-0500
Fax: 886-2-2716-9285
UK
Fairchild Semiconductor Ltd.
10 Interface Business Park
Wootton Bassett
Swindon SN4 8SY
United Kingdom
Tel: 44-1793-856856
Fax: 44-1793-856857
G = Fine-Pitch Ball Grid Array (FBGA)
M = (0.150" wide) Molded Small-Outline Package
(SOIC), JEDEC
WM = (0.300" wide) Molded Small-Outline Package
(SOIC), JEDEC
MEA = Shrink Small-Outline Package
(SSOP 48/56-Lead), JEDEC
MTC = Thin Shrink Small-Outline Package
(TSSOP), 4.4mm body width, JEDEC
MTD = Thin Shrink Small-Outline Package
(TSSOP 48/56-Lead), 6.1mm body width, JEDEC
QSC = Quarter Size Outline Package
Visit our Web site at
www.fairchildsemi.com
(QSOP), JEDEC
M5 = SOT23 5 Lead
P5 = SC70 5 Lead
P6 = SC70 6 Lead
K8 = US8 8 Lead
Special Variations
“X” = Tape and Reel
The following are registered and unregistered trademarks Fairchild Semiconductor owns or is authorized to use and
is not intended to be an exhaustive list of all such trademarks: ACEx™, Bottomless™, CoolFET™, CROSSVOLT™,
E2CMOS™, EnSigna™, FACT™, FACT Quiet Series™, FAST®, FASTr™, GTO™, HiSeC™, ISOPLANAR™,
MICROWIRE™, POP™, PowerTrench®, QFET™, QS™, Quiet Series™, SuperSOT™-3, SuperSOT™-6, SuperSOT™-8,
SyncFET™, TinyLogic™, UHC™, VCX™.
“ ” = Rail/Tube
© 2001 Fairchild Semiconductor International
All Rights Reserved
Lit No. 585401-004
