Page 1
August 2001
Revised September 2001
FSTU3253
Dual 4:1 Multiplexer/Demultiplexer Bus Switch
with
−2V Undershoot Protection
FSTU3253 Dual 4:1 Multiplexer/Demultiplexer Bus Switch with
General Description
The Fairchild Switc h FSTU3253 is a dual 4:1 high-spe ed
CMOS TTL-compatible multiplexer/demultiplexer bus
switch. The low On Resistance of t he switch allows inputs
to be connected to outputs without adding propagation
delay or generating additional ground bounce noise.
When OE
selected B Port output. When OE
OPEN and a high-impedance sta te exist s between the two
ports.
The A and B Ports are protected against undershoot to
support an extended range to 2.0V below ground.
Fairchild’s integrated Undershoot Hardened Circuit
(UHC
preventing voltage differentials from developing and turning the switch on.
is LOW, S0 and S1 connect the A Port to the
is HIGH, the switch is
) senses undershoot at the I/O and responds by
Features
■ Undershoot hardened to −2.0V
Ω switch connection between two ports
■ 4
■ Minimal propagation delay through the switch
■ Low l
CC
■ Zero bounce in flow-through mode
■ Control inputs compatible with TTL level
■ See application no te AN-5008 and AN-502 1 for details
on undershoot
Ordering Code:
Order Number Package Number Package Description
FSTU3253M M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
FSTU3253QSC MQA16 16-Lead Quarter Size Outline Package (QSOP), JEDEC MO-137, 0.150" Wide
FSTU3253MTC MTC16 16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
Device also available in Tape and Reel. Specify by appending suffix letter “X” to the ordering code.
−
2V Undershoot Protection
© 2001 Fairchild Semiconductor Corporation DS500475 www.fairchildsemi.com
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Logic Diagram
FSTU3253
Connection Diagram
Pin Descriptions
Pin Name Description
OE
, OE
1
2
, S
S
0
1
ABus A
B
, B2, B3, B
1
4
Bus Switch Enables
Select Inputs
Bus B
Truth Table
S
S0OE1OE
1
X X H X Disconnect 1A
X X X H Disconnect 2A
LLLL A
LHLL A = B
HLLL A = B
HHL L A = B
2
Function
= B
1
2
3
4
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Page 3
Absolute Maximum Ratings(Note 1) Recommended Operating
Supply Voltage (VCC) −0.5V to +7.0V
DC Switch Voltage (V
DC Input Voltage (V
DC Input Diode Current (l
DC Output (I
DC V
OUT
/GND Current (ICC/I
CC
Storage Temperature Range (T
) −2.0V to +7.0V
S
) (Note 2) −0.5V to +7.0V
IN
) V
< 0V −50 mA
IK
IN
) Sink Current 128 mA
) +/− 100 mA
GND
) −65°C to +150 °C
STG
Conditions
Power Supply Operating (V
Input Voltage (V
Output Voltage (V
Input Rise and Fall Time (t
Switch Control Input 0 ns/V to 5 ns/V
Switch I/O 0 ns/V to DC
Free Air Operating Temperature (T
Note 1: The Absolute Maxi mum Ratings are thos e values beyond which
the safety of the d evice cannot b e guaranteed . The device sh ould not be
operated at these limit s. The parametric values defi ned in the Electrical
Characteristics tables are not guaranteed at the absolute maximum rating.
The Recomme nded Oper ating Co nditions ta bles will de fine the conditions
for actual device operation.
Note 2: The input and output negative voltage ratings may be exceeded if
the input and ou t put diode current ratings are observed.
Note 3: Unused control inputs must be held HIGH or LOW. They may not
float.
(Note 3)
CC)
) 0V to 5.5V
IN
) 0V to 5.5V
OUT
, tf)
r
) −40 °C to −85 °C
A
4.0V to 5.5V
DC Electrical Characteristics
V
Symbol Parameter
V
IK
V
IH
V
IL
I
I
I
OZ
R
ON
I
CC
∆ I
CC
V
IKU
Note 4: Typical values are at VCC = 5.0V and TA = +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.
Clamp Diode Voltage 4.5 −1.2 V IIN = −18 mA
High Level Input Voltage 4.0–5.5 2.0 V
Low Level Input Voltage 4.0–5.5 0.8 V
Input Leakage Current 5.5 ±1.0 µA0 ≤ VIN ≤ 5.5V
OFF-STATE Leakage Current 5.5 ±1.0 µA0 ≤ A, B ≤ V
Switch On Resistance 4.5 4 7 Ω VIN = 0V, IIN = 64 mA
(Note 5) 4.5 4 7 Ω V
Quiescent Supply Current 5.5 3 µAVIN = VCC or GND, I
Increase in I
Voltage Undershoot 5.5 −2.0 V 0.0 mA ≥ IIN ≥ −50 mA
per Input 5.5 2.5 mA One Input at 3.4V
CC
CC
(V)
010µAVIN = 5.5V
4.5 8 15 Ω VIN = 2.4V, IIN = 15 mA
4.0 11 20 Ω V
TA = −40 °C to +85 °C
Min Typ
(Note 4)
Units Conditions
Max
Other Inputs at V
OE = 5.5V
CC
= 0V, IIN = 30 mA
IN
= 2.4V, IIN = 15 mA
IN
or GND
CC
OUT
= 0
FSTU3253
3 www.fairchildsemi.com
Page 4
AC Electrical Characteristics
= −40 °C to +85 °C
T
A
C
= 50pF, RU = RD = 500Ω
Symbol Parameter
FSTU3253
t
, t
PHL
t
PZH
t
PHZ
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 s w it c h and the 50pF load capa citance, when drive n by an ideal voltage the s ource (zero output impedance).
Propagation Delay Bus to Bus (Note 6) 0.25 0.25
PLH
Propagation Delay, Select to Bus A 0.5 5.7 6.2
, t
Output Enable Time, Select to Bus B 0.5 5.7 6.3
PZL
Output Enable Time, I
, t
Output Disable Time, Select to Bus B 0.5 6.2 6.3
PLZ
Output Disable Time, I
to Bus A, B 0.5 4.9 5.4 VI = OPEN for t
OE
to Bus A, B 0.5 6.0 6.1 VI = OPEN for t
OE
L
= 4.5 – 5.5V VCC = 4.0V
V
CC
Min Max Min Max
Units Conditions
ns VI = OPEN
ns
ns
VI = 7V for t
VI = 7V for t
PZL Figures
PLZ Figures
PZH
PHZ
Capacitance (Note 7)
Symbol Parameter Typ Max Units Conditions
C
IN
C
I/O
Note 7: TA = +25°C, f = 1 MHz, Capacitance is characterized but not tested.
Control Pin Input Capacitance 3 pF VCC = 5.0V
A Port Input/Output Capacitance 13 pF
B Port 5 pF
, OE = 5.0V
V
CC
Undershoot Characteristic (Note 8)
Symbol Parameter Min Typ Max Units Conditions
V
OUTU
Note 8: This test is intended to characterize the device’s protective capabilities by ma intaining output signal integrity d uring an input tran sient voltage
undershoot event.
Output Voltage During Undershoot 2.5 VOH - 0.3 V Figure 1
Figure
Number
Figures
2, 3
2, 3
2, 3
FIGURE 1.
Device Test Conditions Transient
Parameter Value Units
V
R1 = R
V
TRI
V
CC
IN
see Waveform V
2
100K Ω
11.0 V
5.5 V
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Input Voltage (V
) Waveform
IN
Page 5
AC Loading and Waveforms
Note: Input driven by 50 Ω source terminated in 50 Ω
includes load and stray capacitance
Note: C
L
Note: Input PRR = 1.0 MHz, t
= 500 ns
W
FSTU3253
FIGURE 2. AC Test Circuit
FIGURE 3. AC Waveforms
5 www.fairchildsemi.com
Page 6
Physical Dimensions inches (millimeters) unless otherwise noted
FSTU3253
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
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Package Number MQA16
Page 7
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
FSTU3253 Dual 4:1 Multiplexer/Demultiplexer Bus Switch with
16-Lead Thin Shrin k Small Ou tlin e Pack age (TSSOP), JEDEC MO-153, 4.4mm Wide
Package Number MTC16
Technology Description
The Fairchild Switch family derives from and embodies Fairchild’s proven switch t echnology used for several years in it s
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 dev ic es or syste ms
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 provide d in the l abe ling, can be reasonably expected to result in a significant injury to the
user.
2. A critical compo nent in any com ponen t of a life s upp ort
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.
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7 www.fairchildsemi.com
−
2V Undershoot Protection
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