Fairchild FST162245 service manual
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FST162245
FST162245 16-Bit Bus Switch with 25
April 2001
Revised April 2001
16-Bit Bus Switch with 25
General Description
The Fairchild Switch FST162245 provid es 16-bits of hig hspeed CMOS TTL-compatible bus switching. The low On
Resistance of the switch allows inputs to be connected to
outputs without adding propagation delay or generating
additional ground bounce noise.
The device is organized as a 16- bit switch. There are two
8-bit switches with separ ate output enable inputs. When
OE
is LOW, the switch is ON and Port a is connected to
Port B. When OE
impedance state exi sts between the A and B Po rts. The
FST162245 has an equivalent 25
reduce signal-reflection noise, eliminating the need for
external terminating resistors.
is HIGH, the switch is OFF an d a high
Ω series resistors to
Ω Series Resistors in Outputs
Features
■ 25Ω switch connection between two ports
■ Minimal propagation delay through the switch
■ Low l
CC
■ Zero bounce in flow-through mode
■ Control inputs compatible with TTL level
Ordering Code:
Order Number Package Number Package Description
FST162245MTD MTD48 48-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 6.1mm Wide
Devices also availab le in Tape and Reel. Specify by appending the suffix letter “X” to the o rdering code.
Connection Diagram
Logic Diagram
Ω
Series Resistors in Outputs
Pin Descriptions
Pin Name Description
OE
1A
1B
© 2001 Fairchild Semiconductor Corporation DS500431 www.fairchildsemi.com
n
, 2An, 3An, 4A
n
, 2Bn, 3Bn, 4B
n
NC No Internal Connection
Output Enable Input (Active LOW)
n
n
Bus A
Bus B
Truth Table
Inputs Outputs
OE
x
LA Port
H = HIGH Voltage Level L = LOW Voltage Level Z = High Impedance
HZ
A, B
= B Port
Absolute Maximum Ratings(Note 1) Recommended Operating
Supply Voltage (VCC) −0.5V to +7.0V
DC Switch Voltage (V
DC Input Voltage (V
FST162245
DC Input Diode Current (l
DC Output Current (I
DC V
/GND Current (ICC/I
CC
Storage Temperature Range (T
) (Note 2) −0.5V to +7.0V
S
) (Note 3) −0.5V to +7.0V
IN
) V
< 0V −50 mA
IK
IN
) 128 mA
OUT
) ±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 Maximum Ratings” are those values bey ond which
the safety of the d evice cannot be guaranteed. The device sh ould not be
operated at these limit s. The parametric values defin ed in the Electrical
Characteristics tables are not guaranteed at the absolute maximum rating.
The “Recomme nded O perat ing Co ndition s” table will defin e the condition s
for actual device operation.
is the volt age observed/applied at either t he A or B Port s across
Note 2: V
S
the switch.
Note 3: The input and output ne gative vo ltage ra tings may be excee ded if
the input and output diode current ratings are observed.
Note 4: Unused control inputs m ust be held HIGH o r LOW. They may no t
float.
(Note 4)
CC)
)0V to 5.5V
IN
)0V to 5.5V
OUT
, tf)
r
)-40 °C to +85 °C
A
DC Electrical Characteristics
TA = −40°C to +85°C
Symbol Parameter
V
IK
V
IH
V
IL
I
I
I
OZ
R
ON
I
CC
∆ I
Note 5: Typi c al values are at VCC = 5.0V and TA = +25°C
Note 6: Measured by the volta ge drop between A an d B pins at the indicated c urrent 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 20 26 38 Ω VIN = 0V, IIN = 64 mA
(Note 6) 4.5 20 27 40 Ω V
Quiescent Supply Current 5.5 3 µAVIN = VCC or GND, I
Increase in I
CC
per Input 5.5 2.5 mA One Input at 3.4V
CC
CC
(V) (Note 5)
0 ±10 µAV
4.5202848 Ω V
4.0203048 Ω VIN = 2.4V, IIN = 15 mA
Min Typ Max
Units ConditionsV
= 5.5V
IN
= 0V, IIN = 30 mA
IN
= 2.4V, IIN = 15 mA
IN
Other Inputs at VCC or GND
CC
4.0V to 5.5V
= 0
OUT
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