PI5C3257
QUAD 2:1 MUX/DEMUX BusSwitch
158
PS7018A 03/13/96
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Product Description:
Pericom Semiconductor's PI5C series of logic circuits are pro-
duced in the Company's advanced 0.8 micron CMOS technology,
achieving industry leading performance.
The PI5C3257 is a Quad 2:1 multiplexer/demultiplexer with three-
state outputs that is pinout and function compatible with the
PI74FCT257T, 74F257, and 74ALS/AS/LS257. Inputs can be
connected to outputs with low on resistance (5
) with no additional
ground bounce noise or propagation delay.
Logic Block Diagram
PI5C3257
Quad 2:1 MUX/DEMUX BusSwitch
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Product Features:
Near zero propagation delay
5
switches connect inputs to outputs
Direct bus connection when switches are ON
Ultra Low Quiescent Power (0.2A Typical)
Ideally suited for notebook applications
Pin compatible with 74 series 257 logic devices
Packages available:
16-pin 150 mil wide plastic QSOP (Q)
16-pin 300 mil wide plastic SOIC (S)
16-pin 150 mil wide plastic SOIC (W)
20-pin 150 mil wide plastic TSSOP (R)
16-Pin Product Configuration
20-Pin Product Configuration
Product Pin Description
Pin Name
Description
IAn-IDn
Data Inputs
S
Select Inputs
E
Enable
YA-YD
Data Outputs
GND
Ground
V
CC
Power
NC
No Connect
E
S
YA
YB
YC
YD
Function
H
X
Hi-Z Hi-Z Hi-Z Hi-Z
Disable
L
L
IA0
IB0
IC0
ID0
S = 0
L
H
IA1
IB1
IC1
ID1
S = 1
Truth Table
(1)
Note: 1. H = High Voltage Level
L = Low Voltage Level
E
IA
0
IA
1
IB
0
IB
1
IC
0
IC
1
ID
0
ID
1
S
YA
YB
YC
YD
V
CC
S
1
E
IA
0
2
ID
0
IA
1
3
ID
1
YA
4
YD
IB
0
5
16
IC
0
IB
1
6
15
IC
1
YB
7
14
YC
8
13
12
GND
11
10
9
16-PIN
V
CC
NC
1
E
S
2
ID
1
IA
0
3
ID
0
IA
1
4
YD
YA
5
20
IB
0
6
19
IC
0
IB
1
7
18
YC
8
17
16
GND
15
14
13
YB
9
10
NC
NC
12
11
NC
IC
1
20-PIN
R20
PI5C3257
QUAD 2:1 MUX/DEMUX BusSwitch
159
PS7018A 03/13/96
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Maximum Ratings
(Above which the useful life may be impaired. For user guidelines, not tested.)
Storage Temperature ................................................................. 55C to +125C
Ambient Temperature with Power Applied ................................. 40C to +85C
Supply Voltage to Ground Potential (Inputs & Vcc Only) .......... 0.5V to +7.0V
Supply Voltage to Ground Potential (Outputs & D/O Only) ....... 0.5V to +7.0V
DC Input Voltage ......................................................................... 0.5V to +7.0V
DC Output Current ................................................................................... 120 mA
Power Dissipation ......................................................................................... 0.5W
Note:
Stresses greater than those listed under
MAXIMUM RATINGS may cause permanent
damage to the device. This is a stress rating
only and functional operation of the device at
these or any other conditions above those
indicated in the operational sections of this
specification is not implied. Exposure to
absolute maximum rating conditions for
extended periods may affect reliability.
DC Electrical Characteristics
(Over the Operating Range, T
A
= 40C to +85C, V
CC
= 5V 5%)
Parameters Description
Test Conditions
(1)
Min.
Typ
(2)
Max.
Units
V
IH
Input HIGH Voltage
Guaranteed Logic HIGH Level
2.0
V
V
IL
Input LOW Voltage
Guaranteed Logic LOW Level
0.5
0.8
V
I
IH
Input HIGH Current
V
CC
= Max., V
IN
= V
CC
1
A
I
IL
Input LOW Current
V
CC
= Max., V
IN
= GND
1
A
I
OZH
High Impedance Output Current
0
I, Y
V
CC
1
A
V
IK
Clamp Diode Voltage
V
CC
= Min., I
IN
= 18 mA
0.7
1.2
V
I
OS
Short Circuit Current
(3)
I (Y) = 0V, Y (I) = V
CC
100
mA
V
H
Input Hysteresis at Control Pins
150
mV
R
ON
Switch On Resistance
(4)
V
CC
= Min., V
IN
= 0.0V, I
ON
= 48 mA
5
7
V
CC
= Min., V
IN
= 2.4V, I
ON
= 15 mA
10
15
Capacitance
(T
A
= 25C, f = 1 MHz)
Parameters
(5)
Description
Test Conditions
Typ
Max.
Units
C
IN
Input Capacitance
V
IN
= 0V
6
pF
C
OFF
In/Yn Capacitance, Switch Off
V
IN
= 0V
6
pF
C
ON
In/Yn Capacitance, Switch On
V
IN
= 0V
14
pF
Notes:
1. For Max. or Min. conditions, use appropriate value specified under Electrical Characteristics for the applicable device type.
2. Typical values are at Vcc = 5.0V, T
A
= 25C ambient and maximum loading.
3. Not more than one output should be shorted at one time. Duration of the test should not exceed one second.
4. Measured by the voltage drop between I and Y pin at indicated current through the switch. ON resistance is determined by the
lower of the voltages on the two (I,Y) pins.
5. This parameter is determined by device characterization but is not production tested.
PI5C3257
QUAD 2:1 MUX/DEMUX BusSwitch
160
PS7018A 03/13/96
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Power Supply Characteristics
Parameters Description
Test Conditions
(1)
Min.
Typ
(2)
Max.
Units
I
CC
Quiescent Power
V
CC
= Max.
V
IN
= GND or V
CC
0.1
3.0
A
Supply Current
I
CC
Supply Current per
V
CC
= Max.
V
IN
= 3.4V
(3)
2.5
mA
Input @ TTL HIGH
I
CCD
Supply Current per
V
CC
= Max.,
0.25
mA/
Input per MHz
(4)
I and Y Pins Open
MHz
BE = GND
Control Input Toggling
50% Duty Cycle
Notes:
1. For Max. or Min. conditions, use appropriate value specified under Electrical Characteristics for the applicable device.
2. Typical values are at Vcc = 5.0V, +25C ambient.
3. Per TTL driven input (V
IN
= 3.4V, control inputs only); I and Y pins do not contribute to Icc.
4. This current applies to the control inputs only and represent the current required to switch internal capacitance at the specified
frequency. The I and Y inputs generate no significant AC or DC currents as they transition. This parameter is not tested, but is
guaranteed by design.
Switching Characteristics over Operating Range
PI5C3257
C o m .
Parameters
Description
Conditions
(1)
Min
Max
Unit
t
IY
Propagation Delay
(2,3)
C
L
= 50 pF
0.25
ns
In to Yn
R
L
= 500
t
SY
Bus Select Time
0.5
5.2
ns
Sn to Yn
t
PZH
Bus Disable Time
0.5
4.8
ns
t
PZL
E to Yn
t
PHZ
Bus Disable Time
0.5
5.0
ns
t
PLZ
E to Yn
Notes:
1. See test circuit and wave forms.
2. This parameter is guaranteed but not tested on Propagation Delays.
3. The bus switch contributes no propagational delay other than the RC delay of the ON resistance of the switch and the load
capacitance. The time constant for the switch alone is of the order of 0.25 ns for 50 pF load. Since this time constant is much
smaller than the rise/fall times of typical driving signals, it adds very little propagational delay to the system. Propagational delay
of the bus switch when used in a system is determined by the driving circuit on the driving side of the switch and its interaction
with the load on the driven side.
Pericom Semiconductor Corporation
2380 Bering Drive San Jose, CA 95131 1-800-435-2336 Fax (408) 435-1100 http://www.pericom.com
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