1
PS7018B 03/17/00
Product Description
Pericom Semiconductors PI5C series of logic circuits are produced
using the Companys advanced submicron 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 Ohms) 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
5ohm 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)
16-pin 173 mil wide plasticTSSOP (L)
20-pin 150 mil wide plastic TSSOP (R)
16-Pin Product Configuration
20-Pin Product Configuration
Product Pin Description
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
IA0
2
ID0
IA1
3
ID1
YA
4
YD
IB0
5
16
IC0
IB1
6
15
IC1
YB
7
14
YC
8
13
12
GND
11
10
9
16-Pin
L, Q,
S, W
V
CC
NC
1
E
S
2
ID1
IA0
3
ID0
IA1
4
YD
YA
5
20
IB0
6
19
IC0
IB1
7
18
YC
8
17
16
GND
15
14
13
YB
9
10
NC
NC
12
11
NC
IC1
20-Pin
R
Pin Name
Description
IAn-IDn
Data Inputs
S
Select Inputs
E
Enable
YA-YD
Data Outputs
GND
Ground
V
CC
Power
NC
No Connect
PI5C3257
Quad 2:1 Mux/Demux BusSwitch
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PS7018B 03/17/00
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Storage Temperature ............................................................ 65C to +150C
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 .............................................................................. 120mA
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 specifica-
tion is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect reli-
ability.
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
= 48mA
5
7
ohm
V
CC
= Min., V
IN
= 2.4V, I
ON
= 15mA
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 V
CC
= 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.
Maximum Ratings
(Above which the useful life may be impaired. For user guidelines, not tested.)
PI5C3257
Quad 2:1 Mux/Demux BusSwitch
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PS7018B 03/17/00
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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
DI
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 V
CC
= 5.0V, +25C ambient.
3. Per TTL driven input (V
IN
= 3.4V, control inputs only); I and Y pins do not contribute to I
CC
.
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
Com.
Parameters Description
Conditions
(1)
Min.
Max. Units
t
IY
Propagation Delay
(2,3)
C
L
= 50 pF
0.25
In to Yn
R
L
= 500ohm
t
SY
Bus Select Time
0.5
5.2
ns
Sn to Yn
t
PZH
Bus Disable Time
0.5
4.8
t
PZL
E to Yn
t
PHZ
Bus Disable Time
0.5
5.0
t
PLZ
E to Yn
Notes:
1. See test circuit and waveforms.
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 0.25ns for 50pF 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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