1
PS8758A 02/24/05
Pin Description
Pin Name
Description
I
A
N
-
I
D
N
Data Inputs
S
Select Inputs
E
Enable
Y
A
-Y
D
Data Outputs
GND
Ground
V
CC
Power
NC
No Connect
Description
Pericom Semiconductor's PI3B3257A is a 3.3 Volt, 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.
Block Diagram
PI3B3257A
3.3V, Quad 2:1 Mux/DeMux NanoSwitch
TM
Features
Near-Zero propagation delay
5 switches connect inputs to outputs
Fast Switching Speed: 4.8ns max.
Ultra-Low Quiescent Power: 0.1A typical
Ideally suited for notebook applications
Pin compatible with 74 series 257 logic devices
Packaging (Pb-free & Green avaliable):
16-pin 150 mil wide plastic QSOP (Q)
Pin Configuration
Note:
1. H = High Voltage Level
L = Low Voltage Level
E
I
A
0
I
A
1 I
B
0 I
B
1 I
C
0 I
C
1 I
D
0 I
D
1
S
Y
A
Y
B
Y
C
Y
D
I
Y
E
SW
SW
SW
SW
SW
SW
SW
SW
SW
Truth Table
(1)
E
S
Y
A
Y
B
Y
C
Y
D
Function
H
X
Hi-Z Hi-Z
Hi-Z
Hi-Z Disable
L
L
I
A
0
I
B
0
I
C
0
I
D
0
S = 0
L
H
I
A
1
I
B
1
I
C
1
I
D
1
S = 1
V
CC
S
1
E
I
A
0
2
I
D
0
I
A
1
3
I
D
1
Y
A
4
Y
D
I
B
0
5
16
I
C
0
I
B
1
6
15
I
C
1
Y
B
7
14
Y
C
8
13
12
GND
11
10
9
2
PS8758A 02/24/05
PI3B3257A
3.3V, Quad 2:1 Mux/DeMux NanoSwitch
TM
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
= 3.3V, T
A
= 25C ambient and maximum loading.
3. 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.
4. This parameter is determined by device characterization but is not production tested.
Storage Temperature .....................................................................65C to +150C
Ambient Temperature with Power Applied ....................................40C to +85C
Supply Voltage to Ground Potential.................................................0.5V to +4.6V
DC Input Voltage .............................................................................0.5V to +4.6V
DC Output Current........................................................................................ 120mA
Power Dissipation ............................................................................................ 0.5W
Note:
1. 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.
Maximum Ratings
(Above which the useful life may be impaired. For user guidelines, not tested.)
DC Electrical Characteristics
(Over the Operating Range, T
A
= 40C to +85C, V
CC
= 3.3V 10%)
Parameters
Description
Test Conditions
(1)
Min. Typ.
(2)
Max. Units
V
IH
Input HIGH Voltage
Guaranteed Logic HIGH Level
2
V
V
IL
Input LOW Voltage
Guaranteed Logic LOW Level
0.5
0.8
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
I
OZH
High Impedance Output Current
0 In, Yn V
CC
1
V
IK
Clamp Diode Voltage
V
CC
= Min., I
IN
= 18mA
1.2
V
R
ON
Switch On-Resistance
(3)
V
CC
= Min., V
IN
= 0.0V,
Ion = 48mA or 64mA
5
7
V
CC
= Min., V
IN
= 2.4V, I
ON
= 15mA
8
17
Capacitance
(T
A
= 25C, f = 1 MHz)
Parameters
Description
Test Conditions
Typical
Units
C
IN
Input Capacitance
V
IN
= 0V
2
pF
C
OFFYN
Y
N
Capacitance, Switch OFF
7.5
C
OFFIN
I
N
Capacitance, Switch OFF
4.0
C
ON
I
N
/Y
N
Capacitance, Switch ON
11
3
PS8758A 02/24/05
PI3B3257A
3.3V, Quad 2:1 Mux/DeMux NanoSwitch
TM
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
= 3.3V, +25C ambient.
3. Per TTL driven input (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.
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
switch's time constant 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.
Power Supply Characteristics
Parameters
Description
Test Conditions
(1)
Min. Typ.
(2)
Max. Units
I
CC
Quiescent Power Supply Current
V
CC
= Max.
V
IN
= GND or V
CC
0.1
3.0
A
I
CC
Supply Current per Input @ TTL
HIGH
(3, 4)
V
CC
= Max.
V
IN
= 3.0
750
Switching Characteristics Over Operating Range
Parameters
Description
Conditions
(1)
Com.
Units
Min.
Max.
t
IY
Propagation Delay In to Yn
(2,3)
C
L
= 50pF
R
L
= 500
0.25
ns
t
SY
Bus Select Time, Sn to Yn
1
4.5
t
PZH
t
PZL
Bus Enable Time, E to Yn
1
4.5
t
PHZ
t
PLZ
Bus Disable Time, E to Yn
1
4.8
Applications Information
Logic Inputs
The logic control inputs can be driven up to +3.6V regardless of the supply voltage. For example, given a + 3.3V supply, IN may be
driven low to 0V and high to 3.6V. Driving IN Rail-to-Rail minimizes power consumption.
Power-Supply Sequencing and Hot-Plug Information
Proper power-supply sequencing is recommended for all CMOS devices. Always apply V
CC
and GND before applying signals to
input/output or control pins.
Rail-to-Rail is a registeredtrademark of Nippon Motorola, Ltd.
4
PS8758A 02/24/05
PI3B3257A
3.3V, Quad 2:1 Mux/DeMux NanoSwitch
TM
.189
.197
.053
.069
.004
.010
SEATING
PLANE
.025
BSC
.007
.010
.228
.244
1
16
.150
.157
.016
.050
X.XX
X.XX
DENOTES DIMENSIONS IN MILLIMETERS
0.635
4.80
5.00
1.35
1.75
5.79
6.19
0.101
0.254
.008
.012
0.203
0.305
3.81
3.99
0.178
0.254
0.38
0.41
1.27
.008
0.203
.015 x 45
REF
Detail A
Detail A
.008
0.20
MIN.
Guage Plane
.010
0.254
.041
1.04
REF
.016
.035
0.41
0.89
0-6
.008
.013
0.20
0.33
Packaging Mechanical: 16-Pin QSOP (Q)
Notes:
1. Thermal characteristics can be found on the company web site at www.pericom.com/packaging/
Ordering Information
Ordering Code
Packaging Code
Package Description
PI3B3257AQ
Q
16-pin 150-mil wide plastic QSOP
PI3B3257AQE
Q
Pb-Free & Green, 16-pin 150-mil wide plastic QSOP
Pericom Semiconductor Corporation 1-800-435-2336 Fax (408) 435-1100 www.pericom.com
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