1
PS8512 03/14/01
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4-Bit BusSwitch with
2V Undershoot Protection
Product Description
Pericom Semiconductors PI5C series of logic circuits are produced
using the Companys advanced submicron CMOS technology,
achieving industry leading performance.
The PI5C3125C and PI5C3126C are 5V, 4-bit, 2-port bus switches.
They are intended for PCI Hot-Plug applications. Industry leading
advantages include a propagation delay of 250ps, resulting from its
5-ohm channel resistance and low I/O capacitance. The A-ports
switch data to B outputs and are bidirectional. The PI5C3125C
device has active LOW enables, and the PI5C3126C has active HIGH
enables.
The A-port can handle up to 2V undershoot when the switch is
disabled.
Product Features
R
ON
is 5ohm typical
Undershoot protection on A port only: 2V
Direct bus connection when switches are ON
Industrial Operation Temperature: 40C to +85C
Near zero propagation delay
Low Channel ON Capacitance: 14pF max.
Packages available:
14-pin 173 mil wide plastic TSSOP (L)
14-pin 150 mil wide plastic SOIC (W)
16-pin 150 mil wide plastic QSOP (Q)
PI5C3125C Logic Block Diagram
PI5C3126C Logic Block Diagram
BE0
A0
B0
BE1
A1
B1
BE2
A2
B2
BE3
A3
B3
BE0
A0
B0
BE1
A1
B1
BE2
A2
B2
BE3
A3
B3
PI5C3125C
PI5C3126C
Applications
PCI Hot Plugging for live insertion
Memory bank sharing
2
PS8512 03/14/01
PI5C3125C/3126C
4-Bit Bus Switch with
2V Undershoot Protection
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PI5C3125C PI5C3126C
BEn
BEn
An
Bn
V
CC
Function
X*
X
Hi-Z
Hi-Z GND
Disconnect
H
L
Hi-Z
Hi-Z
V
CC
Disconnect
L
H
Bn
An
V
CC
Connect
PI5C3125 14-Pin Configuration
PI5C3126 14-Pin Configuration
PI5C3125 16-Pin Configuration
PI5C3126 16-Pin Configuration
Product Pin Description
Pin Name
Description
BEn
Switch Enable (PI5C3125C)
BEn
Switch Enable (PI5C3126C)
A3-A0
Bus A
B3-B0
Bus B
V
CC
Power
GND
Ground
Truth Table
(1)
Notes:
1. H = High Voltage Level, L = Low Voltage Level
HI-Z = High Impedance, X = Dont Care
* A pull-up resistor should be provided for power-up protection.
Storage Temperature ........................................................... 65C to +150C
Ambient Temperature with Power Applied ............................ 40C to +85C
Supply Voltage to Ground Potential (Inputs & V
CC
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 reliability.
Maximum Ratings
(Above which the useful life may be impaired. For user guidelines, not tested.)
14-Pin
L,W
1
2
3
4
5
6
7
14
13
12
11
10
9
8
Vcc
BE3
A3
B3
BE2
A2
B2
BE0
A0
B0
BE1
A1
B1
GND
1
2
3
4
5
6
7
14
13
12
11
10
9
8
Vcc
BE3
A3
B3
BE2
A2
B2
BE0
A0
B0
BE1
A1
B1
GND
14-Pin
L,W
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
Vcc
BE3
A3
B3
BE2
A2
B2
NC
NC
BE0
A0
B0
BE1
A1
B1
GND
16-Pin
Q
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
Vcc
BE3
A3
B3
BE2
A2
B2
NC
NC
BE0
A0
B0
BE1
A1
B1
GND
16-Pin
Q
PI5C3125C/3126C
4-Bit Bus Switch with
2V Undershoot Protection
3
PS8512 03/14/01
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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
100
A
Supply Current
I
CC
Supply Current per
V
CC
= Max.
V
IN
= 3.4V
(3)
2.5
mA
Input @ TTL HIGH
DC Electrical Characteristics
(Over the Operating Range, T
A
= 40C to +85C, V
CC
= 5V 10%)
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
A, B
V
CC
1
A
V
IK
Clamp Diode Voltage
V
CC
= Min., I
IN
= 18mA
1.8
V
V
UP
Undershoot Protection Voltage
(3)
Max Inputs, Undershoot Pulse
2.0
V
Duration <25ns
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
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); A and B 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 A and B inputs generate no significant AC or DC currents as they transition. This parameter is not tested, but is guaranteed
by design.
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
A/B Capacitance, Switch Off
V
IN
= 0V
6
pF
C
ON
A/B Capacitance, Switch On
V
IN
= 0V
8
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 A and B pin at indicated current through the switch. ON resistance is determined by the
lower of the voltages on the two (A, B) pins.
5. This parameter is determined by device characterization but is not production tested.
4
PS8512 03/14/01
PI5C3125C/3126C
4-Bit Bus Switch with
2V Undershoot Protection
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PI5C3125C Switching Characteristics over Operating Range
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 0.25ns 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.
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=
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6
PI5C3126C Switching Characteristics over Operating Range
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6
Applications Information
Logic Inputs
The logic control inputs can be driven up to +5.5V regardless of the
supply voltage. For example, given a +5.0V supply, BE, maybe driven
LOW to 0V and HIGH to 5.5V. Driving BE Rail-to-Rail
minimizes
power consumption.
Power-Supply Sequencing
Proper power-supply sequencing is recommended for all CMOS
devices. Always apply Vcc before applying signals to the input/
output or control pins.
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
PI5C3125C/3126C
4-Bit Bus Switch with
2V Undershoot Protection
5
PS8512 03/14/01
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.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
SEATING PLANE
.050
BSC
1
14
x 45
0-8
.149
.157
X.XX
X.XX
DENOTES DIMENSIONS
IN MILLIMETERS
3.78
3.99
.336
.344
8.55
8.75
.0155
.026
0.393
0.660
1.27
.053
.068
1.35
1.75
.2284
.2440
5.80
6.20
.013
.020
0.330
0.508
.0040
.0098
0.10
0.25
.0099
.0196
0.25
0.50
.0075
.0098
0.19
0.25
.016
.050
0.41
1.27
REF
14-Pin SOIC (W)
16-Pin QSOP (Q)
6
PS8512 03/14/01
PI5C3125C/3126C
4-Bit Bus Switch with
2V Undershoot Protection
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14-Pin TSSOP (L)
0.193
0.201
0.047
0.002
0.006
SEATING
PLANE
0.0256
typical
0.018
0.030
0.004
0.008
0.240
0.264
1
14
0.169
0.177
X.XX
X.XX
DENOTES DIMENSIONS
IN MILLIMETERS
0.05
0.15
6.1
6.7
0.45
0.75
0.09
0.20
4.3
4.5
1.20
max.
4.90
5.10
0.65
0.19
0.30
0.007
0.012
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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