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PS8145 11/07/97
Product Description
Pericom Semiconductor's PI5C series of logic circuits are produced
in the Company's advanced 0.8 micron CMOS technology, achieving
industry leading performance.
The PI5C32244 features a set of eight bus switches which is pinout
and function compatible with the PI74FCT244T, 74F244, and
74ALS/AS/LS 244 8-bit drivers. Two enable signals (BEn) turn the
switches on similar to the enable signals of the 244. The bus switch
creates no additional propagation delay or ground bounce noise.
The device has a built-in 25
resistor to reduce noise resulting from
reflections, thus eliminating the need for an external terminating
resistor.
BE
1
BE
2
1A, 1B
2A, 2B
H
H
Disconnect
Disconnect
L
H
1A = 1B
Disconnect
H
L
Disconnect
2A = 2B
L
L
1A = 1B
2A = 2B
Truth Table
(1)
Logic Block Diagram
Product Pin Description
Pin Name
Description
BEn
Bus Output Enable (Active LOW)
A
0
-A
3
Bus A
B
0
-B
3
Bus B
GND
Ground
V
CC
Power
Product Pin Configuration
PI5C32244
8-bit, 2-Port BusSwitch
with 25
Series Resistor
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Product Features
Near zero propagation delay
25
series resistor termination
Direct bus connection when switches are ON
Ultra Low Quiescent Power (0.2A Typical)
Ideally suited for notebook applications
Pin compatible with 74 Series 244 logic devices
Packages available:
20-pin 150 mil wide plastic QSOP (Q)
Note: 1. H = High Voltage Level
L = Low Voltage Level
1B
0
1A
0
1B
1
1A
1
1B
2
1A
2
1B
3
1A
3
BE
1
2B
0
2A
0
2B
1
2A
1
2B
2
2A
2
2B
3
2A
3
BE
2
V
CC
BE
1
1
20
BE
2
2
19
1
B
0
1
A
0
3
18
2
A
3
2
B
3
4
17
1
B
1
1
A
1
5
16
2
A
2
2
B
2
6
15
1
B
2
1
A
2
7
14
2
A
1
2
B
1
8
13
1
B
3
1
A
3
9
12
2
A
0
2
B
0
10
11
GND
20-PIN
Q
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PS8145 11/07/97
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PI5C32244
8-Bit, 2-Port B
US
S
WITCH
with 25
Series Resistor
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
A, B
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)
A (B) = 0V, B (A) = V
CC
100
m A
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
18
28
40
V
CC
= Min., V
IN
= 2.4V, I
ON
= 15 mA
18
35
48
Maximum Ratings
(Above which the useful life may be impaired. For user guidelines, not tested.)
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 .............................................................................. 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 condi-
tions above those indicated in the operational
sections of this specification is not implied. Expo-
sure to absolute maximum rating conditions for
extended periods may affect reliability.
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 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 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.
PI5C32244
8-Bit, 2-Port B
US
S
WITCH
with 25
Series Resistor
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1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
PI5C32244
Com.
Parameters
Description
Conditions
(1)
Min
Max
Unit
t
PLH
Propagation Delay
(2,3)
C
L
= 50 pF
2
ns
t
PHL
Ax to Bx
R
L
= 500
t
PZH
Bus Enable Time
1.5
5.6
ns
t
PZL
BE
X
to Ax or Bx
t
PHZ
Bus Disable Time
1.5
5.2
ns
t
PLZ
BE
X
to Ax or Bx
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)
A and B Pins Open
MHz
BE
1
or BE
2
= GND
Control Input Toggling
50% Duty Cycle
Notes:
1. For conditions shown as Max. or Min., 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); A and B 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 A and B 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
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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