1
INDUSTRIAL TEMPERATURE RANGE
IDTQS3V245
3.3V HIGH SPEED BUS SWITCH
NOVEMBER 1999
1999 Integrated Device Technology, Inc.
DSC-5512/-
c
IDTQS3V245
INDUSTRIAL TEMPERATURE RANGE
QUICKSWITCH
PRODUCTS
3.3V HIGH SPEED BUS
SWITCH
DESCRIPTION:
FUNCTIONAL BLOCK DIAGRAM
The QS3V245 is an 8-bit high speed bus switch controlled by LVTTL-
compatible active low enable signal. When closed, the switches exhibit near
zero propagation delay without generating additional ground bounce or
switching noise.
The QS3V245 is specially designed for direct interface between 3.3V and
2.5V devices without any external components. When operating from a 3.3V
supply, the logic high level at the switch output is clamped to 2.5V when the
switch input signal exceeds 2.5V. This device can be used for switching 2.5V
buses without signal attenuation. The ON resistance at 3.3V V
CC
is less than
5
typical, providing near zero propagation delay through the switch.
Absence of DC path from switch I/O pins to V
CC
or ground makes QS3V245
an ideal device for hot swapping applications.
The QS3V245 is characterized for operation from -40
C to +85
C.
O E
A 0
B 0
A 1
B 1
A 2
B 2
A 3
B 3
A 4
B 4
A 5
B 5
A 6
B 6
A 7
B 7
1 9
2
3
4
5
6
7
8
9
1 8
1 7
1 6
1 5
1 4
1 3
1 2
1 1
APPLICATIONS:
3.3V to 2.5V Voltage Translation
2.5V to 1.8V Voltage Translation
PCI Bus Isolation Hot Swap
FEATURES:
5
bi-directional switches connect inputs to outputs
Pin Compatibility with QS3245
250ps Propagation Delay
Undershoot Clamp Diodes on all Switch and Control Inputs
LVTTL-Compatible Control Inputs
Available in SOIC (SO), QSOP and TSSOP
2
INDUSTRIAL TEMPERATURE RANGE
IDTQS3V245
3.3V HIGH SPEED BUS SWITCH
PIN CONFIGURATION
SOIC, QSOP AND TSSOP
TOP VIEW
FUNCTION TABLE
(1)
ABSOLUTE MAXIMUM RATING
(1)
Symbol
Description
Max.
Unit
V
TERM(2)
Supply Voltage to Ground
0.5 to 4.6
V
V
s
DC Switch Voltage
0.5 to
4.6
V
V
IN
DC Input Voltage
0.5 to 4.6
V
AC Input Voltage (For a pulse width
20ns)
3
V
DC Output Current Max. Sink Current/Pin
120
mA
Maximum Power Dissipation
0.5
W
T
STG
Storage Temperature
-65 to 150
C
QSlink
PIN DESCRIPTION
Pin Names
Description
OE
Output Enable
An
Data I/Os
Bn
Data I/Os
OE
Outputs
H
Disconnected
L
An = Bn
N C
A0
A2
A3
A7
A6
GN D
2
3
4
5
6
7
8
9
10
11
12
15
14
13
16
17
18
19
20
1
A1
A4
A5
OE
B1
V
C C
B6
B5
B 7
B0
B3
B4
B2
SO20-2
SO20-8
SO20-9
CAPACITANCE
(T
A
= +25
o
C, f = 1MHz, V
IN
= 0V, V
OUT
= 0V)
Symbol
Parameter
(1)
Conditions
Typ.
Max.
Unit
C
IN
Control Inputs
4
6
pF
CI/O
Quickswitch Channels
Switch OFF
5
7
pF
QSlink
NOTE:
1. As applicable to the device type.
NOTES:
1. Stresses greater than those listed under ABSOLUTE 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.
2. V
CC
terminals.
3
INDUSTRIAL TEMPERATURE RANGE
IDTQS3V245
3.3V HIGH SPEED BUS SWITCH
OUTPUT DRIVE CHARACTERISTICS
TA = 40C to +85C, VCC = 3.3V 0.3V
Symbol
Parameter
Test Conditions
(1)
Min.
Max.
Unit
I
CCQ
Quiescent Power Supply Current
V
CC
= Max., V
IN
= GND or V
CC
, f = 0
--
3
A
I
CC
Power Supply Current
(2)
per Input HIGH
V
CC
= Max., V
IN
= 3V or V
CC
, f = 0 per Control Input
--
50
A
I
CCD
Dynamic Power Supply Current per MHz
(3)
V
CC
= Max., A and B Pins Open, Control Input Toggling @ 50%
Duty Cycle
--
0.15
mA/MHz
QSlink
NOTES:
1. For conditions shown in Min. and Max., use the appropriate values specified under DC Specifications.
2. Per TTL driven input (V
IN
= 3V, Control Inputs only). A and B pins do not contribute to I
CC
.
3. This current applies to the control inputs only and represents 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 guaranteed, but not production tested.
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Following Conditions Apply Unless Otherwise Specified: T
A
= 40C to +85C, V
CC
= 3.3V
0.3V
Symbol
Parameter
Test Conditions
Min.
Typ.
(1)
Max.
Unit
V
IH
Input HIGH Voltage Level
Guaranteed Logic HIGH for Control Inputs
2
--
--
V
V
IL
Input LOW Voltage Level
Guaranteed Logic LOW for Control Inputs
--
--
0.8
V
I
IN
Input Leakage Current (Control Inputs)
0V
V
IN
V
CC
--
--
1
A
I
OZ
Off-State Current (Hi-Z)
0V
V
OUT
V
CC
, Switches OFF
--
0.001
1
A
R
ON
Switch ON Resistance
V
CC
= Min., V
IN
= 0V, I
ON
= 8mA
--
5
7
V
CC
= Min., V
IN
= 1.7V, I
ON
= 8mA
--
15
20
V
CC
= 2.3V, V
IN
= 0V, I
ON
= 8mA
--
7
--
V
CC
= 2.3V, V
IN
= 1.3V, I
ON
= 8mA
--
25
--
V
P
Pass Voltage
(2)
V
IN
=
V
CC
= 3.3V, I
OUT
= -5 A
2.5
2.7
2.9
V
V
IN
=
V
CC
= 2.5V, I
OUT
= -5 A
--
1.8
--
V
QSlink
NOTES:
1. Typical values are at V
CC
= 3.3V, +25C ambient.
2. Pass voltage is guaranteed, but not production tested.
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INDUSTRIAL TEMPERATURE RANGE
IDTQS3V245
3.3V HIGH SPEED BUS SWITCH
SWITCHING CHARACTERISTICS
(1)
TA = 40C to +85C, VCC = 3.3V 0.3V
Symbol
Parameter
Min
.
Typ.
Max.
Unit
t
PLH
t
PHL
Data Propagation Delay
(2, 3)
An to/from Bn
0.25
ns
t
PZL
t
PZH
Switch Turn-On Delay
OE to An/Bn
0.5
6.5
ns
t
PLZ
t
PHZ
Switch Turn-Off Delay
(2)
OE to An/Bn
0.5
4
ns
NOTES:
1. See test circuits and waveforms. Minimums guaranteed, but not production tested.
2. This parameter is guaranteed, but not production tested.
3. The bus switch contributes no propagation 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 CL = 30pF. Since this time constant is much smaller than the rise/fall times of typical
driving signals, it adds very little propagation delay to the system. Propagation 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.
14
0.5
1
1.5
2
2.5
V
IN
- (Volts)
R
ON
- (o
h
m
s
)
12
10
8
6
4
2
0
0.
16
TYPICAL ON RESISTANCE vs V
IN
AT V
CC
= 3.3V (QS3V245)
Figure. 1
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INDUSTRIAL TEMPERATURE RANGE
IDTQS3V245
3.3V HIGH SPEED BUS SWITCH
2 5 0
2 0 0
1 5 0
1 0 0
5 0
0
0
0 .5
1
1 .5
2
V
O U T
( V o lts )
IO
s
-
(
m
A
)
-2 5 0
-2 0 0
-1 5 0
-1 0 0
-5 0
1
2
3
4
V
O U T
( V o lts )
IO
s
-
(
m
A
)
-3 0 0
OUTPUT VI CHARACTERISTICS
Outputs Low Characteristic
Outputs High Characteristic
3
2.5
2
1.5
2.2
2.4
2.7
3
3.3
3.6
V
CC
(V)
V
OU
T
-
(
V
o
l
ts
)
V
O U T
= 2.5V @ V
C C
= 3.3V
V
O U T
= 1.8V @ V
C C
= 2.5V
PASS VOLTAGE vs V
CC
Figure. 2
Figure. 3
Figure. 4
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