IDTQS3388Q [IDT]
QUICKSWITCH PRODUCTS HIGH-SPEED CMOS BUS EXCHANGE SWITCH WITH ACTIVE TERMINATION(BUS HOLD); 快速切换产品高速CMOS总线交换器与有源终端（ BUS HOLD ）开关
| 型号： | IDTQS3388Q |
| 厂家： | 
INTEGRATED DEVICE TECHNOLOGY |
| 描述： | QUICKSWITCH PRODUCTS HIGH-SPEED CMOS BUS EXCHANGE SWITCH WITH ACTIVE TERMINATION(BUS HOLD) |
| 文件： | 总6页 (文件大小：54K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
QUICKSWITCH® PRODUCTS
IDTQS3388
HIGH-SPEED CMOS BUS EXCHANGE
SWITCH WITH ACTIVE TERMINATION
(BUS HOLD)
FEATURES:
DESCRIPTION:
• Enhanced N channel FET with no inherent diode to Vcc
• 5Ω bidirectional switches connect inputs to outputs
• Active termination drives bus pins to rails when switches are
off
The QS3388 provides ten high-speed CMOS TTL-compatible bus
switches with active terminators on the bus switch I/O pins. The low ON
resistance(5Ω)ofthe3388allowsinputstobeconnectedtooutputswithout
addingpropagationdelayandwithoutgeneratingadditionalgroundbounce
noise.Whentheswitchesareturnedoff,alowdriveactiveterminatorcircuit
drivesthedisconnectedpinstoVCC orground,awayfromtheTTLthreshold.
This prevents undriven buses from floating. The Bus Enable (BE) signal
turnstheswitcheson. TheBusExchange(BX)signalprovidesnibbleswap
oftheABandCDpairsofsignals. Thisexchangeconfigurationallowsbyte
swapping of buses in systems. It can also be used as a five-wide 2-to-1
multiplexer and to create low delay barrel shifters, etc.
• Zero propagation delay, zero added ground bounce
• Undershoot clamp diodes on all switch and control inputs
• Bus exchange allows nibble swap
• TTL-compatible input and output levels
• Bus-hold eliminates floating bus lines and reduces static
power consumption
• Available in QSOP package
The QS3388 is characterized for operation at -40°C to +85°C.
APPLICATIONS:
• Resource sharing
• Crossbar switching
• Last value latch (graphics and DSP)
FUNCTIONALBLOCKDIAGRAM
C0
A0
R
T
T
T
T
T
=
T
D0
C4
D4
B0
A4
T
T
T
B4
BX
BE
TheIDTlogoisaregisteredtrademarkofIntegratedDeviceTechnology,Inc.
INDUSTRIAL TEMPERATURE RANGE
APRIL 2000
1
c
2000 Integrated Device Technology, Inc.
DSC-5765/1
IDTQS3388
INDUSTRIALTEMPERATURERANGE
HIGH-SPEEDCMOSBUSEXCHANGESWITCHWITHACTIVETERMINATION
PINCONFIGURATION
ABSOLUTEMAXIMUMRATINGS(1)
Symbol
Description
Supply Voltage to Ground
DC Switch Voltage VS
Max
–0.5 to +7
–0.5 to +7
–0.5 to +7
–3
Unit
V
(2)
VTERM
(3)
VTERM
V
1
24
23
VCC
D4
B4
A4
C4
D3
B3
A3
C3
D2
B2
BX
BE
(3)
VTERM
DC Input Voltage VIN
V
2
C0
A0
VAC
AC Input Voltage (pulse width ≤20ns)
DC Output Current
V
3
22
21
20
19
18
17
16
15
14
13
IOUT
PMAX
TSTG
120
mA
W
4
Maximum Power Dissipation (TA = 85°C)
Storage Temperature
0.5
B0
–65 to +150
°C
5
D0
NOTES:
6
C1
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. VCC terminals.
3. All terminals except VCC .
7
A1
8
B1
9
D1
10
11
12
C2
A2
CAPACITANCE (TA = +25°C, f = 1MHz, VIN = 0V, VOUT = 0V)
GND
Pins
Typ.
Max.(1)
Unit
ControlInputs
3
5
5
7
pF
QSOP
TOP VIEW
Quickswitch Channels (Switch OFF)
pF
NOTE:
1. This parameter is guaranteed but not production tested.
PINDESCRIPTION
Pin Names
A0 - A4, B0 - B4
C0 - C4, D0 - D4
BE
I/O
I/O
I/O
I
Description
A and B Buses
C and D Buses
Bus Switch Enable
Bus Exchange
BX
I
FUNCTIONTABLE(1)
BE
BX
A0 - A4
B0 - B4
Hi-Z
Function
Disconnect
Connect
H
X
Hi-Z
L
L
C0 - C4
D0 - D4
D0 - D4
C0 - C4
L
H
Exchange
NOTE:
1. H = HIGH Voltage Level
L = LOW Voltage Level
X = Don't Care
Z = High-Impedance
2
IDTQS3388
INDUSTRIALTEMPERATURERANGE
HIGH-SPEEDCMOSBUSEXCHANGESWITCHWITHACTIVETERMINATION
DCELECTRICALCHARACTERISTICSOVEROPERATINGRANGE
FollowingConditionsApplyUnlessOtherwiseSpecified:
Industrial: TA = –40°C to +85°C, VCC = 5V ± 5%
Symbol
Parameter
Input HIGH Voltage
Test Conditions
Min.
Typ.(1) Max.
Unit
VIH
Guaranteed Logic HIGH for Control Pins
2
—
—
V
VIL
IIN
InputLOWVoltage
GuaranteedLogicLOWforControlPins
0V ≤ VIN ≤ Vcc
Vcc = Min., VIN = 0V, ION = 30mA
Vcc = Min., VIN = 2.4V, ION = 15mA
Vcc = Max., VIN = 0V or Vcc
Vcc = Max., 0.8V < VIN < 2V
—
—
—
—
—
—
—
.01
6
0.8
±1
V
InputLeakageCurrent(ControlInputs)
Switch ON Resistance
µA
Ω
RON
8
12
—
—
17
IBH
InputCurrent(2)
Switch Pins
±20
±500
µA
µA
IBHH
IBHL
Bus Hold Sustaining Source Current - HIGH(3) Vcc = Min., VIN = 2V
Bus Hold Sustaining Sink Current - LOW(4)
Vcc = Min., VIN = 0.8V
– 60
+ 60
—
—
—
—
NOTES:
1. Typical values are at VCC = 5.0V, TA = 25°C.
2. Input current specified under two conditions:
a) Input voltage at GND or Vcc. This indicates the input current under steady-state condition.
b) Input voltage between 0.8V and 2V (TTL input threshold range). This indicates the maximum input current during transient condition. The driver connected to the input
must overcome this current requirement in order to switch the logic state of the bus-hold circuit.
3. IBHH represents the latching capability of the bus-hold circuit in logic HIGH state.
4. IBHL represents the latching capability of the bus-hold circuit in logic LOW state.
IN
CC
TYPICAL ON RESISTANCE vs V AT V = 5V
16
14
RON
(ohms)
12
10
8
6
4
2
0
1.5
2.0
2.5
3.0
3.5
1.0
0.0
0.5
VIN
(Volts)
3
IDTQS3388
INDUSTRIALTEMPERATURERANGE
HIGH-SPEEDCMOSBUSEXCHANGESWITCHWITHACTIVETERMINATION
POWERSUPPLYCHARACTERISTICS
Symbol
ICCQ
Parameter
TestConditions(1)
VCC = Max., VIN = GND or VCC, f = 0
VCC = Max., VIN = 3.4V, f = 0
Max.
1.5
Unit
mA
Quiescent Power Supply Current
Power Supply Current per Input HIGH(2)
∆ICC
2.5
mA
ICCD
Dynamic Power Supply Current per MHz (3) VCC = Max., A - D Pins Open, Control Inputs Toggling @ 50% Duty Cycle
0.25
mA/MHz
NOTES:
1. For conditions shown as Min. or Max., use the appropriate values specified under DC Electrical Characteristics.
2. Per TTL-driven input (VIN = 3.4V, control inputs only). A - D pins do not contribute to ∆Icc.
3. This current applies to the control inputs only and represents the current required to switch internal capacitance at the specified frequency. The A-D inputs generate no significant
AC or DC currents as they transition. This parameter is guaranteed but not production tested.
SWITCHINGCHARACTERISTICSOVEROPERATINGRANGE
TA = -40°C to +85°C, VCC = 5V ± 5%
CLOAD = 50pF, RLOAD = 500Ω unless otherwise noted.
(1)
Symbol
Parameter
Min.
Typ.
Max.
Unit
tPLH
tPHL
DataPropagationDelay(2)
AxBx to CxDx, CxDx to AxBx
0.25(3)
ns
tPZL
tPZH
SwitchTurn-OnDelay
BE to Ax, Bx, Cx, Dx
SwitchTurn-OffDelay(2)
1.5
1.5
6.5
5.5
ns
ns
tPLZ
tPHZ
BE to Ax, Bx, Cx, Dx
tBX
Switch Multiplex Delay
BX to Ax, Bx, Cx, Dx
1.5
6.5
ns
NOTES:
1. Minimums are 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 at CL = 50pF. Since this time constant is much smaller than the rise and 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.
4
IDTQS3388
INDUSTRIALTEMPERATURERANGE
HIGH-SPEEDCMOSBUSEXCHANGESWITCHWITHACTIVETERMINATION
ACTIVE TERMINATOR OR ‘BUS-HOLD’ CIRCUIT
The Active Terminator circuit, also known as the Bus-hold circuit, is configured as a “weak latch” with positive feedback. When connected to a TTL
orCMOSinputport, theBus-holdcircuitholdsthelastlogicstateattheinputwhentheinputis“disconnected”fromthedriver. Whentheoutputofadevice
connectedtosuchaninputattemptsalogicleveltransition, itwillover-drivetheBus-holdcircuit. TheprimarybenefitofthiscircuitisthatitpreventsCMOS
inputsfromfloating, asituationwhichshouldbeavoidedtopreventspuriousswitchingofinputsandunnecessarypowerdissipation. Bus-holdisabetter
solutionthanthetraditionalapproachofusingresistiveterminationtoVCC orGNDtopreventbusfloating, becausetheBus-holdcircuitdoesnotconsume
any static power.
V-I CHARACTERISTICS OF BUS-HOLD CIRCUIT
IBH
+ 500
Sinking
Current
( + )
Voltage
IBHL
IBH
+60
+20
+60 IBHL
VT
+ 20 IBH
– 20 IBH
– 20
– 60
Vcc
IBHH
– 60 IBHH
VIL
VIH
Sourcing
Current
( – )
IBH
– 500
0.8V
2V
VT ≡ Threshold Voltage ≈ 1.5V
VIL ≈ .8 VIH ≈ 2V
ThefigureaboveshowstheinputV-IcharacteristicsofaBus-holdimplementation. Theinputcharacteristicsresemblearesistor. Astheinputvoltage
is increased from 0 volts, the ‘sink’ current increases linearly. When the TTL threshold of the circuit is reached (typically 1.5 volts), the latch changes the
logic state due to positive feedback and the direction of current is reversed. As the voltage is further increased towards VCC, the input ‘source’ current
begins to decrease, reaching the lowest level at VIN = VCC.
5
IDTQS3388
INDUSTRIALTEMPERATURERANGE
HIGH-SPEEDCMOSBUSEXCHANGESWITCHWITHACTIVETERMINATION
ORDERINGINFORMATION
XX
IDTQS
XXXXX
X
Package
Process
Device Type
Industrial (-40°C to +85°C)
Blank
Q
Quarter Size Outline Package
High Speed CMOS Bus Exchange Switch
with Active Termination (Bus Hold)
3388
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fax: 408-492-8674
for Tech Support:
logichelp@idt.com
(408) 654-6459
www.idt.com
6
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