IDT74FST3257 PRELIMINARY QUAD 2:1 MUX/DEMUX BUS SWITCH Integrated Device Technology, Inc. FEATURES: The FST3257 belongs to IDT's family of Bus switches. Bus switch devices perform the function of connecting or isolating two ports without providing any inherent current sink or source capability. Thus they generate little or no noise of their own while providing a low resistance path for an external driver. These devices connect input and output ports through an nchannel FET. When the gate-to-source junction of this FET is adequately forward-biased the device conducts or the resistance between input and output ports is small. Without adequate bias on the gate-to-source junction of the FET, the FET is turned off, therefore with no VCC applied, the device has hot insertion capability. The low on-resistance and simplicity of the connection between input and output ports reduces the delay in this path to close to zero. The FST3257 provides a 4-bit 2:1 multiplexer/demultiplexer. The S pin controls the mux select and the E pin serves as the switch enable. FUNCTIONAL BLOCK DIAGRAM PIN CONFIGURATION • Bus switches provide zero delay paths • Extended commercial range of –40°C to +85°C • Low switch on-resistance: FST3xxx – 5Ω • TTL-compatible input and output levels • ESD > 2000V per MIL-STD-883, Method 3015; > 200V using machine model (C = 200pF, R = 0) • Available in QSOP and SOIC DESCRIPTION: I0A ZA I1A S 1 16 Vcc I0A 2 15 E I1A 3 14 I0C ZA 4 13 I1C I0B 5 12 ZC I1B 6 11 10D ZB 7 10 I1D GND 8 9 ZD I0B-D ZB-D I1B-D 3 Channels SO16-1 SO16-7 S E 3257 drw 01 SOIC/QSOP TOP VIEW 3257 drw 02 PIN DESCRIPTION Pin Names I0A-I0D I/O I/O Port 0 Description I1A-I1D I/O Port 1 E I Switch Enable (Active Low) S I Mux Select ZA-ZB I/O Port Z 3257 tbl 01 The IDT logo is a registered trademark of Integrated Device Technology, Inc. COMMERCIAL TEMPERATURE RANGES 1996 Integrated Device Technology, Inc. AUGUST 1996 10.3 DSC-3257/3 1 IDT74FST3257 QUAD 2:1 MUX/DEMUX BUS SWITCH COMMERCIAL TEMPERATURE RANGES ABSOLUTE MAXIMUM RATINGS(1) Symbol Description VTERM(2) Terminal Voltage with Respect to GND TSTG Storage Temperature I OUT FUNCTION TABLE(1) Max. –0.5 to +7.0 Unit V –65 to +150 °C 128 mA Maximum Continuous Channel Current 3257 tbl 02 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 condiitions for extended periods may affect reliability. E H S X I0A-D X I1A-D X ZA-D Z L H X L L L H X H H L L L X L L L H X H NOTE: 1. H = HIGH Voltage Level L = LOW Voltage Level X = Don't Care Z = High Impedance 3257 tbl 03 2. VCC, Control and Switch terminals. CAPACITANCE(1) Symbol Conditions(2) Typ. Unit Parameter CIN Control Input Capacitance CI/O Switch Input/Output Capacitance 4 Switch Off pF pF 3257 tbl 04 NOTES: 1. Capacitance is characterized but not tested 2. TA = 25°C, f = 1MHz, VIN = 0V, VOUT = 0V DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE Following Conditions Apply Unless Otherwise Specified: Commercial: TA = –40°C to +85°C, VCC = 5.0V ±5% Parameter Input HIGH Voltage Test Conditions(1) Guaranteed Logic HIGH for Control Inputs Min. 2.0 Typ.(2) — Max. — Unit V VIL Input LOW Voltage Guaranteed Logic LOW for Control Inputs — — 0.8 V II H Input HIGH Current VCC = Max. µA II L Input LOW Voltage IOZH High Impedance Output Current IOZL (3-State Output pins) IOS Short Circuit Current VCC = Max., VO = GND (3) VIK Clamp Diode Voltage Symbol VIH RON Switch On Resistance(4) VI = VCC — — ±1 VI = GND — — ±1 VO = VCC — — ±1 VO = GND — — ±1 — 300 — mA VCC = Min., IIN = –18mA — –0.7 –1.2 V — 5 7 Ω — 10 15 Ω — — ±1 µA — 0.1 3 VCC = Max. IOFF Input/Output Power Off Leakage VCC = Min., VIN = 0.0V, ION = 30mA VCC = Min., VIN = 2.4V, ION = 15mA VCC = 0V, VIN or VO ≤ 4.5V ICC Quiescent Power Supply Current VCC = Max., VI = GND or VCC NOTES: 1. For conditions shown as Max. or Min., use appropriate value specified under Electrical Characteristics for the applicable device type. 2. Typical values are at VCC = 5.0V, +25°C ambient. 3. Not more than one output should be tested at one time. Duration of the test should not exceed one second. 4. Measured by voltage drop between ports at indicated current through the switch. 10.3 µA µA 3257 tbl 05 2 IDT54/74FST3257 QUAD 2:1 MUX/DEMUX BUS SWITCH COMMERCIAL TEMPERATURE RANGES POWER SUPPLY CHARACTERISTICS Symbol ∆ICC ICCD IC Parameter Quiescent Power Supply Current TTL Inputs HIGH Dynamic Power Supply Current(4) Total Power Supply Current (6) Test Conditions(1) VCC = Max. VIN = 3.4V(3) VCC = Max. Outputs Open Enable Pin Toggling 50% Duty Cycle VCC = Max. Outputs Open Enable Pin Toggling (4 Switches Toggling) fi = 10MHz 50% Duty Cycle Min. — Typ.(2) 0.5 Max. 1.5 Unit mA VIN = VCC VIN = GND — 30 40 µA/ MHz/ Switch VIN = VCC VIN = GND — 1.2 1.6 mA VIN = 3.4 VIN = GND — 1.5 2.4 NOTES: 1. For conditions shown as Max. or Min., use appropriate value specified under Electrical Characteristics for the applicable device type. 2. Typical values are at VCC = 5.0V, +25°C ambient. 3. Per TTL driven input (VIN = 3.4V). All other inputs at VCC or GND. 4. This parameter is not directly testable, but is derived for use in Total Power Supply Calculations. 5. Values for these conditions are examples of the ICC formula. These limits are guaranteed but not tested. 6. IC = IQUIESCENT + IINPUTS + IDYNAMIC IC = ICC + ∆ICC DHNT + ICCD (fiN) ICC = Quiescent Current ∆ICC = Power Supply Current for a TTL High Input (VIN = 3.4V) DH = Duty Cycle for TTL Inputs High NT = Number of TTL Inputs at DH ICCD = Dynamic Current Caused by an Input Transition Pair (HLH or LHL) fi = Input Frequency N = Number of Switches Toggling at fi All currents are in milliamps and all frequencies are in megahertz. 3257 tbl 06 SWITCHING CHARACTERISTICS OVER OPERATING RANGE Following Conditions Apply Unless Otherwise Specified: Commercial: TA = –40°C to +85°C, VCC = 5.0V ±5% Symbol tPLH tPHL tPLH tPHL tPZH tPZL tPHZ tPLZ |QCI| Description Data Propagation Delay I to Z, Z to I(3,4) Switch Multiplex Delay S to I, Z Switch Turn on Delay E to I, Z Switch Turn off Delay E to I, Z(3) Charge Injection, Typical(5,6) |QCDI| Charge Injection, Typical(6,7) Condition(1) CL = 50pF RL = 500Ω Min.(2) — Typ. — Max. 0.25 Unit ns 1.5 — 5.2 ns 1.5 — 4.8 ns 1.5 — 5.0 ns — 1.5 — pC — 0.5 — pC 3257 tbl 07 NOTES: 1. See test circuit and waveforms. 2. Minimum limits guaranteed but not tested. 3. This parameter is guaranteed by design but not tested. 4. 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 0.25 ns for 50 pF load. Since this time is constant and 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. 5. Measured at switch turn off, load = 50 pF in parallel with 10 mΩ scope probe, VIN = 0.0 volts. 6. Measured at switch turn off through bus multiplexer, (e.g.- I0 to Z = > I1 to Z), load = 50 pF in parallel with 10 MΩ scope probe, V IN at A = 0.0 volts. Charge injection is reduced because the injection from the turn off of the I0 to Z switch is compensated by the turn on of the I1 to Z switch. 7. Characterized parameter. Not 100% tested. 10.3 3 IDT74FST3257 QUAD 2:1 MUX/DEMUX BUS SWITCH COMMERCIAL TEMPERATURE RANGES TEST CIRCUITS AND WAVEFORMS TEST CIRCUITS FOR ALL OUTPUTS V CC SWITCH POSITION 500Ω V OUT VIN Pulse Generator Test Switch Open Drain Disable Low Closed 7.0V Enable Low D.U.T. Open All Other Tests 50pF RT 3257 lnk 08 DEFINITIONS: CL= Load capacitance: includes jig and probe capacitance. RT = Termination resistance: should be equal to ZOUT of the Pulse Generator. 500Ω CL 3257 lnk 03 SET-UP, HOLD AND RELEASE TIMES DATA INPUT TIMING INPUT ASYNCHRONOUS CONTROL PRESET CLEAR ETC. SYNCHRONOUS CONTROL PRESET CLEAR CLOCK ENABLE ETC. tH tSU tREM tSU PULSE WIDTH 3V 1.5V 0V 3V 1.5V 0V LOW-HIGH-LOW PULSE 1.5V tW 3V 1.5V 0V HIGH-LOW-HIGH PULSE 1.5V 3257 lnk 03 3V 1.5V 0V tH 3257 lnk 04 ENABLE AND DISABLE TIMES PROPAGATION DELAY ENABLE SAME PHASE INPUT TRANSITION tPLH tPHL OUTPUT tPLH OPPOSITE PHASE INPUT TRANSITION tPHL 3V 1.5V 0V VOH 1.5V VOL DISABLE 3V 1.5V 0V CONTROL INPUT tPZL OUTPUT NORMALLY LOW 3V 1.5V 0V SWITCH CLOSED tPLZ tPZH OUTPUT NORMALLY HIGH 3257 lnk 06 SWITCH OPEN 3.5V 3.5V 1.5V 0.3V VOL tPHZ 0.3V VOH 1.5V 0V 0V 3257 lnk 07 NOTES: 1. Diagram shown for input Control Enable-LOW and input Control DisableHIGH 2. Pulse Generator for All Pulses: Rate ≤ 1.0MHz; tF ≤ 2.5ns; tR ≤ 2.5ns 10.3 4 IDT54/74FST3257 QUAD 2:1 MUX/DEMUX BUS SWITCH COMMERCIAL TEMPERATURE RANGES ORDERING INFORMATION IDT XX FST XX Temp. Range Device Type X Package SO Q Small Outline IC (SO16-1) Quarter-size Small Outline Package (SO16-7) 3257 Quad 2:1 Mux/Demux Bus Switch 74 –40°C to +85°C 3257 drw 08 10.3 5