FST3245 — 8-Bit Bus Switch Features Description The FST3245 switch provides eight-bits of high-speed CMOS TTL-compatible bus switching in a standard ’245 pin-out. The low on resistance allows inputs to be connected to outputs without adding propagation delay or generating additional ground bounce noise. 4 Ω Switch Connection between Two Ports Minimal Propagation Delay through the Switch Low ICC Zero Bounce in Flow-through Mode Control Inputs Compatible with TTL Level The device is organized as an eight-bit switch. When /OE is LOW, the switch is ON and port A is connected to port B. When /OE is HIGH, the switch is OPEN and a high-impedance state exists between the two ports. Ordering Information Operating Part Number Temperature Range FST3245MTCX -40 to +85°C Packing Method Package 20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4 mm Wide Tape and Reel Logic Diagram A0 2 18 B0 A7 9 11 B 7 /OE 19 Figure 1. Logic Diagram ©1997 Fairchild Semiconductor Corporation FST3245 • Rev. 1.0.3 www.fairchildsemi.com FST3245 — 8-Bit Bus Switch December 2012 FST3245 — 8-Bit Bus Switch Pin Configuration NC 1 20 VCC A0 2 19 /OE A1 3 18 B0 A2 4 17 B1 A3 5 16 B2 A4 6 15 B3 A5 7 14 B4 A6 8 13 B5 A7 9 12 B6 GND 10 11 B7 Figure 2. Pin Configuration Pin Descriptions Pin # Pin Names Description 1 NC No Connnect 19 /OE Bus Switch Enable 2,3,4,5,6,7,8,9 A0,A1,A2,A3,A4,A5,A6,A7 Bus A 10 GND Ground 11,12,13,14,15,16,17,18 B7,B6,B5,B4,B3,B2,B1,B0 Bus B 20 VCC Supply Voltage Truth Table Input /OE Function LOW Connect HIGH Disconnect © 1997 Fairchild Semiconductor Corporation FST3245 • Rev. 1.0.3 www.fairchildsemi.com 2 Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only. Symbol Parameter Min. Max. Unit -0.5 7.0 V 7.0 V VCC Supply Voltage VS DC Switch Voltage -0.5 VIN (1) DC Input Voltage -0.5 7.0 V IIK DC Input Diode Current, VIN < 0 V -50 mA DC Output Sink Current 128 mA ±100 mA +150 °C IOUT ICC / IGND TSTG DC VCC / GND Current Storage Temperature Range -65 FST3245 — 8-Bit Bus Switch Absolute Maximum Ratings Note: 1. The input and output negative voltage ratings may be exceeded if the input and output diode current ratings are observed. Recommended Operating Conditions The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings. Symbol Parameter VCC Power Supply Operating VIN Input Voltage VOUT Min. Max. Unit 4.0 5.5 V 0 5.5 V 0 5.5 V Output Voltage Switch Control Input tr, tf Input Rise and Fall Time TA Operating Temperature, Free Air (2) Switch I/O 0 5 0 DC -40 +85 ns/V °C Note: 2. Unused control inputs must be held HIGH or LOW. They may not float. © 1997 Fairchild Semiconductor Corporation FST3245 • Rev. 1.0.3 www.fairchildsemi.com 3 Typical values are at VCC = 5.0 V and TA = 25°C. Symbol Parameter Conditions VCC (V) VIK Clamp Diode Voltage VIH High-Level Input Voltage 4.0 to 5.5 VIL Low-Level Input Voltage IIN Input Leakage Current IOZ RON ICC ΔICC IIN = -18 mA TA=-40 to +85°C Min. Typ. Max. 4.5 Units -1.2 V 4.0 to 5.5 0.8 V 0 ≤ VIN ≤ 5.5 V 5.5 ±1.0 µA Off-state Leakage Current 0 ≤ A, B ≤ VCC 5.5 ±1.0 µA 2.0 V VIN = 0 V, IIN = 64 mA 4.5 4 7 VIN = 0 V, IIN = 30 mA 4.5 4 7 VIN = 2.4 V, IIN = 15 mA 4.5 8 15 VIN = 2.4 V, IIN = 15 mA 4.0 11 20 Quiescent Supply Current VIN = VCC or GND, IOUT = 0 5.5 3 µA Increase in ICC per Input One Input at 3.4 V, Other Inputs at VCC or GND 5.5 2.5 mA Switch On Resistance(3) FST3245 — 8-Bit Bus Switch DC Electrical Characteristics Ω Note: 3. Measured by the voltage drop between the A and B pins at the indicated current through the switch. On resistance is determined by the lower of the voltages on the A or B pins. AC Electrical Characteristics TA = -40 to +85°C, CL = 50 pF, and RU = RD = 500 Ω. Symbol Parameter VCC = 4.5 – 5.5 V Conditions Min. tPHL, tPLH Propagation Delay Bus-to-Bus(4) VIN = Open tPZH ,tPZL Output Enable Time VIN = 7 V for tPZL VIN = Open for tPZH tPHZ, tPLZ Output Disable Time VIN = 7 V for tPLZ VIN = Open for tPHZ Max. VCC = 4.0 V Min. Max. Units Figure 0.25 0.25 ns Figure 3 Figure 4 1.5 5.9 6.4 ns Figure 3 Figure 4 1.5 6.0 5.7 ns Figure 3 Figure 4 Note: 4. This parameter is guaranteed by design, but is not tested. The bus switch contributes no propagation delay other than the RC delay of the typical on resistance of the switch and the 50 pF load capacitance when driven by an ideal voltage source (zero output impedance). Capacitance TA = +25°C, f = 1 MHz. Capacitance is characterized, but not tested. Symbol Parameter Conditions Typ. Units CIN Control Pin Input Capacitance VCC = 5.0 V 3 pF CI/O Input/Output Capacitance VCC, /OE = 5.0 V 5 pF © 1997 Fairchild Semiconductor Corporation FST3245 • Rev. 1.0.3 www.fairchildsemi.com 4 FST3245 — 8-Bit Bus Switch AC Loadings and Waveforms Notes: Input driven by 50 Ω source terminated in 50 Ω. CL includes load and stray capacitance. Input PRR = 1.0 MHz, tw = 500 ns. Figure 3. AC Test Circuit Figure 4. AC Waveforms © 1997 Fairchild Semiconductor Corporation FST3245 • Rev. 1.0.3 www.fairchildsemi.com 5 FST3245 — 8-Bit Bus Switch Physical Dimensions Figure 5. 20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4 mm Wide Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/ © 1997 Fairchild Semiconductor Corporation FST3245 • Rev. 1.0.3 www.fairchildsemi.com 6 FST3245 — 8-Bit Bus Switch © 1997 Fairchild Semiconductor Corporation FST3245 • Rev. 1.0.3 www.fairchildsemi.com 7