FSTUD32450 Datasheet | Fairchild Semiconductor

FSTUD32450 Configurable 4-Bit to 40-Bit Bus Switch with - 2V Undershoot Protection and Selectable Level Shifting August 2001 Revised July 2002 FSTUD32450 Configurable 4-Bit to 40-Bit Bus Switch with - 2V Undershoot Protection and Selectable Level Shifting General Description The Fairchild Universal Bus Switch FSTUD32450 provides 4-bit, 5-bit, 8-bit, 10-bit, 16-bit, 20-bit...40-bit of high-speed CMOS TTL-patible bus switching. The low On Resistance of the switch allows inputs to be connected to outputs without adding propagation delay or generating additional ground bounce noise. The FSTUD32450 is designed to allow “customer” configuration control of the enable connections. The device can be organized as either a ten 4-bit, eight 5-bit, four 10-bit, two 20-bit or one 40-bit enabled bus switch. Also achievable are 8-bit and 16-bit enabled configurations (see Functional Description). The device's bit configuration is controlled through select pin logic. (see Truth Table). When OEx is LOW, Port Ax is connected to Port Bx. When OEx is HIGH, the switch is OPEN. The A and B Ports are protected against undershoot to support an extended range to 2.0V below ground. Fairchild's integrated Undershoot Hardened Circuit (UHC) senses undershoot at the I/O, and responds by preventing voltage differentials from developing and turning the switch on. Another innovative device feature is the addition of a level shifting select pin, “S2 and S5”. When S2 and S5 are LOW, the device behaves as a standard N-MOS switch. When S2 and S5 are HIGH, a diode to VCC is integrated into the circuit allowing for level shifting between 5V inputs and 3.3V outputs. Features I Undershoot protected to - 2V (A and B Ports) I Voltage level shifting I 4Ω switch connection between two ports I Minimal propagation delay through the switch I Low l CC I Zero bounce in flow-through mode I Control inputs patible with TTL level I See Applications Notes AN-5008 and AN-5021 for UHC details I Packaged in plastic...