器件名称:
74LV257
功能描述:
Quad 2-input multiplexer 3-State
文件大小:
114.18KB 共12页
简 介:
INTEGRATED CIRCUITS 74LV257 Quad 2-input multiplexer (3-State) Product specification Supersedes data of 1997 Jun 06 IC24 Data Handbook 1998 May 20 Philips Semiconductors Philips Semiconductors Product specification Quad 2-input multiplexer (3-State) 74LV257 FEATURES Optimized for low voltage applications: 1.0 to 3.6 V Accepts TTL input levels between VCC = 2.7 V and VCC = 3.6 V Typical VOLP (output ground bounce) < 0.8 V at VCC = 3.3 V, Typical VOHV (output VOH undershoot) > 2 V at VCC = 3.3 V, Non-inverting data path Output capability: bus driver ICC category: MSI Tamb = 25°C Tamb = 25°C DESCRIPTION The 74LV257 is a low-voltage Si-gate CMOS device and is pin and function compatible with 74HC/HCT257. The 74LV257 is a quad 2-input multiplexer with 3-state outputs, which select 4 bits of data from two sources and are controlled by a common data select input (S). The data inputs from source 0 (1l0 to 4l0) are selected when input S is LOW and the data inputs from source 1 (1l1 to 4l1) are selected when S in HIGH. Data appears at the outputs (1Y to 4Y) in true (non-inverting) from the selected inputs. The 74LV257 is the logic implementation of a 4-pole, 2-position switch, where the position of the switch is determined by the logic levels applied to S. The outputs are forced to a high impedance OFF-state when OE is HIGH. The logic equations for the outputs are: 1Y = OE × (1l1 × S + 1l0 × S) 2Y = OE × (2l1 × S + 2l0 × S) 3Y = OE × (3l1 × S + 3l0 × S) 4Y = OE × (4l1 ……
