مدار مجتمع (آی سی) آی سی‌کاربرد ویژه

Product Attributes

Introduction

These TTL medium-scale integrated circuits integrate the equivalent of 86 gate circuits on a single chip. Logic inputs and outputs are fully TTL compatible. Buffered inputs are achieved by connecting relatively large resistors in series with the base of the input transistors, reducing the drive current requirement to half that required by standard 54/74 series TTL inputs. The ripple carry enable is essentially two internal emitters, rated as one standard 54/74 series load. Except for RBO, logic outputs have active pull-up. The driver outputs of the SN54143 and SN74143 are specifically designed to maintain a relatively constant sink current of approximately 15 mA from outputs "a" through "g" and 7 mA from output "dp" over a voltage range of 1 to 5 volts for the digit "9". Any number of LEDs in series may be driven as long as the output voltage ratings are not exceeded. The SN54144 and SN74144 feature high sink current saturation outputs for driving indicators rated up to 15 volts or requiring up to 25 mA of drive current. Within their respective operating temperature ranges, the SN54144 sinks 20 mA and the SN74144 sinks 25 mA at an on-state voltage of 0.6 volts. All inputs are diode clamped.

Features

• Driver output options: SN54143 and SN74143 feature 15mA constant-current outputs for driving common-anode LEDs such as TIL302 or TIL303 without series resistors; SN54144 and SN74144 drive high-current lamps, numeric displays, or LEDs from saturated open-collector outputs.
• General logic capability: Leading-zero blanking, latched outputs for simultaneous logic processor drive, decimal point driver included.
• Synchronous BCD counter capability: Cascadable to N digits; look-ahead enable for minimized speed degradation in large-digit cascaded displays; direct clear input.