Three-State Driver Circuit
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
Disclosed is a three-state push-pull driver circuit designed to interface from on-chip TTL circuits to off-chip TTL circuits. The driver is powered from a 3.4-volt and 1.7-volt supply. At least certain features of this driver circuit are as follows: The output voltage up- and down-going transitions have a desirable dv/dt characteristic, which aids off-chip wireablility and reduces noise generation. Up-going dv/dt control is determined by R6, R7 and T4. Down-going dv/dt control is determined by feedback capacitor CF and resistors R2, R3, R4, R9 and transistors T2, T3 and T5. The two inputs of T8 are provided for driver high impedance control (both system and test applications). A logical "0" at an input to T8 will cause T6 and T3 to turn on and disable the driver.