The MC10H123 is a triple 4-3-3-Input Bus Driver. The MC10H123 consists of three NOR gates designed for bus driving applications on card or between cards. Output low logic levels are specified with V
= -2.1 Vdc so that the bus may be terminated to -2.0 Vdc. The gate output, when low, appears as a high impedance to the bus, because the output emitter-followers of the MC10H123 are "turned-off." This eliminates discontinuities in the characteristic impedance of the bus.
The V
level is specified when driving a 25-ohm load terminated to -2.0 Vdc, the equivalent of a 50-ohm bus terminated at both ends. Although 25 ohms is the lowest characteristic impedance that can be driven by the MC10H123, higher impedance values may be used with this part. A typical 50-ohm bus is shown in Figure 1.

• Propagation Delay, 1.5 ns Typical
• Improved Noise Margin 150 mV (Over Operating Voltage and Temperature Range)
• Voltage Compensated
• MECL 10K-Compatible
• Pb-Free Packages are Available