Triple 3-input NOR gate, 4000B family
The CD4025BMT is a triple 3-input NOR gate from the 4000B series, a mature CMOS logic family known for its wide supply range and low power consumption. It contains three independent NOR gates, each with three inputs, in a single 14-SOIC package. The supply voltage spans 3V to 18V, making it compatible with both 5V and 12V logic systems without a separate regulator. The 1 µA maximum quiescent current keeps the standby power draw negligible in battery-backed or always-on circuits.
Switching speed and drive capability
Maximum propagation delay is 90 ns at 15V supply with a 50 pF load. That's the ceiling for timing closure in a 1-2 MHz clocked system; at lower supply voltages the delay increases, so budget margin if running at 5V. Output current is 3.4 mA for both high and low states. This drives one or two standard CMOS inputs directly; for heavier loads like an LED or a relay coil, buffer the output with a transistor or a gate driver.
The input logic levels are specified relative to the supply: low is 1.5V to 4V, high is 3.5V to 11V (at VDD=5V and 10V respectively). This means the gate interprets a 0-1.5V signal as logic low and a 3.5-5V signal as logic high when running on a 5V rail—standard CMOS thresholds.