The HEF4511B is a BCD to 7-segment latch/decoder/driver with four address inputs (DA to DD), an active LOW latch enable input (EL), an active LOW ripple blanking input (BI), an active LOW lamp test input (LT), and seven active HIGH n-p-n bipolar transistor segment outputs (Oa to Og). When EL is LOW, the state of the segment outputs (Oa to Og) is determined by the data on DA to DD. When EL goes HIGH, the last data present on DA to DD are stored in the latches and the segment outputs remain stable. When LT is LOW, all the segment outputs are HIGH independent of all other input conditions. With LT HIGH, a LOW on BI forces all segment outputs LOW. The inputs LT and BI do not affect the latch circuit.
The HEF4511B integrates a BCD to 7‑segment latch, decoder and driver in a single MSI device. It features four address inputs (Da‑Dp), an active‑LOW latch enable (EL), an active‑LOW ripple‑blanking input (BI) and an active‑LOW lamp‑test input (LT). The segment outputs are driven by n‑p‑n bipolar transistors and can source up to 25 mA.
Typical applications include driving LED, incandescent, fluorescent, gas‑discharge and LCD displays. The datasheet provides detailed pin‑out, electrical characteristics, timing diagrams and recommended connection circuits for various display types.
| Package types | 16‑lead DIL plastic (SOT38‑1), 16‑lead DIL ceramic (SOT74), 16‑lead SO plastic (SOT109‑1) |
|---|---|
| Input transition times | < 20 ns |
It has four address inputs, labeled Da to Dp.