SCHS173C is a low-power latch produced by Harris Semiconductor. It has four operating modes, a typical propagation delay of 15ns, a working voltage range of 2V-6V, buffered inputs and outputs, and a wide operating temperature range of -55oC-125oC. It is compatible with LSTTL circuits.
The CD54HC259, CD74HC259, CD54HCT259 and CD74HCT259 are high‑speed CMOS logic devices that implement an 8‑bit addressable latch with four operating modes: addressable latch, demultiplexer, memory, and reset. The devices feature buffered inputs and outputs, low power consumption, and are compatible with both CMOS and LSTTL logic families.
Key specifications include a typical propagation delay of 15 ns at 5 V, fan‑out of 10 LSTTL loads (standard) or 15 LSTTL loads (bus driver), a wide operating temperature range of –55 °C to 125 °C, and supply voltage ranges of 2 V‑6 V for HC types and 4.5 V‑5.5 V for HCT types. The datasheet also lists pinouts for CERDIP, PDIP and SOIC packages, absolute maximum ratings, and detailed switching characteristics.
| Typical Propagation Delay | 15 ns at VCC = 5 V, CL = 15 pF, Ta = 25 °C |
|---|---|
| Fan‑out (Standard Outputs) | 10 LSTTL loads |
| Fan‑out (Bus Driver Outputs) | 15 LSTTL loads |
| Operating Temperature Range | -55 °C to 125 °C |
| Supply Voltage (HC Types) | 2 V to 6 V |
| Supply Voltage (HCT Types) | 4.5 V to 5.5 V |
The device provides three active modes—addressable latch, demultiplexer, and memory—and one reset mode where all outputs are forced low.
These devices are sensitive to electrostatic discharge, so users should follow proper IC handling procedures.
The series is offered in 16‑lead CERDIP, PDIP, and SOIC packages, with part numbers indicating the specific package.
Standard outputs can drive up to 10 LSTTL loads, while bus driver outputs can drive up to 15 LSTTL loads.