The SN54LS297 and SN74LS297 devices are designed to provide a simple, cost-effective solution to high-accuracy, digital, phase-locked-loop applications. These devices contain all the necessary circuits, with the exception of the divide-by-N counter, to build first order phase-locked loops as described in Figure 1.
Both exclusive-OR (XORPD) and edge-controlled (ECPD) phase detectors are provided for maximum flexibility.
Proper partitioning of the loop function, with many of the building blocks external to the package, makes it easy for the designer to incorporate ripple cancellation or to cascade to higher order phase-locked loops.
The length of the up/down K counter is digitally programmable according to the K counter function table
| SN74LS297 | |
| Voltage Nodes(V) | 5 |
| Rating | Catalog |
| Technology Family | LS |
| 器件 | 状态 | 温度 | 价格（美元） | 封装 | 引脚 | 封装数量 | 封装载体 | 丝印标记 |
| SN74LS297N | ACTIVE | 0 to 70 | 6.55 | 1ku | PDIP (N) | 16 | 25 | TUBE | |
| SN74LS297NE4 | ACTIVE | 0 to 70 | 6.55 | 1ku | PDIP (N) | 16 | 25 | TUBE |
| 器件 | 环保计划* | 铅/焊球涂层 | MSL 等级/回流焊峰 | 环保信息与无铅 (Pb-free) | DPPM / MTBF / FIT 率 |
| SN74LS297N | Pb-Free (RoHS) | CU NIPDAU | N/A for Pkg Type | SN74LS297N | SN74LS297N |
| SN74LS297NE4 | Pb-Free (RoHS) | CU NIPDAU | N/A for Pkg Type | SN74LS297NE4 | SN74LS297NE4 |
