AN214
Description
The 74F Extended Octal-Plus Family incorporates all of the latest Philips Semiconductors octal, 9-bit and 10-bit buffer, transceiver, latch and register functions. all devices in this family utilize the Philips Semiconductors patented “Light-Load” NPN, ±20µA input current structure and have “flow-through” or “broadside” input/output pin configurations where the inputs and outputs are lined-up on opposite sides of a standard 24-pin Slim-DIP package. The - IOH = -15mA/-3mA @ ±5%/10% VCC The 24-pin, 300mil-wide, Slip-DIP Solution With the advent of advanced Schottky TTL technology came the ability to significantly increase the functional density of standard logic building blocks.
Key Features
- 8-, 9-, and 10-bit “Light-Load” bus products - Buffers/Drivers With and without latches or registers With and without 8-bit parity checker/generator - Transceivers With and without dual registers With and without 8-bit parity checker/generator “light-load” inputs, “broadside” design and high functional density/performance of the family make this product line ideal for buffering the limited drive capabilities of standard, custom and semicustom MOS VLSI devices to the rigorous environments of today’s leading edge high performance logic designs. The family also is an excellent choice for all general interface applications. “Flow-Through” Design The “flow-through” or “broadside” chip layout/package design is illustrated in Figure 1 showing the block diagrams and pin configurations of the 74F828 10-bit Inverting buffer. Note that all of these “broadside” designs allow logic signals to flow into one side and out of the other without crossing or folding back on signal paths such as the 74F240 Octal Buffers (Figure 2). If you compare the physical layout requirements of the path of PC board bus lines for the 74F828 to that of the 74F240’s “zig-zag” path, you will see the significant advantages of the 74F Extended Octal-Plus Family’s “flow-through” design in simplifying the design and layout of large, high density, bus-oriented PC boards.
- Patented “Light-Load” inputs: - Input Current = ±20µA per input - Transceiver I/O pins = ±70µA
- High performance output drive currents: - IOL = 64mA/48mA @ ±5%/10% VCC
- “Flow-through” or “broadside” I/O pin configuration
- Ideal for MOS CPU, peripherals and semi-custom bus interface
- 24-pin, 300mil-wide, plastic slim-DIPs
- High performance buffers - tP(max) = 7.5ns
- High performance latches/registers - fT = 100MHz Introduction The 74F Extended Octal-Plus Family incorporates all of the latest Philips Semiconductors octal, 9-bit and 10-bit buffer, transceiver, latch and register functions. all devices in this family utilize the Philips Semiconductors patented “Light-Load” NPN, ±20µA input current structure and have “flow-through” or “broadside” input/output pin configurations where the inputs and outputs are lined-up on opposite sides of a standard 24-pin Slim-DIP package. The - IOH = -15mA/-3mA @ ±5%/10% VCC The 24-pin, 300mil-wide, Slip-DIP Solution With the advent of advanced Schottky TTL technology came the ability to significantly increase the functional density of standard logic building blocks. However, not until the development of the 24-pin, 300mil-wide, Slim-DIP package was it possible to take full advantage of these new chip densities. The entire family provides significant advantages in package count, pin count and packing density when compared to older technologies. Further density enhancements can be achieved by using Philips surface mounted packages. By combining high functional density into a 24-pin 300mil-wide Slim-DIP package, the Philips Semiconductors 74F Extended Octal-Plus Family allows the reduction of PC board parts count and cost while optimizing layout with “broadside” chip designs, reducing total system power dissipation and increasing system reliability.
