74LS37 Quadruple 2-Input Positive-NAND Buffers IC (7437 IC) DIP-14 Package

The 74F393 is a Dual Ripple Counter with separate Clock (CPn) and Master Reset (MR) inputs to each counter. The two counters are identified by the “a” and “b” suffixes in the pin configuration. The operation of each half of the 74F393 is the same. The counters are triggered by a High-to-Low transition of the Clock (CPa and CPb)inputs. The counter outputs are internally connected to provide Clock inputs to succeeding stages. The outputs of the ripple counter do not change synchronously and should not be used for high speed address decoding. The Master Resets (MRa and MRb) are active High asynchronous inputs; one for each 4-bit counter. A High level in the MR input overrides the Clock and sets the outputs Low

Features :-

• Two 4-bit binary counters
• Two Master Resets to clear each 4-bit counter individually

The 74F240 are octal buffers and line drivers designed to be employed as memory and address drivers, clock drivers and bus-oriented transmitters/receivers which provide improved PC and board density.

Features:-

• 3-STATE outputs drive bus lines or buffer memory address registers
• Outputs sink 64mA (48mA mil)
• 12mA source current
• Input clamp diodes limit high-speed termination effects

The 74HC161 is a synchronous presettable binary counter with an internal look-head carry. Synchronous operation is provided by having all flip-flops clocked simultaneously on the positive-going edge of the clock (CP). The outputs (Q0 to Q3) of the counters maybe preset HIGH or LOW. A LOW at the parallel enable input (PE) disables the counting action and causes the data at the data inputs (D0 to D3) to be loaded into the counter on the positive-going edge of the clock. Preset takes place regardless of the levels at count enable inputs (CEP and CET). A LOW at the master reset input (MR) sets Q0 to Q3 LOW regardless of the levels at input pins CP, PE, CET and CEP (thus providing an asynchronous clear function). The look-ahead carry simplifies serial cascading of the counters. Both CEP and CET must be HIGH to count. The CET input is fed forward to enable the terminal count output (TC). The TC output thus enabled will produce a HIGH output pulse of a duration approximately equal to a HIGH output of Q0. This pulse can be used to enable the next cascaded stage. The maximum clock frequency for the cascaded counters is determined by the CP to TC propagation delay and CEP to CP set-up time ,according to the following formula:

The 74HC137 decoder utilizes advanced silicon-gate CMOS technology and is well suited to memory address decoding or data routing applications. The circuit features high noise immunity and low power consumption usually associated with CMOS circuitry, yet has speeds comparable to low power Schottky TTL logic. The 74HC137 has 3 binary select inputs (A, B, and C). If the device is enabled, these inputs determine which one of the eight normally HIGH outputs will go LOW. Two active LOW and one active HIGH enables (G1, G2A and G2B) are provided to ease the cascading of decoders. The decoder’s outputs can drive 10 low power Schottky TTL equivalent loads, and are functionally and pin equivalent to the 74LS137. All inputs are protected from damage due to static discharge by diodes to VCC and ground.

Features:-

• Combines 3-to-8 decoder with 3-bit latch
• Multiple input enable for easy expansion or independent controls
• Active LOW mutually exclusive outputs
• Low-power dissipation
• Complies with JEDEC standard no. 7A
• Multiple package options