74LVC161

NOTES:
1. Stresses beyond those listed may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

2. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.

The 74LVC161 is designed as a highperformance, lowpower, lowvoltage, sigate CMOS device and superior to most advanced CMOS compatible TTL families. It is a synchronous presettable binary counter which features an internal lookhead carry and can be used for highspeed counting. Synchronous operation is provided by having all flipflops clocked simultaneously on the positivegoing edge of the clock (CP).

It has many features. The first one is wide supply voltage range of the 74LVC161 1.2V to 3.6V. The second one is in accordance with JEDEC standard no. 81A. The third one is inputs accept voltages up to 5.5V. The fourth one is CMOS low power consumption. The fifth one is direct interface with TTL levels. The sixth one is asynchronous reset. The seventh one is synchronous counting and loading. The eighth one is two count enable inputs for nbit cascading. The ninth one is positive edgetriggered clock. The tenth one is output drive capability 50 transmission lines at 85°C.

Some absolute maximum ratings of the 74LVC161 have been concluded into several points as follow. The first one is about its DC supply voltage which would be from 0.5 to +6.50V. The second one is about its DC input diode current which would be -50mA. The third one is about its DC input voltage which would be from 0.5 to +5.5V. The fourth one is about its DC output diode current which would be +/-50mA. The fifth one is about its DC output voltage which would be from 0.5 to Vcc+0.5V. The sixth one is about its DC output source or sink current which would be +/-50mA. The seventh one is about its DC Vcc or GND current which would be +/-100mA. The eighth one is about its storage temperature range which would be from 65 to +150°C. The ninth one is about its power dissipation which would be 500mW. It should be noted that stresses beyond those listed may cause permanent damage to the device. Exposure to absolute maximum rated conditions for extended periods may affect device reliability. And so on. For more information of the 74LVC161 please contact us for details.

The 74LVC161 is a highperformance, lowpower, lowvoltage, Sigate CMOS device and superior to most advanced CMOS compatible TTL families.

The 74LVC161 is a synchronous presettable binary counter which features an internal lookhead carry and can be used for highspeed counting. nchronous operation is provided by having all flipflops clocked simultaneously on the positivegoing edge of the clock (CP). The outputs (Q₀ to Q₃) of the counters of the 74LVC161 may be preset to a HIGH or LOW level. A LOW level 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 positivegoing edge of the clock (provided that the setup and hold time requirements for PE are met). Preset takes place regardless of the levels at count enable inputs (CEP and CET). A low level at the master reset input (MR) sets all four outputs of the flipflops (Q₀ to Q₃) to LOW level regardless of the levels at CP, PE, CET and CEP inputs (thus providing an asynchronous clear function).

The lookahead carry simplifies serial cascading of the counters. Both count enable inputs (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 level output of Q₀. This pulse can be used to enable the next cascaded stage. The maximum clock frequency of the 74LVC161 for the cascaded counters is determined by the CP to TC propagation delay and CEP to CP setup time, according to the following formula: