74HCT4520集成電路（IC）的計數(shù)器除法器規(guī)格書PDF中文資料

1. General description

The 74HC4520; 74HCT4520 are dual 4-bit internally synchronous binary counters with two clock

inputs (nCP0 and nCP1). They have buffered outputs from all 4 bit positions (nQ0 to nQ3) and an

asynchronous master reset input (nMR). The counter advances on the LOW-to-HIGH transition of

nCP0 when nCP1 is HIGH. It also advances on the HIGH-to-LOW transition of nCP1 when nCP0

is LOW. Either nCP0 or nCP1 may be used as the clock input to the counter. The other clock input

may be used as a clock enable input. A HIGH on nMR, resets the counter (nQ0 to nQ3 = LOW)

independent of nCP0 and nCP1. Inputs include clamp diodes. It enables the use of current limiting

resistors to interface inputs to voltages in excess of VCC.

2. Features and benefits

? Wide supply voltage range from 2.0 V to 6.0 V

? CMOS low power dissipation

? High noise immunity

? Latch-up performance exceeds 100 mA per JESD 78 Class II Level B

? Complies with JEDEC standards:

? JESD8C (2.7 V to 3.6 V)

? JESD7A (2.0 V to 6.0 V)

? Input levels:

? For 74HC4520: CMOS level

? For 74HCT4520: TTL level

? ESD protection:

? HBM JESD22-A114F exceeds 2000 V

? MM JESD22-A115-A exceeds 200 V

? Specified from -40 °C to +85 °C and -40 °C to +125 °C

3. Applications

? Multistage synchronous counting

? Multistage asynchronous counting

? Frequency dividers