74HC244 是一款常見的驅(qū)動信號芯片，常用于各種單片機(jī)mcu系統(tǒng)中，單片機(jī)io口輸出的電流很小而244芯片就是用來放大電流，他是具有三態(tài)輸出的八路緩沖器和線路驅(qū)動器，他與74HC245的唯一區(qū)別是 74HC244是單向的，數(shù)據(jù)只能從A端流向Y端，而74HC245則是雙向的。他們的驅(qū)動能力相同。74hc244的pdf資料下載：http://www.izizhuan.cn/f/74hc244.pdf
74HC244也常常用于隔離，比如單片機(jī)和并口等設(shè)備直連理論上可以直接用單片機(jī)的幾根I/O口接并口線，但如果電路板沒做好，可能會連帶把計算機(jī)并口燒壞，所以要加個74HC244芯片隔離一下
74HC244 是CMOS電路，74ls244 是雙極晶體管型電路，二者的特性差別很大，LS器件是淘汰型，盡量不要選用。
74HC240，74HC241，74HC244為同一系列的產(chǎn)品，他們的區(qū)別很小在引腳及其功能方面下面的中文資料中都有詳細(xì)的說明.
74hc244實物圖
74hc244管腳圖
下面介紹74hc244的功能：
74hc244邏輯圖和真值表
dip封裝的74hc244引腳圖
貼片74hc244引腳圖
74hc244封裝圖
74hc244真值表
74hc244及74hc241 74hc240功能表
74hc244應(yīng)用電路
74hc244電流最大值
74hc244電壓溫度等操作條件
DC Electrical Specifications直流電氣規(guī)格：
| Parameter 參數(shù) | Symbol 符號 | TEST Conditions 測試條件 | 25℃ | -40℃TO85℃ | -55℃TO125℃ | UNIT 單位 | ||||||||
| VI (V) | IO (mA) | VCC (V) | 最小 | 典型 | 最大 | 最小 | 最大 | 最小 | 最大 | |||||
| High Level Input Voltage輸入高電平電壓 | VIH | - | - | 2 | 1.5 | - | - | 1.5 | - | 1.5 | - | V | ||
| 4.5 | 3.15 | - | - | 3.15 | - | 3.15 | - | V | ||||||
| 6 | 4.2 | - | - | 4.2 | - | 4.2 | - | V | ||||||
| LOW Level Input Voltage 輸入低電平電壓 | VIL | - | - | 2 | - | - | 0.5 | - | 0.5 | - | 0.5 | V | ||
| 4.5 | - | - | 1.35 | - | 1.35 | - | 1.35 | V | ||||||
| 6 | - | - | 1.8 | - | 1.8 | - | 1.8 | V | ||||||
| HIGH Level Output Voltage輸出高電平電壓 CMOS負(fù)載 | VOH | VIH or VIL | -0.02 | 2 | 1.9 | - | - | 1.9 | - | 1.9 | - | V | ||
| -0.02 | 4.5 | 4.4 | - | - | 4.4 | - | 4.4 | - | V | |||||
| -0.02 | 6 | 5.9 | - | - | 5.9 | - | 5.9 | - | V | |||||
| HIGH Level Output Voltage輸出高電平電壓 TTL負(fù)載 | -6 | 4.5 | 3.98 | - | - | 3.84 | - | 3.7 | - | V | ||||
| -7.8 | 6 | 5.48 | - | - | 5.34 | - | 5.2 | - | V | |||||
| Low Level Output Voltage 輸出低電平電壓 CMOS負(fù)載 | VOL | VIH or VIL | 0.02 | 2 | - | - | 0.1 | - | 0.1 | - | 0.1 | V | ||
| 0.02 | 4.5 | - | - | 0.1 | - | 0.1 | - | 0.1 | V | |||||
| 0.02 | 6 | - | - | 0.1 | - | 0.1 | - | 0.1 | V | |||||
| Low Level Output Voltage輸出低電平電壓 TTL負(fù)載 | 6 | 4.5 | - | - | 0.26 | - | 0.33 | - | 0.4 | V | ||||
| 7.8 | 6 | - | - | 0.26 | - | 0.33 | - | 0.4 | V | |||||
| Input Leakage Current輸入漏電流 | II | VCC or GND | - | 6 | - | - | ±0.1 | - | ±1 | - | ±1 | μA | ||
| Quiescent Device Current靜態(tài)電流 | ICC | VCC or GND | 0 | 6 | - | - | 8 | - | 80 | - | 160 | μA | ||
DC Electrical Specifications直流電氣規(guī)格（續(xù)）
| Parameter 參數(shù) | Symbol 符號 | TEST Conditions 條件 | 25℃ | -40℃ TO 85℃ | -55℃ TO 125℃ | UNIT 單位 | |||||||||
| VI (V) | IO (mA) | VCC (V) | 最小 | 典型 | 最大 | 最小 | 最大 | 最小 | 最大 | ||||||
| Three-State Leakage Current三態(tài)泄漏電流 | IOZ | VIL or VIH | - | 6 | - | - | ±0.5 | - | ±0.5 | - | ±10 | μA | |||
| High Level Input Voltage輸入高電平電壓 | VIH | - | - | 4.5 to 5.5 | 2 | - | - | 2 | - | 2 | - | V | |||
| LOW Level Input Voltage 輸入低電平電壓 | VIL | - | - | 4.5 to 5.5 | - | - | 0.8 | - | 0.8 | - | 0.8 | V | |||
| HIGH Level Output Voltage輸出高電平電壓 CMOS 負(fù)載 | VOH | VIH or VIL | -0.02 | 4.5 | 4.4 | - | - | 4.4 | - | 4.4 | - | V | |||
| HIGH Level Output Voltage輸出高電平電壓 TTL負(fù)載 | -6 | 4.5 | 3.98 | - | - | 3.84 | - | 3.7 | - | V | |||||
| Low Level Output Voltage 輸出低電平電壓 CMOS負(fù)載 | VOL | VIH or VIL | 0.02 | 4.5 | - | - | 0.1 | - | 0.1 | - | 0.1 | V | |||
| Low Level Output Voltage 輸出低電平電壓TTL負(fù)載 | 6 | 4.5 | - | - | 0.26 | - | 0.33 | - | 0.4 | V | |||||
| Input Leakage Current輸入漏電流 | II | VCC to GND | 0 | 5.5 | - | - | ±0.1 | - | ±1 | - | ±1 | μA | |||
| Quiescent Device Current靜態(tài)電流 | ICC | VCC or GND | 0 | 5.5 | - | - | 8 | - | 80 | - | 160 | μA | |||
| Additional Quiescent Device Current Per Input Pin: 1 UNIT Load附加靜態(tài)目前的輸入引腳： 1單位負(fù)載 | ΔICC (Note 2) | VCC -2.1 | - | 4.5 to 5.5 | - | 100 | 360 | - | 450 | - | 490 | μA | |||
| Three-State Leakage Current三態(tài)泄漏電流 | IOZ | VIL or VIH | - | 5.5 | - | - | ±0.5 | - | ±5 | - | ±10 | μA | |||
Switching Specifications開關(guān)特性規(guī)格 CL = 50pF, Input tr, tf = 6ns
| Parameter 參數(shù) | Symbol 符號 | TEST CONDI-TIONS | VCC (V) | 25℃ | -40℃ TO 85℃ | -55℃ TO 125℃ | UNIT 單位 | ||||||
| 最小 | 典型 | 最大 | 最小 | 典型 | 最大 | 最小 | 典型 | 最大 | |||||
| Propagation Delay傳播延遲 Data to Outputs 74HC240 | tPLH, tPHL | CL = 50pF | 2 | - | - | 100 | - | - | 125 | - | - | 150 | ns |
| 4.5 | - | - | 20 | - | - | 25 | - | - | 30 | ns | |||
| CL = 15pF | 5 | - | 8 | - | - | - | - | - | - | - | ns | ||
| CL = 50pF | 6 | - | - | 17 | - | - | 21 | - | - | 26 | ns | ||
| Data to Outputs數(shù)據(jù)輸出 74HC241 | tPLH, tPHL | CL = 50pF | 2 | - | - | 110 | - | - | 140 | - | - | 165 | ns |
| 4.5 | - | - | 22 | - | - | 28 | - | - | 33 | ns | |||
| CL = 15pF | 5 | - | 9 | - | - | - | - | - | - | - | ns | ||
| CL = 50pF | 6 | - | - | 19 | - | - | 24 | - | - | 28 | ns | ||
| Data to Outputs數(shù)據(jù)輸出 74HC244 | tPLH, tPHL | CL = 50pF | 2 | - | - | 110 | - | - | 140 | - | - | 165 | ns |
| 4.5 | - | - | 22 | - | - | 28 | - | - | 33 | ns | |||
| CL = 15pF | 5 | - | 9 | - | - | - | - | - | - | - | ns | ||
| CL = 50pF | 6 | - | - | 19 | - | - | 24 | - | - | 28 | ns | ||
| Output Enable and Disable Time輸出啟用和停用時間 | tTHL, tTLH | CL = 50pF | 2 | - | - | 150 | - | - | 190 | - | - | 225 | ns |
| 4.5 | - | - | 30 | - | - | 38 | - | - | 45 | ns | |||
| 5 | - | 12 | - | - | - | - | - | - | - | ns | |||
| 6 | - | - | 26 | - | - | 33 | - | - | 38 | ns | |||
| Output Transition Time輸出過渡時間 | tTLH, tTHL | CL = 50pF | 2 | - | - | 60 | - | - | 75 | - | - | 90 | ns |
| 4.5 | - | - | 12 | - | - | 15 | - | - | 18 | ns | |||
| 6 | - | - | 10 | - | - | 13 | - | - | 15 | ns | |||
| Input Capacitance輸入電容 | CI | CL = 50pF | - | 10 | - | 10 | - | - | 10 | - | - | 10 | pF |
| Three-State Output Capacitance三態(tài)輸出電容 | CO | CL = 50pF | - | - | - | 20 | - | - | 20 | - | - | 20 | pF |
| Power Dissipation Capacitance 功耗電容 | |||||||||||||
| 74HC240 | - | CL = 15pF | 5 | - | 38 | - | - | - | - | - | - | - | pF |
| 74HC241 | - | - | 5 | - | 34 | - | - | - | - | - | - | - | pF |
| 74HC244 | - | - | 5 | - | 46 | - | - | - | - | - | - | - | pF |
| HCT 類型 | |||||||||||||
| 數(shù)據(jù)輸出傳播延遲 HCT240 | tPHL, tPLH | CL = 50pF | 4.5 | - | - | 22 | - | - | 28 | - | - | 33 | ns |
| CL = 15pF | 5 | - | 9 | - | - | - | - | - | - | - | ns | ||
| Data to Outputs 數(shù)據(jù)輸出HCT241 | tPHL, tPLH | CL = 50pF | 4.5 | - | - | 25 | - | - | 31 | - | - | 38 | ns |
| CL = 15pF | 5 | - | 10 | - | - | - | - | - | - | - | ns | ||
| Data to Outputs 數(shù)據(jù)輸出HCT244 | tPHL, tPLH | CL = 50pF | 4.5 | - | - | 25 | - | - | 31 | - | - | 38 | ns |
| CL = 15pF | 5 | - | 10 | - | - | - | - | - | - | - | ns | ||