74LS154 4线-16 线译码器/解调器
·将4 个二进制编码输入译成16 个彼独立的输出之一
·将数据从一个输入线分配到16 个输出的任意一个而实现解调功能
·输入箝位二极管简化了系统设计
·与大部分TTL 和DTL 电路完全兼容
原理:这种单片4 线—16 线译码器非常适合用于高性能存储器的译码器。当两个选通输入G1 和G2 为低时, 它可将4 个二进制编码的输入译成16 个互相独立的输出之一。实现解调功能的办法是:用4 个输入线写出输出线的地址,使得在一个选通输入为低时数据通过另一个选通输入。当任何一个选通输入是高时,所有输出都为高。
功能表:
Inputs输入 | Outputs输出 | ||||||||||||||||||||
G1 | G2 | D | C | B | A | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 |
L | L | L | L | L | L | L | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H |
L | L | L | L | L | H | H | L | H | H | H | H | H | H | H | H | H | H | H | H | H | H |
L | L | L | L | H | L | H | H | L | H | H | H | H | H | H | H | H | H | H | H | H | H |
L | L | L | L | H | H | H | H | H | L | H | H | H | H | H | H | H | H | H | H | H | H |
L | L | L | H | L | L | H | H | H | H | L | H | H | H | H | H | H | H | H | H | H | H |
L | L | L | H | L | H | H | H | H | H | H | L | H | H | H | H | H | H | H | H | H | H |
L | L | L | H | H | L | H | H | H | H | H | H | L | H | H | H | H | H | H | H | H | H |
L | L | L | H | H | H | H | H | H | H | H | H | H | L | H | H | H | H | H | H | H | H |
L | L | H | L | L | L | H | H | H | H | H | H | H | H | L | H | H | H | H | H | H | H |
L | L | H | L | L | H | H | H | H | H | H | H | H | H | H | L | H | H | H | H | H | H |
L | L | H | L | H | L | H | H | H | H | H | H | H | H | H | H | L | H | H | H | H | H |
L | L | H | L | H | H | H | H | H | H | H | H | H | H | H | H | H | L | H | H | H | H |
L | L | H | H | L | L | H | H | H | H | H | H | H | H | H | H | H | H | L | H | H | H |
L | L | H | H | L | H | H | H | H | H | H | H | H | H | H | H | H | H | H | L | H | H |
L | L | H | H | H | L | H | H | H | H | H | H | H | H | H | H | H | H | H | H | L | H |
L | L | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H | L |
L | H | X | X | X | X | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H |
H | L | X | X | X | X | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H |
H | H | X | X | X | X | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H | H |
H=高电平 L=低电平 ×=不定
图1 74LS154 引脚功能图及逻辑图
Absolute Maximum Ratings绝对最大额定值
Supply Voltage 电源电压 | 7V |
Input Voltage输入电压 | 7V |
Operating Free Air Temperature Range自由空气温度范围 | 0℃ to +70℃ |
Storage Temperature Range储存温度范围 | -65℃ to +150℃ |
Recommended Operating Conditions建议操作条件
Symbol 符号 | Parameter 参数 | 最小 | 典型 | 最大 | Units 单位 |
VCC | Supply Voltage 电源电压 | 4.75 | 5 | 5.25 | V |
VIH | HIGH Level Input Voltage高电平输入电压 | 2 | - | - | V |
VIL | LOW Level Input Voltage低电平输入电压 | - | - | 0.8 | V |
IOH | HIGH Level Output Current高电平输出电流 | - | - | -0.4 | mA |
IOL | LOW Level Output Current低电平输出电流 | - | - | 8 | mA |
TA | Free Air Operating Temperature工作温度 | 0 | - | 70 | ℃ |
Electrical Characteristics 电气特性 | ||||||
over recommended operating free air temperature range (unless otherwise noted) | ||||||
Symbol 符号 | Parameter 参数 | Conditions 条件 | 最小 | 典型 | 最大 | UNIT 单位 |
VI | Input Clamp Voltage输入钳位电压 | VCC = 最小, II = -18 mA | - | - | -1.5 | V |
VOH | HIGH Level Output Voltage输出高电平电压 | VCC = 最小, IOH = 最大 VIL = 最大, VIH = 最小 | 2.7 | 3.4 | - | V |
VOL | LOW LevelOutput Voltage输出低电平电压 | VCC = 最小, IOL = 最大 VIL = 最大, VIH = 最小 | - | 0.25 | 0.4 | V |
- | 0.35 | 0.5 | ||||
IOL = 4 mA, VCC = 最小 | - | 0.25 | 0.4 | |||
II | Input Current @ MAX Input Voltage输入电流@最大输入电压 | VCC = 最大, VI = 7V | - | - | 0.1 | mA |
IIH | HIGH Level Input Current输入高电平电流 | VCC = 最大, VI = 2.7V | - | - | 20 | μA |
IIL | LOW Level Input Current低电平输入电流 | VCC = 最大, VI = 0.4V | - | - | -0.4 | mA |
IOS | Short Circuit Output Current短路输出电流 | VCC = 最大 (Note 3) | -20 | - | -100 | mA |
ICC | Supply Current电源电流 | VCC = 最大 (Note 4) | - | 9 | 14 | mA |
Note 2: All typicals are at VCC = 5V, TA = 25℃. | ||||||
Note 3: Not more than one output should be shorted at a time, and the duration should not exceed one second. | ||||||
Note 4: ICC is measured with all outputs OPEN and all inputs GROUNDED. |
Switching Characteristics交流开关特性 | |||||||
at VCC = 5V and TA = 25℃ | |||||||
Symbol 符号 | Parameter 参数 | From (Input) To (Output) | RL=2kΩ | UNIT 单位 | |||
CL= 15pF | CL=50pF | ||||||
最小 | 最大 | 最小 | 最大 | ||||
tPLH | Propagation Delay Time LOW-to-HIGH Level Output低到高电平输出传递延迟时间 | Data to Output | - | 30 | - | 35 | ns |
tPHL | Propagation Delay Time HIGH-to-LOW Level Output高到低电平输出传递延迟时间 | Data to Output | - | 30 | - | 35 | ns |
tPLH | Propagation Delay Time LOW-to-HIGH Level Output低到高电平输出传递延迟时间 | Strobe to Output | - | 20 | - | 25 | ns |
tPHL | Propagation Delay Time HIGH-to-LOW Level Output高到低电平输出传递延迟时间 | Strobe to Output | - | 25 | - | 35 | ns |
图2 应用电路-LED驱动电路 (点击查看大图片)